Publications by authors named "François Regoli"

86 Publications

Short P-Wave Duration is a Marker of Higher Rate of Atrial Fibrillation Recurrences after Pulmonary Vein Isolation: New Insights into the Pathophysiological Mechanisms Through Computer Simulations.

J Am Heart Assoc 2021 Jan 7;10(2):e018572. Epub 2021 Jan 7.

Division of Cardiology Cardiocentro Ticino Lugano Switzerland.

Background Short ECG P-wave duration has recently been demonstrated to be associated with higher risk of atrial fibrillation (AF). The aim of this study was to assess the rate of AF recurrence after pulmonary vein isolation in patients with a short P wave, and to mechanistically elucidate the observation by computer modeling. Methods and Results A total of 282 consecutive patients undergoing a first single-pulmonary vein isolation procedure for paroxysmal or persistent AF were included. Computational models studied the effect of adenosine and sodium conductance on action potential duration and P-wave duration (PWD). About 16% of the patients had a PWD of 110 ms or shorter (median PWD 126 ms, interquartile range, 115 ms-138 ms; range, 71 ms-180 ms). At Cox regression, PWD was significantly associated with AF recurrence (=0.012). Patients with a PWD <110 ms (hazard ratio [HR], 2.20; 95% CI, 1.24-3.88; =0.007) and patients with a PWD ≥140 (HR, 1.87, 95% CI, 1.06-3.30; =0.031) had a nearly 2-fold increase in risk with respect to the other group. In the computational model, adenosine yielded a significant reduction of action potential duration 90 (52%) and PWD (7%). An increased sodium conductance (up to 200%) was robustly accompanied by an increase in conduction velocity (26%), a reduction in action potential duration 90 (28%), and PWD (22%). Conclusions One out of 5 patients referred for pulmonary vein isolation has a short PWD which was associated with a higher rate of AF after the index procedure. Computer simulations suggest that shortening of atrial action potential duration leading to a faster atrial conduction may be the cause of this clinical observation.
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http://dx.doi.org/10.1161/JAHA.120.018572DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7955300PMC
January 2021

Challenges in activation of remote monitoring in patients with cardiac rhythm devices during the coronavirus (COVID-19) pandemic.

Int J Cardiol 2021 04 2;328:247-249. Epub 2020 Dec 2.

Division of Cardiology, Cardiocentro Ticino, Lugano, Switzerland.

Background: Remote monitoring (RM) technology embedded in cardiac rhythm devices permits continuous monitoring of device function, and recording of selected cardiac physiological parameters and cardiac arrhythmias and may be of utmost utility during Coronavirus (COVID-19) pandemic, when in-person office visit for regular follow-up were postponed. However, patients not alredy followed-up via RM represent a challenging group of patients to be managed during the lockdown.

Methods: We reviewed patient files scheduled for an outpatient visit between January 1, 2020 and May 11th, 2020 to assess the proportion of patients in whom RM activation was possible without office visit, and compared them to those scheduled for visit before the lockdown.

Results: During COVID-19 pandemic, RM activation was feasible in a minority of patients (7.8% of patients) expected at outpatient clinic for a follow-up visit and device check-up. This was possible in a good proportion of complex implantable devices such as cardiac resynchronization therapy and implantable cardioverter defibrillator but only in a minority of patients with a pacemaker the RM function could be activated during the period of restricted access to hospital.

Conclusions: Our experience strongly suggest to consider the systematic activation of RM function at the time of implantation or - by default programming - in all cardiac rhythm management devices.
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http://dx.doi.org/10.1016/j.ijcard.2020.11.063DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7709476PMC
April 2021

Reconstruction of three-dimensional biventricular activation based on the 12-lead electrocardiogram via patient-specific modelling.

Europace 2021 Apr;23(4):640-647

Center for Computational Medicine in Cardiology, Institute of Computational Science, Università della Svizzera italiana, Via Giuseppe Buffi 13, CH-6904 Lugano, Switzerland.

Aims: Non-invasive imaging of electrical activation requires high-density body surface potential mapping. The nine electrodes of the 12-lead electrocardiogram (ECG) are insufficient for a reliable reconstruction with standard inverse methods. Patient-specific modelling may offer an alternative route to physiologically constraint the reconstruction. The aim of the study was to assess the feasibility of reconstructing the fully 3D electrical activation map of the ventricles from the 12-lead ECG and cardiovascular magnetic resonance (CMR).

Methods And Results: Ventricular activation was estimated by iteratively optimizing the parameters (conduction velocity and sites of earliest activation) of a patient-specific model to fit the simulated to the recorded ECG. Chest and cardiac anatomy of 11 patients (QRS duration 126-180 ms, documented scar in two) were segmented from CMR images. Scar presence was assessed by magnetic resonance (MR) contrast enhancement. Activation sequences were modelled with a physiologically based propagation model and ECGs with lead field theory. Validation was performed by comparing reconstructed activation maps with those acquired by invasive electroanatomical mapping of coronary sinus/veins (CS) and right ventricular (RV) and left ventricular (LV) endocardium. The QRS complex was correctly reproduced by the model (Pearson's correlation r = 0.923). Reconstructions accurately located the earliest and latest activated LV regions (median barycentre distance 8.2 mm, IQR 8.8 mm). Correlation of simulated with recorded activation time was very good at LV endocardium (r = 0.83) and good at CS (r = 0.68) and RV endocardium (r = 0.58).

Conclusion: Non-invasive assessment of biventricular 3D activation using the 12-lead ECG and MR imaging is feasible. Potential applications include patient-specific modelling and pre-/per-procedural evaluation of ventricular activation.
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http://dx.doi.org/10.1093/europace/euaa330DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8025079PMC
April 2021

Assessment of injury current during leadless pacemaker implantation.

Int J Cardiol 2021 Jan 9;323:113-117. Epub 2020 Sep 9.

Electrophysiology, Department of Cardiology, University Heart Center, University Hospital Zurich, Zurich, Switzerland.

Background: Leadless pacemakers are an established treatment option for bradyarrhythmias. Similar to conventional transvenous pacemakers, satisfying pacing values during implantation are targeted for optimal long-term device function. The objective is to investigate the role of a local injury current (IC) in leadless pacemaker implantations.

Method: The IC, sensing value, capture threshold and impedance were collected in 30 consecutive patients receiving a leadless pacemaker.

Results: 39 EGMs were recorded from 30 patients (including 9 device repositions). An IC was detected in 15 cases (38%). At implantation, the presence of an IC was associated with a significantly lower sensing (7.1 ± 3.7 mV vs 12.0 ± 4.0 mV; P = 0.004) and a higher capture threshold (median threshold 1.13 V at 0.24 ms [0.50-2.00] vs 0.50 V at 0.24 ms [0.25-0.75]; P = 0.002) and with a 26 fold higher likelihood of device repositioning compared to the absence of an IC (OR 26.3 [2.79-248], P < 0.001). Patients with an IC in their final implant position had a lower sensing (9.3 ± 4.4 mV vs 13.6 ± 4.7 mV at implantation, P = 0.04), while the initially similar capture threshold was lower after 24 h in the IC group. After 2 weeks, all parameters were similar between the two groups.

Conclusions: Our study shows that an IC can readily be observed during leadless pacemaker implantation associated with a lower sensing and a higher capture threshold at implantation but with similar to even better values during follow-up.
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http://dx.doi.org/10.1016/j.ijcard.2020.08.098DOI Listing
January 2021

High-density mapping in patients undergoing ablation of atrial fibrillation with the fourth-generation cryoballoon and the new spiral mapping catheter.

Europace 2020 11;22(11):1653-1658

Division of Cardiology, Cardiocentro Ticino, Lugano, Switzerland.

Aims: To assess the value of high-density mapping (HDM) in revealing undetected incomplete pulmonary vein isolation (PVI) after the fourth-generation cryoballoon (CB4G) ablation compared to the previous cryoballoon's versions.

Methods And Results: Consecutive patients with paroxysmal or early-persistent atrial fibrillation (AF) undergoing CB ablation as the index procedure, assisted by HDM, were retrospectively included in this study. A total of 68 patients (52 males; mean age: 60 ± 12 years, 58 paroxysmal AF) were included, and a total of 272 veins were mapped. Fourth-generation cryoballoon with the new spiral mapping catheter (SMC) was used in 35 patients (51%). Time to PVI was determined in 102/132 (77%) and in 112/140 (80%) veins during second-generation cryoballoon/third-generation cryoballoon (CB2G/CB3G) and CB4G ablation, respectively (P = 0.66). There was a statistically significant difference in terms of discrepancy rate between the SMC and the mini-basket catheter in PV detection after CB4G and CB2G/CB3G ablation(1.4% vs. 7.6%; P = 0.01). A total of 57 patients (84%) remained free of symptomatic AF during a mean follow-up of 9.8 ± 4.6 months.

Conclusion: High-density mapping after cryoballoon ablation using CB4G and the new SMC identifies incomplete PVI, not detected by the new SMC, in a significantly lower proportion of veins compared to HDM performed after the other generation CB ablation.
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http://dx.doi.org/10.1093/europace/euaa160DOI Listing
November 2020

The influence of scar on the spatio-temporal relationship between electrical and mechanical activation in heart failure patients.

Europace 2020 05;22(5):777-786

Center for Computational Medicine in Cardiology, Università della Svizzera italiana, Via G. Buffi 13, CH-6900 Lugano, Switzerland.

Aims: The aim of this study was to determine the relationship between electrical and mechanical activation in heart failure (HF) patients and whether electromechanical coupling is affected by scar.

Methods And Results: Seventy HF patients referred for cardiac resynchronization therapy or biological therapy underwent endocardial anatomo-electromechanical mapping (AEMM) and delayed-enhancement magnetic resonance (CMR) scans. Area strain and activation times were derived from AEMM data, allowing to correlate mechanical and electrical activation in time and space with unprecedented accuracy. Special attention was paid to the effect of presence of CMR-evidenced scar. Patients were divided into a scar (n = 43) and a non-scar group (n-27). Correlation between time of electrical and mechanical activation was stronger in the non-scar compared to the scar group [R = 0.84 (0.72-0.89) vs. 0.74 (0.52-0.88), respectively; P = 0.01]. The overlap between latest electrical and mechanical activation areas was larger in the absence than in presence of scar [72% (54-81) vs. 56% (36-73), respectively; P = 0.02], with smaller distance between the centroids of the two regions [10.7 (4.9-17.4) vs. 20.3 (6.9-29.4) % of left ventricular radius, P = 0.02].

Conclusion: Scar decreases the association between electrical and mechanical activation, even when scar is remote from late activated regions.
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http://dx.doi.org/10.1093/europace/euz346DOI Listing
May 2020

Acute fluctuating neurological deficits after pulmonary vein isolation: unmasking a rare complication due to spontaneous spinal subdural bleeding: a case report.

Eur Heart J Case Rep 2019 Sep 5;3(3):ytz109. Epub 2019 Jul 5.

Department of Cardiology, Fondazione Cardiocentro Ticino, Via Tesserete 48, CH-6900 Lugano, Switzerland.

Background: Pulmonary vein isolation (PVI) is becoming the therapy of choice for symptomatic paroxysmal drug-refractory atrial fibrillation (AF). The most frequently reported complications are vascular complications (1.4%). Bleeding complications of the central nervous system have rarely been described. We report a case of spontaneous spinal bleed after PVI.

Case Summary: A 68-year-old woman with a 2-year history of highly symptomatic paroxysmal AF (EHRA 3) was referred for a PVI redo procedure. A high-density mapping showed pulmonary vein reconnection of all pulmonary veins successfully isolated by radiofrequency ablation. During the entire procedure, the patient had sinus rhythm with an ACT around 300 s. No intraprocedural and peri-procedural complications occurred. Four hours after haemostasis, the anticoagulation clotting time (ACT) was 110 s and rivaroxaban (20 mg) was reinitiated. In the following hours, the patient developed fluctuating neurological lower limb symptoms. A lumbar magnetic resonance imaging showed a subdural spinal haematic collection with an associated epidural component from L3 to S2 exerting compression over the dural sheath. A conservative treatment approach was adopted with progressive recovery of sensorial and motor deficits. After 5 months, the patient still presented residual lower limb motor deficits necessitating the support of a walking stick.

Discussion: We describe the first case of a spontaneous spinal bleeding following PVI. Given the gradual diffusion of PVI to treat AF in more clinically complex patients with a larger range of comorbidities, particular consideration should be given to seek predisposing bleeding factors in order to assess the risk for neurological complications.
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http://dx.doi.org/10.1093/ehjcr/ytz109DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6764566PMC
September 2019

Clinical impact of antithrombotic therapy in transvenous lead extraction complications: a sub-analysis from the ESC-EORP EHRA ELECTRa (European Lead Extraction ConTRolled) Registry.

Europace 2019 Jul;21(7):1096-1105

Second Division of Cardiology, Department of Cardiac-Thoracic & Vascular, Azienda Ospedaliera Pisana, Via Paradisa 2, Pisa, Italy.

Aims: A sub-analysis of the ESC-EHRA European Lead Extraction ConTRolled (ELECTRa) Registry to evaluate the clinical impact of antithrombotic (AT) on transvenous lead extraction (TLE) safety and efficacy.

Methods And Results: ELECTRa outcomes were compared between patients without AT therapy (No AT Group) and with different pre-operative AT regimens, including antiplatelets (AP), anticoagulants (AC), or both (AP + AC). Out of 3510 pts, 2398 (68%) were under AT pre-operatively. AT patients were older with more comorbidities (P < 0.0001). AT subgroups, defined as AP, AC, or AP + AC, were 1096 (31.2%), 985 (28%), and 317 (9%), respectively. Regarding AP patients, 1413 (40%) were under AP, 1292 (91%) with a single AP, interrupted in 26% about 3.8 ± 3.7 days before TLE. In total, 1302 (37%) patients were under AC, 881 vitamin K antagonist (68%), 221 (17%) direct oral anticoagulants, 155 (12%) low weight molecular heparin, and 45 (3.5%) unfractionated heparin. AC was 'interrupted without bridging' in 696 (54%) and 'interrupted with bridging' in 504 (39%) about 3.3 ± 2.3 days before TLE, and 'continued' in 87 (7%). TLE success rate was high in all subgroups. Only overall in-hospital death (1.4%), but not the procedure-related one, was higher in the AT subgroups (P = 0.0500). Age >65 years and New York Heart Association Class III/IV, but not AT regimens, were independent predictors of death for any cause. Haematomas were more frequent in AT subgroups, especially in AC 'continued' (P = 0.025), whereas pulmonary embolism in the No-AT (P < 0.01).

Conclusions: AT minimization is safe in patients undergoing TLE. AT does not seem to predict death but identifies a subset of fragile patients with a worse in-hospital TLE outcome.
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http://dx.doi.org/10.1093/europace/euz062DOI Listing
July 2019

Out-of-hospital cardiac arrest due to idiopathic ventricular fibrillation in patients with normal electrocardiograms: results from a multicentre long-term registry.

Europace 2019 Nov;21(11):1670-1677

Electrophysiology Unit, Department of Cardiology, Fondazione Cardiocentro Ticino, via Tesserete 48, Lugano, Switzerland.

Aims : To define the clinical characteristics and long-term clinical outcomes of a large cohort of patients with idiopathic ventricular fibrillation (IVF) and normal 12-lead electrocardiograms (ECGs).

Methods And Results: Patients with ventricular fibrillation as the presenting rhythm, normal baseline, and follow-up ECGs with no signs of cardiac channelopathy including early repolarization or atrioventricular conduction abnormalities, and without structural heart disease were included in a registry. A total of 245 patients (median age: 38 years; males 59%) were recruited from 25 centres. An implantable cardioverter-defibrillator (ICD) was implanted in 226 patients (92%), while 18 patients (8%) were treated with drug therapy only. Over a median follow-up of 63 months (interquartile range: 25-110 months), 12 patients died (5%); in four of them (1.6%) the lethal event was of cardiac origin. Patients treated with antiarrhythmic drugs only had a higher rate of cardiovascular death compared to patients who received an ICD (16% vs. 0.4%, P = 0.001). Fifty-two patients (21%) experienced an arrhythmic recurrence. Age ≤16 years at the time of the first ventricular arrhythmia was the only predictor of arrhythmic recurrence on multivariable analysis [hazard ratio (HR) 0.41, 95% confidence interval (CI) 0.18-0.92; P = 0.03].

Conclusion : Patients with IVF and persistently normal ECGs frequently have arrhythmic recurrences, but a good prognosis when treated with an ICD. Children are a category of IVF patients at higher risk of arrhythmic recurrences.
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http://dx.doi.org/10.1093/europace/euz221DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6826207PMC
November 2019

Arrhythmic episodes in patients implanted with a cardioverter-defibrillator - results from the Prospective Study on Predictive Quality with Preferencing PainFree ATP therapies (4P).

BMC Cardiovasc Disord 2019 06 17;19(1):146. Epub 2019 Jun 17.

University Hospital of Lausanne (CHUV), Lausanne, Switzerland.

Background: Little is known about the ICD performance using enhanced detection algorithms in unselected, non-trial patients. Performance of recent generation ICD equipped with SmartShock™ technology (SST) for detection and conversion of ventricular tachyarrhythmias (VTA) was investigated.

Methods: 4P was a prospective, multicenter, observational study conducted in 10 Swiss implanting centers. Patients with a Class I indication according to international guidelines were included and received an ICD with SST. ICD discrimination capability was assessed by evaluating SST performance; therapy efficacy was assessed by rate of VTA conversions by ATP and by rescue shocks.

Results: Overall, 196 patients were included in the analysis with a mean duration of follow-up of 27.7 months (452 patient-years of observation). Patient-specific rather than recommended programming was preferred. Device-detected episodes were frequent (5147 episodes in 146 patients, 74.5%). In 44 patients (22.4%), 1274 episodes were categorized as VTA; only 215 episodes were symptomatic. ATP was the first-line therapy and highly effective (99.9% success rate at the episode level, 100.0% at the patient level). Rescue shocks were rare (66 episodes in 28 patients); 7 shocks in 5 patients (2.6%) were inappropriate. Death and hospitalization rates were low.

Conclusions: In a cohort of non-trial, unselected ICD patients, VTA episodes were frequent. The 4P results confirm the robustness of VTA detection by SST and the effectiveness of ATP treatment, hence limiting overall ICD shock burden.
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http://dx.doi.org/10.1186/s12872-019-1121-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6580638PMC
June 2019

Impact of anticoagulation therapy on outcomes in patients with cardiac implantable resynchronization devices undergoing transvenous lead extraction: A substudy of the ESC-EHRA EORP ELECTRa (European Lead Extraction ConTRolled) Registry.

J Cardiovasc Electrophysiol 2019 07 29;30(7):1086-1095. Epub 2019 Apr 29.

Cardiac Thoracic and Vascular Department, Azienda Ospedaliero-Universitaria Pisana, Pisa, Italy.

Introduction: Little data are available on anticoagulation (AC) management in patients with cardiac resynchronization (CRT) devices who undergo transvenous lead extraction (TLE) procedure. We investigated the impact of AC on periprocedural complications in CRT patients undergoing TLE, enrolled in the ESC-EHRA European Lead Extraction ConTrolled (ELECTRa) registry.

Methods And Results: All CRT patients treated with TLE enrolled in the registry were considered. Perioperative AC management was left to the discretion of the Center. Major and minor intraprocedural and postprocedural complications were compared between patients without AC (Gp1) and patients with AC (Gp2). Regression analyses were performed to identify predictors of complications for Gp2. Out of 734 CRT pts, 328 (44.7%) were under AC (Gp2). Patients from Gp2 presented lower LVEF (Gp2 32.5 ± 10.9 vs Gp1 34.5 ± 11.9%; P = 0.03), more advanced heart failure disease (NYHA III/IV: Gp2 42.0 vs Gp1 31.5%; P = 0.02), and renal impairment (Gp2 39.0 vs Gp1 24.3%; P < 0.001). Perioperative regimens included AC interruption (Gp2A: n = 169, 51.5%), "bridging" (Gp2B: n = 135, 41.2%), or continued AC (Gp2C: n = 24, 7.3%). TLE complete success rates (98% in both groups) and major complication rates were comparable for both groups; minor bleeding events were more frequent in Gp2 (5.5%) compared to Gp1 (2.5%; P = 0.051). No independent predictors were identified for Gp2, but minor complications were associated with "bridging" approach (Gp2B: 16 events vs Gp2A/C: 9 events; P = 0.020).

Conclusion: CRT patients treated with TLE under AC were more compromised but did not present more major complications compared to patients without AC. More minor complications were associated with "bridging" AC regimen.
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http://dx.doi.org/10.1111/jce.13946DOI Listing
July 2019

Major cardiac and vascular complications after transvenous lead extraction: acute outcome and predictive factors from the ESC-EHRA ELECTRa (European Lead Extraction ConTRolled) registry.

Europace 2019 May;21(5):771-780

Second Department of Cardiology, Cardiac Thoracic and Vascular Department - University Hospital of Pisa, Via Paradisa, 2, Cisanello, Italy.

Aims: We aimed at describing outcomes and predictors of cardiac avulsion or tear (CA/T) with tamponade and vascular avulsion or tear (VA/T) after transvenous lead extraction (TLE) in the ESC-EHRA European Lead Extraction ConTRolled (ELECTRa) registry.

Methods And Results: A total of 3555 consecutive patients of whom 3510 underwent TLE at 73 centres in 19 European countries were enrolled. Among 58 patients (1.7%) with procedure-related major complications, 49 (84.5%) patients (30 CA/T and 19 VA/T) presented cardiovascular complications requiring pericardiocentesis, chest tube positioning and/or surgical repair. The mortality was 20% in patients with tamponade due to CA/T and 31.6% in patients with VA/T. Pericardiocentesis as first manoeuvre followed by rescue surgical repair was highly effective in case of CA/T (93.8%). At multivariate analysis, CA/T with tamponade was more common in RIATA lead extraction, female patients, leads with a mean dwelling time more than 10 years, and when ≥3 leads were extracted or multiple sheaths required. Occlusion or critical stenosis of superior venous access and the leads mean dwelling time more than 10 years were independent predictors for VA/T, while mechanical dilatation was an independent predictor of a lower incidence of this complication as compared to the use of powered sheaths.

Conclusions: In the ELECTRa registry, RIATA lead extraction and superior venous access occlusion/thrombosis are two new independent predictors for cardiac tamponade and major vascular complications, respectively. The use of mechanical sheaths seems to be associated with a lower incidence of VA/T. A strategy of pericardiocentesis followed by a rescue surgical approach seems to be reasonable in order to treat a CA/T with tamponade.
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http://dx.doi.org/10.1093/europace/euy300DOI Listing
May 2019

A left bundle branch block activation sequence and ventricular pacing influence voltage amplitudes: an in vivo and in silico study.

Europace 2018 Nov;20(suppl_3):iii77-iii86

Center for Computational Medicine in Cardiology (CCMC), Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland.

Aims: The aim of this study was to investigate the influence of the activation sequence on voltage amplitudes by evaluating regional voltage differences during a left bundle branch block (LBBB) activation sequence vs. a normal synchronous activation sequence and by evaluating pacing-induced voltage differences.

Methods And Results: Twenty-one patients and three computer models without scar were studied. Regional voltage amplitudes were evaluated in nine LBBB patients who underwent endocardial electro-anatomic mapping (EAM). Pacing-induced voltage differences were evaluated in 12 patients who underwent epicardial EAM during intrinsic rhythm and right ventricular (RV) pacing. Three computer models customized for LBBB patients were created. Changes in voltage amplitudes after an LBBB (intrinsic), a normal synchronous, an RV pacing, and a left ventricular pacing activation sequence were assessed in the computer models. Unipolar voltage amplitudes in patients were approximately 4.5 mV (4.4-4.7 mV, ∼33%) lower in the septum when compared with other segments. A normal synchronous activation sequence in the computer models normalized voltage amplitudes in the septum. Pacing-induced differences were larger in electrograms with higher voltage amplitudes during intrinsic rhythm and furthermore larger and more variable at the epicardium [mean absolute difference: 3.6-6.2 mV, 40-53% of intrinsic value; interquartile range (IQR) differences: 53-63% of intrinsic value] compared to the endocardium (mean absolute difference: 3.3-3.8 mV, 28-30% of intrinsic value; IQR differences: 37-40% of intrinsic value).

Conclusion: In patients and computer models without scar, lower septal unipolar voltage amplitudes are exclusively associated with an LBBB activation sequence. Pacing substantially affects voltage amplitudes, particularly at the epicardium.
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http://dx.doi.org/10.1093/europace/euy233DOI Listing
November 2018

Beat-to-beat P-wave morphological variability in patients with paroxysmal atrial fibrillation: an in silico study.

Europace 2018 Nov;20(suppl_3):iii26-iii35

Center for Computational Medicine in Cardiology, Università della Svizzera italiana, Lugano, Switzerland.

Aims: P-wave beat-to-beat morphological variability can identify patients prone to paroxysmal atrial fibrillation (AF). To date, no computational study has been carried out to mechanistically explain such finding. The aim of this study was to provide a pathophysiological explanation, by using a computer model of the human atria, of the correlation between P-wave beat-to-beat variability and the risk of AF.

Methods And Results: A physiological variability in the earliest activation site (EAS), on a beat-to-beat basis, was introduced into a computer model of the human atria by randomizing the EAS location. A methodology for generating multi-scale, spatially-correlated regions of heterogeneous conduction was developed. P-wave variability in the presence of such regions was compared with a control case. Simulations were performed with an eikonal model, for the activation map, and with the lead field approach, for P-wave computation. The methodology was eventually compared with a reference monodomain simulation. A total of 60 P-waves were simulated for each sinus node exit location (12 in total), and for each of the 15 patterns of heterogeneous conduction automatically generated by the model. A P-wave beat-to-beat variability was observed in all cases. Variability was significantly increased in presence of heterogeneous slow conducting regions, up to two-fold the variability in the control case. P-wave variability increased non-linearly with respect to the EAS variability and total area of slow conduction. Distribution of the heterogeneous conduction was more effective in increasing the variability when it surrounded the EAS locations and the fast conducting bundles. P-waves simulated by the eikonal approach compared excellently with the monodomain-based ones.

Conclusion: P-wave variability in patients with paroxysmal AF could be explained by a variability in sinoatrial node exit location in combination with slow conducting regions.
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http://dx.doi.org/10.1093/europace/euy227DOI Listing
November 2018

The definition of left bundle branch block influences the response to cardiac resynchronization therapy.

Int J Cardiol 2018 Oct 17;269:165-169. Epub 2018 Jul 17.

Fondazione Cardiocentro Ticino, Lugano, Switzerland.

Background: CRT has been proven to achieve most benefit in patients with left bundle branch block morphology (LBBB). However, ECG criteria to define LBBB significantly differ from each other. Objective of the study was to evaluate the impact of different ECG criteria for LBBB definition on survival, hospitalization for heart failure and reverse remodelling in patients who received cardiac resynchronization therapy (CRT).

Methods And Results: Three-hundred-sixteen consecutive patients were included in the analysis. Six different classifications were assessed in baseline ECGs of patients who received a CRT device: a QRS duration of ≥150 ms and LBBB according to AHA/ACC/HRS, ESC 2006, ESC 2009, ESC 2013 and the classification proposed by Strauss and colleagues. In univariate analysis, the ESC 2009 and 2013 and the Strauss classifications were significantly associated with a reduction in cumulative probability for heart failure (HF) and mortality (HR 0.60, 95%CI 0.42-0.86, HR 0.61, 95% CI 0.43-0.87 and HR 0.57, 95% CI 0.40-0.80, respectively). In multivariate analysis, the association with the combined endpoint was confirmed only for ESC 2009 and 2013 classifications and for Strauss. Moreover, the cumulative probability of all-cause death and HF hospitalizations was higher in patients who were negative for all the 5 LBBB classifications.

Conclusions: This study shows that the strength of the association of LBBB to outcome in CRT depends on the ECG classifications used to define LBBB, the simplest criteria (ESC 2009 and 2013) providing the best association with clinical endpoints in CRT.
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http://dx.doi.org/10.1016/j.ijcard.2018.07.060DOI Listing
October 2018

Value of high-resolution mapping in optimizing cryoballoon ablation of atrial fibrillation.

Int J Cardiol 2018 Nov 1;270:136-142. Epub 2018 Jun 1.

Division of Cardiology, Cardiocentro Ticino, Lugano, Switzerland; Centre for Computational Medicine in Cardiology, Faculty of Informatics, Università della Svizzera Italiana, Lugano, Switzerland.

Background: Unrecognized incomplete pulmonary vein isolation (PVI), as opposed to post-PVI pulmonary vein reconnection, may be responsible for clinical recurrences of atrial fibrillation (AF). To date, no data are available on the use of high-resolution mapping (HRM) during cryoballoon (CB) ablation for AF as the index procedure. The aims of this study were: - to assess the value of using a HRM system during CB ablation procedures in terms of ability in acutely detecting incomplete CB lesions; - to compare the 8-pole circular mapping catheter (CMC, Achieve) and the 64-pole mini-basket catheter (Orion) with respect to pulmonary vein (PV) signals detection at baseline and after CB ablation; - to characterize the extension of the lesion produced by CB ablation by means of high-density voltage mapping.

Methods: Consecutive patients with drug-resistant paroxysmal or early-persistent AF undergoing CB ablation as the index procedure, assisted by a HRM system, were retrospectively included in this study.

Results: A total of 33 patients (25 males; mean age: 59 ± 18 years, 28 paroxysmal AF) were included. At baseline, CMC catheter revealed PV activity in 102 PVs (77%), while the Orion documented PV signals in all veins (100%). Failure of complete CB-PVI was more frequently revealed by atrial re-mapping with the Orion as compared to the Achieve catheter (24% vs 0%, p < 0.05). A repeat ablation was performed in 8 patients (24%). In 9% of cases, the Orion catheter detected far-field signals originating from the right atrium. Quantitative assessment of the created lesion revealed a significant reduction of the left atrial area having voltage >0.5 mV. A total of 29 patients (88%) remained free of symptomatic AF during a mean follow-up of 13.2 ± 3.7 months.

Conclusion: Atrial re-mapping after CB ablation by means of a HRM system improves the detection of areas of incomplete ablation, characterizes the extension of the cryo-ablated tissue and can identify abolishment of potential non-PVI related sources of AF.
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http://dx.doi.org/10.1016/j.ijcard.2018.05.135DOI Listing
November 2018

New onset of phrenic nerve palsy after laser-assisted transvenous lead extraction: a single-centre experience.

Europace 2018 11;20(11):1827-1832

Division of Cardiology, Fondazione Cardiocentro Ticino, Via Tesserete 48, Lugano, Switzerland.

Aims: Phrenic nerve palsy (PNP) after mechanical transvenous lead extraction (TLE) was recently described for the first time. We aimed to analyse our TLE database for the presence of PNP.

Methods And Results: All consecutive patients referred to our institution were included in this study. Every available post-procedural chest X-ray was compared to the routinely performed pre-procedural radiographs. A newly elevated hemidiaphragm ipsilateral to TLE was considered indicative of PNP. Altogether 255 TLE procedures with extraction of 364 leads were performed. Most common TLE indication was lead malfunction (63%). Complete radiographic success rate was 97.3% with an in-hospital procedure-related major complication rate of 2.4%, including one intra-procedural death (0.4%). We identified five cases with PNP (2%), all occurring after laser-assisted TLE. Clinical presentation varied from subtle and aspecific chest pain/discomfort to severe and acute dyspnoea, with time to diagnosis varying from immediate to several weeks after the procedure. In 80% of cases, the explanted lead was a defibrillator electrode and the median lead dwelling time was 70.2 months (29.3; 1084.9). In four cases, the extraction was performed using high-energy laser (pulse repetition rate 80 Hz).

Conclusion: The present study reports the incidence of PNP after laser-assisted TLE. We postulate that the thermal energy generated by laser is not dissipated quickly enough in occluded or heavily calcified lesions, injuring the ipsilateral phrenic nerve. Our findings advise to carefully consider to increase pulse repetition rate at the subclavian level. Larger, possibly prospective studies are needed to evaluate the real incidence through systematic radiological assessment after TLE.
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http://dx.doi.org/10.1093/europace/euy044DOI Listing
November 2018

Integrated Assessment of Left Ventricular Electrical Activation and Myocardial Strain Mapping in Heart Failure Patients: A Holistic Diagnostic Approach for Endocardial Cardiac Resynchronization Therapy, Ablation of Ventricular Tachycardia, and Biological Therapy.

JACC Clin Electrophysiol 2018 01 6;4(1):138-146. Epub 2017 Nov 6.

Center for Computational Medicine in Cardiology, Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland; Division of Cardiology, Fondazione Cardiocentro Ticino, Lugano, Switzerland.

Objectives: This study sought to test the accuracy of strain measurements based on anatomo-electromechanical mapping (AEMM) measurements compared with magnetic resonance imaging (MRI) tagging, to evaluate the diagnostic value of AEMM-based strain measurements in the assessment of myocardial viability, and the additional value of AEMM over peak-to-peak local voltages.

Background: The in vivo identification of viable tissue, evaluation of mechanical contraction, and simultaneous left ventricular activation is currently achieved using multiple complementary techniques.

Methods: In 33 patients, AEMM maps (NOGA XP, Biologic Delivery Systems, Division of Biosense Webster, a Johnson & Johnson Company, Irwindale, California) and MRI images (Siemens 3T, Siemens Healthcare, Erlangen, Germany) were obtained within 1 month. MRI tagging was used to determine circumferential strain (E) and delayed enhancement to obtain local scar extent (%). Custom software was used to measure E and local area strain (LAS) from the motion field of the AEMM catheter tip.

Results: Intertechnique agreement for E was good (R = 0.80), with nonsignificant bias (0.01 strain units) and narrow limits of agreement (-0.03 to 0.06). Scar segments showed lower absolute strain amplitudes compared with nonscar segments: E (median [first to third quartile]: nonscar -0.10 [-0.15 to -0.06] vs. scar -0.04 [-0.06 to -0.02]) and LAS (-0.20 [-0.27 to -0.14] vs. -0.09 [-0.14 to -0.06]). AEMM strains accurately discriminated between scar and nonscar segments, in particular LAS (area under the curve: 0.84, accuracy = 0.76), which was superior to peak-to-peak voltages (nonscar 9.5 [6.5 to 13.3] mV vs. scar 5.6 [3.4 to 8.3] mV; area under the curve: 0.75). Combination of LAS and peak-to-peak voltages resulted in 86% accuracy.

Conclusions: An integrated AEMM approach can accurately determine local deformation and correlates with the scar extent. This approach has potential immediate application in the diagnosis, delivery of intracardiac therapies, and their intraprocedural evaluation.
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http://dx.doi.org/10.1016/j.jacep.2017.08.011DOI Listing
January 2018

New-onset pericardial effusion during transvenous lead extraction: incidence, causative mechanisms, and associated factors.

J Interv Card Electrophysiol 2018 Apr 23;51(3):253-261. Epub 2018 Feb 23.

Division of Cardiology, Fondazione Cardiocentro Ticino, Via Tesserete 48, CH-6900, Lugano, Switzerland.

Purpose: Pericardial effusion (PE) may occur during the lead extraction procedure (TLE). Little is known about the incidence, causes, and predictors of this complication.

Methods: From January 2009 to October 2016, TLE was attempted for 297 leads in 212 patients (age 69.3 ± 12.9 years, 169 male, BMI 27.2 ± 9.9 m²/kg, LVEF 43.4 ± 24.6%) for lead dysfunction (62.7%), upgrade (16.0%), infection (14.2%), or other (7.0%) indications. TLE was performed under general anesthesia with continuous invasive arterial blood pressure and transesophageal echocardiography (TEE) monitoring. For lead removal, the mechanical approach was first attempted, followed by the laser-assisted technique when needed. Severity of PE was defined by the presence of hemodynamically significant PE > 10 mm at TEE.

Results: Clinical success was achieved for 292 leads (98.3%). New-onset PE was observed in 14 patients (6.6%) [mild entity in 7 patients (3.3%) and severe in 7 (3.3%)]. In these latter patients, intra-procedural management included surgery (n = 3), pericardiocentesis (n = 2), or a conservative approach (n = 2). Right ventricular (RV) site lesions were treated with a simple fluid infusion. Laceration of the superior vena cava and other vessels resulted in rescue surgery. Lesions of the right atrial free wall (n = 1) and coronary sinus (n = 1) were treated with pericardiocentesis. NYHA III/IV, LVEF < 35%, renal impairment, right-sided implant, and ≥2 leads targeted for TLE were associated with new-onset PE. More than two factors identified a higher risk group (16.2%, 95% CI 6.2-32.0%, P = 0.02).

Conclusions: New-onset PE is common during TLE and is associated with specific factors. PE severity and subsequent patient management depend on the site of injury.
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http://dx.doi.org/10.1007/s10840-018-0327-1DOI Listing
April 2018

Concealed abnormal atrial phenotype in patients with Brugada syndrome and no history of atrial fibrillation.

Int J Cardiol 2018 02;253:66-70

Division of Cardiology, Fondazione Cardiocentro Ticino, Lugano, Switzerland; Centre for Computational Medicine in Cardiology, Faculty of Informatics, Università della Svizzera Italiana, Lugano, Switzerland.

Objectives: The electrocardiogram (ECG) of patients with BrS in sinus rhythm might reflect intrinsic atrial electrical abnormalities independent from any previous atrial fibrillation (AF). Aim of this study is to investigate the presence of P-wave abnormalities in patients with BrS and no history of AF, and to compare them with those displayed by patients with documented paroxysmal AF and by healthy subjects.

Methods: Continuous 5-min 16-lead ECG recordings in sinus rhythm were obtained from 72 participants: 32 patients with a type 1 Brugada ECG, 20 patients with a history of paroxysmal AF and 20 age-matched healthy subjects. Different ECG-based features were computed on the P-wave first principal component representing the predominant morphology across leads and containing the maximal information on atrial depolarization: duration, full width half maximum (FWHM), area under the curve and number of peaks in the wave.

Results: Patients with BrS and no history of AF (mean age: 53±12years; males: 28 pts., spontaneous type 1 ECG: 20 pts., SCN5A mutation: 10 pts) presented with longer P-wave duration, higher FWHM and wider area under the curve in comparison with the other two groups. Although P-wave features were abnormal in BrS patients, no significant difference was found between patients with spontaneous type 1 ECG and ajmaline-induced type 1 ECG, symptomatic and asymptomatic ones, and between patients with a pathogenic SCNA5 mutation and patients without a known gene mutation.

Conclusions: Patients with BrS without previous occurrence of AF present with a concealed abnormal atrial phenotype. In these patients atrial electrical abnormalities can be detected even in the absence of an overt ECG ventricular phenotype, symptoms and a SCN5A mutation.
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http://dx.doi.org/10.1016/j.ijcard.2017.09.214DOI Listing
February 2018

Key Lessons from the ELECTRa Registry in the Modern Era of Transvenous Lead Extraction.

Arrhythm Electrophysiol Rev 2017 Aug;6(3):111-113

Division of Cardiology, Fondazione Cardiocentro Ticino, Lugano, Switzerland.

The implantation rate of cardiac electronic devices has grown over the past decades. The number of treated patients has increased in parallel with the complexity of the patient population treated, being older, frailer, having more complex devices (in particular, cardiac resynchronisation therapy) and presenting with a greater comorbidity burden. As a consequence, there is a rising number of related implanted system complications, including malfunction and infection. Thus, the demand for transvenous lead extraction (TLE) has also substantially increased. To identify the indication to TLE by various operators and centres, techniques used to perform TLE, and the safety and efficacy of the current clinical practice of TLE, a large prospective registry has been started in Europe - the European Lead Extraction Controlled (ELECTRa) Registry. The key findings of the ELECTRa Registry are discussed in the present review and placed in the context of previous knowledge. The ELECTRa Registry confirms that the TLE procedure is a safe and effective treatment, with an acceptable risk-benefit ratio that is comparable with other well-known cardiological invasive procedures. Of course, TLE is accompanied by potential life-threatening complications; the vast majority of these can be managed by an experienced multidisciplinary team. Multiple factors predict complications, including patient/lead profile, centre experience and procedure volumes, which may suggest caution when accepting a patient for TLE.
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http://dx.doi.org/10.15420/aer.2017.25.1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5610740PMC
August 2017

Evaluation of the use of unipolar voltage amplitudes for detection of myocardial scar assessed by cardiac magnetic resonance imaging in heart failure patients.

PLoS One 2017 5;12(7):e0180637. Epub 2017 Jul 5.

Center for Computational Medicine in Cardiology, Institute of Computational Science, Università della Svizzera italiana, Lugano, Switzerland.

Background: Validation of voltage-based scar delineation has been limited to small populations using mainly endocardial measurements. The aim of this study is to compare unipolar voltage amplitudes (UnipV) with scar on delayed enhancement cardiac magnetic resonance imaging (DE-CMR).

Methods: Heart failure patients who underwent DE-CMR and electro-anatomic mapping were included. Thirty-three endocardial mapped patients and 27 epicardial mapped patients were investigated. UnipV were computed peak-to-peak. Electrograms were matched with scar extent of the corresponding DE-CMR segment using a 16-segment/slice model. Non-scar was defined as 0% scar, while scar was defined as 1-100% scar extent.

Results: UnipVs were moderately lower in scar than in non-scar (endocardial 7.1 [4.6-10.6] vs. 10.3 [7.4-14.2] mV; epicardial 6.7 [3.6-10.5] vs. 7.8 [4.2-12.3] mV; both p<0.001). The correlation between UnipV and scar extent was moderate for endocardial (R = -0.33, p<0.001), and poor for epicardial measurements (R = -0.07, p<0.001). Endocardial UnipV predicted segments with >25%, >50% and >75% scar extent with AUCs of 0.72, 0.73 and 0.76, respectively, while epicardial UnipV were poor scar predictors, independent of scar burden (AUC = 0.47-0.56). UnipV in non-scar varied widely between patients (p<0.001) and were lower in scar compared to non-scar in only 9/22 (41%) endocardial mapped patients and 4/19 (21%) epicardial mapped patients with scar.

Conclusion: UnipV are slightly lower in scar compared to non-scar. However, significant UnipV differences between and within patients and large overlap between non-scar and scar limits the reliability of accurate scar assessment, especially in epicardial measurements and in segments with less than 75% scar extent.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0180637PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5498065PMC
October 2017

Potential Clinical Utility and Feasibility of Combined Left Atrial Appendage Closure and Positioning of Miniaturized Pacemaker Through a Single Right Femoral Vein Access.

Am J Cardiol 2017 Jul 27;120(2):236-242. Epub 2017 Apr 27.

Cardiology Department, Fondazione Cardiocentro Ticino, Lugano, Switzerland.

This study assessed the clinical utility and feasibility of concomitant of combined left atrial appendage (LAA) closure and positioning of miniaturized pacemaker (Micra TPS). All consecutive patients who underwent VVI-PM implant from November 2015 to October 2016 were considered. VVI-PM implant was conducted either using transvenous approach or by positioning Micra TPS. In selected patients with concomitant contraindication to OAC, Micra TPS was combined with LAA occlusion ("combined approach"), performed in general anesthesia and guided by multimodality imaging; procedural and follow-up data of these specific patients were registered. Sixty patients were treated with VVI-PM implant. Six patients (10.0%) presented OAC contraindication, of which 4 (6.7%) were eligible for the "combined procedure"; 2 of 4 of these patients presented chronic hemodialysis-dependent renal failure. The combined approach was successful in all 4 patients without intra- or periprocedural complications. No adverse events linked to the combined approach occurred during mid-term follow-up (7.5, interquartile range 5.0 to 7.9 months). In conclusion, VVI-PM indication and concomitant contraindication to OAC is not uncommon; in selected patients, combined LAA closure and positioning of Micra TPS may be a feasible therapeutic option.
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http://dx.doi.org/10.1016/j.amjcard.2017.04.014DOI Listing
July 2017

High rate of subcutaneous implantable cardioverter-defibrillator sensing screening failure in patients with Brugada syndrome: a comparison with other inherited primary arrhythmia syndromes.

Europace 2018 07;20(7):1188-1193

Division of Cardiology, Electrophysiology Unit, Fondazione Cardiocentro Ticino, via tesserete 48, Lugano, Switzerland.

Aims: Subcutaneous implantable cardioverter-defibrillator (S-ICD) can avoid important complications associated with transvenous leads in patients with inherited primary arrhythmia syndromes, who do not need pacing therapy. Few data are available on the percentage of patients with inherited arrhythmia syndromes eligible for S-ICD implantation. Aim of this study was to analyse the eligibility for S-ICD in a series of patients with Brugada syndrome (BrS), and to compare it with patients with other channelopathies.

Methods And Results: Patients presenting with BrS, long-QT syndrome (LQTS), early repolarization syndrome (ERS), and idiopathic ventricular fibrillation (IVF) were considered eligible for this study. ECG screening was performed by analysis of QRS complex and T wave morphology recorded in standing and supine position. Eligibility was defined when ≥1 sense vector was acceptable in both supine and standing position. A total of 100 patients (72 males; mean age: 46 ± 17 years) underwent S-ICD sensing screening. Sixty-one patients presented with BrS, 21 with LQTS, 14 with IVF, and 4 with ERS. Thirty-four patients with BrS (56%) presented with spontaneous type 1 ECG. In the other 27 patients (44%), type 1 ECG was unmasked by ajmaline. Overall, rate of screening failure was 13%. Patients with BrS had a higher rate of inappropriate morphology analysis as compared with other channelopathies (18% vs. 5%, P = 0.07) and had a lower number of suitable sensing vectors (49.6% vs. 84.7% vs. P < 0.001). Ajmaline challenge unmasked sensing failure in 14.8% of drug-induced BrS patients previously considered eligible. In all patients, the reason for sensing inappropriateness was due to the presence of high T wave voltages.

Conclusion: S-ICD screening failure occurs in up to 13% of patients with inherited primary arrhythmia syndromes. Patients with BrS present a higher rate of screening failure as compared with other cardiac channelopathies.
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http://dx.doi.org/10.1093/europace/eux009DOI Listing
July 2018

The relation between local repolarization and T-wave morphology in heart failure patients.

Int J Cardiol 2017 Aug 22;241:270-276. Epub 2017 Feb 22.

Maastricht University, Maastricht, The Netherlands. Electronic address:

Background: Both duration and morphology of the T-wave are regarded important parameters describing repolarization of the ventricles. Conventionally, T-wave concordance is explained by an inverse relation between the time of depolarization (TD) and repolarization (TR). Little is known about T-wave morphology and TD-TR relations in patients with heart failure.

Methods: Electro-anatomic maps were obtained in the left (LV) and right ventricle (RV) and in the coronary sinus (CS) in patients with heart failure with narrow (nQRS, n=8) and wide QRS complex with (LBBB, n=15) and without left bundle branch block (non-LBBB, n=7). TD and TR were determined from the thus acquired electrograms.

Results: In nQRS and non-LBBB patients, TD-TR relations had a slope between 0 and +1, indicating that repolarization followed the sequence of depolarization. In LBBB patients, repolarization occurred significantly earlier in the RV than in the LV, fitting with the idea that the discordant T-waves in LBBB are secondary to the abnormal depolarization sequence. However, the slopes of the TD-TR relations in the LV and CS were not significantly different from zero, indicating no major spatial gradient in LV repolarization, despite a considerable gradient in depolarization. Remarkable was also the large (~100ms) transseptal gradient in repolarization. Values of the slopes of the TD-TR relation overlapped between the three patient groups, despite a difference in T-wave morphology between LBBB (all discordant) and nQRS patients (all flat/biphasic).

Conclusions: Discordant T-waves in LBBB patients are explained by interventricular dispersion in repolarization. T-wave morphology is determined by more factors than the TD-TR relation alone.
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http://dx.doi.org/10.1016/j.ijcard.2017.02.056DOI Listing
August 2017

Lay persons alerted by mobile application system initiate earlier cardio-pulmonary resuscitation: A comparison with SMS-based system notification.

Resuscitation 2017 05 6;114:73-78. Epub 2017 Mar 6.

Division of Cardiology, Fondazione Cardiocentro Ticino, Lugano, Switzerland.

Aim: We compared the time to initiation of cardiopulmonary resuscitation (CPR) by lay responders and/or first responders alerted either via Short Message Service (SMS) or by using a mobile application-based alert system (APP).

Methods: The Ticino Registry of Cardiac Arrest collects all data about out-of-hospital cardiac arrests (OHCAs) occurring in the Canton of Ticino. At the time of a bystander's call, the EMS dispatcher sends one ambulance and alerts the first-responders network made up of police officers or fire brigade equipped with an automatic external defibrillator, the so called "traditional" first responders, and - if the scene was considered safe - lay responders as well. We evaluated the time from call to arrival of traditional first responders and/or lay responders when alerted either via SMS or the new developed mobile APP.

Results: Over the study period 593 OHCAs have occurred. Notification to the first responders network was sent via SMS in 198 cases and via mobile APP in 134 cases. Median time to first responder/lay responder arrival on scene was significantly reduced by the APP-based system (3.5 [2.8-5.2]) compared to the SMS-based system (5.6 [4.2-8.5] min, p 0.0001). The proportion of lay responders arriving first on the scene significantly increased (70% vs. 15%, p<0.01) with the APP. Earlier arrival of a first responder or of a lay responder determined a higher survival rate.

Conclusions: The mobile APP system is highly efficient in the recruitment of first responders, significantly reducing the time to the initiation of CPR thus increasing survival rates.
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http://dx.doi.org/10.1016/j.resuscitation.2017.03.003DOI Listing
May 2017

Anatomic characterization of cavotricuspid isthmus by 3D transesophageal echocardiography in patients undergoing radiofrequency ablation of typical atrial flutter.

Eur Heart J Cardiovasc Imaging 2018 01;19(1):84-91

Division of Cardiology, Fondazione Cardiocentro Ticino, Via Tesserete 48, CH-6900 Lugano, Switzerland.

Aims: Radiofrequency ablation (RFA) is the treatment of choice of cavotricuspid isthmus (CTI)-dependent atrial flutter. Procedural time is highly variable due to anatomical structures. This study aimed to characterize CTI anatomy by transesophageal 3D echocardiography imaging (3D-TEE) to identify anatomic structures related to longer ablation time.

Methods And Results: Thirty-one consecutive patients (mean age 67.3 ± 11.5 years, 22 males) underwent CTI-ablation procedure. Before ablation, TEE was performed and 3D-TEE images were acquired to evaluate CTI anatomy qualitatively as well as perform measures of CTI morphological features. The electrophysiologist performing RFA was blinded to 3D-TEE data. Bidirectional block of CTI was achieved in all patients without procedural complications after a median ablation time of 11 (IQR 7-14) min. Patients with RFA time ≥11 min (Group 2) presented lower left ventricular ejection fraction (51.1 ± 17.0 vs. 59.5 ± 6.6%, P < 0.010), a larger left atrium (46.2 ± 8.4 vs. 39.9 ± 9.4 mm, P < 0.058), and, more frequently, a right atrial pouch (12/16 patients vs. 4/15, P = 0.012) compared with patients with RFA time < 11 min (Group 1); CTI pouch was significantly deeper in Group 2 compared with Group 1: telediastolic (TD) pouch depth was 10.4 ± 4.5 vs. 6.3 ± 1.5 mm (P = 0.003) and telesystolic (TS) depth 12.8 ± 4.4 vs. 7.0 ± 1.4 mm (P < 0.001), respectively. TD isthmus length, prominent pectinate muscle, and presence of an Eustachian ridge (ER) did not differ between the two groups.

Conclusion: Routine pre-procedural 3D-TEE imaging is extremely helpful in qualitative and quantitative evaluation of CTI anatomy in patients undergoing RFA for symptomatic typical atrial flutter. Detection of a deep right atrial pouch was found to be associated with significantly prolonged CTI ablation time to achieve bidirectional block.
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http://dx.doi.org/10.1093/ehjci/jew336DOI Listing
January 2018

True idiopathic ventricular fibrillation in out-of-hospital cardiac arrest survivors in the Swiss Canton Ticino: prevalence, clinical features, and long-term follow-up.

Europace 2017 02;19(2):259-266

Cardiocentro Ticino, Lugano, Switzerland.

Aims: Out-of-hospital cardiac arrest (OHCA) in the absence of evident structural heart disease is rare and can be due to subclinical cardiomyopathy and primary electrical disorders, including idiopathic ventricular fibrillation (IVF) with early repolarization (ER) pattern. Aim of this study was to investigate prevalence, clinical features, and long-term prognosis of IVF in OHCA survivors with otherwise normal 12-lead electrocardiograms (ECGs).

Methods And Results: Patients with IVF in the absence of ER pattern or atrioventricular conduction abnormalities were considered eligible for this study. A total of 3407 OHCAs occurred in our region from 2000 to 2014. Out-of-hospital cardiac arrests of presumed cardiac origin were 2192; of them, 644 presented with a ventricular arrhythmia (VT/VF) as first shockable rhythm. Among them, a total of 74 implantable cardioverter-defibrillators were implanted for secondary prevention. Ventricular arrhythmia was considered idiopathic in 11 (15%) of these patients. Over a mean follow-up time of 85 ± 47 months (median: 42 months), ECG was found abnormal in three cases. In the remaining eight patients (6 males; median age: 45 years), no ECG or structural abnormalities were detected during the follow-up. Prevalence of IVF in OHCA survivors with first-shockable rhythm was 1.2%. During the long-term follow-up, no patient died or experienced ICD interventions. No new echocardiographic abnormal findings were revealed.

Conclusion: Idiopathic ventricular fibrillation is rare occurring in 1.2% of OHCA survivors presenting with a shockable rhythm. The initial diagnosis can change in up to 27% of cases. Patients with IVF and no ER pattern or AV conduction disturbances have a good prognosis during a long-term follow-up.
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http://dx.doi.org/10.1093/europace/euv447DOI Listing
February 2017

Changes in P-wave morphology after pulmonary vein isolation: insights from computer simulations.

Europace 2016 Dec;18(suppl 4):iv23-iv34

Département de Physiologie Moléculaire et Intégrative, Institut de Génie Biomédical, Université de Montréal, Montréal, QC, Canada

Aims: Apparently conflicting clinical measurements of P-wave duration (PWD) pre- vs. post-ablation have been reported. To assist the interpretation of these clinical data, we used a computer model of the atria and torso to simulate P waves before and after pulmonary vein (PV) isolation.

Methods And Results: Twenty ablation patterns were designed (segmental or ipsilateral ablation; five distances to PV sleeves; addition of a roof line or not). Possible PV reconnections were introduced as gaps in the ablation lines. PWD and area were measured during sinus rhythm in vectorcardiogram (VCG) magnitude signals and on the 16-lead ECG before and after ablation, and after PV reconnection. After PV isolation, biatrial activation time was prolonged by 0-5 ms without and by 48±5 ms with roof line. Yet PWD was shortened in lead V3 and V4 by up to 15 ms. The effect of ablation on P-wave morphology was stronger when larger PV areas were isolated. Segmental and ipsilateral PV isolation led to concordant results. P-wave area increased in V1 and decreased in V6. Changes in PWD and area on the VCG were sensitive to the threshold used for detecting the end of the P wave. The occurrence of PV reconnection was best identified on leads V3, V4, and V9.

Conclusion: PV isolation and reconnection induced measurable changes on the 16-lead ECG that might be used to improve patient follow-up after ablation.
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http://dx.doi.org/10.1093/europace/euw348DOI Listing
December 2016