Publications by authors named "Cory Tschabrunn"

71 Publications

Endovascular occlusion balloon-related thrombosis during transvenous lead extraction.

Europace 2021 Apr 5. Epub 2021 Apr 5.

Electrophysiology Section, Division of Cardiovascular Medicine, Perelman School of Medicine at the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA.

Aims: The aim of this study is to evaluate the incidence, predictors, and outcomes of balloon-related thrombosis (BRT) in patients undergoing transvenous lead extraction (TLE). Use of an endovascular occlusion balloon has improved outcomes of superior vena cava injuries during TLE. Its thrombogenicity in clinical practice is unknown.

Methods And Results: We prospectively evaluated consecutive patients undergoing prophylactic balloon placement during TLE utilizing two procedural workflows: one with the balloon within the inferior vena cava during the entire case (standard cohort) and one limiting the balloon's dwell time (abbreviated cohort). Intracardiac echocardiography was used to evaluate for significant BRT (thrombus > 1 cm) after TLE. Forty-two patients (21 in each group) were included. Age, left ventricular ejection fraction, procedural indication, number of leads, and lead dwell time were similar between the groups. Balloon dwell time was significantly longer in the standard group (128 ± 74 vs. 25 ± 18 min, P < 0.001) as was BRT (14/21 vs. 1/21, P < 0.001). Mean thrombus length and width in the standard group was 3.99 ± 1.40 and 0.45 ± 0.16 cm, respectively and 5.2 × 0.4 cm in one patient in the abbreviated group. Between patients with and without BRT in the standard group, balloon dwell times were similar (113 ± 64 vs. 156 ± 88 min, P = 0.21). One patient in the standard group had a pulmonary embolism on post-operative Day 3 and was initiated on oral anticoagulation.

Conclusion: Prophylactic balloon placement for the entirety of the case is associated with a high incidence of BRT; a finding that is decreased when an abbreviated workflow is utilized.
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http://dx.doi.org/10.1093/europace/euab074DOI Listing
April 2021

Active esophageal cooling for the prevention of thermal injury during atrial fibrillation ablation: a randomized controlled pilot study.

J Interv Card Electrophysiol 2021 Feb 23. Epub 2021 Feb 23.

Cardiac Electrophysiology Section, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, 3400 Spruce Street, 9 Founders Pavilion, Philadelphia, PA, 19104, USA.

Background: Severe endoscopically detected esophageal thermal lesions (EDELs) have been associated with higher risk of progression to atrio-esophageal fistula (AEF) following radiofrequency catheter ablation (RFCA) of atrial fibrillation (AF). We sought to evaluate safety and feasibility of active esophageal cooling using the Attune Medical Esophageal Heat Transfer Device (EnsoETM) to limit frequency or severity of EDELs.

Objective: We sought To evaluate safety and feasibility of active esophageal cooling using the Attune Medical Esophageal Heat Transfer Device (EnsoETM) to limit frequency or severity of EDELs METHODS: Consecutive patients undergoing first-time RFCA were randomized in a 1:1 fashion to esophageal cooling (device group) or standard temperature monitoring (control group). Ablation on the posterior wall was performed with a maximum power of 30W for up to 20s. All patients underwent EGD within 48 h. Endoscopy findings were classified as 1, erythema-mild injury; 2, superficial ulceration-moderate injury; 3, deep ulceration-significant injury; and 4, fistula/perforation. Severe EDELs were defined as grade 3 or 4 lesions.

Results: Forty-four patients completed the study (22 device group, 22 control group). Adjunctive posterior wall isolation was performed more frequently in the device group (11/22, 50% vs. 4/22, 18%). EDELs were detected in 5/22 (23%) control group patients, with mild or moderate injury in 2/5 patients (40%) and severe thermal injury in 3/5 patients (60%). In the device group, EDELs were detected in 8/22 (36%) patients, with mild or moderate injury in 7/8 (87%) patients and severe thermal injury in 1/8 (12%) patients. There was no acute perforation or AEF during follow-up.

Conclusions: Active esophageal cooling may reduce the occurrence of severe EDELs. A larger randomized study is warranted to further evaluate the benefit of this strategy.
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http://dx.doi.org/10.1007/s10840-021-00960-wDOI Listing
February 2021

The Evolution of Ventricular Scar Substrate Assessment by Using High-Resolution Mapping Platforms: Ongoing Quest for "Ground Truth".

JACC Clin Electrophysiol 2021 02;7(2):206-209

Cardiac Electrophysiology Section, Division of Cardiovascular Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.

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http://dx.doi.org/10.1016/j.jacep.2020.11.018DOI Listing
February 2021

Periprocedural Acute Kidney Injury in Patients With Structural Heart Disease Undergoing Catheter Ablation of VT.

JACC Clin Electrophysiol 2021 02 28;7(2):174-186. Epub 2020 Oct 28.

Electrophysiology Section, Cardiovascular Medicine Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA. Electronic address:

Objectives: This study sought to examine the impact of periprocedural acute kidney injury (AKI) in scar-related ventricular tachycardia (VT) patients undergoing radiofrequency catheter ablation (RFCA) on short- and long-term outcomes.

Background: The clinical significance of periprocedural AKI in patients with scar-related VT undergoing RFCA has not been previously investigated.

Methods: This study included 317 consecutive patients with scar-related VT undergoing RFCA (age: 64 ± 13 years, mean left ventricular ejection fraction: 33 ± 13%, 55% ischemic cardiomyopathy). Periprocedural AKI was defined as an absolute increase in creatinine of ≥0.3 mg/dl over 48 h or an increase of >1.5× the baseline values within 1 week post-procedure.

Results: Periprocedural AKI occurred in 31 patients (10%). Independent predictors of AKI included chronic kidney disease (odds ratio [OR]: 3.43; 95% confidence interval [CI]: 1.48 to 7.96; p = 0.004), atrial fibrillation (OR: 2.42; 95% CI: 1.01 to 5.78; p = 0.047), and peri-procedural acute hemodynamic decompensation (OR: 3.98; 95% CI: 1.17 to 13.52; p = 0.003). After a median follow-up of 39 months (interquartile range: 6 to 65 months), 95 patients (30%) died. Periprocedural AKI was associated with increased risk of early mortality (within 30 days; hazard ratio [HR]: 9.91; 95% CI: 2.87 to 34.22; p < 0.001) and late mortality (within 1 year) (HR: 4.57; 95% CI: 2.08 to 10.05; p < 0.001). After multivariable adjustment, AKI remained independently associated with increased risk of early and late mortality (HR: 4.49; 95% CI: 1.1 to 18.36; p = 0.04, and HR: 3.28; 95% CI: 1.43 to 7.49; p = 0.005, respectively).

Conclusions: Periprocedural AKI occurs in 10% of patients undergoing RFCA of scar-related VT and is strongly associated with increased risk of early and late post-procedural mortality.
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http://dx.doi.org/10.1016/j.jacep.2020.08.018DOI Listing
February 2021

Myocardial Substrate Characterization by CMR T Mapping in Patients With NICM and No LGE Undergoing Catheter Ablation of VT.

JACC Clin Electrophysiol 2021 Jul 27;7(7):831-840. Epub 2021 Jan 27.

Cardiac Electrophysiology, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA. Electronic address:

Objectives: The goal of this study was to characterize the relationship between DF, the electroanatomic mapping (EAM) substrate, and outcomes of catheter ablation of VT in NICM.

Background: A substantial proportion of patients with nonischemic dilated cardiomyopathy (NICM) and ventricular tachycardia (VT) do not have scar detectable by cardiac magnetic resonance late gadolinium enhancement (LGE) imaging. In these patients, the significance of diffuse fibrosis (DF) detected with T mapping has not been previously investigated.

Methods: This study included 51 patients with NICM and VT undergoing catheter ablation (median age 55 years; 77% male subjects) who had no evidence of LGE on pre-procedural cardiac magnetic resonance. Post-contrast T relaxation time determined on the septum was assessed as a surrogate of DF burden. The extent of endocardial low-voltage areas (LVAs) at EAM was correlated with T mapping data.

Results: Bipolar LVAs were present in 22 (43%) patients (median extent 15 cm [8 to 29 cm]) and unipolar LVA in all patients (median extent 48 cm [26 to 120 cm]). A significant inverse correlation was found between T values and both unipolar-LVA (R = 0.64; β = -0.85; p < 0.01) and bipolar-LVA (R = 0.16; β = -1.63; p < 0.01). After a median follow-up of 45 months (22 to 57 months), 2 (4%) patients died, 3 (6%) underwent heart transplantation, and 8 (16%) experienced VT recurrence. Shorter post-contrast T time was associated with an increased risk of VT recurrence (hazard ratio: 1.16; 95% confidence interval: 1.03 to 1.33 per 10 ms decrease; p = 0.02).

Conclusions: In patients with NICM and no evidence of LGE undergoing catheter ablation of VT, DF estimated by using post-contrast T mapping correlates with the voltage abnormality at EAM and seems to affect post-ablation outcomes.
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http://dx.doi.org/10.1016/j.jacep.2020.10.002DOI Listing
July 2021

Impact of Left Atrial Bipolar Electrogram Voltage on First Pass Pulmonary Vein Isolation During Radiofrequency Catheter Ablation.

Front Physiol 2020 15;11:594654. Epub 2020 Dec 15.

Electrophysiology Section, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, PA, United States.

Background: First pass pulmonary vein isolation (PVI) is associated with durable isolation and reduced recurrence of atrial fibrillation (AF).

Objective: We sought to investigate the relationship between left atrial electrogram voltage using multielectrode fast automated mapping (ME-FAM) and first pass isolation with radiofrequency ablation.

Methods: We included consecutive patients (pts) undergoing first time ablation for paroxysmal AF (pAF), and compared the voltage characteristics between patients with and without first pass isolation. Left atrium (LA) adjacent to PVs was divided into 6 regions, and mean voltages obtained with ME-FAM (Pentaray, Biosense Webster) in each region and compared. LA electrograms with marked low voltage (<0.5 mV) were identified and the voltage characteristics at the site of difficult isolation was compared to the voltage in adjacent region.

Results: Twenty consecutive patients (10 with first pass and 10 without) with a mean age of 63.3 ± 6.2 years, 65% males, were studied. Difficult isolation occurred on the right PVs in eight pts and left PVs in three pts. The mean voltage in pts without first pass isolation was lower in all 6 regions; posterior wall (1.93 ± 1.46 versus 2.99 ± 2.19; < 0.001), roof (1.83 ± 2.29 versus 2.47 ± 1.99; < 0.001), LA-LPV posterior (1.85 ± 3.09 versus 2.99 ± 2.19, < 0.001), LA-LPV ridge (1.42 ± 1.04 versus 1.91 ± 1.61; < 0.001), LA-RPV posterior (1.51 ± 1.11 versus 2.30 ± 1.77, < 0.001) and LA-RPV septum (1.55 ± 1.23 versus 2.31 ± 1.40, < 0.001). Patients without first pass isolation also had a larger percentage of signal with an amplitude of <0.5 mV for each of the six regions (12.8% versus 7.5%). In addition, the mean voltage at the site of difficult isolation was lower at 8 out of 11 sites compared to mean voltage for remaining electrograms in that region.

Conclusion: In patients undergoing PVI for paroxysmal AF, failure in first pass isolation was associated with lower global LA voltage, more marked low amplitude signal (<0.5 mV) and lower local signal voltage at the site with difficult isolation. The results suggest that a greater degree of global and segmental fibrosis may play a role in ease of PV isolation with radiofrequency energy.
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http://dx.doi.org/10.3389/fphys.2020.594654DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7769759PMC
December 2020

Right bundle branch block ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy more commonly originates from the right ventricle: Criteria for identifying chamber of origin.

Heart Rhythm 2021 Feb 1;18(2):163-171. Epub 2020 Sep 1.

Cardiac Electrophysiology Section, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Background: Right bundle branch block (RBBB) ventricular tachycardia (VT) morphology is a criterion for left ventricular (LV) involvement in arrhythmogenic right ventricular cardiomyopathy (ARVC).

Objective: The purpose of this study was to determine the frequency and chamber of origin of RBBB VT in patients with ARVC and VT.

Methods: We studied 110 consecutive patients with VT who met the diagnostic International Task Force criteria for ARVC and underwent VT mapping/ablation. Patients with ≥1 RBBB VT were identified. Right ventricular (RV) origin of the RBBB VT was determined based on standard mapping criteria and elimination with ablation.

Results: Nineteen patients (17%) had 26 RBBB VTs. Eleven of these 19 patients (58%) had 16 RBBB VTs from the RV, and 9 patients (47%) had 10 RBBB VTs originating from the LV, with 1 patient demonstrating both. RBBB VT from RV most commonly (13/16 RBBB VTs) had an early precordial QRS transition (V or V), with superiorly and typically leftward directed frontal plane axis, consistent with exit from dilated RV adjacent to inferior LV septum, whereas all 10 VTs from LV had RBBB morphology with positive R waves to V or V and rightward axis in 6 VTs characteristic of basal lateral origin.

Conclusion: In patients with ARVC and VT presenting for VT ablation, RBBB VT occurs in 17% of cases, with most RBBB VTs (62%) originating from the RV and not indicative of LV origin. Precordial R-wave transition and frontal plane axis can be used to identify the anticipated chamber of origin of RBBB VT.
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http://dx.doi.org/10.1016/j.hrthm.2020.08.016DOI Listing
February 2021

Automatically steering cardiac catheters in vivo with respiratory motion compensation.

Int J Rob Res 2020 Apr 19;39(5):586-597. Epub 2020 Feb 19.

John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA.

A robotic system for automatically navigating ultrasound (US) imaging catheters can provide real-time intra-cardiac imaging for diagnosis and treatment while reducing the need for clinicians to perform manual catheter steering. Clinical deployment of such a system requires accurate navigation despite the presence of disturbances including cyclical physiological motions (e.g., respiration). In this work, we report results from in vivo trials of automatic target tracking using our system, which is the first to navigate cardiac catheters with respiratory motion compensation. The effects of respiratory disturbances on the US catheter are modeled and then applied to four-degree-of-freedom steering kinematics with predictive filtering. This enables the system to accurately steer the US catheter and aim the US imager at a target despite respiratory motion disturbance. In vivo animal respiratory motion compensation results demonstrate automatic US catheter steering to image a target ablation catheter with 1.05 mm and 1.33° mean absolute error. Robotic US catheter steering with motion compensation can improve cardiac catheterization techniques while reducing clinician effort and X-ray exposure.
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http://dx.doi.org/10.1177/0278364920903785DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7357965PMC
April 2020

Iron imaging in myocardial infarction reperfusion injury.

Nat Commun 2020 06 29;11(1):3273. Epub 2020 Jun 29.

Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.

Restoration of coronary blood flow after a heart attack can cause reperfusion injury potentially leading to impaired cardiac function, adverse tissue remodeling and heart failure. Iron is an essential biometal that may have a pathologic role in this process. There is a clinical need for a precise noninvasive method to detect iron for risk stratification of patients and therapy evaluation. Here, we report that magnetic susceptibility imaging in a large animal model shows an infarct paramagnetic shift associated with duration of coronary artery occlusion and the presence of iron. Iron validation techniques used include histology, immunohistochemistry, spectrometry and spectroscopy. Further mRNA analysis shows upregulation of ferritin and heme oxygenase. While conventional imaging corroborates the findings of iron deposition, magnetic susceptibility imaging has improved sensitivity to iron and mitigates confounding factors such as edema and fibrosis. Myocardial infarction patients receiving reperfusion therapy show magnetic susceptibility changes associated with hypokinetic myocardial wall motion and microvascular obstruction, demonstrating potential for clinical translation.
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http://dx.doi.org/10.1038/s41467-020-16923-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7324567PMC
June 2020

Evaluation of Radiofrequency Ablation Irrigation Type: In Vivo Comparison of Normal Versus Half-Normal Saline Lesion Characteristics.

JACC Clin Electrophysiol 2020 06 27;6(6):684-692. Epub 2020 May 27.

Cardiac Electrophysiology Section, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, USA.

Objectives: This study investigated the impact of the type of catheter irrigant used during delivery of radiofrequency ablation.

Background: The use of half-normal saline (HNS) as an irrigant has been suggested as a method for increasing ablation lesion size but has not been rigorously studied in the beating heart or the use of a low-flow irrigation catheter.

Methods: Sixteen swine underwent left ventricular mapping and ablation using either normal saline (NS) (group 1: n = 9) or half-normal saline (HNS) (group 2: n = 7). All lesions were delivered using identical parameters (40 W with 10-second ramp, 30-second duration, 15 ml/min flow, and 8- to14-g target contact force). An occurrence of steam pop, catheter char, or thrombus was assessed using intracardiac echocardiography and catheter inspection following each application. Lesion depth, width, and area were measured using electronic calibers.

Results: A total of 109 lesions were delivered in group 1 and 77 in group 2. There were significantly more steam pops in group 2 (32 of 77 [42%] vs. 24 of 109 [22%], respectively). The frequencies of catheter tip char were similar (group 1: 9 of 109 [8%] vs. group 2: 10 of 77 [13%]; p = 0.29). Lesion depths, widths, and areas also were similar in both groups.

Conclusions: The use of an HNS irrigant using a low-flow open irrigated ablation catheter platform results in more tissue heating due to higher radiofrequency current delivery directed to tissue, but this can lead to higher rate of steam pops. In this in vivo porcine beating-heart model, the use of HNS does not appear to significantly increase lesion size in normal myocardium despite evidence of increased radiofrequency heating.
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http://dx.doi.org/10.1016/j.jacep.2020.02.013DOI Listing
June 2020

Overcoming challenges in the management of arrhythmogenic right ventricular cardiomyopathy.

Kardiol Pol 2020 05 19;78(5):386-395. Epub 2020 May 19.

Electrophysiology Section, Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, United States.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) appears in most patients to be an inherited disease characterized by fibrofatty replacement of myocytes extending from the epicardium to the endocardium in the right ventricle. The disease process results in life‑threatening ventricular arrhythmias and ventricular dysfunction. In the absence of a gold‑standard diagnostic test and despite the progress in imaging techniques, ARVC is often misdiagnosed and earlier detection of the disease is challenging. Preprocedural identification and localization of the substrate can be determined from the analysis of surface electrocardiography and cardiac magnetic resonance imaging. Typically, perivalvular arrhythmogenic substrate, defined by electroanatomic mapping, is present and can be isolated to the epicardium. Ablation targets are further identified with activation, entrainment, and local electrogram abnormalities based on detailed electroanatomic mapping. Extensive combined endo / epicardial ablation performed in experienced centers is frequently required to prevent ventricular tachycardia (VT). Catheter ablation significantly reduces recurrences of VT, appropriate implantable cardioverter‑defibrillator shocks, and the use of antiarrhythmic drugs and cardiac transplant as a management strategy for refractory arrhythmias is rarely required. Progression of the disease is poorly understood and may require a distinct triggering mechanism. Biventricular involvement is more common than previously recognized. However, left ventricular involvement leading to significant terminal heart failure is fortunately uncommon and left ventricular tachycardias are also infrequent. Many questions remain regarding prevention and management of coexisting tricuspid valve regurgitation, atrial arrhythmias, and intracardiac thrombosis. Although data on genotype‑phenotype correlations is growing, long‑term follow‑up studies of families with ARVC are still lacking. Ongoing research will contribute to better understanding of this pathological condition.
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http://dx.doi.org/10.33963/KP.15374DOI Listing
May 2020

Collateral injury of the conduction system during catheter ablation of septal substrate in nonischemic cardiomyopathy.

J Cardiovasc Electrophysiol 2020 07 5;31(7):1726-1739. Epub 2020 May 5.

Department of Medicine, Cardiac Electrophysiology, Cardiovascular Medicine Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.

Introduction: In patients with nonischemic cardiomyopathy (NICM) little is known about the clinical impact of catheter ablation (CA) of septal ventricular tachycardia (VT) resulting in the collateral injury of the conduction system (CICS).

Methods And Results: Ninety-five consecutive patients with NICM underwent CA of septal VT. Outcomes in patients with no baseline conduction abnormalities who developed CICS (group 1, n = 28 [29%]) were compared to patients with no CICS (group 2, n = 17 [18%]) and to patients with preexisting conduction abnormalities or biventricular pacing (group 3, n = 50 [53%]). Group-1 patients were younger, had a higher left ventricular ejection fraction and a lower prevalence of New York Heart Association III/IV class compared to group 3 while no significant differences were observed with group 2. After a median follow-up of 15 months, VT recurred in 14% of patients in group 1, 12% in group 2 (P = .94) and 32% in group 3 (P = .08) while death/transplant occurred in 14% of patients in group 1, 18% in group 2 (P = .69) and 28% in group 3 (P = .15). A worsening of left ventricular ejection fraction (LVEF) (median LVEF variation, -5%) was observed in group 1 compared to group 2 (median LVEF variation, 0%; P < .01) but not group-3 patients (median LVEF variation, -4%; P = .08) with a consequent higher need for new biventricular pacing in group 1 (43%) compared to group 2 (12%; P = .03) and group 3 (16%; P < .01).

Conclusions: In patients with NICM and septal substrate, sparing the abnormal substrate harboring the conduction system provides acceptable VT control while preventing a worsening of the systolic function.
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http://dx.doi.org/10.1111/jce.14498DOI Listing
July 2020

Cooling or Warming the Esophagus to Reduce Esophageal Injury During Left Atrial Ablation in the Treatment of Atrial Fibrillation.

J Vis Exp 2020 03 15(157). Epub 2020 Mar 15.

Department of Emergency Medicine, University of Texas, Southwestern Medical Center;

Ablation of the left atrium using either radiofrequency (RF) or cryothermal energy is an effective treatment for atrial fibrillation (AF) and is the most frequent type of cardiac ablation procedure performed. Although generally safe, collateral injury to surrounding structures, particularly the esophagus, remains a concern. Cooling or warming the esophagus to counteract the heat from RF ablation, or the cold from cryoablation, is a method that is used to reduce thermal esophageal injury, and there are increasing data to support this approach. This protocol describes the use of a commercially available esophageal temperature management device to cool or warm the esophagus to reduce esophageal injury during left atrial ablation. The temperature management device is powered by standard water-blanket heat exchangers, and is shaped like a standard orogastric tube placed for gastric suctioning and decompression. Water circulates through the device in a closed-loop circuit, transferring heat across the silicone walls of the device, through the esophageal wall. Placement of the device is analogous to the placement of a typical orogastric tube, and temperature is adjusted via the external heat-exchanger console.
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http://dx.doi.org/10.3791/60733DOI Listing
March 2020

Characterization of Structural Changes in Arrhythmogenic Right Ventricular Cardiomyopathy With Recurrent Ventricular Tachycardia After Ablation: Insights From Repeat Electroanatomic Voltage Mapping.

Circ Arrhythm Electrophysiol 2020 01 10;13(1):e007611. Epub 2020 Jan 10.

Electrophysiology Section, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia.

Background: Data characterizing structural changes of arrhythmogenic right ventricular (RV) cardiomyopathy are limited.

Methods: Patients presenting with left bundle branch block ventricular tachycardia in the setting of arrhythmogenic RV cardiomyopathy with procedures separated by at least 9 months were included.

Results: Nineteen consecutive patients (84% males; mean age 39±15 years [range, 20-76 years]) were included. All 19 patients underwent 2 detailed sinus rhythm electroanatomic endocardial voltage maps (average 385±177 points per map; range, 93-847 points). Time interval between the initial and repeat ablation procedures was mean 50±37 months (range, 9-162). No significant progression of voltage was observed (bipolar: 38 cm [interquartile range (IQR), 25-54] versus 53 cm [IQR, 25-65], =0.09; unipolar: 116 cm [IQR, 61-209] versus 159 cm [IQR, 73-204], =0.36) for the entire study group. There was a significant increase in RV volumes (percentage increase, 28%; 206 mL [IQR, 170-253] versus 263 mL [IQR, 204-294], <0.001) for the entire study population. Larger scars at baseline but not changes over time were associated with a significant increase in RV volume (bipolar: Spearman ρ, 0.6965, =0.006; unipolar: Spearman ρ, 0.5743, =0.03). Most patients with progressive RV dilatation (8/14, 57%) had moderate (2 patients) or severe (6 patients) tricuspid regurgitation recorded at either initial or repeat ablation procedure.

Conclusions: In patients with arrhythmogenic RV cardiomyopathy presenting with recurrent ventricular tachycardia, >10% increase in RV endocardial surface area of bipolar voltage consistent with scar is uncommon during the intermediate term. Most recurrent ventricular tachycardias are localized to regions of prior defined scar. Voltage indexed scar area at baseline but not changes in scar over time is associated with progressive increase in RV size and is consistent with adverse remodeling but not scar progression. Marked tricuspid regurgitation is frequently present in patients with arrhythmogenic RV cardiomyopathy who have progressive RV dilation.
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http://dx.doi.org/10.1161/CIRCEP.119.007611DOI Listing
January 2020

Esophageal cooling for protection during left atrial ablation: a systematic review and meta-analysis.

J Interv Card Electrophysiol 2020 Nov 22;59(2):347-355. Epub 2019 Nov 22.

Department of Emergency Medicine, UT Southwestern Medical Center, 5323 Harry Hines Blvd, 75390, Dallas, TX, United States.

Purpose: Thermal damage to the esophagus is a risk from radiofrequency (RF) ablation of the left atrium for the treatment of atrial fibrillation (AF). The most extreme type of thermal injury results in atrio-esophageal fistula (AEF) and a correspondingly high mortality rate. Various strategies for reducing esophageal injury have been developed, including power reduction, esophageal deviation, and esophageal cooling. One method of esophageal cooling involves the direct instillation of cold water or saline into the esophagus during RF ablation. Although this method provides limited heat-extraction capacity, studies of it have suggested potential benefit. We sought to perform a meta-analysis of published studies evaluating the use of esophageal cooling via direct liquid instillation for the reduction of thermal injury during RF ablation.

Methods: We searched PubMed for studies that used esophageal cooling to protect the esophagus from thermal injury during RF ablation. We then performed a meta-analysis using a random effects model to calculate estimated effect size with 95% confidence intervals, with an outcome of esophageal lesions stratified by severity, as determined by post-procedure endoscopy.

Results: A total of 9 studies were identified and reviewed. After excluding preclinical and mathematical model studies, 3 were included in the meta-analysis, totaling 494 patients. Esophageal cooling showed a tendency to shift lesion severity downward, such that total lesions did not show a statistically significant change (OR 0.6, 95% CI 0.15 to 2.38). For high-grade lesions, a significant OR of 0.39 (95% CI 0.17 to 0.89) in favor of esophageal cooling was found, suggesting that esophageal cooling, even with a low-capacity thermal extraction technique, reduces the severity of lesions resulting from RF ablation.

Conclusions: Esophageal cooling reduces the severity of the lesions that may result from RF ablation, even when relatively low heat extraction methods are used, such as the direct instillation of small volumes of cold liquid. Further investigation of this approach is warranted, particularly with higher heat extraction capacity techniques.
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http://dx.doi.org/10.1007/s10840-019-00661-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7591442PMC
November 2020

Clarifying the Definition of Non-Pulmonary Vein Triggers of Atrial Fibrillation.

JACC Clin Electrophysiol 2019 11;5(11):1328-1330

Cardiac Electrophysiology Section, Cardiovascular Division, Hospital of the University of Pennsylvania and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania.

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http://dx.doi.org/10.1016/j.jacep.2019.08.004DOI Listing
November 2019

Looking Near and Far: Utility of Multielectrode Mapping in Redefining Voltage Standards.

JACC Clin Electrophysiol 2019 10;5(10):1141-1143

Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.

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http://dx.doi.org/10.1016/j.jacep.2019.07.005DOI Listing
October 2019

Improved co-registration of ex-vivo and in-vivo cardiovascular magnetic resonance images using heart-specific flexible 3D printed acrylic scaffold combined with non-rigid registration.

J Cardiovasc Magn Reson 2019 10 10;21(1):62. Epub 2019 Oct 10.

School of Biomedical Engineering and Imaging Sciences, King's College, London, Fourth Floor Lambeth Wing, St Thomas' Hospital, London, SE1 7EH, UK.

Background: Ex-vivo cardiovascular magnetic resonance (CMR) imaging has played an important role in the validation of in-vivo CMR characterization of pathological processes. However, comparison between in-vivo and ex-vivo imaging remains challenging due to shape changes occurring between the two states, which may be non-uniform across the diseased heart. A novel two-step process to facilitate registration between ex-vivo and in-vivo CMR was developed and evaluated in a porcine model of chronic myocardial infarction (MI).

Methods: Seven weeks after ischemia-reperfusion MI, 12 swine underwent in-vivo CMR imaging with late gadolinium enhancement followed by ex-vivo CMR 1 week later. Five animals comprised the control group, in which ex-vivo imaging was undertaken without any support in the LV cavity, 7 animals comprised the experimental group, in which a two-step registration optimization process was undertaken. The first step involved a heart specific flexible 3D printed scaffold generated from in-vivo CMR, which was used to maintain left ventricular (LV) shape during ex-vivo imaging. In the second step, a non-rigid co-registration algorithm was applied to align in-vivo and ex-vivo data. Tissue dimension changes between in-vivo and ex-vivo imaging were compared between the experimental and control group. In the experimental group, tissue compartment volumes and thickness were compared between in-vivo and ex-vivo data before and after non-rigid registration. The effectiveness of the alignment was assessed quantitatively using the DICE similarity coefficient.

Results: LV cavity volume changed more in the control group (ratio of cavity volume between ex-vivo and in-vivo imaging in control and experimental group 0.14 vs 0.56, p < 0.0001) and there was a significantly greater change in the short axis dimensions in the control group (ratio of short axis dimensions in control and experimental group 0.38 vs 0.79, p < 0.001). In the experimental group, prior to non-rigid co-registration the LV cavity contracted isotropically in the ex-vivo condition by less than 20% in each dimension. There was a significant proportional change in tissue thickness in the healthy myocardium (change = 29 ± 21%), but not in dense scar (change = - 2 ± 2%, p = 0.034). Following the non-rigid co-registration step of the process, the DICE similarity coefficients for the myocardium, LV cavity and scar were 0.93 (±0.02), 0.89 (±0.01) and 0.77 (±0.07) respectively and the myocardial tissue and LV cavity volumes had a ratio of 1.03 and 1.00 respectively.

Conclusions: The pattern of the morphological changes seen between the in-vivo and the ex-vivo LV differs between scar and healthy myocardium. A 3D printed flexible scaffold based on the in-vivo shape of the LV cavity is an effective strategy to minimize morphological changes in the ex-vivo LV. The subsequent non-rigid registration step further improved the co-registration and local comparison between in-vivo and ex-vivo data.
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http://dx.doi.org/10.1186/s12968-019-0574-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6785908PMC
October 2019

Analysis of local ventricular repolarization using unipolar recordings in patients with arrhythmogenic right ventricular cardiomyopathy.

J Interv Card Electrophysiol 2020 Mar 23;57(2):261-270. Epub 2019 Aug 23.

Cardiac Electrophysiology Program, Cardiovascular Division Hospital of the University of Pennsylvania, 9 Founders Pavilion - Cardiology, 3400 Spruce St., Philadelphia, PA, 19104, USA.

Purpose: In arrhythmogenic right ventricular cardiomyopathy (ARVC), abnormal electroanatomic mapping (EAM) areas are proportional to extent of T-wave inversion on 12-lead ECG. We aimed to evaluate local repolarization changes and their relationship to EAM substrate in ARVC.

Methods: Using unipolar recordings, we analyzed the proportion of negative T waves ≥ 1 mV in depth (NegT), NegT area, Q-Tpeak (QTP), Tpeak-Tend (TPE) intervals and their relationship to bipolar (< 1.5 mV ENDO, < 1.0 mV EPI) and unipolar (< 5.5 mV) endocardial (ENDO) and epicardial (EPI) low-voltage area (LVA) in 21 pts. (15 men, mean age 39 ± 14) with ARVC. Control group included 5 pts. with normal hearts and idiopathic PVCs.

Results: On ENDO, the % of NegT (7 ± 5% vs 30 ± 20%, p = 0.004) and the NegT area (12.9 ± 9.7 c m vs 61.4 ± 30.0 cm, p = 0.001) were smaller in ARVC compared to controls. On EPI, the % of NegT was similar (5 ± 7% vs 3 ± 4%, p = 0.323) and the NegT area, larger (11.0 ± 8.4 cm vs 2.7 ± 0.9 cm, p = 0.027) in ARVC group. In ARVC group, the % of NegT area inside LVA was larger on EPI compared to ENDO for both bipolar (81 ± 27% vs 31 ± 33%, p < 0.001) and unipolar (90 ± 19% vs 73 ± 28%, p = 0.036) recordings. Compared to normal voltage regions, QTP inside ENDO abnormal LVA was on average 58 ± 26 ms shorter and TPE, 25 ± 56 ms longer (97 ± 26 ms and 56 ± 86 ms on EPI, respectively).

Conclusions: In ARVC, NegT areas are more closely associated with abnormal depolarization LVA on the EPI and QTP is shorter and TPE longer inside ENDO and EPI abnormal LVA compared to normal voltage regions. The results add to our understanding of ARVC arrhythmia substrate.
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http://dx.doi.org/10.1007/s10840-019-00594-zDOI Listing
March 2020

Cardiovascular Magnetic Resonance-Based Three-Dimensional Structural Modeling and Heterogeneous Tissue Channel Detection in Ventricular Arrhythmia.

Sci Rep 2019 06 27;9(1):9317. Epub 2019 Jun 27.

Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.

Geometrical structure of the myocardium plays an important role in understanding the generation of arrhythmias. In particular, a heterogeneous tissue (HT) channel defined in cardiovascular magnetic resonance (CMR) has been suggested to correlate with conduction channels defined in electroanatomic mapping in ventricular tachycardia (VT). Despite the potential of CMR for characterization of the arrhythmogenic substrate, there is currently no standard approach to identify potential conduction channels. Therefore, we sought to develop a workflow to identify HT channel based on the structural 3D modeling of the viable myocardium within areas of dense scar. We focus on macro-level HT channel detection in this work. The proposed technique was tested in high-resolution ex-vivo CMR images in 20 post-infarct swine models who underwent an electrophysiology study for VT inducibility. HT channel was detected in 15 animals with inducible VT, whereas it was only detected in 1 out of 5 animal with non-inducible VT (P < 0.01, Fisher's exact test). The HT channel detected in the non-inducible animal was shorter than those detected in animals with inducible VTs (inducible-VT animals: 35 ± 14 mm vs. non-inducible VT animal: 9.94 mm). Electrophysiology study and histopathological analyses validated the detected HT channels. The proposed technique may provide new insights for understanding the macro-level VT mechanism.
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http://dx.doi.org/10.1038/s41598-019-45586-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6597699PMC
June 2019

P-wave morphology and multipolar intracardiac atrial activation to facilitate nonpulmonary vein trigger localization.

J Cardiovasc Electrophysiol 2019 06 12;30(6):865-876. Epub 2019 Mar 12.

Cardiac Electrophysiology Program, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.

Introduction: Nonpulmonary vein (non-PV) triggers of atrial fibrillation (AF) are targets for ablation but their localization remains challenging. The aim of this study was to describe P-wave (PW) morphologic characteristics and intra-atrial activation patterns and timing from multipolar coronary sinus (CS) and crista terminalis (CT) catheters that localize non-PV triggers.

Methods And Results: Selective pacing from six right and nine left atrial common non-PV trigger sites was performed in 30 consecutive patients. We analyzed 12 lead ECG features based on PW duration, amplitude and morphology, and patterns and timing of multipolar activation for all 15 sites. Regionalization and then precise localization required criteria present in at least 70% of assessments at each pacing site. The algorithm was then prospectively evaluated by four blinded observers in a validation cohort of 18 consecutive patients undergoing the same pacing protocol and 60 consecutive patients who underwent successful non-PV trigger ablation. The algorithm for site regionalization included 1) negative PW in V1, ≥30 µV change in PW amplitude across the leads V1-V3, and PW duration ≤100 milliseconds in lead 2 and 2) unique intra-atrial activation patterns and timing noted in the multipolar catheters. Specific ECG and intra-atrial activation timing characteristics included in the algorithm allowed for more precise site localization after regionalization. In the prospective evaluation, the algorithm identified the site of origin for 72% of paced and 70% of spontaneous non-PV trigger sites.

Conclusion: An algorithm based on PW morphology and intra-atrial multipolar activation pattern and timing can help identify non-PV trigger sites of origin.
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http://dx.doi.org/10.1111/jce.13899DOI Listing
June 2019

Three-dimensional myocardial scar characterization from the endocardium: Usefulness of endocardial unipolar electroanatomic mapping.

J Cardiovasc Electrophysiol 2019 03 12;30(3):427-437. Epub 2019 Jan 12.

Electrophysiology Section, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.

Epicardial ablation may be required to eliminate ventricular tachycardia (VT) in patients with underlying structural heart disease. The decision to gain epicardial access is frequently based on the suspicion of an epicardial origin for the VT and/or presence of an arrhythmogenic substrate. Epicardial pathology and VT is frequently present in patients with nonischemic right and/or left cardiomyopathies even in the setting of modest or no endocardial bipolar voltage substrate. In this setting, unipolar voltage mapping from the endocardium serves to help identify midmyocardial and/or epicardial VT substrate. The additional value of endocardial unipolar mapping includes its usefulness to predict the clinical outcome after VT ablation, to determine the irreversibility of myocardial disease, and to guide endomyocardial biopsy procedures to specific areas of intramural scarring. In this review, we aim to provide a guide to the use of endocardial unipolar mapping and its appropriate interpretation in a variety of clinical situations.
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http://dx.doi.org/10.1111/jce.13842DOI Listing
March 2019

Premature Ventricular Complex-Induced Cardiomyopathy: Providing Insights on the Pathogenesis.

J Am Coll Cardiol 2018 12;72(23 Pt A):2883-2885

Cardiac Electrophysiology, Cardiovascular Medicine Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.

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http://dx.doi.org/10.1016/j.jacc.2018.09.060DOI Listing
December 2018

Three-dimensional holographic visualization of high-resolution myocardial scar on HoloLens.

PLoS One 2018 8;13(10):e0205188. Epub 2018 Oct 8.

Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, United States of America.

Visualization of the complex 3D architecture of myocardial scar could improve guidance of radio-frequency ablation in the treatment of ventricular tachycardia (VT). In this study, we sought to develop a framework for 3D holographic visualization of myocardial scar, imaged using late gadolinium enhancement (LGE), on the augmented reality HoloLens. 3D holographic LGE model was built using the high-resolution 3D LGE image. Smooth endo/epicardial surface meshes were generated using Poisson surface reconstruction. For voxel-wise 3D scar model, every scarred voxel was rendered into a cube which carries the actual resolution of the LGE sequence. For surface scar model, scar information was projected on the endocardial surface mesh. Rendered layers were blended with different transparency and color, and visualized on HoloLens. A pilot animal study was performed where 3D holographic visualization of the scar was performed in 5 swines who underwent controlled infarction and electroanatomic mapping to identify VT substrate. 3D holographic visualization enabled assessment of the complex 3D scar architecture with touchless interaction in a sterile environment. Endoscopic view allowed visualization of scar from the ventricular chambers. Upon completion of the animal study, operator and mapping specialist independently completed the perceived usefulness questionnaire in the six-item usefulness scale. Operator and mapping specialist found it useful (usefulness rating: operator, 5.8; mapping specialist, 5.5; 1-7 scale) to have scar information during the intervention. HoloLens 3D LGE provides a true 3D perception of the complex scar architecture with immersive experience to visualize scar in an interactive and interpretable 3D approach, which may facilitate MR-guided VT ablation.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0205188PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6175509PMC
April 2019

Infarct-Related Ventricular Tachycardia: Redefining the Electrophysiological Substrate of the Isthmus During Sinus Rhythm.

JACC Clin Electrophysiol 2018 08 27;4(8):1033-1048. Epub 2018 Jun 27.

Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.

Objectives: In this study, the scientific objective was to characterize the electrophysiological substrate of the ventricular tachycardia (VT) isthmus during sinus rhythm.

Background: The authors have recently described the electrophysiological characteristics of the VT isthmus using a novel in vivo high-resolution mapping technology.

Methods: Sixteen swine with healed infarction were studied using high-resolution mapping technology (Rhythmia, Boston Scientific, Cambridge, Massachusetts) in a closed-chest model. The left ventricle was mapped during sinus rhythm and analyzed for activation, conduction velocity, electrogram shape, and amplitude. Twenty-four VTs allowed detailed mapping of the common-channel "isthmus," including the "critical zone." This was defined as the zone of maximal conduction velocity slowing in the circuit, often occurring at entrance and exit from the isthmus caused by rapid angular change in activation vectors.

Results: The VT isthmus corresponded to sites displaying steep activation gradient (SAG) during sinus rhythm with conduction velocity slowing of 58.5 ± 22.4% (positive predictive value [PPV] 60%). The VT critical zone displayed SAG with greater conduction velocity slowing of 68.6 ± 18.2% (PPV 70%). Critical-zone sites were consistently localized in areas with bipolar voltage ≤0.55 mV, whereas isthmus sites were localized in areas with variable voltage amplitude (1.05 ± 0.80 mV [0.03 to 2.88 mV]). Importantly, critical zones served as common-site "anchors" for multiple VT configurations and cycle lengths. Isthmus and critical-zone sites occupied only 18.0 ± 7.0% of the low-voltage area (≤1.50 mV). Isolated late potentials were present in both isthmus and nonisthmus sites, including dead-end pathways (PPV 36%; 95% confidence interval: 34.2% to 39.6%).

Conclusions: The VT critical zone corresponds to a location characterized by SAG and very low voltage amplitude during sinus rhythm. Thus, it allows identification of a re-entry anchor with high sensitivity and specificity. By contrast, voltage and electrogram characteristics during sinus rhythm have limited specificity for identifying the VT isthmus.
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http://dx.doi.org/10.1016/j.jacep.2018.04.007DOI Listing
August 2018

Highly conductive, stretchable and biocompatible Ag-Au core-sheath nanowire composite for wearable and implantable bioelectronics.

Nat Nanotechnol 2018 11 13;13(11):1048-1056. Epub 2018 Aug 13.

Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, Republic of Korea.

Wearable and implantable devices require conductive, stretchable and biocompatible materials. However, obtaining composites that simultaneously fulfil these requirements is challenging due to a trade-off between conductivity and stretchability. Here, we report on Ag-Au nanocomposites composed of ultralong gold-coated silver nanowires in an elastomeric block-copolymer matrix. Owing to the high aspect ratio and percolation network of the Ag-Au nanowires, the nanocomposites exhibit an optimized conductivity of 41,850 S cm (maximum of 72,600 S cm). Phase separation in the Ag-Au nanocomposite during the solvent-drying process generates a microstructure that yields an optimized stretchability of 266% (maximum of 840%). The thick gold sheath deposited on the silver nanowire surface prevents oxidation and silver ion leaching, making the composite biocompatible and highly conductive. Using the nanocomposite, we successfully fabricate wearable and implantable soft bioelectronic devices that can be conformally integrated with human skin and swine heart for continuous electrophysiological recording, and electrical and thermal stimulation.
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http://dx.doi.org/10.1038/s41565-018-0226-8DOI Listing
November 2018

High-Power and Short-Duration Ablation for Pulmonary Vein Isolation: Biophysical Characterization.

JACC Clin Electrophysiol 2018 04 2;4(4):467-479. Epub 2018 Feb 2.

Harvard-Thorndike Electrophysiology Institute, Cardiovascular Division, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts. Electronic address:

Objectives: This study sought to examine the biophysical properties of high-power and short-duration (HP-SD) radiofrequency ablation for pulmonary vein isolation.

Background: Pulmonary vein isolation is the cornerstone of atrial fibrillation ablation. However, pulmonary vein reconnection is frequent and is often the result of catheter instability, tissue edema, and a reversible nontransmural injury. We postulated that HP-SD ablation increases lesion-to-lesion uniformity and transmurality.

Methods: This study included 20 swine and a novel open-irrigated ablation catheter with a thermocouple system able to record temperature at the catheter-tissue interface (QDOT Micro Catheter). Step 1 compared 3 HP-SD ablation settings: 90 W/4 s, 90 W/6 s, and 70 W/8 s in a thigh muscle preparation. Ablation at 90 W/4 s was identified as the best compromise between lesion size and safety parameters, with no steam-pop or char. In step 2, a total of 174 single ablation applications were performed in the beating heart and resulted in 3 (1.7%) steam-pops, all occurring at catheter-tissue interface temperature ≥85°C. Additional 233 applications at 90 W/4 s and temperature limit of 65°C were applied without steam-pop. Step 3 compared the presence of gaps and lesion transmurality in atrial lines and pulmonary vein isolation between HP-SD (90 W/4 s, T ≤65°C) and standard (25 W/20 s) ablation.

Results: HP-SD ablation resulted in 100% contiguous lines with all transmural lesions, whereas standard ablation had linear gaps in 25% and partial thickness lesions in 29%. Ablation with HP-SD produced wider lesions (6.02 ± 0.2 mm vs. 4.43 ± 1.0 mm; p = 0.003) at similar depth (3.58 ± 0.3 mm vs. 3.53 ± 0.6 mm; p = 0.81) and improved lesion-to-lesion uniformity with comparable safety end points.

Conclusions: In a preclinical model, HP-SD ablation (90 W/4 s, T ≤65°C) produced an improved lesion-to-lesion uniformity, linear contiguity, and transmurality at a similar safety profile of conventional ablation.
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http://dx.doi.org/10.1016/j.jacep.2017.11.018DOI Listing
April 2018

12-Lead Electrocardiogram to Localize Region of Abnormal Electroanatomic Substrate in Arrhythmogenic Right Ventricular Cardiomyopathy.

JACC Clin Electrophysiol 2017 07 26;3(7):654-665. Epub 2017 Apr 26.

Cardiac Electrophysiology Program, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Objectives: The purpose of this study was to evaluate the relationship between electrocardiogram (ECG) QRS fragmentation (fQRS) and right ventricular (RV) endocardial (ENDO) and epicardial (EPI) electroanatomic substrate abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).

Background: fQRS is frequently observed in patients with ARVC and reflects delayed conduction due to RV fibrosis.

Methods: A total of 30 consecutive patients met the task force criteria for ARVC (19 men, mean age 41.1 ± 14.3 years) presenting for ventricular tachycardia ablation with detailed RV ENDO and EPI electroanatomic maps were included. Of these, 25 patients had depolarization abnormalities (fragmentation during and/or immediately after the QRS complex [fQRS]) in ≥2 contiguous ECG leads. Inferior (II, III, aVF) fQRS was identified in 23 patients, anterior (V to V) in 15 patients, and basal superior (I/aVR) in 11 patients. The surface area and anatomic distribution of ENDO and EPI bipolar low-voltage regions (ENDO ≤1.5 mV, <0.5 mV "dense scar"/EPI ≤1.0 mV) and degree of isolated late potential activity consistent with a marked substrate abnormality were compared to the location of region-specific fQRS.

Results: In fQRS patients, ENDO very low bipolar voltage area (27.4 ± 24.9 cm [median 19 cm] vs. 5.8 ± 5.4 cm [median 5 cm]; p = 0.02) and EPI late potential percentage (22.6 ± 9.6% [median 24%] vs. 6.8 ± 3.9% [median 8%]; p = 0.002) were significantly larger than in patients without fQRS. Overall, ENDO and EPI bipolar low voltage area and late potential density increased as the number of fQRS ECG regions (0 to 3) increased. Inferior fQRS most frequently identified EPI inferior substrate (82% sensitivity, 100% specificity), anterior fQRS identified RV EPI mid-free wall substrate (55% sensitivity, 100% specificity), and basal superior fQRS identified ENDO (45.8% sensitivity, 100% specificity) and EPI (52% sensitivity, 100% specificity) RV outflow tract substrate abnormalities.

Conclusions: The extent and distribution of RV voltage substrate abnormalities can be predicted by region-specific ECG depolarization changes in patients with ARVC and ventricular tachycardia.
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http://dx.doi.org/10.1016/j.jacep.2017.01.009DOI Listing
July 2017

Electrocardiographic Repolarization Abnormalities and Electroanatomic Substrate in Arrhythmogenic Right Ventricular Cardiomyopathy.

Circ Arrhythm Electrophysiol 2018 03;11(3):e005553

From the Cardiac Electrophysiology Program, Cardiovascular Division, Hospital of the University of Pennsylvania, Philadelphia.

Background: Repolarization abnormalities in arrhythmogenic right ventricular (RV) cardiomyopathy and their relationship to ventricular tachycardia substrate are incompletely understood.

Methods And Results: In 40 patients (29 men, mean age 38 years) with arrhythmogenic RV cardiomyopathy, we compared the extent and location of abnormal T (NegT) waves ≥1 mm in depth (n=32) and downsloping elevated ST segment (n=13), in ≥2 adjacent leads, to area and location of endocardial bipolar (<1.5 mV) and unipolar (<5.5 mV) and epicardial bipolar (<1.0 mV) voltage abnormalities. Abnormal unipolar RV endocardial area of 33.4±19.3% was present in 8 patients without NegT waves. Patients with NegT waves extending beyond lead V (n=20) had larger low bipolar (31.4±18.9% versus 16.5±14.6%; =0.008) and unipolar endocardial areas (66.0±19.6% versus 47.4±25.1%; =0.013) and larger epicardial low bipolar area (56.0±19.3% versus 40.1±24.9%; =0.030) compared with those with NegT waves limited to leads V through V (n=20). ECG location of NegT waves regionalized to location of substrate. Patients with downsloping elevated ST segment, all localized to leads V and V, had more unipolar endocardial abnormalities (71.8±18.1% versus 49.4±23.5%; =0.005) involving outflow and mid-RV, compared with patients without downsloping elevated ST segment.

Conclusions: In arrhythmogenic RV cardiomyopathy, abnormal electroanatomic mapping areas are proportional to extent of T-wave inversion on 12-lead ECG. Marked voltage abnormalities can exist without repolarization change. Downsloping elevated ST-segment pattern in V and V occurs with more unipolar endocardial voltage abnormality, consistent with more advanced transmural disease.
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http://dx.doi.org/10.1161/CIRCEP.117.005553DOI Listing
March 2018
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