Publications by authors named "Saman Nazarian"

287 Publications

Mapping Endocardial-Epicardial Dissociation: Significance for Atrial Fibrillation Ablation.

JACC Clin Electrophysiol 2020 07;6(7):846-848

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

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http://dx.doi.org/10.1016/j.jacep.2020.04.026DOI Listing
July 2020

Direct hepatic vein puncture and transseptal access for atrial flutter and fibrillation ablation in a patient with prior ligation of the inferior vena cava.

HeartRhythm Case Rep 2020 Jul 29;6(7):382-385. Epub 2020 Mar 29.

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

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http://dx.doi.org/10.1016/j.hrcr.2020.03.011DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7360982PMC
July 2020

Multimodality Imaging to Guide Ventricular Tachycardia Ablation in Patients with Non-ischaemic Cardiomyopathy.

Arrhythm Electrophysiol Rev 2020 Feb;8(4):255-264

Electrophysiology Section, Cardiovascular Division, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, US.

Catheter ablation is an effective treatment option for ventricular tachycardia (VT) in patients with non-ischaemic cardiomyopathy (NICM). The heterogeneous nature of NICM aetiologies and VT substrate in patients with NICM play a role in long-term ablation outcomes in this population. Over the past decades, more precise identification of NICM aetiologies and better characterisation of various substrates have been made. Application of multimodal imaging has greatly contributed to the accurate diagnosis of NICM subtypes and improved VT ablation strategies. This article summarises the current knowledge of multimodal imaging used in the characterisation of non-ischaemic NICM substrates, procedural planning and image integration for the optimisation of VT ablation.
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http://dx.doi.org/10.15420/aer.2019.37.3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7358957PMC
February 2020

COVID-19 and cardiac arrhythmias.

Heart Rhythm 2020 Sep 22;17(9):1439-1444. Epub 2020 Jun 22.

Division of Cardiovascular Medicine, Department of Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Background: Early studies suggest that coronavirus disease 2019 (COVID-19) is associated with a high incidence of cardiac arrhythmias. Severe acute respiratory syndrome coronavirus 2 infection may cause injury to cardiac myocytes and increase arrhythmia risk.

Objectives: The purpose of this study was to evaluate the risk of cardiac arrest and arrhythmias including incident atrial fibrillation (AF), bradyarrhythmias, and nonsustained ventricular tachycardia (NSVT) in a large urban population hospitalized for COVID-19. We also evaluated correlations between the presence of these arrhythmias and mortality.

Methods: We reviewed the characteristics of all patients with COVID-19 admitted to our center over a 9-week period. Throughout hospitalization, we evaluated the incidence of cardiac arrests, arrhythmias, and inpatient mortality. We also used logistic regression to evaluate age, sex, race, body mass index, prevalent cardiovascular disease, diabetes, hypertension, chronic kidney disease, and intensive care unit (ICU) status as potential risk factors for each arrhythmia.

Results: Among 700 patients (mean age 50 ± 18 years; 45% men; 71% African American; 11% received ICU care), there were 9 cardiac arrests, 25 incident AF events, 9 clinically significant bradyarrhythmias, and 10 NSVTs. All cardiac arrests occurred in patients admitted to the ICU. In addition, admission to the ICU was associated with incident AF (odds ratio [OR] 4.68; 95% confidence interval [CI] 1.66-13.18) and NSVT (OR 8.92; 95% CI 1.73-46.06) after multivariable adjustment. Also, age and incident AF (OR 1.05; 95% CI 1.02-1.09) and prevalent heart failure and bradyarrhythmias (OR 9.75; 95% CI 1.95-48.65) were independently associated. Only cardiac arrests were associated with acute in-hospital mortality.

Conclusion: Cardiac arrests and arrhythmias are likely the consequence of systemic illness and not solely the direct effects of COVID-19 infection.
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http://dx.doi.org/10.1016/j.hrthm.2020.06.016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7307518PMC
September 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

Association of scar distribution with epicardial electrograms and surface ventricular tachycardia QRS duration in nonischemic cardiomyopathy.

J Cardiovasc Electrophysiol 2020 08 24;31(8):2032-2040. Epub 2020 Jun 24.

Section of Cardiac Electrophysiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.

Introduction: The association of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) with epicardial and surface ventricular tachycardia (VT) electrogram features, in nonischemic cardiomyopathy (NICM), is unknown. We sought to define the association of LGE and viable wall thickness with epicardial electrogram features and exit site paced QRS duration in patients with NICM.

Methods: A total of 19 patients (age 53.5 ± 11.5 years) with NICM (ejection fraction 40.2 ± 13.2%) underwent CMR before VT ablation. LGE transmurality was quantified on CMR and coregistered with 2294 endocardial and 2724 epicardial map points.

Results: Both bipolar and unipolar voltage were associated with transmural signal intensity on CMR. Longer electrogram duration and fractionated potentials were associated with increased LGE transmurality, but late potentials or local abnormal ventricular activity were more prevalent in nontransmural versus transmural LGE regions (p < .05). Of all critical VT sites, 19% were located adjacent to regions with LGE but normal bipolar and unipolar voltage. Exit site QRS duration was affected by LGE transmurality and intramural scar location, but not by wall thickness, at the impulse origin.

Conclusions: In patients with NICM and VT, LGE is associated with epicardial electrogram features and may predict critical VT sites. Additionally, exit site QRS duration is affected by LGE transmurality and intramural location at the impulse origin or exit.
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http://dx.doi.org/10.1111/jce.14618DOI Listing
August 2020

Association between interatrial block, left atrial fibrosis, and mechanical dyssynchrony: Electrocardiography-magnetic resonance imaging correlation.

J Cardiovasc Electrophysiol 2020 07 15;31(7):1719-1725. Epub 2020 Jun 15.

Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland.

Introduction: Advanced interatrial block (IAB) on a 12-lead electrocardiogram (ECG) is a predictor of stroke, incident atrial fibrillation (AF), and AF recurrence after catheter ablation. The objective of this study was to determine which features of IAB structural remodeling is associated with left atrium (LA) magnetic resonance imaging structure and function.

Methods/results: We included 152 consecutive patients (23% nonparoxysmal AF) who underwent preprocedural ECG and cardiac magnetic resonance (CMR) in sinus rhythm before catheter ablation of AF. IAB was defined as P-wave duration ≥120 ms, and was considered partial if P-wave was positive and advanced if P-wave had a biphasic morphology in inferior leads. From cine CMR and late gadolinium enhancement, we derived LA maximum and minimum volume indices, strain, LA fibrosis, and LA dyssynchrony. A total of 77 patients (50.7% paroxysmal) had normal P-wave, 52 (34.2%) partial IAB, and 23 (15.1%) advanced IAB. Patients with advanced IAB had significantly higher LA minimum volume index (25.7 vs 19.9 mL/m , P = .010), more LA fibrosis (21.9% vs 13.1%, P = .020), and lower LA maximum strain rate (0.99 vs 1.18, P = .007) than those without. Advanced IAB was independently associated with LA (minimum [P = .032] and fibrosis [P = .009]). P-wave duration was also independently associated with LA fibrosis (β = .33; P = .049) and LA mechanical dyssynchrony (β = 2.01; P = .007).

Conclusion: Advanced IAB is associated with larger LA volumes, lower emptying fraction, and more fibrosis. Longer P-wave duration is also associated with more LA fibrosis and higher LA mechanical dyssynchrony.
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http://dx.doi.org/10.1111/jce.14608DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7703864PMC
July 2020

QRS morphology in lead V for the rapid localization of idiopathic ventricular arrhythmias originating from the left ventricular papillary muscles: A novel electrocardiographic criterion.

Heart Rhythm 2020 10 23;17(10):1711-1718. Epub 2020 May 23.

Electrophysiology Section, Division of Cardiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Background: Twelve-lead electrocardiogram (ECG) criteria have been developed to identify idiopathic ventricular arrhythmias (VAs) from the left ventricular (LV) papillary muscles (PAPs), but accurate localization remains a challenge.

Objective: The purpose of this study was to develop ECG criteria for accurate localization of LV PAP VAs using lead V exclusively.

Methods: Consecutive patients undergoing mapping and ablation of VAs from the LV PAPs guided by intracardiac echocardiography from 2007 to 2018 were reviewed (study group). The QRS morphology in lead V was compared to patients with VAs with a "right bundle branch block" morphology from other LV locations (reference group). Patients with structural heart disease were excluded.

Results: One hundred eleven patients with LV PAP VAs (mean age 54 ± 16 years; 65% men) were identified, including 64 (55%) from the posteromedial PAP and 47 (42%) from the anterolateral PAP. The reference group included patients with VAs from the following LV locations: fascicles (n = 21), outflow tract (n = 36), ostium (n = 37), inferobasal segment (n = 12), and apex (5). PAP VAs showed 3 distinct QRS morphologies in lead V 93% of the time: Rr (53%), R with a slurred downslope (29%), and RR (11%). Sensitivity, specificity, positive predictive value, and negative predictive value for the 3 morphologies combined are 93%, 98%, 98%, and 93%, respectively. The intrinsicoid deflection of PAP VAs in lead V was shorter than that of the reference group (63 ± 13 ms vs 79 ± 24 ms; P < .001). An intrinsicoid deflection time of <74 ms best differentiated the 2 groups (sensitivity 79%; specificity 87%).

Conclusion: VAs originating from the LV PAPs manifest unique QRS morphologies in lead V, which can aid in rapid and accurate localization.
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http://dx.doi.org/10.1016/j.hrthm.2020.05.021DOI Listing
October 2020

Utility of Cardiac MRI in Atrial Fibrillation Management.

Card Electrophysiol Clin 2020 06;12(2):131-139

Division of Cardiology, Section for Cardiac Electrophysiology, Johns Hopkins University, Baltimore, MD, USA. Electronic address:

Advances in cardiac magnetic resonance (CMR) techniques and image acquisition have made it an excellent tool in the assessment of atrial myopathy. Remolding of the left atrium is the mainstay of atrial fibrillation (AF) development and its progression. CMR can detect phasic atrial volumes, atrial function, and atrial fibrosis using cine, and contrast-enhanced or non-contrast-enhanced images. These abilities make CMR a versatile and extraordinary tool in management of patients with AF including for risk stratification, ablation prognostication and planning, and assessment of stroke risk. We review the latest advancements in utility of CMR in management of patients with AF.
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http://dx.doi.org/10.1016/j.ccep.2020.02.006DOI Listing
June 2020

Association of right atrial structure with incident atrial fibrillation: a longitudinal cohort cardiovascular magnetic resonance study from the Multi-Ethnic Study of Atherosclerosis (MESA).

J Cardiovasc Magn Reson 2020 05 21;22(1):36. Epub 2020 May 21.

Cardiology Division, Department of Medicine, Johns Hopkins Hospital, Blalock 524D, 600 North Wolfe Street, Baltimore, MD, 21287, USA.

Background: While studies of the left atrium (LA) have demonstrated associations between volumes and emptying fraction with atrial fibrillation (AF), the contribution of right atrial (RA) abnormalities to incident AF remains poorly understood.

Objectives: Assess the association between RA structure and function with incident AF using feature-tracking cardiovascular magnetic resonance (CMR).

Methods: This is a prospective cohort study of all participants in the Multi-Ethnic Study of Atherosclerosis with baseline CMR, sinus rhythm, and free of clinical cardiovascular disease at study initiation. RA volume, strain, and emptying fraction in participants with incident AF (n = 368) were compared against AF-free (n = 2779). Cox proportional-hazards models assessed association between variables.

Results: Participants were aged 60 ± 10 yrs., 55% female, and followed an average 11.2 years. Individuals developing AF had higher baseline RA maximum volume index (mean ± standard deviation [SD]: 24 ± 9 vs 22 ± 8 mL/m, p = 0.002) and minimum volume index (13 ± 7 vs 12 ± 6 mL/m, p < 0.001), and lower baseline RA emptying fraction (45 ± 15% vs 47 ± 15%, p = 0.02), peak global strain (34 ± 17% vs 36 ± 19%, p < 0.001), and peak free-wall strain (40 ± 23% vs 42 ± 26%, p = 0.049) compared with the AF-free population. After adjusting for traditional cardiovascular risk factors and LA volume and function, we found RA maximum volume index (hazards ratio [HR]: 1.13 per SD, p = 0.041) and minimum volume index (HR: 1.12 per SD, p = 0.037) were independently associated with incident AF.

Conclusions: In a large multiethnic population, higher RA volume indices were independently associated with incident AF after adjustment for conventional cardiovascular risk factors and LA parameters. It is unclear if this predictive value persists when additional adjustment is made for ventricular parameters.
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http://dx.doi.org/10.1186/s12968-020-00631-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7240918PMC
May 2020

Durability of posterior wall isolation after catheter ablation among patients with recurrent atrial fibrillation.

Heart Rhythm 2020 10 7;17(10):1740-1744. Epub 2020 May 7.

Department of Medicine, Division of Cardiology, Section for Cardiac Electrophysiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania.

Background: Electrical posterior wall isolation (PWI) is increasingly being used for the treatment of patients with atrial fibrillation (AF). Few data exist on the durability of PWI using current technology.

Objective: The purpose of this study was to characterize the frequency and location of posterior wall reconnection at the time of repeat catheter ablation for AF.

Methods: We performed a single-center retrospective cohort study of 50 patients undergoing repeat AF ablation after previous PWI. Durability of PWI was assessed at the time of repeat ablation based on posterior wall entrance and exit block. Sites of posterior wall reconnection were characterized based on review of recorded electrical signals and electroanatomic maps.

Results: At the time of repeat ablation, mean age was 67 ± 10 years, 31 of 50 patients had persistent AF, and mean CHADS-VASc score was 3.0 ± 1.8. Of the 50 patients, 30 had durable PWI at repeat ablation, 1.4 ± 1.6 years after the index procedure. Patients with posterior wall reconnection required repeat ablation earlier (0.9 ± 0.6 years vs1.8 ± 1.9 years from index PWI; P = .048) and were more likely to have atypical atrial flutter (55% vs 27%; P = .043). Among patients with posterior wall reconnection, the roof was the most common site of reconnection (14/20), and 12 patients had multiple regions of reconnection noted.

Conclusion: Posterior wall reconnection is noted in 40% of patients undergoing repeat ablation after an index PWI. The roof of the left atrium is the most common site of posterior wall reconnection.
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http://dx.doi.org/10.1016/j.hrthm.2020.05.005DOI Listing
October 2020

Recognizing COVID-19-related myocarditis: The possible pathophysiology and proposed guideline for diagnosis and management.

Heart Rhythm 2020 09 5;17(9):1463-1471. Epub 2020 May 5.

Division of Cardiovascular Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania; Mayo Clinic, Rochester, Minnesota; Royal Papworth Hospital, Cambridge, United Kingdom. Electronic address:

Human coronavirus-associated myocarditis is known, and a number of coronavirus disease 19 (COVID-19)-related myocarditis cases have been reported. The pathophysiology of COVID-19-related myocarditis is thought to be a combination of direct viral injury and cardiac damage due to the host's immune response. COVID-19 myocarditis diagnosis should be guided by insights from previous coronavirus and other myocarditis experience. The clinical findings include changes in electrocardiogram and cardiac biomarkers, and impaired cardiac function. When cardiac magnetic resonance imaging is not feasible, cardiac computed tomographic angiography with delayed myocardial imaging may serve to exclude significant coronary artery disease and identify myocardial inflammatory patterns. Because many COVID-19 patients have cardiovascular comorbidities, myocardial infarction should be considered. If the diagnosis remains uncertain, an endomyocardial biopsy may help identify active cardiac infection through viral genome amplification and possibly refine the treatment risks of systemic immunosuppression. Arrhythmias are not uncommon in COVID-19 patients, but the pathophysiology is still speculative. Nevertheless, clinicians should be vigilant to provide prompt monitoring and treatment. The long-term impact of COVID-19 myocarditis, including the majority of mild cases, remains unknown.
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http://dx.doi.org/10.1016/j.hrthm.2020.05.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7199677PMC
September 2020

Moving Toward Improved Risk Stratification in Patients With Dilated Cardiomyopathy.

Circ Cardiovasc Imaging 2020 04 21;13(4):e010629. Epub 2020 Apr 21.

Division of Cardiology, Section for Cardiac Electrophysiology, Hospital of the University of Pennsylvania, Philadelphia.

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http://dx.doi.org/10.1161/CIRCIMAGING.120.010629DOI Listing
April 2020

Diagnosis of cardiac amyloidosis in patients undergoing catheter ablation for atrial arrhythmias.

J Interv Card Electrophysiol 2020 Apr 19;57(3):489-490. Epub 2020 Mar 19.

Hospital of the University of Pennsylvania, Philadelphia, PA, USA.

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http://dx.doi.org/10.1007/s10840-020-00719-9DOI Listing
April 2020

Trends in Antiarrhythmic Drug Use Among Patients in the United States Between 2004 and 2016.

Circulation 2020 03 16;141(11):937-939. Epub 2020 Mar 16.

Cardiovascular Division (T.M.M., A.E.E., S.N., R.D., F.E.M., D.S.F.), Perelman School of Medicine.

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http://dx.doi.org/10.1161/CIRCULATIONAHA.119.044109DOI Listing
March 2020

Atrial fibrillation burden and subsequent heart failure events in patients with cardiac resynchronization therapy devices.

J Cardiovasc Electrophysiol 2020 06 3;31(6):1519-1526. Epub 2020 Apr 3.

Medtronic, Mounds View, Minnesota.

Background: Atrial fibrillation (AF) and heart failure (HF) often coexist but little is known on how AF burden associates with subsequent episodes of HF.

Objective: The aim of this study was to quantitatively assess the short- and long-term association of AF burden with subsequent episodes of HF events in patients with reduced ejection fraction.

Methods: Patients with cardiac resynchronization therapy (CRT) devices with at least 90 days of device data were included in the study. Time-dependent Cox regression with a 7-day window was used to evaluate the association of short- and long-term AF burden with subsequent HF events. Each patient with HF was matched to two control patients without an HF event based on age, gender, year of implant and CRT defibrillation capability.

Results: In our cohort with 2:1 matching (N = 549), 183 patients developed HF events and 275 (50.1%) had AF over an average follow-up of 24 ± 11 months. A 1-hour increase in short-term AF burden was associated with a 3% increased risk of HF events (HR, 1.034; 95% confidence interval [CI], 1.012-1.056; P = .01; HR for 24-hour = 2.23). In contrast, the association between long-term AF burden and subsequent HF events was not statistically significant (HR, 1.009; 95% CI, 0.992-1.026; P = .373).

Conclusion: A 24-hour increase in AF burden is associated with a more than two-fold increased risk of HF events over the subsequent week while the long-term AF burden is not significantly associated with HF events.
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http://dx.doi.org/10.1111/jce.14444DOI Listing
June 2020

The Relationship between MRI Radiofrequency Energy and Function of Nonconditional Implanted Cardiac Devices: A Prospective Evaluation.

Radiology 2020 05 3;295(2):307-313. Epub 2020 Mar 3.

From the Department of Medicine, Division of Cardiology (A.A.R., R.H., M.A.G., V.C., D.M., H.R.H., S.N.), and Russell H. Morgan Department of Radiology and Radiological Science (S.L.Z.), Johns Hopkins University, School of Medicine, Baltimore, MD; Department of Radiology, Division of Cardiovascular Imaging, Northwestern University, Feinberg School of Medicine, Chicago, Ill (A.A.R.); Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston, Mass (J.E.K.); and Department of Medicine, Division of Cardiology, University of Pennsylvania, Perelman School of Medicine, 3400 Spruce Street, Founders 9, Philadelphia, PA 19104 (S.N.).

Background The risks associated with MRI in individuals who have implanted cardiac devices are thought to arise from the interaction between the implanted device and static, gradient, and radiofrequency magnetic fields. Purpose To determine the relationship between the peak whole-body averaged specific absorption rate (SAR) and change in magnetic field per unit time (dB/dt), maximum specific energy dose, imaging region, and implanted cardiac device characteristics and their function in patients undergoing MRI. Materials and Methods This prospective observational cohort study was conducted from October 16, 2003, to January 22, 2015 (, NCT01130896). Any individual with an implanted cardiac device who was referred for MRI was included. Clinical MRI protocols without SAR restriction were used. Exclusion criteria were newly implanted leads, abandoned or epicardial leads, and dependence on a pacemaker with an implantable cardioverter defibrillator without asynchronous pacing capability. For each MRI pulse sequence, the calculated whole-body values for SAR, dB/dt, and scan duration were collected. Atrial and ventricular sensing, lead impedance, and capture threshold were evaluated before and immediately after (within 10 minutes) completion of each MRI examination. Generalized estimating equations with Gaussian family, identity link, and an exchangeable working correlation matrix were used for statistical analysis. Results A total of 2028 MRI examinations were performed in 1464 study participants with 2755 device leads (mean age, 67 years ± 15 [standard deviation]; 930 men [64%]). There was no evidence of an association between radiofrequency energy deposition, dB/dt, or scan duration and changes in device parameters. Thoracic MRI was associated with decreased battery voltage immediately after MRI (β = -0.008 V, < .001). Additionally, right ventricular (RV) lead length was associated with decreased RV sensing (β = -0.012 mV, .05) and reduced RV capture threshold (β = -0.002 V, < .01) immediately after MRI. Conclusion There was no evidence of an association between MRI parameters that characterize patient exposure to radiofrequency energy and changes in device and lead parameters immediately after MRI. Nevertheless, device interrogation before and after MRI remains mandatory due to the potential for device reset and changes in lead or generator parameters. © RSNA, 2020 See also the editorial by Shellock in this issue.
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http://dx.doi.org/10.1148/radiol.2020191132DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7193917PMC
May 2020

Clinical and procedural characteristics predicting need for chronotropic support and permanent pacing post-heart transplantation.

Heart Rhythm 2020 07 27;17(7):1132-1138. Epub 2020 Feb 27.

Cardiac Electrophysiology, Department of Medicine, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Background: Postoperative bradycardia can complicate orthotopic heart transplantation (OHT). Previous studies suggested donor age and surgical technique as possible risk factors. However, risk factors in the era of bicaval anastomosis have not been elucidated.

Objective: We sought to examine the association between donor/recipient characteristics with need for chronotropic support and permanent pacemaker (PPM) implantation in patients with OHT.

Methods: All patients treated with OHT between January 2003 and January 2018 at the Hospital of the University of Pennsylvania were retrospectively evaluated until June 2018. Chronotropic support was given upon postoperative inability to increase the heart rate to patient's demands and included disproportionate bradycardia and junctional rhythm.

Results: A total of 820 patients (mean age 51.3 ± 12.6 years; 607, 74% men) underwent 826 OHT procedures (787 patients, 95.3% bicaval anastomosis). Patients who were exposed to amiodarone (odds ratio [OR] 2.30; 95% confidence interval [CI] 1.58-3.34; P < .001) and have older donor (OR 1.02; 95% CI 1.01-1.04; P = .001) were more likely to develop need for chronotropic support. In multivariable analysis, recipient age (OR 1.03; 95% CI 1.00-1.06; P = .04) and biatrial anastomosis (OR 6.12; 95% CI 2.48-15.09) were significantly associated with PPM implantation within 6 months of OHT. No association was found between pre-OHT amiodarone use and PPM implantation. No risk factors assessed were associated with PPM implantation 6 months post-OHT.

Conclusion: Surgical technique and donor age were the main risk factors for the need for chronotropic support post-OHT, whereas surgical technique and recipient age were risk factors for early PPM implantation.
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http://dx.doi.org/10.1016/j.hrthm.2020.02.021DOI Listing
July 2020

Daytime QT by Routine 12-Lead ECG Is Prolonged in Patients with Severe Obstructive Sleep Apnea.

Sleep Disord 2020 5;2020:3029836. Epub 2020 Feb 5.

Division of Cardiovascular Medicine, Department of Medicine, University of Virginia, USA.

Background: Obstructive sleep apnea (OSA) has been linked to sudden cardiac death (SCD). Prolonged QT is a recognized electrocardiographic (ECG) marker of abnormal ventricular repolarization linked to increased risk of SCD. We hypothesized that individuals with OSA have more pronounced abnormality in daytime QT interval.

Methods: We reviewed consecutive patients who underwent clinically indicated polysomnography with 12-lead ECG within 1 year at a single center. Heart rate-corrected QT interval (QTc) was compared by OSA severity class (normal/mild: apnea-hypopnea index (AHI) < 15/hr ( = 72); moderate: 15-30 ( = 72); moderate: 15-30 ( = 72); moderate: 15-30 (.

Results: A total of 249 patients were included. QTc was similar between the normal/mild and moderate groups, and the overall QTc trend increased across OSA (normal/mild: 435.6 ms; moderate: 431.36; severe: 444.4;  trend = 0.03). Abnormal QTc was found amongst 34% of male and 31% of female patients. Patients with severe OSA had longer QTc compared with normal/mild OSA (mean difference (95% CI): 10.0 ms (0.5, 19.0),  trend = 0.03). Abnormal QTc was found amongst 34% of male and 31% of female patients. Patients with severe OSA had longer QTc compared with normal/mild OSA (mean difference (95% CI): 10.0 ms (0.5, 19.0),  trend = 0.03). Abnormal QTc was found amongst 34% of male and 31% of female patients. Patients with severe OSA had longer QTc compared with normal/mild OSA (mean difference (95% CI): 10.0 ms (0.5, 19.0),  trend = 0.03). Abnormal QTc was found amongst 34% of male and 31% of female patients. Patients with severe OSA had longer QTc compared with normal/mild OSA (mean difference (95% CI): 10.0 ms (0.5, 19.0).

Conclusions: In a sleep clinic cohort, severe OSA was associated with higher QTc and clinically defined abnormal QTc compared with nonsevere OSA.
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http://dx.doi.org/10.1155/2020/3029836DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7025071PMC
February 2020

Non-Scar-Related and Purkinje-Related Ventricular Tachycardia in Patients With Structural Heart Disease: Prevalence, Mapping Features, and Clinical Outcomes.

JACC Clin Electrophysiol 2020 02 18;6(2):231-240. Epub 2019 Dec 18.

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

Objectives: This study sought to evaluate the prevalence, mapping features, and ablation outcomes of non-scar-related ventricular tachycardia (NonScar-VT) and Purkinje-related VT (Purkinje-VT) in patients with structural heart disease.

Background: VT in structural heart disease is typically associated with scar-related myocardial re-entry. NonScar-VTs arising from areas of normal myocardium or Purkinje-VTs originating from the conduction system are less common.

Methods: We retrospectively analyzed 690 patients with structural heart disease who underwent VT ablation between 2013 and 2017.

Results: A total of 37 (5.4%) patients (16 [43%] with ischemic cardiomyopathy, 16 [43%] with nonischemic dilated cardiomyopathy, and 5 [14%] others) demonstrated NonScar/Purkinje-VTs, which represented the clinical VT in 76% of cases. Among the 37 VTs, 31 (84%) were Purkinje-VTs (28 bundle branch re-entrant VT). The remaining 6 (16%) VTs were NonScar-VTs and included 4 idiopathic outflow tract VTs. A total of 16 patients had prior history of VT ablations: empirical scar substrate modification was performed in 6 (38%) patients and residual inducibility of VT had not been assessed in 7 (44%). In all 37 patients, the NonScar/Purkinje-VT was successfully ablated. After a median follow-up of 18 months, the targeted NonScar/Purkinje-VT did not recur in any patients, and 28 (76%) of patients were free from any recurrent VT episodes.

Conclusions: NonScar/Purkinje-VTs can be identified in 5.4% of patients undergoing VT ablation in the setting of structural heart disease. Careful effort to induce, characterize, and map these VTs is important because substrate-based ablation strategies would fail to eliminate these types of VT.
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http://dx.doi.org/10.1016/j.jacep.2019.09.014DOI Listing
February 2020

Genetic Susceptibility for Atrial Fibrillation in Patients Undergoing Atrial Fibrillation Ablation.

Circ Arrhythm Electrophysiol 2020 03 14;13(3):e007676. Epub 2020 Feb 14.

Department of Medicine, Vanderbilt University Medical Center, Nashville, TN (M.B.S., C.S., L.L.R., D.M.C., J.M., Z.Y., Q.W., T.I., P.W., G.M.).

Background: Ablation is a widely used therapy for atrial fibrillation (AF); however, arrhythmia recurrence and repeat procedures are common. Studies examining surrogate markers of genetic susceptibility to AF, such as family history and individual AF susceptibility alleles, suggest these may be associated with recurrence outcomes. Accordingly, the aim of this study was to test the association between AF genetic susceptibility and recurrence after ablation using a comprehensive polygenic risk score for AF.

Methods: Ten centers from the AF Genetics Consortium identified patients who had undergone de novo AF ablation. AF genetic susceptibility was measured using a previously described polygenic risk score (N=929 single-nucleotide polymorphisms) and tested for an association with clinical characteristics and time-to-recurrence with a 3 month blanking period. Recurrence was defined as >30 seconds of AF, atrial flutter, or atrial tachycardia. Multivariable analysis adjusted for age, sex, height, body mass index, persistent AF, hypertension, coronary disease, left atrial size, left ventricular ejection fraction, and year of ablation.

Results: Four thousand two hundred seventy-six patients were eligible for analysis of baseline characteristics and 3259 for recurrence outcomes. The overall arrhythmia recurrence rate between 3 and 12 months was 44% (1443/3259). Patients with higher AF genetic susceptibility were younger (<0.001) and had fewer clinical risk factors for AF (=0.001). Persistent AF (hazard ratio [HR], 1.39 [95% CI, 1.22-1.58]; <0.001), left atrial size (per cm: HR, 1.32 [95% CI, 1.19-1.46]; <0.001), and left ventricular ejection fraction (per 10%: HR, 0.88 [95% CI, 0.80-0.97]; =0.008) were associated with increased risk of recurrence. In univariate analysis, higher AF genetic susceptibility trended towards a higher risk of recurrence (HR, 1.08 [95% CI, 0.99-1.18]; =0.07), which became less significant in multivariable analysis (HR, 1.06 [95% CI, 0.98-1.15]; =0.13).

Conclusions: Higher AF genetic susceptibility was associated with younger age and fewer clinical risk factors but not recurrence. Arrhythmia recurrence after AF ablation may represent a genetically different phenotype compared to AF susceptibility.
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http://dx.doi.org/10.1161/CIRCEP.119.007676DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7080569PMC
March 2020

Clinical Care Recommendations for Cardiologists Treating Adults With Myotonic Dystrophy.

J Am Heart Assoc 2020 02 6;9(4):e014006. Epub 2020 Feb 6.

University of Texas Southwestern Medical Center Dallas TX.

Myotonic dystrophy is an inherited systemic disorder affecting skeletal muscle and the heart. Genetic testing for myotonic dystrophy is diagnostic and identifies those at risk for cardiac complications. The 2 major genetic forms of myotonic dystrophy, type 1 and type 2, differ in genetic etiology yet share clinical features. The cardiac management of myotonic dystrophy should include surveillance for arrhythmias and left ventricular dysfunction, both of which occur in progressive manner and contribute to morbidity and mortality. To promote the development of care guidelines for myotonic dystrophy, the Myotonic Foundation solicited the input of care experts and organized the drafting of these recommendations. As a rare disorder, large scale clinical trial data to guide the management of myotonic dystrophy are largely lacking. The following recommendations represent expert consensus opinion from those with experience in the management of myotonic dystrophy, in part supported by literature-based evidence where available.
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http://dx.doi.org/10.1161/JAHA.119.014006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7070199PMC
February 2020

Incidence of Left Atrial Appendage Triggers in Patients With Atrial Fibrillation Undergoing Catheter Ablation.

JACC Clin Electrophysiol 2020 01 30;6(1):21-30. Epub 2019 Oct 30.

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

Objective: This study sought to investigate incidence of left atrial appendage (LAA) triggers of atrial fibrillation (AF) and/or organized atrial tachycardias (OAT) in patients undergoing AF ablation and to evaluate outcomes after ablation.

Background: Although LAA isolation is being increasingly performed during AF ablation, the true incidence of LAA triggers for AF remains unclear.

Methods: All patients with LAA triggers of AF and/or OAT during AF ablation from 2001 to 2017 were included. LAA triggers were defined as atrial premature depolarizations from the LAA, which initiated sustained AF and/or OAT.

Results: Out of 7,129 patients undergoing AF ablation over 16 years, LAA triggers were observed in 21 (0.3%) subjects (age 60 ± 9 years; 57% males; 52% persistent AF). Twenty (95%) patients were undergoing repeat ablation. The LAA was the only nonpulmonary vein trigger in 3 patients; the remaining 18 patients had both LAA and other nonpulmonary vein triggers. LAA triggers were eliminated in all patients (focal ablation in 19 patients; LAA isolation in 2 patients). Twelve months after ablation, 47.6% remained free from recurrent arrhythmia. After overall follow-up of 5.0 ± 3.6 years (median: 3.7 years; interquartile range: 1.4 to 8.9 years), 38.1% were arrhythmia-free. All 3 patients with triggers limited to the LAA remained free of AF recurrence. One patient undergoing LAA isolation developed LAA thrombus during follow-up.

Conclusions: The incidence of true LAA triggers is very low (0.3%). Most patients with LAA triggers have additional nonpulmonary vein triggers, and despite elimination of LAA triggers, long-term arrhythmia recurrence rates remain high. Potential risks of empiric LAA isolation during AF ablation (especially first-time AF ablation) may outweigh benefits.
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http://dx.doi.org/10.1016/j.jacep.2019.08.012DOI Listing
January 2020

Association of Left Atrial High-Resolution Late Gadolinium Enhancement on Cardiac Magnetic Resonance With Electrogram Abnormalities Beyond Voltage in Patients With Atrial Fibrillation.

Circ Arrhythm Electrophysiol 2020 02 15;13(2):e007586. Epub 2020 Jan 15.

Cardiovascular Imaging Section, Department of Radiology (B.D), Perelman School of Medicine at the University of Pennsylvania, Philadelphia.

Background: Conflicting data have been reported on the association of left atrial (LA) late gadolinium enhancement (LGE) with atrial voltage in patients with atrial fibrillation. The association of LGE with electrogram fractionation and delay remains to be examined. We sought to examine the association between LA LGE on cardiac magnetic resonance and electrogram abnormalities in patients with atrial fibrillation.

Methods: High-resolution LGE cardiac magnetic resonance was performed before electrogram mapping and ablation in atrial fibrillation patients. Cardiac magnetic resonance features were quantified using LA myocardial signal intensity score (SI-Z), a continuous normalized variable, as well as a dichotomous LGE variable based on previously validated methodology. Electrogram mapping was performed pre-ablation during sinus rhythm or LA pacing, and electrogram locations were coregistered with cardiac magnetic resonance images. Analyses were performed using multilevel patient-clustered mixed-effects regression models.

Results: In the 40 patients with atrial fibrillation (age, 63.2±9.2 years; 1312.3±767.3 electrogram points per patient), lower bipolar voltage was associated with higher SI-Z in patients who had undergone previous ablation (coefficient, -0.049; <0.001) but not in ablation-naive patients (coefficient, -0.004; =0.7). LA electrogram activation delay was associated with SI-Z in patients with previous ablation (SI-Z: coefficient, 0.004; <0.001 and LGE: coefficient, 0.04; <0.001) but not in ablation-naive patients. In contrast, increased LA electrogram fractionation was associated with SI-Z (coefficient, 0.012; =0.03) and LGE (coefficient, 0.035; <0.001) only in ablation-naive patients.

Conclusions: The association of LA LGE with voltage is modified by ablation. Importantly, in ablation-naive patients, atrial LGE is associated with electrogram fractionation even in the absence of voltage abnormalities.
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http://dx.doi.org/10.1161/CIRCEP.119.007586DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7031051PMC
February 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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January 2020

Impact of a nurse-led limited risk factor modification program on arrhythmia outcomes in patients with atrial fibrillation undergoing catheter ablation.

J Cardiovasc Electrophysiol 2020 02 15;31(2):423-431. Epub 2020 Jan 15.

Cardiovascular Division, Hospital of The University of Pennsylvania, Philadelphia, Pennsylvania.

Background: We have previously demonstrated the feasibility of a nurse-led risk factor modification (RFM) program for improving weight loss and obstructive sleep apnea (OSA) care among patients with atrial fibrillation (AF).

Objective: We now report its impact on arrhythmia outcomes in a subgroup of patients undergoing catheter ablation.

Methods: Participating patients with obesity and/or need for OSA management (high risk per Berlin Questionnaire or untreated OSA) underwent in-person consultation and monthly telephone calls with the nurse for up to 1 year. Arrhythmias were assessed by office ECGs and ≥2 wearable monitors. Outcomes, defined as Arrhythmia control (0-6 self-terminating recurrences, with ≤1 cardioversion for nonparoxysmal AF) and Freedom from arrhythmias (no recurrences on or off antiarrhythmic drugs), were compared at 1 year between patients undergoing catheter ablation who enrolled and declined RFM.

Results: Between 1 November 2016 and 1 April 2018, 195 patients enrolled and 196 declined RFM (body mass index, 35.1 ± 6.7 vs 34.3 ± 6.3 kg/m ; 50% vs 50% paroxysmal AF; P = NS). At 1 year, enrolled patients demonstrated significant weight loss (4.7% ± 5.3% vs 0.3% ± 4.4% in declined patients; P < .0001) and improved OSA care (78% [n = 43] of patients diagnosed with OSA began treatment). However, outcomes were similar between enrolled and declined patients undergoing ablation (arrhythmia control in 80% [n = 48] vs 79% [n = 38]; freedom from arrhythmia in 58% [n = 35] vs 71% [n = 34]; P = NS).

Conclusion: Despite improving weight loss and OSA care, our nurse-led RFM program did not impact 1-year arrhythmia outcomes in patients with AF undergoing catheter ablation.
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February 2020

Cardiac magnetic resonance-derived right atrial functional analysis in patients with atrial fibrillation and typical atrial flutter.

J Interv Card Electrophysiol 2020 Nov 5;59(2):381-391. Epub 2019 Dec 5.

Department of Cardiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.

Background: Typical atrial flutter (AFL) often occurs in patients with atrial fibrillation (AF). Decision-making tools for application of prophylactic cavo-tricuspid isthmus (CTI) ablation at the time of AF ablation may improve outcomes. In this study, we sought to define the right atrial (RA) functional characteristics of AF patients with documented typical AFL.

Methods: Consecutive patients that underwent cardiac magnetic resonance (CMR) prior to initial AF ablation in the Johns Hopkins Hospital were enrolled. The AF database was reviewed to identify prevalent and incident documented typical AFL. Feature tracking CMR analysis during sinus rhythm was utilized to quantify RA longitudinal strain and strain rate, as well as RA passive and active emptying fractions derived from phasic RA volumes.

Results: A total of 115 patients were analyzed (mean age 59.1 ± 11.4 years, 78.3% male, 74.8% paroxysmal AF). Of all patients, 30 (26.1%) had typical AFL. Clinical characteristics and AF type did not differ among groups defined by the absence or presence of typical AFL. In contrast, RA longitudinal strain (41.6 ± 16.8% vs. 55.8 ± 17.1%, p ≤ 0.001), systolic strain rate (1.71 ± 0.85 s vs. 2.33 ± 0.93 s, p = 0.002), and late diastolic strain rate (1.78 ± 1.02 s vs. 2.50 ± 0.91 s p ≤ 0.001) were significantly lower in patients with typical AFL. Although RA passive emptying fraction was similar among groups (18.9 ± 8.1 vs. 19.5 ± 8.0, p = 0.75), RA active emptying fraction was lower in patients with typical AFL (34.8 ± 12.3 vs. 40.8 ± 12.1, p = 0.02).

Conclusions: The reservoir and pump function of the RA is significantly reduced in patients with typical AFL. Prophylactic CTI ablation warrants further study as adjunctive therapy to AF catheter ablation in selected patients with RA dysfunction.
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http://dx.doi.org/10.1007/s10840-019-00636-6DOI Listing
November 2020

Septal Versus Lateral Mitral Isthmus Ablation for Treatment of Mitral Annular Flutter.

JACC Clin Electrophysiol 2019 11 30;5(11):1292-1299. Epub 2019 Oct 30.

Electrophysiology Section, Division of Cardiovascular Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania. Electronic address:

Objectives: This study sought to compare efficacy and safety of the septal mitral isthmus line (SMIL) with that of the lateral mitral isthmus line (LMIL) for treatment of mitral annular flutter (MAF).

Background: MAF is the most common left atrial macro-re-entrant organized atrial tachycardia (OAT) occurring after catheter ablation of atrial fibrillation. The 2 most common lesion sets for treating MAF include linear ablation from the anteroseptal mitral annulus to the right superior pulmonary vein (SMIL) and from the lateral mitral annulus to left inferior pulmonary vein (LMIL).

Methods: The study included all mitral isthmus ablations performed at the Hospital of the University of Pennsylvania in 2016 and 2017. Acute procedural results and long-term arrhythmia-free survival were compared between groups.

Results: Of 114 total MILs, conduction block was achieved across 73 (93.6%) SMILs compared with 29 (80.6%) LMILs (p = 0.05). Although the length of the SMIL was longer (48.9 ± 12.8 cm vs. 38.7 ± 12.8 cm; p = 0.001), time required to achieve block was shorter (25.2 ± 15.9 min vs. 36.6 ± 21.3 min; p = 0.03). Coronary sinus ablation was required in 58.3% of LMILs due to inability to achieve conduction block with left atrial ablation alone. In multivariate analysis, only failure to achieve acute MIL block remained significantly associated with subsequent OAT recurrence (hazard ratio: 6.39; 95% confidence interval: 1.37 to 29.9; p = 0.02).

Conclusions: The SMIL requires less time to complete and more frequently results in acute MIL block than the LMIL. Additionally, ablation is rarely required outside the left atrium. Failure to achieve acute MIL block is strongly associated with subsequent OAT recurrence.
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November 2019
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