Publications by authors named "William H Sauer"

155 Publications

Bucindolol Decreases Atrial Fibrillation Burden in Patients with Heart Failure and the Arg389Arg Genotype.

Circ Arrhythm Electrophysiol 2021 Jul 16. Epub 2021 Jul 16.

Population Health Research Institute, McMaster University, Hamilton, ON, Canada.

- Bucindolol is a genetically targeted β-blocker/mild vasodilator with the unique pharmacologic properties of sympatholysis and Arg389 receptor inverse agonism. In the GENETIC-AF trial conducted in a genetically defined heart failure (HF) population at high risk for recurrent atrial fibrillation (AF), similar results were observed for bucindolol and metoprolol succinate for the primary endpoint of time to first atrial fibrillation (AF) event; however, AF burden and other rhythm control measures were not analyzed. - The prevalence of ECGs in normal sinus rhythm, AF interventions for rhythm control (cardioversion, ablation and antiarrhythmic drugs), and biomarkers were evaluated in the overall population entering efficacy follow-up (N=257). AF burden was evaluated for 24 weeks in the device substudy (N=67). - In 257 patients with HF the mean age was 65.6 ± 10.0 years, 18% were female, mean left ventricular ejection fraction (LVEF) was 36%, and 51% had persistent AF. Cumulative 24-week AF burden was 24.4% (95% CI: 18.5, 30.2) for bucindolol and 36.7% (95% CI: 30.0, 43.5) for metoprolol (33% reduction, p < 0.001). Daily AF burden at the end of follow-up was 15.1% (95% CI: 3.2, 27.0) for bucindolol and 34.7% (95% CI: 17.9, 51.2) for metoprolol (55% reduction, p < 0.001). For the metoprolol and bucindolol respective groups the prevalence of ECGs in normal sinus rhythm was 4.20 and 3.03 events per patient (39% increase in the bucindolol group, p < 0.001), while the rate of AF interventions was 0.56 and 0.82 events per patient (32% reduction for bucindolol, p = 0.011). Reductions in plasma norepinephrine (p = 0.038) and NT-proBNP (p = 0.009) were also observed with bucindolol compared to metoprolol. - Compared with metoprolol, bucindolol reduced AF burden, improved maintenance of sinus rhythm, and lowered the need for additional rhythm control interventions in patients with HF and the Arg389Arg genotype.
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http://dx.doi.org/10.1161/CIRCEP.120.009591DOI Listing
July 2021

Fasciculoventricular and atrioventricular accessory pathways in patients with Danon disease and preexcitation: A multicenter experience.

Heart Rhythm 2021 Jul 16;18(7):1194-1202. Epub 2021 Mar 16.

Division of Cardiology, Department of Medicine, University of California, San Diego, La Jolla, California.

Background: Studies have suggested that a fasciculoventricular pathway (FVP) may be the cause of preexcitation in patients with Danon disease, a rare X-linked dominant genetic disorder of hypertrophic cardiomyopathy.

Objective: The purpose of this study was to describe the prevalence of ventricular preexcitation on resting 12-lead electrocardiogram (ECG) in patients with Danon disease and the electrophysiological study (EPS) results of those with preexcitation.

Methods: Patients with confirmed Danon disease diagnosed with preexcitation (PR ≤120 ms, delta wave, QRS >110 ms) on ECG were included from a multicenter registry. The incidence of arrhythmias, implantable cardioverter-defibrillator (ICD) procedures, ICD shocks, and EPS results were collected.

Results: Thirteen of 40 patients (32.5%) with Danon disease were found to have preexcitation (mean age 17.3 years; 38% women). EPS performed in 9 of 13 patients (69%) demonstrated FVP only in 2 (22.2%), extranodal pathway without exclusion of FVP in 2 (22.2%), and both FVP and extranodal pathway in 5 (55.6%). Two patients had malignant accessory pathway (AP) properties. Over median follow-up of 842 days (interquartile range 138-1678), 11 patients (85%) had ICD placement, and 6 (46.1%) underwent heart transplantation. No patients required therapy for ventricular tachycardia, and 2 patients (15%) had paroxysmal atrial fibrillation.

Conclusion: In a large multicenter cohort of patients with Danon disease, there was a high prevalence of FVP and extranodal pathways diagnosed on EPS in those with preexcitation. These findings suggest patients with preexcitation and Danon disease should undergo EPS to assess for FVP and potentially malignant extranodal AP.
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http://dx.doi.org/10.1016/j.hrthm.2021.03.024DOI Listing
July 2021

Arrhythmias in Cardiac Sarcoidosis Bench to Bedside: A Case-Based Review.

Circ Arrhythm Electrophysiol 2021 02 16;14(2):e009203. Epub 2021 Feb 16.

University of Washington School of Medicine, Seattle (L.L.V., K.K.P., R.K.C.).

Cardiac sarcoidosis is a component of an often multiorgan granulomatous disease of still uncertain cause. It is being recognized with increasing frequency, mainly as the result of heightened awareness and new diagnostic tests, specifically cardiac magnetic resonance imaging and F-fluorodeoxyglucose positron emission tomography scans. The purpose of this case-based review is to highlight the potentially life-saving importance of making the early diagnosis of cardiac sarcoidosis using these new tools and to provide a framework for the optimal care of patients with this disease. We will review disease mechanisms as currently understood, associated arrhythmias including conduction abnormalities, and atrial and ventricular tachyarrhythmias, guideline-directed diagnostic criteria, screening of patients with extracardiac sarcoidosis, and the use of pacemakers and defibrillators in this setting. Treatment options, including those related to heart failure, and those which may help clarify disease mechanisms are included.
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http://dx.doi.org/10.1161/CIRCEP.120.009203DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8142901PMC
February 2021

Catheter ablation of ventricular tachycardia in patients with prior cardiac surgery: An analysis from the International VT Ablation Center Collaborative Group.

J Cardiovasc Electrophysiol 2021 Feb 24;32(2):409-416. Epub 2021 Jan 24.

Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.

Introduction: Patients with prior cardiac surgery may represent a subgroup of patients with ventricular tachycardia (VT) that may be more difficult to control with catheter ablation.

Methods: We evaluated 1901 patients with ischemic and nonischemic cardiomyopathy who underwent VT ablation at 12 centers. Clinical characteristics and VT radiofrequency ablation procedural outcomes were assessed and compared between those with and without prior cardiac surgery. Kaplan-Meier analysis was used to estimate freedom from recurrent VT and survival.

Results: There were 578 subjects (30.4%) with prior cardiac surgery identified in the cohort. Those with prior cardiac surgery were older (66.4 ± 11.0 years vs. 60.5 ± 13.9 years, p < .01), with lower left ventricular ejection fraction (30.2 ± 11.5% vs. 34.8 ± 13.6%, p < .01) and more ischemic heart disease (82.5% vs. 39.3%, p < .01) but less likely to undergo epicardial mapping or ablation (9.0% vs. 38.1%, p<.01) compared to those without prior surgery. When epicardial mapping was performed, a significantly greater proportion required surgical intervention for access (19/52 [36.5%] vs. 14/504 [2.8%]; p < .01). Procedural complications, including epicardial access-related complications, were lower (5.7% vs. 7.0%, p < .01) in patients with versus without prior cardiac surgery. VT-free survival (75.1% vs. 74.1%, p = .805) and survival (86.5% vs. 87.9%, p = .397) were not different between those with and without prior heart surgery, regardless of etiology of cardiomyopathy. VT recurrence was associated with increased mortality in patients with and without prior cardiac surgery.

Conclusion: Despite different clinical characteristics and fewer epicardial procedures, the safety and efficacy of VT ablation in patients with prior cardiac surgery is similar to others in this cohort. The incremental yield of epicardial mapping in predominant ischemic cardiomyopathy population prior heart surgery may be low but appears safe in experienced centers.
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http://dx.doi.org/10.1111/jce.14849DOI Listing
February 2021

Arrhythmias and COVID-19: A Review.

JACC Clin Electrophysiol 2020 Sep 10;6(9):1193-1204. Epub 2020 Aug 10.

Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA. Electronic address:

Current understanding of the impact of coronavirus disease-2019 (COVID-19) on arrhythmias continues to evolve as new data emerge. Cardiac arrhythmias are more common in critically ill COVID-19 patients. The potential mechanisms that could result in arrhythmogenesis among COVID-19 patients include hypoxia caused by direct viral tissue involvement of lungs, myocarditis, abnormal host immune response, myocardial ischemia, myocardial strain, electrolyte derangements, intravascular volume imbalances, and drug sides effects. To manage these arrhythmias, it is imperative to increase the awareness of potential drug-drug interactions, to monitor QTc prolongation while receiving COVID therapy and provide special considerations for patients with inherited arrhythmia syndromes. It is also crucial to minimize exposure to COVID-19 infection by stratifying the need for intervention and using telemedicine. As COVID-19 infection continues to prevail with a potential for future surges, more data are required to better understand pathophysiology and to validate management strategies.
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http://dx.doi.org/10.1016/j.jacep.2020.08.002DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7417167PMC
September 2020

Uncovering a unique path: Antidromic AVRT utilizing a left anteroseptal Mahaim-like accessory pathway.

Pacing Clin Electrophysiol 2021 01 25;44(1):185-188. Epub 2020 Aug 25.

Section of Electrophysiology, Brigham and Women's Hospital, Boston, Massachusetts.

A 40-year-old man presented to our emergency department 2 hours after onset of shortness of breath, palpitations, and presyncope secondary to an adenosine-responsive wide complex tachycardia. Electrophysiology study was diagnostic for antidromic atrioventricular (AV) reentrant tachycardia utilizing a muscular connection from the anterior interventricular vein to the left ventricle with Mahaim-like properties, successfully treated with ablation in the distal coronary sinus (CS) system. This case highlights accessory pathways (a) with unique features (i.e., Mahaim-like characteristics) and (b) involving musculature from the distal CS system, thereby limiting the value of endocardial ablation for durable treatment. Importantly, the coronary venous system is an accessible vascular network for evaluation and catheter ablation of such arrhythmias.
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http://dx.doi.org/10.1111/pace.14024DOI Listing
January 2021

A Maze-ing crisscross interval plot: what is the diagnosis?

Europace 2020 08;22(8):1233

Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital, 75 Francis St, Boston, MA 02115, USA.

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http://dx.doi.org/10.1093/europace/euaa099DOI Listing
August 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

Patients with bicuspid aortic valves may be associated with infra-hisian conduction disease requiring pacemakers.

J Interv Card Electrophysiol 2021 Jun 26;61(1):29-35. Epub 2020 May 26.

Section of Cardiac Electrophysiology, Department of Medicine, Cardiology Division, Stanford University, 870 Quarry Road Extension, Stanford, CA, 94305, USA.

Background: Bicuspid aortic valves (BAVs) are associated with accelerated valvular dysfunction. Increasing rates of conduction system disease are seen in patients with calcific tricuspid aortic valves (TAVs). However, little is known regarding the extent of conduction disorders in BAV patients. We sought to determine the extent of infra-hisian conduction pathology among patients with BAVs undergoing EP studies.

Methods: We prospectively analyzed patients presenting to the EP laboratory from 2006 to 2017 at our institution. Thirty-three BAV patients had measured HV intervals. Each individual was matched by age and gender to two control patients. Clinical characteristics were collected and compared, and patients followed for outcomes.

Results: The BAV cohort had a mean age of 47.8 ± 17.2 years (range 19-76 years). Indications for referral to the EP lab in the BAV cohort included SVT ablation (n = 16), VT ablation (n = 10), and EP study for syncope, pre-syncope, or palpitations (n = 29). Patients with BAVs had a mean HV interval of 58.7 ms ± 18.6 ms, compared to a mean of 47.2 ms ± 9.6 ms for controls (p value = 0.0001). Over a 10-year follow-up period, 9 BAV patients (27%) went on to require permanent pacing compared to 6 patients (9%) in the control group (p value = 0.03).

Conclusion: Compared to patients with TAVs presenting for EP evaluation, individuals with BAVs have longer HV intervals and a significantly increased requirement for pacemaker therapy over long-term follow-up. Closer monitoring of progressive conduction system disease in BAV patients may be warranted.
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http://dx.doi.org/10.1007/s10840-020-00785-zDOI Listing
June 2021

Use of cell phone adapters is associated with reduction in disparities in remote monitoring of cardiac implantable electronic devices.

J Interv Card Electrophysiol 2021 Apr 12;60(3):469-475. Epub 2020 May 12.

University of Colorado, Aurora, CO, 80045, USA.

Background: Remote monitoring (RM) of cardiac implantable electronic devices (CIEDs) is standard of care. However, it is underutilized. In July 2012, our institution began providing cell phone adapters (CPAs) to patients free of charge following CIED implantation to improve remote transmission (RT) adherence.

Methods: Patients in our institution's RM database from January 1, 2010, thru June 30, 2015, were retrospectively reviewed. There were 2157 eligible patients. Remote transmission proportion (RTP) and time to transmission (TT) were compared pre- and post-implementation of free CPA. Chi-squared analysis and Kruskal-Wallis tests were performed to compare RTP and TT.

Results: There was a significant increase in RTP (134 [18.4%] vs 99 [54.7%]; p < 0.001) and decrease in median TT in days (189[110-279] vs 58 [10-149]; p < 0.001) after CPAs were provided to patients. Caucasian patients were more likely than African Americans and Hispanics to use RM prior to CPAs (p = 0.04). After the implementation of CPAs, there was a significant increase in RTP for all racial groups (< 0.001) with no difference in RTP among racial groups (p = 0.18). The RTP for urban residents was significantly greater than non-urban residents with CPAs (p = 0.008). Patients greater than 70 years of age were significantly less likely to participate in RT before and after CPAs were provided (p = 0.03, p = 0.01, respectively).

Conclusions: CPAs significantly improve RTP and reduce median TT for all patients regardless of race, geographic residence, and age (> 70 years old to lesser extent). Broad institution of CPAs following ICD implantation could potentially reduce disparity in RTP and deserves more study.
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http://dx.doi.org/10.1007/s10840-020-00743-9DOI Listing
April 2021

Continuous ablation improves lesion maturation compared with intermittent ablation strategies.

J Cardiovasc Electrophysiol 2020 07 27;31(7):1687-1693. Epub 2020 Apr 27.

Section of Cardiac Electrophysiology, Division of Cardiovascular Medicine, Stanford University, Stanford, California.

Background: Interrupted ablation is increasingly proposed as part of high-power short-duration radiofrequency ablation (RFA) strategies and may also result from loss of contact from respiratory patterns or cardiac motion. To study the extent that ablation interruption affects lesions.

Methods: In ex vivo and in vivo experiments, lesion characteristics and tissue temperatures were compared between continuous (group 1) and interrupted (groups 2 and 3) RFA with equal total ablation duration and contact force. Extended duration ablation lesions were also characterized from 1 to 5 minutes.

Results: In the ex vivo study, continuous RFA (group 1) produced larger total lesion volumes compared with each interrupted ablation lesion group (273.8 ± 36.5 vs 205.1 ± 34.2 vs 174.3 ± 32.3 mm , all P < .001). Peak temperatures for group 1 were higher at 3 and 5 mm than groups 2 and 3. In vivo, continuous ablation resulted in larger lesions, greater lesion depths, and higher tissue temperatures. Longer ablation durations created larger lesion volumes and increased lesion depths. However, after 3 minutes of ablation, the rate of lesion volume, and depth formation decreased.

Conclusions: Continuous RFA delivery resulted in larger and deeper lesions with higher tissue temperatures compared with interrupted ablation. This study may have implications for high-power short duration ablation strategies, motivates strategies to reduce variations in ablation delivery, and provides an upper limit for ablation duration beyond which power delivery has diminishing returns.
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http://dx.doi.org/10.1111/jce.14510DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7534961PMC
July 2020

Unintentional magnet reversion of an implanted cardiac defibrillator by an electronic cigarette.

HeartRhythm Case Rep 2020 Mar 16;6(3):121-123. Epub 2020 Mar 16.

Cardiovascular Arrhythmia Service, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.

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http://dx.doi.org/10.1016/j.hrcr.2020.01.013DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7076322PMC
March 2020

Radiofrequency Catheter Ablation of Atrial Fibrillation: May the Force (and Stability) Be With You, Always.

JACC Clin Electrophysiol 2020 02;6(2):153-156

Division of Cardiology, Brigham and Women's Hospital Cardiac Arrhythmia Service, Harvard Medical School, Boston, Massachusetts, USA.

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http://dx.doi.org/10.1016/j.jacep.2019.12.006DOI Listing
February 2020

Impact of epicardial adipose tissue and catheter ablation strategy on biophysical parameters and ablation lesion characteristics.

J Cardiovasc Electrophysiol 2020 05 18;31(5):1114-1124. Epub 2020 Feb 18.

Section of Cardiac Electrophysiology, Division of Cardiology, Stanford University, Palo Alto, California.

Background: Epicardial adipose (EA) tissue may limit effective radiofrequency ablation (RFA).

Objectives: We sought to evaluate the lesion formation of different ablation strategies on ventricular myocardium with overlying EA.

Methods: Bovine myocardium with EA was placed in a circulating saline bath in an ex vivo model. Open-irrigated (OI) RFA was performed, parallel to the myocardium, over fat at 50 W for variable RF durations, variable contact force, catheter configurations (unipolar RF vs bipolar RF), and catheter irrigants (normal saline vs half-normal saline). Ablation was also performed with a needle-tipped ablation catheter (NTAC), perpendicular to the myocardium.

Results: Increasingly thick EA attenuated lesion size regardless of ablation strategy. RF applied with longer durations and increasing CF produced larger lesion volumes and deeper lesions with ablation over EA more than 3 mm but was unable to produce measurable lesions when EA less than 3 mm. Similarly, ablation with half normal saline irrigant created slightly deeper lesions than bipolar RF and unipolar RF with normal saline as EA thickness increased, but was unable to produce measurable lesions when EA more than 3 mm. Of all ablation strategies, only NTAC produced effective lesion volumes when ablating over thick (>3 mm) EA.

Conclusions: While EA attenuates lesion depth and size, relatively larger, and deeper lesions can be achieved with longer RFA duration, higher CF, half normal saline irrigant, and, to a greater extent, by utilizing bipolar RF or NTAC, but only over thin adipose (<3 mm). Of those catheters/strategies tested, only NTAC was able to effectively deliver RF over thick (>3 mm) EA with this model.
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http://dx.doi.org/10.1111/jce.14383DOI Listing
May 2020

Follow-Up After Catheter Ablation of Papillary Muscles and Valve Cusps.

JACC Clin Electrophysiol 2019 10 28;5(10):1185-1196. Epub 2019 Aug 28.

University of Colorado, Section of Cardiac Electrophysiology, Division of Cardiology, Aurora, Colorado. Electronic address:

Objectives: The goal of this study was to determine the impact of catheter ablation in the region of papillary muscles (PMs) and valvular cusps (VC) on mitral, tricuspid, or aortic valve function.

Background: Ventricular arrhythmias arising from PMs and VCs often require extensive catheter ablation. Little is known regarding the risk of valve dysfunction after radiofrequency catheter ablation of such arrhythmias.

Methods: A retrospective analysis was completed for 149 PM and VC VT/premature ventricular contraction (PVC) ablations from 2008 to 2018 at our institution. Patient and procedural details were collected for VT and PVC ablation cases involving PMs and VCs with available echocardiographic data pre-ablation and post-ablation (within 6 months). Degree of valvular regurgitation (VR) was graded from 0 (none) to 4 (severe), and significant valvular dysfunction was defined as a 2+ change in VR.

Results: Of 149 radiofrequency catheter ablation cases, there were 84 (56%) aortic valve cusp ablations, 60 (40%) left ventricular PM ablations, and 5 (3%) right ventricular PM ablations. There were no statistically significant differences between pre-ablation and post-ablation VR severity (p = 0.33). No patients had a 2+ grade change in VR severity when pre-ablation and post-ablation echocardiograms were compared. There were no significant sequelae requiring intervention in the post-ablation period. On follow-up of 36 ± 9 months, for those with a change in VR, the severity had improved to baseline or remained stable.

Conclusions: Despite often-times extensive ablation on and around valvular networks, risk of longstanding or permanent valvular dysfunction after VT/PVC ablation is rare.
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http://dx.doi.org/10.1016/j.jacep.2019.07.004DOI Listing
October 2019

Bipolar radiofrequency ablation creates different lesion characteristics compared to simultaneous unipolar ablation.

J Cardiovasc Electrophysiol 2019 12 13;30(12):2960-2967. Epub 2019 Oct 13.

Section of Cardiac Electrophysiology, Division of Cardiology, Brigham and Women's Hospital, Boston, Massachusetts.

Introduction: Both bipolar and simultaneous radiofrequency ablation (bRFA, simRFA) have been used to treat thick midmyocardial substrate as well as during circular, multipolar ablation between shorter distances.

Objectives: We sought to evaluate the biophysical parameters of simRFA, sequential unipolar RFA (seqRFA), and bRFA.

Methods: Bovine myocardium was placed in a circulating saline bath. To simulate thick substrate conditions, two open irrigated ablation catheters were oriented across from each other, with myocardium in between. Thermocouples were placed in the center, ±2 mm, of the myocardium. Unipolar ablations were performed sequentially or simultaneously at 50 W for 60 seconds and compared to bRFA using the same settings. In addition, to simulate multipolar ablation, two open irrigated ablation catheters were oriented on the same side and perpendicular to myocardium at 1, 2, and 4 mm spacing. SimRFA were performed at 15 and 25 W for 60 seconds and compared to bRFA.

Results: For thicker tissue, simRFA produced similar lesion volume and depth compared to bRFA but with a lesion geometry similar to seqRFA. Unlike seqRFA and simRFA, bRFA had a necrotic core spanning the myocardium. Core depths, volumes, and temperatures were significantly greater for bRFA lesions compared to simRFA or seqRFA (Figure, P < .001). Similar results were consistent for bRFA and simRFA at shorter spacings.

Conclusions: BRFA has greater core lesion temperatures, corresponding to a denser and larger necrotic core, than either simRFA or seqRFA. This may have implications for considering the optimal strategy for deep midmyocardial substrates or during multipolar ablation.
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http://dx.doi.org/10.1111/jce.14213DOI Listing
December 2019

Mapping Atrial Fibrillation and Finding a Method to the Madness.

JACC Clin Electrophysiol 2019 07;5(7):830-832

Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts.

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http://dx.doi.org/10.1016/j.jacep.2019.05.021DOI Listing
July 2019

Electrophysiologic testing for diagnostic evaluation and risk stratification in patients with suspected cardiac sarcoidosis with preserved left and right ventricular systolic function.

J Cardiovasc Electrophysiol 2019 10 23;30(10):1939-1948. Epub 2019 Jul 23.

Division of Cardiology, Section of Cardiac Electrophysiology, University of Colorado, Aurora, Colorado.

Introduction: While cardiac sarcoidosis (CS) carries a risk of ventricular arrhythmias (VAs) and sudden cardiac death (SCD), risk stratification of patients with CS and preserved left ventricular/right ventricular (LV/RV) systolic function remains challenging. We sought to evaluate the role of electrophysiologic testing and programmed electrical stimulation of the ventricle (EPS) in patients with suspected CS with preserved ventricular function.

Methods: One hundred twenty consecutive patients with biopsy-proven extracardiac sarcoidosis and preserved LV/RV systolic function underwent EPS. All patients had either probable CS defined by an abnormal cardiac positron emission tomography or cardiac magnetic resonance imaging, or possible CS with normal advanced imaging but abnormal echocardiogram (ECG), SAECG, Holter, or clinical factors. Patients were followed for 4.5 ± 2.6 years for SCD and VAs.

Results: Seven of 120 patients (6%) had inducible ventricular tachycardia (VT) with EPS and received an implantable cardioverter defibrillator (ICD). Three patients (43%) with positive EPS later had ICD therapies for VAs. Kaplan-Meier analysis stratified by EPS demonstrated a significant difference in freedom from VAs and SCD (P = 0.009), though this finding was driven entirely by patients within the cohort with probable CS (P = 0.018, n = 69). One patient with possible CS and negative EPS had unrecognized progression of the disease and unexplained death with evidence of CS at autopsy.

Conclusions: EPS is useful in the risk stratification of patients with probable CS with preserved LV and RV function. A positive EPS was associated with VAs. While a negative EPS appeared to confer low risk, close follow-up is needed as EPS cannot predict fatal VAs related to new cardiac involvement or disease progression.
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http://dx.doi.org/10.1111/jce.14058DOI Listing
October 2019

With Great Power Comes Great Responsibility: Defining the Safety of High-Power Short-Duration Atrial Ablation.

Circ Arrhythm Electrophysiol 2019 06 5;12(6):e007456. Epub 2019 Jun 5.

Division of Cardiovascular Medicine, Brigham and Women's Hospital Cardiac Arrhythmia Service and Harvard Medical School, Boston, MA (W.H.S.). Division of Cardiology, Section of Cardiac Electrophysiology, University of Colorado School of Medicine, Aurora (W.S.T.).

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http://dx.doi.org/10.1161/CIRCEP.119.007456DOI Listing
June 2019

Ambulatory Rhythm Monitoring to Detect Late High-Grade Atrioventricular Block Following Transcatheter Aortic Valve Replacement.

J Am Coll Cardiol 2019 05;73(20):2538-2547

University of Colorado School of Medicine, Division of Cardiology, Aurora, Colorado. Electronic address:

Background: High-grade atrioventricular block (H-AVB) is a well-described in-hospital complication of transcatheter aortic valve replacement (TAVR). Delayed high-grade atrioventricular block (DH-AVB) has not been systematically studied among outpatients post-TAVR, using latest-generation TAVR technology and in the early post-TAVR discharge era.

Objectives: The purpose of this study was to assess utility of ambulatory event monitoring (AEM) in identifying post-TAVR DH-AVB and associated risk factors.

Methods: Patients without pre-existing pacing device undergoing TAVR at the University of Colorado Hospital from October 2016 to March 2018, and who did not require permanent pacemaker implantation pre-discharge, were discharged with 30-day AEM to assess for DH-AVB (≥2 days post-TAVR). Clinical and follow-up data were collected and compared among those without incident H-AVB.

Results: Among 150 consecutive TAVR patients without a prior pacing device, 18 (12%) developed H-AVB necessitating permanent pacemaker <2 days post-TAVR, 1 died pre-discharge, and 13 declined AEM; 118 had 30-day AEM data. DH-AVB occurred in 12 (10% of AEM patients, 8% of total cohort) a median of 6 days (range 3 to 24 days) post-TAVR. DH-AVB versus non-AVB patients were more likely to have hypertension and right bundle branch block (RBBB). Sensitivity and specificity of RBBB in predicting DH-AVB was 27% and 94%, respectively.

Conclusions: DH-AVB is an underappreciated complication of TAVR among patients without pre-procedure pacing devices, occurring at rates similar to in-hospital, acute post-TAVR H-AVB. RBBB is a risk factor for DH-AVB but has poor sensitivity, and other predictors remain unclear. In this single-center analysis, AEM was helpful in expeditious identification and treatment of 10% of post-TAVR outpatients. Prospective study is needed to clarify incidence, risk factors, and patient selection for outpatient monitoring.
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http://dx.doi.org/10.1016/j.jacc.2019.02.068DOI Listing
May 2019

Long term follow-up after ventricular tachycardia ablation in patients with congenital heart disease.

J Cardiovasc Electrophysiol 2019 09 11;30(9):1560-1568. Epub 2019 Jun 11.

Electrophysiology Section, Division of Cardiology, University of Colorado, Aurora, Colorado.

Background: Ventricular tachycardia (VT) is frequently encountered in patients with repaired and unrepaired congenital heart disease (CHD), causing significant morbidity and sudden cardiac death. Data regarding underlying VT mechanisms and optimal ablation strategies in these patients remain limited.

Objective: To describe the electrophysiologic mechanisms, ablation strategies, and long-term outcomes in patients with CHD undergoing VT ablation.

Methods: Forty-eight patients (mean age 41.3 ± 13.3 years, 77.1% male) with CHD underwent a total of 57 VT ablation procedures at two centers from 2000 to 2017. Electrophysiologic and follow-up data were analyzed.

Results: Of the 77 different VTs induced at initial or repeat ablation, the underlying mechanism in 62 (81.0%) was due to scar-related re-entry; the remaining included four His-Purkinje system-related macrore-entry VTs and focal VTs mainly originating from the outflow tract region (8 of 11, 72.7%). VT-free survival after a single procedure was 72.9% (35 of 48) at a median follow-up of 53 months. VT-free survival after multiple procedures was 85.4% (41 of 48) at a median follow-up of 52 months. There were no major complications. Three patients died during the follow-up period from nonarrhythmic causes, including heart failure and cardiac surgery complication.

Conclusion: While scar-related re-entry is the most common VT mechanism in patients with CHD, importantly, nonscar-related VT may also be present. In experienced tertiary care centers, ablation of both scar-related and nonscar-related VT in patients with CHD is safe, feasible, and effective over long-term follow-up.
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http://dx.doi.org/10.1111/jce.13996DOI Listing
September 2019

Bucindolol for the Maintenance of Sinus Rhythm in a Genotype-Defined HF Population: The GENETIC-AF Trial.

JACC Heart Fail 2019 07 29;7(7):586-598. Epub 2019 Apr 29.

Population Health Research Institute, McMaster University, Hamilton, Ontario, Canada.

Objectives: The purpose of this study was to compare the effectiveness of bucindolol with that of metoprolol succinate for the maintenance of sinus rhythm in a genetically defined heart failure (HF) population with atrial fibrillation (AF).

Background: Bucindolol is a beta-blocker whose unique pharmacologic properties provide greater benefit in HF patients with reduced ejection fraction (HFrEF) who have the beta-adrenergic receptor (ADRB1) Arg389Arg genotype.

Methods: A total of 267 HFrEF patients with a left ventricular ejection fraction (LVEF) <0.50, symptomatic AF, and the ADRB1 Arg389Arg genotype were randomized 1:1 to receive bucindolol or metoprolol therapy and were up-titrated to target doses. The primary endpoint of AF or atrial flutter (AFL) or all-cause mortality (ACM) was evaluated by electrocardiogram (ECG) during a 24-week period.

Results: The hazard ratio (HR) for the primary endpoint was 1.01 (95% confidence interval [CI]: 0.71 to 1.42), but trends for bucindolol benefit were observed in several subgroups. Precision therapeutic phenotyping revealed that a differential response to bucindolol was associated with the interval of time from the initial diagnoses of AF and HF to randomization and with the onset of AF relative to that of the initial HF diagnosis. In a cohort whose first AF and HF diagnoses were <12 years prior to randomization, in which AF onset did not precede HF by more than 2 years (n = 196), the HR was 0.54 (95% CI: 0.33 to 0.87; p = 0.011).

Conclusions: Pharmacogenetically guided bucindolol therapy did not reduce the recurrence of AF/AFL or ACM compared to that of metoprolol therapy in HFrEF patients, but populations were identified who merited further investigation in future phase 3 trials.
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http://dx.doi.org/10.1016/j.jchf.2019.04.004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7205445PMC
July 2019

VT arising from sub-aortic muscular outflow tract structures: In two patients with ventricular septal defects.

Pacing Clin Electrophysiol 2019 08 13;42(8):1155-1157. Epub 2019 Apr 13.

Electrophysiology Section, Division of Cardiology, University of Colorado, Denver, Colorado.

Background: Outflow tract ventricular tachycardias (OTVT) most commonly occur in the absence of structural abnormalities. We present two cases in which a structural variant in the outflow tract was critical to the OTVT.

Cases: Subaortic muscular bands were identified using intracardiac echocardiography (ICE) in each of our cases with history of VSD and VT. Mapping demonstrating their critical involvement to the tachycardia and ablation along the muscular bands rendered the ventricular tachycardias non-inducible.

Conclusion: In rare instances, a structural variant may be involved in OTVTs. The use of ICE along with electroanatomic mapping can assist in successful ablation of these ventricular tachycardias.
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http://dx.doi.org/10.1111/pace.13688DOI Listing
August 2019

Ablation of atrial arrhythmias in patients with cardiogenic shock on mechanical circulatory support.

HeartRhythm Case Rep 2019 Mar 28;5(3):115-119. Epub 2018 Nov 28.

Division of Cardiology, Section of Electrophysiology, University of Colorado, Denver, Aurora, Colorado.

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http://dx.doi.org/10.1016/j.hrcr.2018.11.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6404096PMC
March 2019

Esophageal position, measured luminal temperatures, and risk of atrioesophageal fistula with atrial fibrillation ablation.

Pacing Clin Electrophysiol 2019 Apr 28;42(4):458-463. Epub 2019 Feb 28.

Section of Electrophysiology, The University of Colorado, Aurora, Colorado.

Background: Despite improvement in catheter ablation for atrial fibrillation (AF), ability to recognize and prevent esophageal injury remains challenging. We hypothesized that esophageal course may impact esophageal heating, as measured through ablation, and thereby, risk of injury.

Methods: We evaluated all patients undergoing first-time AF ablation with preprocedural computed tomography (CT) imaging from 2014 to 2016 at our institution, focusing on esophageal position at the left atrial (LA)/pulmonary vein junction. Esophageal luminal temperatures (ELTs) were analyzed by esophageal course. In exploratory work by investigation of published reports of atrioesophageal fistula (AEF), we evaluated for a relationship between esophageal course and risk of AEF.

Results: Of 68 patients, 48.5% had midline, 36.8% leftward, and 14.7% rightward esophageal positions. Of 20 patients (29% of cohort) with esophageal confinement-defined as a midline or leftward position relative to the LA, vertebrae, and aorta, with luminal distortion-14 had leftward position. No significant differences in patient or procedure characteristics were noted between confinement and nonconfinement cohorts. The average peak ELT was significantly higher in those with confinement (36.9°C vs 36.2°C, P < 0.05) and confinement with a left-sided esophagus (37.1°C vs 36.2°C, P < 0.05). There was a significant correlation between esophageal confinement and risk of AEF (odds ratio [OR]: 2.7, 95% confidence interval [CI]: 1.2-6.2, P < 0.01).

Conclusion: Approximately one-third of patients undergoing AF ablation display leftward esophageal course along the ablation zone on preprocedure CT imaging, with a significant portion exhibiting esophageal confinement. In those with confinement, higher peak ELTs are noted with ablation. Esophageal confinement may be a risk factor for development of AEF.
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http://dx.doi.org/10.1111/pace.13639DOI Listing
April 2019

Effect of Environmental Impedance Surrounding a Radiofrequency Ablation Catheter Electrode on Lesion Characteristics

J Cardiovasc Electrophysiol 2018 11 22;28(5):564-569. Epub 2018 Nov 22.

University of Colorado, Section of Cardiac Electrophysiology, Division of Cardiology, Aurora, Colorado, USA.

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http://dx.doi.org/10.1111/jce.13185DOI Listing
November 2018

Safety and outcomes of catheter ablation for atrial fibrillation in adults with congenital heart disease: A multicenter registry study.

Heart Rhythm 2019 06 26;16(6):846-852. Epub 2018 Dec 26.

University of Colorado, Aurora, Colorado. Electronic address:

Background: An increasing number of adults with congenital heart disease (CHD) are undergoing catheter ablation for atrial fibrillation (AF). Data on ablation strategy and outcomes in CHD are limited. Rhythm control is often believed to be of greater importance among patients with complex CHD.

Objective: The purpose of this study was to examine the safety and efficacy of AF ablation in adult patients with CHD.

Methods: A multicenter retrospective analysis was performed of CHD patients undergoing AF ablation. Clinical data were collected, including AF and CHD type, procedural data, and outcomes. Patients were divided into 3 groups (simple, moderate, and severe) based on CHD complexity, as defined by the 2014 PACES/HRS (Pediatric and Congenital Electrophysiology Society/Heart Rhythm Society) consensus statement. One-year procedural success was defined as freedom from recurrent AF, off antiarrhythmic drugs (complete) or off/on previously failed antiarrhythmic drugs (partial).

Results: Overall, 84 CHD patients (mean age 51.5 ± 12.1 years; 65.5% male; 45.2% with paroxysmal AF) undergoing AF ablation (51 simple, 22 moderate, 11 severe complexity) were included. Pulmonary vein isolation was performed in 80 (95.2%), of whom 30 (35.7%) underwent pulmonary vein isolation alone. Overall, complete and complete/partial freedom was achieved at 1 year in 53.1% and 71.6%, respectively, with no significant differences between those with simple, moderate, or severe complexity. There were no major complications and 7 minor complications, and 2 patients died during follow-up.

Conclusion: There are dramatic differences in the degree of CHD complexity among patients referred for AF ablation. When performed at experienced centers, AF ablation is safe and effective even among patients with the most complex forms of CHD.
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http://dx.doi.org/10.1016/j.hrthm.2018.12.024DOI Listing
June 2019

Predictive Score for Identifying Survival and Recurrence Risk Profiles in Patients Undergoing Ventricular Tachycardia Ablation: The I-VT Score.

Circ Arrhythm Electrophysiol 2018 12;11(12):e006730

San Raffaele Hospital, Milan, Italy (P.V., P.D.B.).

Background: Several distinct risk factors for arrhythmia recurrence and mortality following ventricular tachycardia (VT) ablation have been described. The effect of concurrent risk factors has not been assessed so far; thus, it is not yet possible to estimate these risks for a patient with several comorbidities. The aim of the study was to identify specific risk groups for mortality and VT recurrence using the Survival Tree (ST) analysis method.

Methods: In 1251 patients 16 demographic, clinical and procedure-related variables were evaluated as potential prognostic factors using ST analysis using a recursive partitioning algorithm that searches for relationships among variables. Survival time and time to VT recurrence in groups derived from ST analysis were compared by a log-rank test. A random forest analysis was then run to extract a variable importance index and internally validate the ST models.

Results: Left ventricular ejection fraction, implantable cardioverter defibrillator/cardiac resynchronization device, previous ablation were, in hierarchical order, identified by ST analysis as best predictors of VT recurrence, while left ventricular ejection fraction, previous ablation, Electrical storm were identified as best predictors of mortality. Three groups with significantly different survival rates were identified. Among the high-risk group, 65.0% patients were survived and 52.1% patients were free from VT recurrence; within the medium- and low-risk groups, 84.0% and 97.2% patients survived, 72.4% and 88.4% were free from VT recurrence, respectively.

Conclusions: Our study is the first to derive and validate a decisional model that provides estimates of VT recurrence and mortality with an effective classification tree. Preprocedure risk stratification could help optimize periprocedural and postprocedural care.
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http://dx.doi.org/10.1161/CIRCEP.118.006730DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6301075PMC
December 2018
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