Faculty Bibliography

Background: Left ventricular outflow tract (LVOT) obstruction is associated with adverse outcomes in hypertrophic cardiomyopathy (HCM). AV sequential pacing has not demonstrated benefit for patients with medication-refractory LVOT obstruction in prospective, randomized clinical trials, although these trials did not include transthoracic echocardiogram (TTE) guided optimization or concomitant pharmacotherapy with disopyramide.
Objective(s): To evaluate efficacy of a standardized TTE guided AV optimization protocol for patients with persistent LVOT obstruction despite AV sequential pacing for reduction in LVOT gradient.
Method(s): Outcomes of 20 consecutive HCM patients with medication refractory LVOT gradients who were not surgical candidates and underwent AV sequential pacing from 8/2014 to 6/2017 were analyzed. ECG guided AV intervals were determined by the implanting cardiac electrophysiologist at the time of implant. Patients with incomplete response to initial settings underwent Doppler TTE guided AV optimization.
Result(s): All patients received maximally tolerated disopyramide and beta or calcium channel blockade. Following initial implant, 8 of 20 (40%) of patients had complete elimination of LVOT gradient with, and 12 of 20 (60%) had incomplete response and underwent TTE guided optimization. Compared to initial ECG guided programming, the TTE optimized sensed AV delays were shorter in all patients (mean reduction 51 +/- 48ms). Following TTE guided AV optimization, 9 of 12 patients had elimination of LVOT gradient, and 3 of 12 patients had 82.6 +/- 5.2% reduction in LVOT gradient. Patients undergoing TTE optimization had significant reduction in NYHA heart failure class (1.0 +/- 0 vs. 2.2 +/- 0.7, p=0.004).
Conclusion(s): TTE guided AV optimization shows promise as a means of improving outcomes in patients with incomplete response to medical therapy including disopyramide and AV sequential pacing for reduction of LVOT gradient in HCM.
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PURPOSE OF REVIEW/OBJECTIVE:Atrial fibrillation is the most common arrhythmia worldwide and is a major risk factor for embolic stroke. For patients with atrial fibrillation who are unable to tolerate systemic anticoagulation, left atrial appendage (LAA) occlusion has been shown to mitigate stroke risk. In this article, we describe the vital role of the echocardiographer in intraprocedural guidance of percutaneous LAA occlusion procedures as well as in the pre- and post-procedure assessment of these patients. RECENT FINDINGS/RESULTS:A few percutaneously delivered devices for LAA exclusion from the systemic circulation are available in contemporary practice. These devices employ an either exclusive endocardial LAA occlusion approach, such as the Watchman (Boston Scientific, Maple Grove, MN) and Amulet (St. Jude Medical, Minneapolis, MN), or both an endocardial and pericardial (epicardial) approach such as the Lariat procedure (SentreHEART, Palo Alto, CA). Two- and three-dimension transesophageal echocardiography is critical for patient selection, procedure planning, procedural guidance, and ensuring satisfactory immediate as well as long-term LAA occlusion/exclusion efficacy. This review will provide an overview of the role of the echocardiographer in all aspects of LAA occlusion/exclusion procedures for the most commonly used commercially available devices in current practice.

OBJECTIVES/OBJECTIVE:This study sought to determine whether a radiation safety time-out reduces radiation exposure in electrophysiology procedures. BACKGROUND:Time-outs are integral to improving quality and safety. The authors hypothesized that a radiation safety time-out would reduce radiation exposure levels for patients and the health care team members. METHODS:The study was performed at the New York University Langone Health Electrophysiology Lab. Baseline data were collected for 6 months prior to the time-out. On implementation of the time-out, data were collected prospectively with analyses to be performed every 3 months. The primary endpoint was dose area product. The secondary endpoints included reference point dose, fluoroscopy time, use of additional shielding, and use of alternative imaging such as intracardiac and intravascular ultrasound. RESULTS:, representing a 21% reduction (p = 0.007). The median reference point dose prior to time-out was 163 mGy, and during the time-out was 122 mGy (p = 0.011). The use of sterile disposable protective shields and ultrasound imaging for access increased significantly during the time-out. CONCLUSIONS:A radiation safety time-out significantly reduces radiation exposure in electrophysiology procedures. Electrophysiology laboratories, as well as other areas of cardiovascular medicine using fluoroscopy, should strongly consider the use of radiation safety time-outs to reduce radiation exposure and improve safety.

PURPOSE/OBJECTIVE:Elimination of pace-capture along pulmonary vein isolation (PVI) lesion sets reduces atrial fibrillation (AF) recurrence in catheter ablation of paroxysmal AF. Pacing from the RF ablation electrode during RF application is prevented within the CARTO electroanatomic mapping system (Biosense Webster, Inc.) due to theoretical safety considerations. We evaluated a method of pacing the distal ablation electrode during RF application in the CARTO system, thus avoiding repeated activation and inactivation of the pacing channel and facilitating immediate recognition of pace-capture loss. We investigated the safety, feasibility, and utility of simultaneous pace-ablate (SPA) during AF ablation with the CARTO-3 system and a contact-force sensing RF ablation catheter. METHODS:Safety of feasibility of SPA was evaluated in 250 patients undergoing first-time AF ablation. Frequency and regional distribution of pace-capture following PVI was evaluated in a cohort of 50 consecutive patients undergoing catheter ablation of paroxysmal AF. RESULTS:SPA was successfully performed in all 250 patients without adverse event. At least one pace-capture site was noted in 22 of 50 PAF patients (44%), and pace-capture following PVI was most common at anterior and superior left atrial sites. There were 2.0 ± 3.3 RF applications during pacing via the distal ablation electrode per patient, and all lesions sets were successfully rendered unexcitable. CONCLUSIONS:Pace-capture along the completed PVI lesion set remains common despite utilization of contact-force sensing RF ablation catheters and automated lesion annotation. Simultaneous pace-ablate in AF ablation using the CARTO system may be safely used to render atrial lesion sets unexcitable.

OBJECTIVES/OBJECTIVE:This study sought to investigate the effect of pacing mediated heart rate modulation on catheter-tissue contact and impedance reduction during radiofrequency ablation in human atria during atrial fibrillation (AF) ablation. BACKGROUND:In AF ablation, improved catheter-tissue contact enhances lesion quality and acute pulmonary vein isolation rates. Previous studies demonstrate that catheter-tissue contact varies with ventricular contraction. The authors investigated the impact of modulating heart rate on the consistency of catheter-tissue contact and its effect on lesion quality. METHODS:Twenty patients undergoing paroxysmal AF ablation received ablation lesions at 15 pre-specified locations (12 left atria, 3 right atria). Patients were assigned randomly to undergo rapid atrial pacing for either the first half or the second half of each lesion. Contact force and ablation data with and without pacing were compared for each of the 300 ablation lesions. RESULTS:Compared with lesion delivery without pacing, pacing resulted in reduced contact force variability, as measured by contact force SD, range, maximum, minimum, and time within the pre-specified goal contact force range (p < 0.05). There was no difference in the mean contact force or force-time integral. Reduced contact force variability was associated with a 30% greater decrease in tissue impedance during ablation (p < 0.001). CONCLUSIONS:Pacing induced heart rate acceleration reduces catheter-tissue contact variability, increases the probability of achieving pre-specified catheter-tissue contact endpoints, and enhances impedance reduction during ablation. Modulating heart rate to improve catheter-tissue contact offers a new approach to optimize lesion quality in AF ablation. (The Physiological Effects of Pacing on Catheter Ablation Procedures to Treat Atrial Fibrillation [PEP AF]; NCT02766712).

Background: Unfavorable outcomes for stepwise linear ablation of non-paroxysmal atrial fbrillation (NPAF) in clinical trials may be attributable to pro-arrhythmic effects of incomplete ablation lines. It is unknown if recurrent arrhythmia following stepwise linear ablation is more likely to be successfully ablated compared to recurrent arrhythmia following a more limited initial procedure The optimal ablation strategy for catheter ablation of NPAF using a contact-force sensing (CFS) radiofrequency ablation (RFA) catheter remains unclear. Objective: To compare 2-procedure outcomes of stepwise linear RFA to left atrial posterior wall isolation in patients undergoing NPAF ablation using a CFS RFA catheter. Methods: We compared clinical outcomes of two cohorts of 100 consecutive NPAF patients undergoing frst-time RFA using a CFS RFA catheter. Group 1: stepwise linear ablation (July 2014-July 2015); Group 2: left atrial posterior wall isolation (October 2015-June 2016). Arrhythmia recurrence was assessed using 2-week event monitors at 3-month intervals following ablation procedures. Results: Baseline characteristics of the two groups were similar. Mean follow-up time was 656 +/- 361 days for Group 1 and 436 +/- 228 days for Group 2. At 24-month follow up, Kaplan-Meier estimated single procedure arrhythmia free survival was signifcantly greater in Group 2 compared to Group 1 (76% vs 59%, respectively; p = 0.01), primarily driven by a higher rate of recurrence of atrial tachycardia (12% vs 35%, respectively; p < 0.001). Among patients with recurrent arrhythmia after a single procedure, Group 2 patients were less likely to require repeat ablation compared to Group 1 (6/24 vs 34/41, respectively; p < 0.001) and less likely to recur after repeat ablation (1/6 vs 13/34, respectively; p = 0.001). Conclusion: Compared to stepwise linear ablation, LA posterior wall isolation for catheter ablation of NPAF resulted in a lower incidence of recurrent arrhythmia at 2 years, a lower likelihood of requiring repeat ablation amongst patients with recurrence, and a lower likelihood of recurrence following a second ablation

Background: Catheter ablation has become an increasingly common elective therapy for symptomatic atrial fbrillation (AF). Few data are available regarding outcomes of urgent AF ablation performed during AF related hospital admission, and the impact of these procedures on healthcare utilization. Objective: To evaluate patient characteristics, procedural outcomes, and impact on healthcare utilization in patients undergoing urgent AF ablation. Methods: Procedural outcomes of patients undergoing urgent frst-time AF ablation during an AF related hospital admission between 1/2014 and 8/2017 at a single tertiary care medical center were compared to those of 2:1 matched control patients undergoing frst-time elective AF ablation. An inverse probability weighted marginal structural model was constructed and the weighted means of the average hospital days and number of hospital visits in the six-months post ablation were compared. Results: 25 patients (1% of frst-time AF ablations) underwent an urgent procedure. There were no major procedural complications in either group. Incidence of arrhythmia recurrence within one year was similar in urgent and elective patients (20% vs. 18%, respectively, p=0.85). Urgent ablation patients had a greater number of hospital utilization days in the 6-months pre-ablation (mean 8.9+/-4.5 vs 2.6+/-1.1, p<.001) and a similar number of hospital utilization days in the 6-months post-ablation (1.8+/-4.5 vs 0.59+/- 1.07, p=.05) The marginal structural model of the change in number of hospital visits due to being in the urgent ablation group was-0.924 (-1.43 to-0.41; P <0.001). Conclusion: Urgent ablation for treatment resistant, symptomatic AF is feasible and safe with procedural outcomes were similar to those of elective AF ablation. There is and increased rate of healthcare utilization in prior to ablation in the urgent group, and a statistically signifcant reduction in healthcare utilization following urgent AF ablation. Defning the cost-effectiveness of and optimal patient selection for urgent ablation requires further investigation

Background: Optimal contact-force during atrial fbrillation (AF) radiofrequency (RF) ablation is associated with improved procedural outcomes The extent to which ablation catheter spatial stability varies between patients and predicts procedural success is unknown. Objective: To examine the prognostic signifcance of intra-procedure ablation catheter spatial stability on one year arrhythmia recurrence following ablation of paroxysmal atrial fbrillation. Methods: 100 consecutive patients undergoing frst time RF ablation for paroxysmal AF under general anesthesia were analyzed. Spatial localization of the ablation catheter sampled at 60 Hz during RF application was extracted from the CARTO3 system (Biosense Webster, Inc.) and analyzed using custom software (MATLAB, Mathworks, USA) to determine mean and maximum catheter excursion relative to mean catheter location during point-by-point RF ablation. All lesions for a given patient were then averaged to form composite measures of catheter stability The primary end point was freedom from documented recurrence of atrial arrhythmia lasting longer than 30 seconds after a single ablation procedure. Results: At one year, 86% of patients were free from recurrent AF. There was no signifcant difference in clinical and echocardiographic baseline characteristics between patients with and without recurrent arrhythmia There was no signifcant difference in lesion number, average contact-force, average impedance decrease, or RF time between patients who did recur and those who did not. For all patients, maximum catheter excursion was 2.84 +/- 0.40mm and mean catheter excursion was 0.99 +/- 0.16mm. Patients with arrhythmia recurrence had signifcantly greater maximum (3.07 +/- 0.38mm vs 2.80 +/- 0.40mm, p = 0.03) and mean (1.08 +/- 0.13mm vs 0.98 +/- 0.17mm, p = 0.01) catheter excursion compared to those without recurrence. Univariate regression demonstrated that maximal catheter excursion was a signifcant predictor of arrhythmia recurrence (OR 5.1 per 1mm excursion increase, 95% CI 1.2-21.9, p=0.03). Conclusion: Quantitative measures of ablation catheter spatial stability may be novel and potentially modifable predictors of procedural success during RF ablation of AF