Kairav Vakil

FREEDOM FROM RECURRENT VENTRICULAR TACHYCARDIA AFTER CATHETER ABLATION IS ASSOCIATED WITH IMPROVED SURVIVAL IN PATIENTS WITH STRUCTURAL HEART DISEASE: AN INTERNATIONAL VT ABLATION CENTER COLLABORATIVE GROUP STUDY

BACKGROUND The impact of catheter ablation of ventricular tachycardia (VT) on all-cause mortality remains unknown. OBJECTIVE The purpose of this study was to examine the association between VT recurrence after ablation and survival in patients with scar-related VT. METHODS Analysis of 2061 patients with structural heart disease referred for catheter ablation of scar-related VT from 12 international centers was performed. Data on clinical and procedural variables, VT recurrence, and mortality were analyzed. Kaplan-Meier analysis was used to estimate freedom from recurrent VT, transplant, and death. Cox proportional hazards frailty models were used to analyze the effect of risk factors on VT recurrence and mortality. RESULTS One-year freedom from VT recurrence was 70% (72% in ischemic and 68% in nonischemic cardiomyopathy). Fifty-seven patients (3%) underwent cardiac transplantation, and 216 (10%) died during follow-up. At 1 year, the estimated rate of transplant and/or mortality was 15% (same for ischemic and nonischemic cardiomyopathy). Transplant-free survival was significantly higher in patients without VT recurrence than in those with recurrence (90% vs 71%, P<.001). In multivariable analysis, recurrence of VT after ablation showed the highest risk for transplant and/or mortality [hazard ratio 6.9 (95% CI 5.3-9.0), P<.001]. In patients with ejection fraction <30% and across all New York Heart Association functional classes, improved transplant-free survival was seen in those without VT recurrence. CONCLUSION Catheter ablation of VT in patients with structural heart disease results in 70% freedom from VT recurrence, with an overall transplant and/or mortality rate of 15% at 1 year. Freedom from VT recurrence is associated with improved transplant-free survival, independent of heart failure severity.

Safety and efficacy of the MitraClip® system for severe mitral regurgitation: a systematic review.

The MitraClip® system is a newer percutaneous device that has shown promising results but data on its safety and efficacy in low‐ and high‐surgical risk populations continues to evolve. We performed a systematic review of the published studies reporting the safety and efficacy of MitraClip® implantation for treatment of moderate to severe and severe mitral regurgitation (MR).

A retrospective analysis of proceduralist-directed, nurse-administered propofol sedation for implantable cardioverter-defibrillator procedures

BACKGROUND There is controversy whether proceduralist-directed, nurse-administered propofol sedation (PDNAPS) is safe. OBJECTIVE To assess the frequency of adverse events when PDNAPS is used for implantable cardioverter-defibrillator (ICD)-related procedures and to determine the patient and procedural characteristics associated with adverse events. METHODS Consecutive ICD-related procedures using PDNAPS from May 2006 to July 2009 at a tertiary-care hospital were evaluated. Serious adverse events were defined as procedural death, unexpected transfer to an intensive care unit, respiratory failure requiring intubation/bag-mask ventilation, or hypotension requiring vasoconstrictor/inotrope support. Nonserious adverse events were defined as hypotension requiring fluid resuscitation or hypoxemia requiring augmented respiratory support with non-rebreather mask, oral airway, or jaw lift. RESULTS Of 582 patients (age 64 ± 14 years, 72.3% males) undergoing ICD-related procedures using PDNAPS, 58 (10.0%) patients had serious adverse events with no procedural death and 225 (38.7%) had nonserious adverse events. Longer procedure duration (relative risk [RR] = 2.1 per hour; 95% confidence interval [CI] = 1.6-2.8; P < .001) and biventricular implant (RR = 2.7; CI = 1.4-5.3; P = .003) were independent predictors of serious adverse events. A longer procedure duration (RR = 1.4 per hour; CI = 1.1-1.7; P = .001), heart failure class (RR = 1.4 per 1 class; CI = 1.1-1.7; P = .002), and use of propofol infusion (RR = 3.5; CI = 2.2-5.7; P < .001) were independent predictors of nonserious adverse events. CONCLUSION PDNAPS for shorter ICD procedures including single- and dual-chamber implants, generator changes, and defibrillation threshold testing have acceptable rates of serious adverse events and manageable nonserious adverse events and should be considered for further study. Biventricular implants and other complex procedures should be done with an anesthesiologist.

Incidence, predictors, and temporal trends of sudden cardiac death after heart transplantation.

BACKGROUND Sudden cardiac death (SCD) has been reported to be a significant mode of death after heart transplantation (HT) in small case series. However, the incidence, timing, and predictors of SCD have not been examined in a large multicenter HT cohort. OBJECTIVE The purpose of this study was to examine the incidence, timing, predictors, and temporal trends of SCD after HT. METHODS Adults (≥18 years) who underwent first-time HT in the United States between 1987 and 2012 were retrospectively identified from the United Network for Organ Sharing (UNOS) registry. Patients with sudden cardiac arrest as the primary cause of death constituted the SCD group. RESULTS Data on 37,492 HT recipients (mean age 51.9 ± 11.7 years, 77% male, 78% Caucasian) were analyzed. During mean follow-up of 6.5 ± 5.7 years, there were 17,324 (46%) deaths, of which 1659 (9.6%) were SCD. On multivariate Cox regression analysis, left ventricular ejection fraction (LVEF) ≤40% (hazard ratio [HR] 3.67, 95% confidence interval [CI] 3.23-4.17, P < .0001), allograft rejection (HR 1.51, 95% CI 1.35-1.70, P < .0001), and donor age (HR 1.17, 95% CI 1.13-1.23, P < .0001) were associated with increased risk of SCD, whereas recipient age (HR 0.90, 95% CI 0.86-0.95, P < .0001) and Caucasian race (HR 0.61, 95% CI 0.54-0.69, P < .0001) were associated with reduced risk. The incidence of SCD has shown no significant temporal improvement since 1987 (log-rank P = .84). CONCLUSION Approximately 10% of deaths after HT are due to SCD. Allograft rejection and LVEF ≤40% are strong predictors of SCD in adult HT patients. Whether implantable cardioverter-defibrillators would reduce mortality in these patients with a relative higher risk of non-SCD remains to be determined.

Impact of pre-transplant pulmonary hypertension on survival after heart transplantation: a UNOS registry analysis.

INTRODUCTION Severe pre-transplant pulmonary hypertension (PH) has been associated with adverse short-term clinical outcomes after heart transplantation in relatively small single-center studies. The impact of pre-transplant PH on long-term survival after heart transplantation has not been examined in a large, multi-center cohort. METHODS Adults (≥18 years) who underwent first time heart transplantation in the United States between 1987 and 2012 were retrospectively identified from the United Network for Organ Sharing registry. Pre-transplant PH was classified as mild, moderate, or severe based on pulmonary vascular resistance (PVR), trans-pulmonary gradient (TPG), and pulmonary artery (PA) mean pressure. Primary outcome was all-cause mortality. RESULTS Data from 26,649 heart transplant recipients (mean age 52±12 years; 76% male; 76% Caucasian) were analyzed. During a mean follow-up of 5.7±4.8 years, there were 10,334 (39%) deaths. Pre-transplant PH (PVR≥2.5 WU) was a significant predictor of mortality (hazard ratio 1.10, 95% confidence interval 1.05-1.14, p<0.0001) in multivariable analysis. However, the severity of pre-transplant PH (mild/moderate vs. severe) did not affect short or long-term survival. Similarly, even in patients who were supported with either a left ventricular assist device or a total artificial heart prior to transplant, severe pre-transplant PH was not associated with worse survival when compared to patients with mild/moderate pre-transplant PH. CONCLUSION Pre-transplant PH (PVR≥2.5 WU) is associated with a modest increase in mortality when compared to patients without pre-transplant PH. However, the severity of pre-transplant PH, assessed by PVR, TPG, or mean PA pressure, is not a discriminating factor for poor survival in patients listed for heart transplantation.

Association of implantable cardioverter defibrillators with survival in patients with and without improved ejection fraction secondary analysis of the sudden cardiac death in heart failure trial

Importance Improvement in left ventricular ejection fraction (EF) to >35% occurs in many patients with reduced EF at baseline. To our knowledge, whether implantable cardioverter defibrillator (ICD) therapy improves survival for these patients is unknown. Objective To examine the efficacy of ICD therapy in reducing risk of all-cause mortality and sudden cardiac death among patients with an EF ⩽35% at baseline, with or without an improvement in EF to >35% during follow-up. Design, Setting, and Participants This retrospective analysis examined data collected in the Sudden Cardiac Death in Heart Failure Trial (SCD-HeFT), which randomly assigned 2521 patients to placebo, amiodarone, or ICD between 1997 and 2001. A subset of 1902 participants (75.4%) of the SCD-HeFT had a repeated assessment of EF a mean (SD) of 13.5 (6) months after randomization. We stratified these patients by EF ⩽35% and >35% based on the first repeated EF measurement after randomization and compared all-cause mortality in 649 patients randomized to placebo vs 624 patients randomized to ICD. Follow-up started with the repeated EF assessment. Analysis was performed between January 2016 and July 2016. Exposures Implantable cardioverter-defibrillator therapy. Main Outcomes and Measures All-cause mortality and sudden cardiac death. Results Of the included 1273 patients, the mean (SD) age was 59 (12) years, and 977 (76.7%) were male and 1009 (79.3%) were white. Repeated EF was >35% in 186 participants (29.8%) randomized to ICD and 185 participants (28.5%) randomized to placebo. During a median follow-up of 30 months, the all-cause mortality rate was lower in the ICD vs placebo group, both in patients whose EF remained ⩽35% (7.7 vs 10.7 per 100 person-year follow-up) and in those whose EF improved to >35% (2.6 vs 4.5 per 100 person-year follow-up). Compared with placebo, the adjusted hazard ratio for the effect of ICD on mortality was 0.64 (95% CI, 0.48-0.85) in patients with a repeated EF of ⩽35% and 0.62 (95% CI, 0.29-1.30) in those with a repeated EF >35%. There was no interaction between treatment assignment and repeated EF for predicting mortality. Conclusions and Relevance Among participants in the SCD-HeFT who had a repeated EF assessment during the course of follow-up, those who had an improvement in EF to >35% accrued a similar relative reduction in mortality with ICD therapy as those whose EF remained ⩽35%. Prospective randomized clinical trials are needed to test ICD efficacy in patients with an EF >35%. Trial Registration clinicaltrials.gov Identifier: NCT01114269

Effect of coronary artery bypass grafting on left ventricular ejection fraction in men eligible for implantable cardioverter-defibrillator

Implantable cardioverter-defibrillator (ICD) therapy for primary prevention of sudden cardiac death is not routinely recommended within 90 days of coronary artery bypass grafting (CABG) because of the possibility of an improvement in left ventricular ejection fraction (EF) to>35% after revascularization. We sought to determine the incidence and predictors of EF improvement to >35% after isolated CABG in patients who had a preoperative EF ≤35%. We studied 375 patients who underwent CABG at a tertiary institution and had an echocardiogram preoperatively and postoperatively. Of these, 74 patients (20%) with a preoperative EF ≤35% were included in this analysis. Improvement in EF was defined as postoperative EF >35%. In the overall study population (n = 74), mean EF improved from 28 ± 6% preoperatively to 36 ± 12% postoperatively (p <0.0001). A total of 38 patients (51%) had postoperative improvement in EF to >35% (mean EF in these patients increased from 30 ± 5% to 46 ± 8%; p <0.0001). Patients with EF improvement had a higher preoperative EF than those with no improvement (30 ± 5% vs 26 ± 7%, p <0.005). Improvement in EF was 5 times more likely in patients with preoperative EF 26% to 35% (odds ratio 4.95, 95% CI 1.73 to 14.1; p = 0.003) than those with preoperative EF ≤25%. Other clinical characteristics were not significantly different between patients with versus without EF improvement. In conclusion, more than half of the ICD-eligible patients who underwent CABG improved their EF to >35% after surgery and became ineligible for a primary prevention ICD. EF improvement was unlikely in patients with preoperative EF <25%.

Outcomes after repeat ablation of ventricular tachycardia in structural heart disease: An analysis from the International VT Ablation Center Collaborative Group

BACKGROUND Data evaluating repeat radiofrequency ablation (>1RFA) of ventricular tachycardia (VT) are limited. OBJECTIVE The purpose of this study was to determine the safety and outcomes of VT >1RFA in patients with structural heart disease. METHODS Patients with structural heart disease undergoing VT RFA at 12 centers with data on prior RFA history were included. Characteristics and outcomes were compared between first-time (1RFA) and >1RFA patients. RESULTS Of 1990 patients, 740 had >1RFA (mean 1.4 ± 0.9, range 1-10). >1RFA vs 1RFA patients did not differ with regard to age (62 ± 13 years vs 62 ± 13 years), left ventricular ejection fraction (33% ± 13% vs 34% ± 13%), or sex (88% vs 87% men), but they more often were nonischemic (53% vs 41%), had implantable cardioverter-defibrillator shocks (70% vs 63%) or VT storm (38% vs 33%), and had been treated with amiodarone (55% vs 48%) or ≥2 antiarrhythmic drugs (22% vs 14%). >1RFA procedures were longer (300 ± 122 minutes vs 266 ± 110 minutes), involved more epicardial access (41% vs 21%), induced VTs (2.4 ± 2.2 vs 1.9 ± 1.6) and only unmappable VTs (15% vs 9%), and VT was more often inducible after RFA (42% vs 33%, all P <.03). Total complications were higher for >1RFA vs 1RFA (8% vs 5%, P <.01), mostly related to pericardial effusion (2.4% vs 1.3%, P = .07) and venous thrombosis (0.8% vs 0.2%, P = .06). VT recurrence was higher for >1RFA vs 1RFA (29% vs 24%, P <.001). Survival was worse for >1RFA vs 1RFA if VT recurred (67% vs 78%, P = .003) but was equivalent if successful (93% vs 92%, P = .96). CONCLUSION Patients requiring repeat VT ablation differ significantly from those undergoing first-time ablation. Despite more challenging ablation characteristics, VT-free survival after repeat ablations is encouraging. Mortality is comparable if VT does not recur after RFA at specialized centers.

Sex and Catheter Ablation for Ventricular Tachycardia: An International Ventricular Tachycardia Ablation Center Collaborative Group Study.

Importance Significant differences have been described between women and men regarding presentation, mechanism, and treatment outcome of certain arrhythmias. Previous studies of ventricular tachycardia (VT) ablation have not included sufficient women for meaningful comparison. Objective To compare outcomes between women and men with structural heart disease undergoing VT ablation. Design, Setting, and Participants Investigator-initiated, multicenter, observational study performed between 2002 and 2013, conducted by the International VT Ablation Center Collaborative Group, consisting of 12 high-volume ablation centers. Consecutive patients with structural heart disease undergoing VT ablation were studied. Structural heart disease was defined as left ventricular ejection fraction less than 55%, hypertrophic cardiomyopathy, or right ventricular cardiomyopathy, with scar confirmed during electroanatomic mapping. Exposures Catheter ablation. Main Outcomes and Measures Ventricular tachycardia-free survival and transplant-free survival were compared between women and men. Cox proportional hazard modeling was performed. Results Of 2062 patients undergoing ablation, 266 (12.9%) were women. Mean (SD) age was 62.4 (13.3) years and 1095 (53.1%) had ischemic cardiomyopathy. Compared with men, women were younger, with higher left ventricular ejection fraction and less VT storm. Despite this, women had higher rates of 1-year VT recurrence following ablation (30.5% vs 25.3%; P = .03). This difference was only partially explained by higher prevalence of nonischemic cardiomyopathy among women and was actually most pronounced among those with ischemic cardiomyopathy. Conclusions and Relevance In 12 high-volume ablation centers, women with structural heart disease have worse VT-free survival following ablation than men. Whether this is owing to differences in referral pattern, arrhythmia substrate, or undertreatment requires further study.

Ventricular Tachycardia Ablation in Severe Heart Failure: An International Ventricular Tachycardia Ablation Center Collaboration Analysis

Background— Ventricular tachycardia (VT) radiofrequency ablation has been associated with reduced VT recurrence and mortality, although it is typically not considered among New York Heart Association class IV (NYHA IV) heart failure patients. We compared characteristics and VT radiofrequency ablation outcomes of those with and without NYHA IV in the International VT Ablation Center Collaboration. Methods and Results— NYHA II–IV patients undergoing VT radiofrequency ablation at 12 international centers were included. Clinical variables, VT recurrence, and mortality were analyzed by NYHA IV status using Kaplan–Meier analysis and Cox proportional hazard models. There were significant differences between NYHA IV (n=111) and NYHA II and III (n=1254) patients: NYHA IV had lower left ventricular ejection fraction; more had diabetes mellitus, kidney disease, cardiac resynchronization implantable cardioverter–defibrillator, and VT storm despite greater antiarrhythmic drug use (P<0.01). NYHA IV subjects required more hemodynamic support, were inducible for more and slower VTs, and were less likely to undergo final programmed stimulation. There was no significant difference in acute complications. In-hospital deaths, recurrent VT, and 1-year mortality were higher in the NYHA IV group, in the context of greater baseline comorbidities. Importantly, NYHA IV patients without recurrent VT had similar survival compared with NYHA II and III patients with recurrent VT (68% versus 73%). Early VT recurrence (⩽30 days) was significantly associated with mortality, especially in NYHA IV patients. Conclusions— Despite greater baseline comorbidities, VT radiofrequency ablation can be safely performed among NYHA IV patients. Early VT recurrence is significantly associated with subsequent mortality regardless of NYHA status. Elimination of recurrent VT in NYHA IV patients may reduce mortality to a level comparable to NYHA II and III with arrhythmia recurrence.