Atrial fibrillation symptom reduction and improved quality of life following the hybrid convergent procedure: a CONVERGE trial subanalysis.

Background: CONVERGE was a prospective, multicenter, randomized controlled trial that evaluated the safety of Hybrid Atrial Fibrillation Convergent (HC) and compared its effectiveness to endocardial catheter ablation (CA) for the treatment of persistent atrial fibrillation (PersAF) and longstanding PersAF (LSPAF). In 2020, we reported that CONVERGE met its primary safety and effectiveness endpoints. The primary objective of the present study is to report CONVERGE trial results for quality of life (QOL) and Class I/III anti-arrhythmic drug (AAD) utilization following HC. Methods: Eligible patients had drug-refractory symptomatic PersAF or LSPAF and a left atrium diameter ≤6.0 cm. Enrolled patients were randomized 2:1 to receive HC or CA. Atrial Fibrillation Severity Scale (AFSS) and the 36-Item Short Form Health Survey (SF-36) were assessed at baseline and 12 months; statistical comparison was performed using paired t-tests. AAD utilization at baseline through 12 and 18 months post-procedure was evaluated; statistical comparison was performed using McNemar's tests. Results: A total of 153 patients were treated with either HC (n=102) or CA (n=51). Of the 102 HC patients, 38 had LSPAF. AFSS and SF-36 Mental and Physical Component scores were significantly improved at 12 months versus baseline with HC overall and for the subset of LSPAF patients treated with either HC or CA. The proportion of HC patients (n=102) who used Class I /III AADs at 12 and 18 months was significantly less (33.3% and 36.3%, respectively) than baseline (84.3%; P<0.001). In LSPAF patients who underwent HC (n=38), AADs use was 29.0% through 18 months follow-up versus 71.1% at baseline (P<0.001). Conclusions: HC reduced AF symptoms, significantly improved QOL, and reduced AAD use in patients with PersAF and LSPAF. ClinicalTrialsgov Identifier: NCT01984346.

Cost-effectiveness of the convergent procedure and catheter ablation for non-paroxysmal atrial fibrillation.

OBJECTIVE: Patients with persistent or longstanding atrial fibrillation have modest success achieving sinus rhythm with catheter ablation or rhythm control medications. Their high risk of stroke, bleed, and heart failure leads to significant morbidity and health care costs. The convergent procedure has been shown to be successful in this population, with 80% of patients in sinus rhythm after 1 year. This study evaluated the cost-effectiveness of the convergent procedure, catheter ablation, and medical management for non-paroxysmal AF patients. METHODS: A Markov micro-simulation model was used to estimate costs and effectiveness from a payer perspective. Parameter estimates were from the literature. Three patient cohorts were simulated, representing lower, medium, and higher risks of stroke, bleed, heart failure, and hospitalization. Effects were estimated by quality-adjusted life-years (QALYs). Single-variable sensitivity analysis was performed. RESULTS: After 5 years, convergent procedure patients averaged 1.10 procedures, with 75% of survivors in sinus rhythm; catheter ablation patients had 1.65 procedures, with 49% in sinus rhythm. Compared to medical management, catheter ablation and the convergent procedure were cost-effective for the lower risk (ICER <$35,000) and medium risk (ICER <$15,000) cohorts. The procedures dominated medical management for the higher risk cohort (lower cost and higher QALYs). The convergent procedure dominated catheter ablation for all risk cohorts. RESULTS were subject to simplifying assumptions and limited by uncertain factors such as long-term maintenance of sinus rhythm after successful procedure and incremental AF-associated event rates for AF patients relative to patients in sinus rhythm. In the absence of clinical trial data, convergent procedure efficacy was estimated with observational evidence. Limitations were addressed with sensitivity analyses and a moderate 5 year time horizon. CONCLUSION: The convergent procedure results in superior maintenance of post-ablation sinus rhythm with fewer repeat ablation procedures compared to catheter ablation, leading to lower cost and higher QALYs after 5 years.

The impact of myocardial viability on the clinical outcome of cardiac resynchronization therapy.

INTRODUCTION: Around 30% of patients do not respond to cardiac resynchronization therapy (CRT). Nonischemic cardiomyopathy has been identified as an independent predictor of response to CRT, probably due to the absence of compact scar. METHODS AND RESULTS: The relationship between cardiac scar, ischemia, and hibernation (both at the left-ventricular pacing site and as a total burden) and response to CRT was studied in patients with ischemic cardiomyopathy using the perfusion-viability positron emission tomography (PET) test. Sixty-six patients with ischemic cardiomyopathy and traditional criteria for CRT were included. All patients underwent PET scan prior to CRT. Using PET, the amount and location of scarred, ischemic, and hibernating myocardium were characterized. No revascularization was indicated. Responders were defined by an improvement of left-ventricular ejection fraction (LVEF) >or= 5% and/or New York Heart Association (NYHA) class >or= 1 degree. During a mean follow-up of 26.2 +/- 22.2 months, there was a significant improvement in NYHA class and reverse remodeling in patients with the LV lead inserted remotely from the scar. However, reverse remodeling of a similar degree was present also in patients with extensive scarring including the lateral wall. The presence of ischemia, hibernation, or nontransmural scar at the pacing-site did not significantly modify the outcome of CRT as compared with viable myocardium. There were only 38% of CRT-nonresponders. Neither the extent of scar, ischemia, hibernation, or viability predicted outcome or mortality. Twenty patients died during the follow-up, one patient underwent heart transplant. CONCLUSIONS: At follow-up, response to CRT is observed regardless of the presence of extensive scarring. Left ventricular (LV) pacing at sites with ischemia, hibernation, or nontransmural scar does not appear to modify the effect of CRT as compared to viable tissue.

The magnitude of reverse remodelling irrespective of aetiology predicts outcome of heart failure patients treated with cardiac resynchronization therapy.

AIMS: We assessed the relationship between cardiac resynchronization therapy (CRT)-induced reverse remodelling and mortality during a long-term follow-up in a prospective observational study. METHODS AND RESULTS: We analyzed data from a prospective registry including 398 consecutive patients who underwent CRT between September 1998 and September 2007. Left ventricular ejection fraction (LVEF) was assessed before CRT and in the period between 3 and 6 months following implant. All-cause mortality, urgent transplantation and implantation of left ventricular assist device were all considered relevant events. A total of 398 (179 non-ischaemic and 219 ischaemic) patients were analysed. Overall, the increase of LVEF was statistically significant and was computed with 7.0 points (95% CI 5.8-8.3, P < 0.001). Non-ischaemic patients had a larger increase [9.2 points (95% CI 7.0-11.1), P < 0.001] of their LVEF from baseline, when compared with the ischaemic group. The median duration of follow-up was 4.4 years. The cumulative incidence of all events at the end of the 96 months period of follow-up was 55% and it was 34% (95% CI 29-40) at 5 years. At the multivariable analysis of the event-free survival, aetiology lost its predictive value (HR 0.92, P = 0.47), while a change in LVEF >or=6 points still significantly decreased the risk of event during the follow-up (HR 0.30, P = 0.001). CONCLUSION: Reverse remodelling measured by LVEF after 3 months is a good predictor of long-term outcome. Patients with an increase in LVEF >or=6 points have an excellent event-free survival approaching 66% at 5 years of follow-up.

Prognostic value of electrocardiographic measurements before and after cardiac resynchronization device implantation in patients with heart failure due to ischemic or nonischemic cardiomyopathy.

Postimplant QRS narrowing may predict clinical response after cardiac resynchronization therapy (CRT), but identification of nonresponders remains difficult. We studied the predictive value of electrocardiographic characteristics for mortality or cardiac transplantation in patients after CRT. Patients who had electrocardiograms available for review from before and after CRT device implantation were identified from a clinical database. Bivariate and multivariate Cox regression analyses were performed for the end point of death or transplantation. Of 337 patients (age 65+/-12 years, 76% men, left ventricular ejection fraction 22+/-12%, pre-QRS 175+/-30 ms), 84 died and 7 underwent transplantation during a follow-up of 27+/-15 months. Variables predictive of death or transplantation included QRS increase after CRT (45% vs 32%, p=0.03), older age, higher New York Heart Association class, lower left ventricular ejection fraction, and higher tertile of postimplant QRS (p=0.04), but not preimplant rhythm, QRS duration, or QRS morphology. After adjusting for confounding variables, independent predictors of mortality were older age (hazard ratio [HR] 1.03, 95% confidence interval [CI] 1.00 to 1.05, p=0.04), lack of angiotensin-converting enzyme inhibitor or angiotensin receptor blocker (HR 2.17, 95% CI 1.16 to 4.08, p<0.02), and longer postimplant QRS by tertile (HR 1.50, 95% CI 1.09 to 2.05, p=0.01). In conclusion, wider QRS after CRT device implantation is an independent predictor of mortality or transplantation. In patients with increased QRS durations despite CRT, closer follow-up or reassessment for alternative management strategies may be warranted.

Remote magnetic navigation: human experience in pulmonary vein ablation.

OBJECTIVES: We aimed at assessing the feasibility and efficacy of remote magnetic navigation (MN) and ablation in patients with atrial fibrillation (AF). BACKGROUND: This novel MN system could facilitate standardization of the procedures, reducing the importance of the operator skill. METHODS: After becoming familiar with the system in 48 previous patients, 45 consecutive patients with AF were considered for ablation using the Niobe II remote magnetic system (Stereotaxis, St. Louis, Missouri) in a stepwise approach: circumferential pulmonary vein ablation (CPVA), pulmonary vein antrum isolation (PVAI), and, if failed, PVAI using the conventional approach. Remote navigation was done using the coordinate or the wand approach. Ablation end point was electrical disconnection of the pulmonary veins (PVs). RESULTS: Using the coordinate approach, the target location was reached in only 60% of the sites, whereas by using the wand approach 100% of the sites could be reached. After step 2 ablation, only 1 PV in 4 patients (8%) could be electrically isolated. Charring on the ablation catheter tip was seen in 15 (33%) of the cases. In 23 patients, all PVs were isolated with the conventional thermocool catheter, and in 22 patients only the right PVs were isolated with the conventional catheter. After a mean follow-up period of 11 +/- 2 months, recurrence was seen in 5 patients (22%) with complete PVAI and in 20 patients (90%) with incomplete PVAI. CONCLUSIONS: Remote navigation using a magnetic system is a feasible technique. With the present catheter technology, effective lesions cannot be achieved in most cases. This appears to impact the cure rate of AF patients.

The effects of altering time delays of coupled pacing during acute atrial fibrillation.

BACKGROUND: Coupled pacing (CP), which consists of delivering a premature electrical stimulation to the heart after the effective refractory period of ventricular activation, is a novel method for controlling ventricular rate during atrial fibrillation (AF). It also has been established that CP improves pump function by enhancing external cardiac work and myocardial efficiency. OBJECTIVE: The purpose of the present study was to determine if two time delays for CP (short and long) would result in similar improvements in ventricular function. METHODS: In a canine model, we applied CP at two time delays (CP-S and CP-L) during two stages: sinus rhythm (SR) and acute AF. The cardiac responses to CP during SR served as the nontachycardic and nondepressed control. During both rhythms, we shortened the coupling interval until we obtained maximal contractility, designated CP-S. Next, we increased the delay until we started to see a measurable secondary contraction (left ventricular pressure development of approximately 20 mmHg). These longer delays were designated CP-L. RESULTS: Our results showed that the ventricular rate of intrinsic activation (VRIA) remained decreased despite prolongation of the time delay of CP during both AF and SR. Also, both delays of CP increased left ventricular systolic pressure (LVSP) and dLVP/dt, which are indices of myocardial contractility. In contrast, CP increased external cardiac work only during AF. Prolonging this time delay did not markedly decrease the improvement in external cardiac work. Myocardial O(2) consumption (MVO(2)) did not significantly change as the result of CP during either SR or AF. Finally, myocardial efficiency improved during AF as the result of CP at both time delays. CONCLUSIONS: In conclusion, shorter time delays for CP increased contractile strength during both SR and AF. However, extending the time delay of CP had minimal effects on diminishing the improved ventricular pump function and energetics that resulted from CP during AF. Thus, the maximal enhancement of myocardial contractility via CP-S was not needed to maintain the improved ventricular function during acute AF when CP is applied.