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.

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.

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.