Burden of atrial fibrillation after cardiac resynchronization therapy

Cardiac resynchronization therapy in the presence of total atrioventricular block reduces long-lasting atrial fibrillation episodes

Background

There is an ongoing debate on how cardiac resynchronization therapy (CRT) in the presence of total AV block affects atrial fibrillation (AF) episodes and symptoms in patients with AF.

Methods

Seventy-five patients with symptomatic, drug and ablation refractory AF received, irrespective of their left ventricular ejection fraction (EF), either a CRT device and underwent subsequent atrioventricular node (AVN) ablation or already had a total AV block and underwent CRT upgrade. Long-lasting AF episodes (>48 h), left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), left atrial diameter (LAD), NTproBNP levels, EHRA score, and NYHA class had been monitored on the follow-up.

Results

The number of patients experiencing long-lasting AF episodes (>48 h) and symptoms decreased significantly within 24 months after CRT implantation in the presence of total AV block (p < .001) from 57 (76%) to 25 (33.3%). Mean LAD decreased from 52 mm (IQR 48.0-56.0) to 48 mm (IQR 42.0-52.0, p < .001) and LVEDD from 54 mm (IQR 49.0-58.0) to 51 mm (IQR 46.5-54.0, p < .001).

Conclusion

A combination of total AVN block and biventricular pacing markedly reduces long-lasting AF episodes, symptoms, left atrial diameter, and left ventricular end-diastolic diameter.

Is cardiac resynchronization therapy an antiarrhythmic therapy for atrial fibrillation? A systematic review and meta-analysis

The impact of cardiac resynchronization therapy (CRT) on atrial fibrillation (AF) burden is poorly characterized. To assess the influence of CRT on AF, we performed a systematic literature search in MEDLINE using the MeSH headings "cardiac resynchronization therapy" or "cardiac pacing, artificial" and "atrial fibrillation." Selected studies were peer-reviewed and written in English. Most studies enrolled patients meeting traditional CRT criteria. Ten observational studies and two secondary analyses of clinical trials were identified. Although ten studies suggest that CRT favorably impacts AF, one secondary analysis of a clinical trial showed no effect of CRT on new-onset AF. In a meta-analysis of three studies examining the effect of CRT on persistent or permanent AF, the combined rate of conversion from persistent or permanent AF to sinus rhythm was 0.107 (95 % confidence interval 0.069-0.163). Prospective studies, particularly among patients not meeting traditional CRT criteria, are needed.

Impact of chronic atrial fibrillation in patients with severe heart failure and indication for CRT: data of two registries with 711 patients (1999-2006 and 2007-6/2008)

AIMS

Atrial fibrillation (AF) is a relevant comorbidity in heart failure (HF) patients. In milestone cardiac resynchronization therapy (CRT) studies, patients with AF were excluded. We sought to investigate the influence of chronic atrial fibrillation (AF) on patients with CRT. AV node (AVN) ablation is frequently recommended. Converting AF to sinus rhythm (SR) is not a standard concept.

METHODS

A total of 584 consecutive patients with CRT devices were included in a single-center registry from 1999-2006 (retrospective registry) and 127/324 patients from 2007-06/2008 (prospective registry). The impact of persistent AF (group 1) on clinical and echocardiographic improvement compared with patients in SR (group 2) after 12 (6) months follow-up were analyzed. Re-establishing SR after initial cardioversion or need for AVN ablation was examined.

RESULTS

In the retrospective registry, 139 (24%) patients presented with AF (group 1) and 445 with SR (group 2). The groups differed in age, gender, and left atrium (LA) size but not in NYHA class, ejection fraction (EF), left ventricular end-diastolic dimension (LVEDD), B-type natriuretic peptide (BNP) levels, QRS width, and underlying disease. After 1 year, CRT improvement of NYHA class and EF was similar with higher mortality in group 1 (12% vs. 7%; OR 1.80; 95% confidence interval 0.95-3.4). The AF group presented with SR in 33/82 (40%) patients and 11% needed AVN ablation. The prospective data showed 27 (21%) patients in AF with conversion to SR in 41% after 6 months.

CONCLUSION

Patients with severe HF and chronic AF had a comparable improvement with CRT as those in SR. CRT is a successful treatment option in patients with chronic AF offering the potential to restore SR in a significant number of patients.

Frequency of atrial tachyarrhythmias in patients treated by cardiac resynchronization (from the Prospective, Multicenter Mona Lisa Study)

The continuous measurement of sustained atrial tachyarrhythmia (AT) is now possible with some permanently implanted devices. Data on this subject remain controversial. The aim of this study was to evaluate the incidence of sustained AT in patients treated with cardiac resynchronization therapy using pacemakers without backup defibrillators (CRT-P), within the first year after implantation, using strict definition criteria for sustained AT and a systematic review of all high-quality electrographically recorded episodes. The Mona Lisa study was a prospective, multicenter, cohort study carried out from February 2004 to February 2006, with a 12-month follow-up period. Sustained AT was defined as an episode lasting > or =5 minutes; episodes were confirmed by a systematic review of electrograms in the whole study population. Of the 198 patients who underwent CRT-P device implantation and were enrolled in the study, 173 were in stable sinus rhythm at baseline and were included in the analysis (mean age 70 +/- 9 years, 66% men, 91% in New York Heart Association class III, mean QRS duration 164 +/- 26 ms, mean left ventricular ejection fraction 25 +/- 7%). During a mean follow-up period of 9.9 +/- 3.6 months, 34 patients experienced > or =1 episode of sustained AT, for an incidence rate of 27.5% (95% confidence interval 18.2 to 36.7). Only a history of AT was independently associated with the occurrence of sustained AT within the 12 months after CRT-P device implantation (hazard ratio 2.3, 95% confidence interval 1.2 to 4.4, p = 0.02). In conclusion, this first prospective electrogram-based evaluation of AT incidence demonstrated that 27% of patients developed > or =1 episode of sustained AT lasting > or =5 minutes in the 12 months after CRT-P device implantation.

Atrial fibrillation in heart failure: current treatment of patients with remodeled atria

Atrial fibrillation (AF) and chronic heart failure (CHF) can be caused by each other, and therefore constitute a vicious circle. The prevalence of both conditions is about 1% in industrialized countries and increases with age. Although mortality is increased in heart failure, the additional prognostic relevance of AF in these patients is less clear. AF in patients with CHF can worsen heart failure symptoms, cause complications (eg, stroke), and is difficult to treat. Thus, prevention of AF entirely is an important goal. This review summarizes recent data concerning prognostic relevance, treatment, and means of primary and secondary prevention of AF in patients with CHF.

Atrial fibrillation in recipients of cardiac resynchronization therapy device: 1-year results of the randomized MASCOT trial

BACKGROUND

Atrial fibrillation (AF) is associated with increased morbidity and mortality in patients suffering from heart failure (HF). Patients in New York Heart Association HF classes III or IV, with systolic dysfunction and a wide QRS, are candidates for cardiac resynchronization therapy (CRT), and might benefit from atrial overdrive pacing (AOP).

METHODS

The Management of Atrial fibrillation Suppression in AF-HF COmorbidity Therapy (MASCOT) trial enrolled 409 CRT device recipients (79% men), who were randomly assigned to AOP ON (n = 197), versus AOP OFF (n = 197) and followed up for 1 year. Their mean age was 68 +/- 10 years, left ventricular ejection fraction 25 +/- 6%, QRS duration 163 +/- 29 milliseconds. New York Heart Association class III was present in 86% of patients and 19% had a history of paroxysmal AF. The primary study end point was incidence of permanent AF at 1 year.

RESULTS

Atrial overdrive pacing increased the percentage of atrial pacing from 30% to 80% (P < .0001), was well tolerated, and did not interfere with (a) delivery of CRT (95% mean ventricular pacing in both groups), (b) response to CRT (70% responders in the control vs 67% in the treatment group), or (c) cardiac function (left ventricular ejection fraction increased from 24.5% +/- 6.2% to 32.7% +/- 10.9% in the control and from 25.8% +/- 6.8% to 33.1% +/- 12.6% in the treatment group). The incidence of permanent AF was 3.3% in both groups. By logistic regression analysis, a history of AF (P < .001) and absence of antiarrhythmic drugs (P = .002) were associated with permanent AF.

CONCLUSIONS

In this first trial of a specific AF prevention algorithm in CRT recipients, AOP was safe and did not worsen HF. The prevention algorithm did not lower the 1-year incidence of AF.