Role of AV Nodal Ablation in Cardiac Resynchronization in Patients With Coexistent Atrial Fibrillation and Heart Failure: A Systematic Review
What is the impact of atrioventricular (AV) nodal ablation in patients with heart failure (HF) and atrial fibrillation receiving cardiac resynchronization therapy (CRT)?
This was a systematic review of studies (n = 6) examining outcomes in patients with systolic HF (left ventricular ejection fraction [LVEF] ≤35%), atrial fibrillation, and a wide baseline QRS (≥120 ms), who underwent CRT. Four of the six studies were retrospective cohorts. Outcomes of interest included all-cause mortality, cardiovascular mortality, and change in functional status.
In patients undergoing AV node ablation, biventricular capture was “near complete.” Biventricular capture was 82-96.5% in those without ablation. There were 86 deaths amongst 450 patients. AV node ablation led to a 58% reduction in all-cause mortality (relative risk [RR], 0.42; 95% confidence interval [CI], 0.26-0.68; n = 3 studies with data), a 56% reduction in cardiovascular mortality (RR, 0.44; 95% CI, 0.24-0.81; n = 2 studies with data), and an improvement in New York Heart Association [NYHA] functional class (mean difference in NYHA change, -0.34; 95% CI, -0.56 to -0.13; n = 3 studies with data). There was no difference in EF measures between the groups.
The authors concluded that AV node ablation improves outcomes in those with atrial fibrillation and systolic HF.
In this systematic review, AV node ablation appeared to afford a marked improvement in outcome in those with concomitant atrial fibrillation and HF. In fact, the average benefit was higher than that seen in studies of CRT in patients with sinus rhythm. The etiology for such benefit is not clear, as both atrial fibrillation groups had a relatively high proportion of biventricular pacing. The authors explain that the benefit of AV node ablation may lie in the quality of biventricular pacing—through both slowing of heart rate and regularization of rhythm. They also cite studies suggesting that very high biventricular pacing percentages (>95%) are needed for outcome benefits. These results support the need for a randomized study.
Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Implantable Devices, EP Basic Science, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Chronic Heart Failure
Keywords: Heart Failure, Stroke Volume, Atrial Fibrillation, Confidence Intervals, New York, Heart Rate, Heart Failure, Systolic, Cardiac Resynchronization Therapy, Atrioventricular Node
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