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Meta‐analysis of biventricular vs. right ventricular pacing mode in patients with atrial fibrillation undergoing atrioventricular nodal ablation: what was the quality of the included trials?

We read with interest the meta-analysis by Chatterjee et al. which reported that, compared with right ventricular (RV) pacing, biventricular (BiV) pacing had no effects on mortality, adverse events, or exercise capacity, but significantly improved quality of life and left ventricular ejection fraction (LVEF) in patients with atrial fibrillation (AF) undergoing atrioventricular nodal ablation (AVNA). We would like to raise a number of questions regarding this meta-analysis. The authors stated that the Jadad score was used to perform quality assessment of the included randomized controlled trials (RCTs). However, the actual results of their assessment were not provided. Although the Jadad score remains a commonly used scale, its use is discouraged by the Cochrane Collaboration, an organization that publishes the highest number of meta-analyses. The main issue with the Jadad score is that it ignores the impact of allocation concealment, which has been known as an important source of biases. On our preliminary assessment of the published trial reports, none of them explicitly described the method of randomization sequence concealment, and two studies [Doshi et al. (2005) and Orlov et al. (2010)] did not provide any information on the method of randomization. We feel that it is of great importance and relevance for a meta-analysis to include adequate quality assessment in order to show the readers that the conclusions drawn are indeed valid. There are also a few questions on the results presented. A flow diagram illustrating the study selection process shows that the four included trials were selected out of 36 potentially relevant citations. However, for the 32 excluded records, reasons for exclusion were only provided for 29. In addition, we are uncertain how Chatterjee et al. extracted data on all-cause and cardiac mortality from Brignole et al. (2011) since the trial publication did not describe mortality rates per group. The current evidence on the benefits of BiV pacing over RV pacing in patients with AF and left ventricular systolic dysfunction remains inconclusive. Despite the above issues, we welcome the findings of this interesting and well-written meta-analysis, and congratulate Chatterjee and colleagues for their effort in rightly highlighting the need for further randomized evidence to establish an effective selection strategy of AF patients at risk of the adverse effects of RV pacing who would thereby benefit from BiV pacing.