Left atrial volume index predicts response to cardiac resynchronisation therapy: a systematic review and meta-analysis

INTRODUCTION: In responders, cardiac resynchronisation therapy (CRT) results in improved left ventricular (LV) function and reduced atrial arrhythmia. The aim of this meta-analysis was to assess the potential relationship between the left atrium (LA) volume and CRT response. MATERIAL AND METHODS: We systematically searched all electronic databases up to August 2018 in order to select clinical trials and observational studies that assessed the predictive value of LA volume index (LAVI) of CRT response. Left ventricular end-systolic volume (LVESV) reduction ≥ 15 ml and/or LV ejection fraction (EF) increase ≥ 10% were the documented criteria for positive CRT response. RESULTS: A total of 2191 patients recruited in 10 studies with mean follow-up duration of 10.5 months were included in this meta-analysis. The pooled analysis showed that CRT responders had lower baseline LAVI compared to non-responders, with a weighted mean difference (WMD) of –5.89% (95% CI: –9.47 to –3.22, p < 0.001). At follow-up, LAVI fell in the CRT responders (WMD –4.36%, 95% CI: –3.54 to –5.17, p < 0.001) compared to non-responders (WMD 1.45 %, 95% CI: –0.75 to 3.65, p = 0.20). The mean change of LAVI in the CRT responders was related to the fall in LVESV, β = –1.02 (–1.46 to –0.58), p < 0.001 and the increase in LVEF, β = 2.02 (1.86 to 4.58), p = 0.001. A baseline LAVI < 34 ml/m(2) predicted CRT response with summary sensitivity 0.80% (0.53–0.95), specificity 0.74% (0.53–0.89), and odds ratio > 11. CONCLUSIONS: Baseline LAVI predicts CRT response, and its reduction reflects devise-related LA remodelling. These results emphasis the role of LAVI assessment as an integral part of cardiac function response to CRT.