Left atrial strain increases in CRT responders : a systematic review and meta-analysis

Background and aim: Impaired left atrial (LA) strain is associated with myocardial fibrosis and carries poor prognosis, especially arrhythmia. Cardiac resynchronization therapy (CRT) is associated with reserved LA remodeling and reduced arrhythmia. The aim of this meta-analysis was to assess the relationship between CRT and LA function improvement. Methods: We systematically searched PubMed-Medline, EMBASE, Scopus, Google Scholar and the Cochrane Central Registry, up to February 2018 in order to select clinical trials and observational studies, which assessed the predictive value of LA strain of CRT response. The left ventricular end-systolic volume (LVESV) reduction ≥15 ml and/or LV ejection fraction (EF) increase ≥10% were the documented criteria for assessment of CRT response. Results: A total of 299 patients (181 responders and 118 non-responders to CRT) from 5 observational studies, with mean follow-up period of 6 months were included in this meta-analysis. The pooled analysis showed no difference between baseline LA strain in the two groups with weighted mean difference (WMD) 1.07% [95% CI -2.37 to 4.51, P=0.54, Figure 1]. After the follow-up period, LA strain in the CRT responders significantly increased, WMD 27.7% [95% CI 23.1 to 32.6, P<0.001, Figure 2, a)], but not in the non-responders, WMD -34.5 [95% CI -38.4 to -30.6, p<0.001, Figure 2, b)]. Conclusions: Improvement of LA strain in CRT responders reflects LA reserve remodeling. These results support the importance of LA function in patients treated by CRT for heart failure.
Supplement: 1Meeting Abstract: P1949