Left ventricular response after cardiac resynchronization therapy is related to early left atrial volume reduction

Background/Aims: The current study aimed to elucidate a time-course change in left atrial volume after cardiac resynchronization therapy (CRT) and to verify factors associated with left atrial volume reduction (LAVR) and its prognostic im-plications. Methods: The records of 97 patients were retrospectively reviewed after CRT. Echocardiographic data were analyzed at baseline before CRT, at early follow-up (FU) (≤ 1 year, median 6 months), and at late FU (median 30 months). Left ventricular volume response (LVVR) was defined as 15% reduction in left ventricular (LV) end-systolic volume (ESV). LAVR was classified into two groups by the median value at early FU: LAVR (≥ 7.5%) and no LAVR (< 7.5%). Results: LV ESV index continuously decreased from baseline to early FU and from early FU to late FU (106.1 ± 47.4 mL/m² vs. 87.6 ± 51.6 mL/m² vs. 72.5 ± 57.1 mL/m²). LA volume index decreased from baseline to early FU, but there were no reduc-tions thereafter (51.8 ± 21.9 mL/m² vs. 45.1 ± 19.6 mL/m² vs. 44.9 ± 23.0 mL/m²). The only echocardiographic factor associated with LAVR was change in E velocity (odds ratio [OR], 1.04; p = 0.002). Early LAVR (OR, 10.05; p = 0.002) was an independent predictor for late LVVR. Conclusions: LAVR was related to reduction in E velocity, suggesting its relation with optimization of LV filling pressure. Early LAVR was a predictor for LVVR to CRT in long-term FU.