Echocardiography
Echocardiographic parameters, including left atrial (LA) dimension, LVEF, LV end-diastolic volume (LVEDV), and TR grade/TRPG, were measured using GE Vivid 9 or Philips IE33 acccording to the recommendations from the american society of echocardiography. LVEF and LVEDV were quantified by the M-mode and corrected by the two-dimensional guided biplane Simpson’s method of disc measurements by echocardiography. Echocardiography was performed before implantation and at 2-year intervals thereafter in the absence of clinical events or at the onset of HF.