Echocardiography
Echocardiography was performed within one month before ICD/CRT-D
implantation and during the follow-up period in all the study patients.
Echocardiographic parameters, including LVEF, LA dimension, LV volume,
and estimated pulmonary artery systolic pressure (PASP), were measured
using GE Vivid 9 or Philips IE33. LVEF and LV volume (end-diastolic
phase and end-systolic phase) were quantified by the two-dimensional
guided biplane Simpson’s method of disc measurements by
echocardiography. PASP was estimated from the tricuspid regurgitant jet
velocity using the modified Bernoulli equation and adding the estimated
right atrial pressure based on the diameter and collapsibility of the
inferior vena cava.