2.2 Echocardiography study
All patients underwent transthoracic echocardiography before the
ablation. The left atrial diameter was measured at end-systole on the
M-mode image obtained from the parasternal long-axis view. Transthoracic
echocardiography was performed with a 5 MHz multiplane probe and live
images were interpreted by experienced physicians who were blinded to
the outcome of the ablation. Transesophageal echocardiography prior to
the PVI was performed to exclude any left atrial or left atrial
appendage thrombi.