2.1 Echocardiographic Examination and Measurement of Atrial Conduction Time
Echocardiographic examination was performed in all patients before pulmonary vein RF ablation and 3 months after the ablation with GE VividS6 system (GE Vingmed, Horten, Norway) using a probe of 2-4 MHz frequency. Echocardiographic examination was performed with the patient in the supine position and lying on the left side, using appropriate echocardiographic windows with M mode, two-dimensional (2D), pulse wave doppler, continuous wave doppler, color flow, and tissue doppler imaging (TDI) methods.
2.2 M-mode echocardiography: Right ventricular end-systole and diastole sizes and ejection fraction, end-diastole septum and posterior wall thicknesses, and left atrial end-diastole dimensions were measured with M-mode echocardiography.
2.3 2D echocardiography: Wall motion of both ventricles, valvular structure and functions, and pericardial window were examined with 2D echocardiography. Mitral flow parameters were measured at the end of expiration by averaging three cardiac cycles.
2.4 Tissue Doppler Echocardiography: Simultaneous ECG recordings were taken during tissue Doppler echocardiographic examination. The time from the beginning of the P wave on the ECG to the onset of the A’ wave in tissue Doppler (wave indicating atrial contraction) was defined as the PA distance (atrial electromechanical time) (Fig 1). Atrial electromechanical time was measured separately from the lateral mitral annulus, septal mitral annulus, and lateral tricuspid annulus; and defined as PA lateral, PA septum, and PA tricuspid, respectively. The difference between PA lateral and PA tricuspid (PA lateral – PA tricuspid) was defined as interatrial conduction delay; and the difference between PA septum and PA tricuspid (PA septum – PA tricuspid) as intraatrial conduction delay.
2.5 Transesophageal Echocardiography: All patients underwent TEE with in 48 hours before the ablation. The echogenic mass in the LAA that continued in more than one plane and distinguished from the surrounding tissues was considered thrombus, and patients with thrombus in the LAA were excluded.