OBJECTIVETo observe the incidence of ventricular desynchronization in patients with or without pacemaker syndrome (PMS).

METHODSThe systolic peak velocity, the acceleration and the time to peak velocity of the interventricular septum (IVS), left ventricular (LV) and right ventricular (RV) lateral wall were detected by tissue Doppler imaging (TDI) in 14 atrial fibrillation patients without pacemaker implantation (control), 18 atrial fibrillation patients without PMS and 16 atrial fibrillation patients with PMS. All patients were free of valve disease, myocardial infarction, severe pulmonary hypertension, low left ventricular eject fraction (< or = 50%), significant segmental hypokinesis of ventricular wall or complete bundle branch block.

RESULTSCompared to the control patients, the systolic peak velocity and the accelerations on lateral walls of the LV and RV reduced significantly in patients with implanted pacemakers (P < 0.05). The intervals to peak velocity of the IVS and LV lateral walls were significantly prolonged [PMS group (80.13 +/- 26.92) ms vs. (25.60 +/- 4.30) ms, P < 0.01; without PMS group (76.22 +/- 23.32) ms vs. (25.60 +/- 4.30) ms, P < 0.01] and the intervals to peak velocity of the IVS and RV lateral walls significantly shortened [PMS group (16.33 +/- 6.85) ms vs. (40.70 +/- 7.60) ms, P < 0.01; without PMS group (21.20 +/- 7.34) ms vs. (40.70 +/- 7.60) ms, P < 0.01]. The systolic peak velocities, the accelerations of the IVS and bilateral walls and the intervals to peak velocity of the IVS and LV lateral wall were similar in patients with and without PMS (P > 0.05), however, the intervals to peak velocity of the IVS and RV lateral wall was significant shorter in patients with PMS compared to that of patients without PMS [(16.33 +/- 6.85) ms vs. (21.20 +/- 7.34) ms, P < 0.01].

CONCLUSIONRV desynchronization but not LV desynchronization might play an important role in patients with PMS.