[The influence of atrioventricular asynchronous contraction on left and right ventricular performance]

To investigate the influence of atrioventricular asynchronous contraction on left and right ventricular performance, pulsed Doppler echocardiographic studies were performed in 10 patients who received permanent pacemaker (VVI mode), but without significant heart disease except for complete heart block. After setting the pacing rate at 40 per min, the performance was analyzed during the patient's own slow ventricular rate. Flow velocity patterns at the left (LVOT) and right ventricular outflow tracts (RVOT) were recorded by pulsed Doppler echocardiography, and ejection time (EjT), acceleration time (AcT), peak velocity (PV) and flow velocity integral (FVI), which is proportional to stroke volume, were measured for each outflow tract. When the patient's own atrial contraction occurred during ventricular systole, EjT, AcT, PV and FVI of flow at the LVOT and EjT, AcT and FVI of flow at the RVOT were decreased. Percent change of the FVI of flow at the RVOT (-34.6%) was significantly greater than that of flow at the LVOT (-16.2%, p < 0.01). These results indicate that the loss of right ventricular performance might play a prominent role in the genesis of the hemodynamic deterioration with atrioventricular asynchronous contraction.