[Atrioventricular delay and diastolic mitral regurgitation in patient with DDD pacemaker implantation, and cardiac function].

We examined the mitral valve motion, the mitral valve flow pattern, and changing atrioventricular (AV) delay in 34 patients with DDD pacemaker implantation, using M-mode echocardiography and pulse Doppler echocardiography. In 28 patients, B-B' step and diastolic mitral regurgitation (DMR) were induced by extending the AV delay. 8 of 12 patients who showed B-B' step and DMR with the AV delay less than or equal to 165 mS had heart failures. In such patients, P-B-B' step (DMR) interval was 174 +/- 31 mS shorter than the other patients (216 +/- 26 mS, p less than 0.001), and Q-C interval was 131 +/- 26 mS longer than the other patients (63 +/- 31 mS, p less than 0.001). The minimal value of the AV delay that induces B-B' step and DMR can be decided under the influence of cardiac functions, and this echocardiographic examination is useful, giving us information about the cardiac function of the patients with DDD-PM. B-B' step is the mitral valve motion that corresponds with the DMR, so we can check the DMR through the B-B' step easily.