Hemodynamic Effect of Physiological Dual Chamber Pacing in a Patient with End-Stage Dilated Cardiomyopathy: A Case Report

I report a case of end-stage dilated cardiomyopathy with first-degree atrioventricular (AV) block, which had been resistant to intensive medical therapy and was eventually treated by DDD pacemaker. The optimal AV interval setting was decided using invasive right-heart catheterization and Doppler echocardiography. At a pacing rate of 92/minute, an AV interval setting of between 200 and 100 msec increased left ventricular filling and enhanced myocardial contractility. An AV interval setting of 50 msec increased the left ventricular filling further. However, this resulted in deteriorated left ventricular function. Based on these findings, the pacemaker was programmed at an optimal AV delay of 100 msec, a rate of 82-150 beats/min and a DDD mode, resulting in a good clinical course for 4 months after the therapy. Thus, it is suggested that in patients with end-stage dilated cardiomyopathy and first-degree AV block, an optimal AV delay setting using a DDD pacemaker can improve deteriorated myocardial function probably by increasing the left ventricular filling, and thus promote utility of the Frank-Starling mechanism.