Definition of the Optimal Atrioventricular Delay by Simultaneous Measurement of Electrocardiographic and Doppler Echocardiographic Parameters

In atrioventricular (AV) block patients, AV synchrony can be restored by implanting DDD pacing systems if an individual optimization of the pacemaker AV delay is performed. If the latter is neglected and the AV delay is left at nominal settings, adverse hemodynamic effects may develop. Therefore, several methods were proposed to calculate or to estimate the individual hemodynamically optimal length of the AV interval [1-11]. Most of them are time-consuming and require additional techniques. Furthermore, they are limited to resting conditions. Individual AV delay optimization is an essential part in cardiac resynchronization therapy in patients with chronic heart failure and biventricular DDD pacing systems. Nevertheless, it should also be performed in any AV block therapy. Depending on available technology, methods can be chosen based on two principles: • An estimation of optimal AV delay which requires serial measurement of a hemodynamic parameter at several practicable AV delay steps. • A calculation of optimal AV delay which is based on exact measurement of anly a few parameters. It should receive preference if higher accuracy is required.