Choice of the Optimum Pulse Duration for Precordial Cardiac Pacing: A Theoretical Study

In precordial pacing with skin‐surface electrodes, the goal is to excite the ventricles with minimal stiniuiation of overlying tissues. A theoretical analysis is presented to identify the relevant factors; the two most important are electrode location and pulse duration. Using the basic law of stimulalion, we developed a model which indicates that the optimum pulse duration for the closed‐chest pacing pulse is one that is long with respect to the membrane time constant of cardiac muscle. Current‐versus‐duration curves are presented for pacing and pain, based on experimentally obtained data. For pacing with minimum pain, the optimum stimulus duration was found to be about 10 ms.