Effects of intervening sinus beats on ectopic cycle length in a patient with ventricular parasystole.

The intrinsic cycle length of the ventricular parasystolic pacemaker may be modulated by electrotonic influence of intervening ventricular depolarizations. In order to quantify the magnitude of modulation in relation to the timing of the intervening depolarization, a curve of influence was constructed in a patient with ventricular parasystole. The current communication deals with the detailed description of a step-by-step method for the construction of the curve of influence.