Studies on left ventricular function during sustained ventricular tachycardia.

The acute effects of rapid ventricular pacing and sustained ventricular tachycardia on left ventricular function were examined in patients with recurrent sustained ventricular tachycardia. Programmed electrical stimulation and left ventricular hemodynamic measurements were performed in 20 patients (19 men and 1 woman), with an age range of 49 to 79 years (mean 63 +/- 9). Indexes of left ventricular function that were analyzed included left ventricular peak systolic pressure, end-diastolic pressure, first derivative of peak left ventricular pressure (dP/dt) and negative left ventricular dP/dt. Measurements were obtained during sinus rhythm, after paced premature ventricular depolarizations, during rapid ventricular pacing (cycle lengths 600 to 250 ms) and immediately after induction of sustained ventricular tachycardia. Mean left ventricular peak systolic blood pressure was 123 +/- 19 mm Hg during sinus rhythm, decreased to 77 +/- 23 mm Hg (p less than 0.05) at the induction of ventricular tachycardia and remained decreased during arrhythmia (p less than 0.01). Mean left ventricular end-diastolic pressure was 22 +/- 5 mm Hg during sinus rhythm, did not change after arrhythmia induction (22 +/- 9 mm Hg, p greater than 0.2) and remained unchanged during sustained ventricular tachycardia (p greater than 0.2). Mean peak left ventricular dP/dt was 1,400 +/- 620 mm Hg/s in sinus rhythm, decreased to 810 +/- 580 mm Hg/s (p less than 0.05) at ventricular tachycardia induction and remained decreased during sustained ventricular tachycardia (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)