Termination of sustained ventricular tachycardia by external noninvasive pacing.

Cardiac pacing has proven useful in the termination of sustained ventricular tachycardia (VT). In this study, the effectiveness of external noninvasive temporary pacing was compared with traditional endocardial burst ventricular pacing for the termination of sustained and hemodynamically stable VT. In 14 patients, 16 VT morphologies induced by programmed right ventricular extrastimulation were reproducibly terminated by endocardial burst pacing (3 to 9 complexes). VT cycle lengths averaged 392 +/- 97 ms (standard deviation) and ranged from 300 to 690 ms. The endocardial burst pacing cycle length used to terminate VT averaged 298 +/- 93 ms (range 220 to 600 ms). External burst pacing terminated 14 of 16 VT morphologies (88%). The pacing cycle length used to terminate these 14 VTs averaged 282 +/- 44 ms. The number of ventricular captures ranged from 5 to 20 beats. Failure to terminate 2 VT morphologies probably represented a failure of the device to capture the ventricle. Acceleration of VT occurred in 1 patient with burst external noninvasive pacing. These observations suggest that external burst pacing may be an effective means of terminating sustained VT in some patients.