Comparison of the characteristics of nonsustained ventricular tachycardia on Holter monitoring and sustained ventricular tachycardia observed spontaneously or induced by programmed stimulation.

The characteristics of nonsustained ventricular tachycardias (VT) on Holter monitor recordings were compared with the characteristics of sustained VT noted spontaneously or induced by programmed stimulation in 50 patients with a history of spontaneous sustained VT. At baseline before antiarrhythmic therapy, all patients had nonsustained VT (triplets or longer) on Holter recordings and sustained VT inducible by programmed stimulation. The mean rate of the fastest nonsustained VT on Holter monitoring (150 +/- 52 beats/min) was significantly slower that that of induced sustained VT (246 +/- 56 beats/min) (p less than 0.001). Compared with nonsustained VT on Holter monitoring, sustained VT by programmed stimulation were faster in 45 of 50 patients, similar in 2 and slower in 3. There was a poor correlation between the rates of nonsustained VT and sustained VT (r = 0.2195). The duration of the longest nonsustained VT was fewer than 6 beats in 24 patients and 6 beats or more in 26. The mean rates of induced sustained VT were not significantly different between patients with shorter (fewer than 6 beats) and longer (6 or more beats) nonsustained VT. In 12 patients, the rate of spontaneous sustained VT was available. The rate of spontaneous sustained VT (217 +/- 59 beats/min) was similar to that of sustained VT by programmed stimulation (277 +/- 60 beats/min). There was a close correlation (r = 0.8036) between the rates of spontaneous and induced sustained VT. However, the rate of nonsustained VT on Holter monitoring (151 +/- 76 beats/min) was significantly slower than the rate of spontaneous sustained VT (p = 0.002).(ABSTRACT TRUNCATED AT 250 WORDS)