The prognostic value of the changes in the mode of ventricular tachycardia induction noted during therapy with a marked reduction of ventricular ectopic activity.

The prognostic significance of changes in the mode of induction of ventricular tachycardia (VT) noted during therapy was studied in 49 patients with sustained VT or ventricular fibrillation. Before treatment, all patients had inducible sustained VT by programmed stimulation (one to three extrastimuli) and frequent (greater than or equal to 30/hr) ventricular premature complexes (VPCs). On the discharge regimen, VT was no longer inducible by programmed stimulation in 22 patients (group 1). Twenty-seven patients (group 2) with persistent induction of VT despite extensive serial drug testings were discharged on a regimen that resulted in a marked reduction of VPCs on Holter monitoring (greater than or equal to 50% reduction of VPCs, greater than or equal to 90% reduction of couplets, and abolition of nonsustained VT). The modes of induction at baseline and on the discharge regimen were compared in each patient in group 2. Induction of VT was more difficult, requiring more aggressive stimulation protocol in 5 of 27 patients, unchanged in 14 patients, and easier in 8 patients. The duration of follow-up was 20 +/- 13 months (mean +/- SD). Arrhythmia-free survival rates at 6, 12, 18, and 24 months were 95%, 89%, 82%, and 73% in group 1, 92%, 84%, 75%, and 75% in group 2, 93%, 83%, 77%, and 69% in 27 patients with noninducibility or harder induction, and 95%, 90%, 79%, and 79% in 22 patients with the same or easier induction, respectively. The differences were not significant.(ABSTRACT TRUNCATED AT 250 WORDS)