Concordance between programmed stimulation and 24 hour ambulatory electrocardiographic (Holter) monitoring was studied in 54 patients with sustained ventricular tachycardia during 84 therapeutic trials with class IA antiarrhythmic agents. During baseline studies before treatment, all patients had frequent (greater than or equal to 30/h) ventricular premature complexes on Holter recordings and sustained ventricular tachycardia inducible by one to three extrastimuli. During treatment, programmed stimulation and Holter monitoring were repeated. Efficacy of treatment determined by programmed stimulation (ventricular tachycardia no longer inducible or nonsustained) was compared with three Holter criteria of efficacy: I = 83% or more reduction of ventricular premature complexes and abolition of ventricular tachycardia; II = 50% or more reduction of ventricular premature complexes and 90% or more reduction of couplets and abolition of ventricular tachycardia; III = abolition of ventricular tachycardia in patients with ventricular tachycardia during a baseline Holter recording. Treatments were judged effective by programmed stimulation criteria in only 25% of cases but in 51, 63 and 75% of cases by Holter criterion I, II and III, respectively. Results of programmed stimulation and Holter monitor were discordant (effective by one criterion but ineffective by the other) in 50% of cases using Holter criterion I, in 54% using Holter criterion II and in 61% using Holter criterion III. In the majority of discordant results, treatments appeared efficacious by Holter criteria but ineffective by programmed stimulation criteria, suggesting insensitivity of efficacy by Holter criteria or nonspecificity of induced ventricular tachycardia during treatment, or both.
We studied the value of programmed stimulation in assessing the efficacy of antiarrhythmic agents in 52 patients with sustained ventricular tachycardia. All patients in this nonrandomized study had ventricular tachycardia inducible by programmed stimulation and also had frequent ventricular premature complexes (greater than or equal to 30 per hour) on Holter-monitor recordings before therapy. The efficacy of antiarrhythmic agents was assessed by both programmed stimulation and Holter recordings during serial drug testing. A regimen was deemed effective according to the programmed-stimulation criteria in 25 patients (Group 1). Twenty-seven patients in whom tachycardia could still be induced during programmed stimulation despite extensive drug trials were discharged on a regimen that caused a marked reduction of ventricular premature complexes according to Holter monitoring (Group 2). In 23 patients no effective drug regimen was identified by either set of efficacy criteria, and these patients were excluded from the present analysis. Follow-up lasted 18.6 +/- 13.9 months. Rates of arrhythmia-free survival at 12 and 24 months were 88 percent and 72 percent, respectively, in Group 1 and 84 percent and 75 percent in Group 2 (P = 0.637). We conclude that demonstration of antiarrhythmic efficacy by programmed stimulation predicts a good clinical outcome, that inefficacy as shown by the programmed-stimulation protocol used in this study may not preclude a good outcome if there is a marked reduction of spontaneous ventricular premature complexes on Holter monitoring, and that randomized trials should be conducted to validate the results of this observational study.
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