[Value of Holter's dynamic ECG a as predictor of the effectiveness of anti-arrhythmia therapy].

Holter/exercise approach has been designed to evaluate and predict the efficacy of the antiarrhythmic therapy. Acute drug testing permit to identify drug responders to effective antiarrhythmic agents. So far only one group has reported the long-term outcome of patients managed using this approach. Patients with malignant ventricular arrhythmias in which efficacy was achieved had better chance of surviving during follow-up than did the nonresponder patients (3 year mortality 14% vs 84%). In addition to acute drug testing chronic trials have been undertaken in order to evaluate the efficacy of drugs. Long-term Holter evaluation of antiarrhythmic therapy has to face the problem of the spontaneous changes in VPD frequency mimicking drug efficacy. To overtake these considerable variations a critical suppression is required in 24 hour Holter. One group has reported the long-term results in 124 drug trials performed in arrhythmic patients. Cumulative probability of survival at 12 months was 0.93 for "responders" and 0.64 for "nonresponders" (p less than 0.005). New perspective trials have now been undertaken. Long-term Holter evaluation of antiarrhythmic therapy has to recognize the problem of "proarrhythmic effect" of antiarrhythmic agents which in ambulatory monitoring has been observed cumulatively in 9% of the treated patients.