THE USEFULNESS OF HOLTER MONITORING IN SELECTING PHARMACOLOGICAL THERAPY FOR PATIENTS WITH SUSTAINED MONOMORPHIC VENTRICULAR-TACHYCARDIA - STUDIES IN PATIENTS IN WHOM NO EFFECTIVE PHARMACOLOGICAL THERAPY COULDBE DETERMINED BY ELECTROPHYSIOLOGIC STUDY

The usefulness of Holter monitoring (HM) in selecting pharmacologic th erapy for patients with sustained monomorphic ventricular tachycardia (VT) was evaluated in patients in whom no effective pharmacologic ther apy could be determined in an electrophysiologic study (EPS). The stud y population consisted of 49 consecutive patients with sustained VT wh o were receiving long-term pharmacologic therapy despite the fact that no pharmacologic therapy had been found to be effective in the EPS. T he efficacy of the pharmacologic therapies was assessed by HM. A reduc tion in frequent (10/h) premature ventricular contractions (PVCs) was used as an index of treatment efficacy, with therapies achieving subst antial PVC suppression (>70% of all PVCs) being considered to be effec tive (HM effective group). When no therapy was found to be effective w hen assessed by HM, a drug with any other beneficial effect, eg, reduc tion in VT rate, was chosen (HM ineffective group). VT recurrence and survival were compared between groups. During the follow-up period of 31+/-28 months, VT recurrence was observed in a total of 25/49 patient s: 3/17 patients in the HM effective group, in 18/25 in the HM ineffec tive group, and in 4/7 in the HM undetermined group (p=0.0487). Sudden cardiac death occurred in a total 7/49 patients: 2/17 patients in the HM effective group, 4/25 patients in the HM ineffective group, and 1/ 7 patient in the HM undetermined group (p=0.2828). Among patients in w hom no effective therapy could be determined by EPS, the VT recurrence rate was significantly lower in the group in whom treatment was effec tive as assessed by HM than among those in whom treatment was assessed by HM to be ineffective. Sudden cardiac death rate was also lowest in the HM effective group, although the difference was not statistically significant. HM assessment was considered useful in selection of phar macologic therapy for patients in whom no effective therapy could be d etermined in the EPS.