title: Evaluation of the need to modify antiarrhythmic therapy because of drug intolerance or inefficacy in patients evaluated by electrophysiology study.
abstract: The incidence of recurrent ventricular tachycardia (VT) and drug intolerance after therapy guided by electrophysiology study (EPS) leading to a change in antiarrhythmic therapy is unknown. To explore this issue, we studied 138 patients undergoing EPS with a serial drug-testing protocol. Patients were followed for 24 +/- 21 months (range 1 to 91 months) for recurrent VT, drug intolerance, or both. At baseline EPS, sustained VT (76%), nonsustained VT (20%), and ventricular fibrillation (4%) were induced. On discharge antiarrhythmic therapy, 70 (51%) patients were noninducible (< 16 beats) and 68 (49%) patients remained inducible. Of the 138 patients, 56 (41%) required modification of antiarrhythmic therapy (change in drug or dose) for recurrent VT (n = 20) or drug intolerance (n = 36). These events occurred early during follow-up (8 +/- 12 months). Patients who were rendered noninducible had a greater likelihood of remaining free of antiarrhythmic modification than patients who remained inducible at 1-year (68% and 60%, respectively) and 2-year (63% and 52%, respectively) follow-up examinations (p < 0.05). Likewise, the noninducible patients had a greater likelihood of remaining free of recurrent VT than inducible patients at 1-year (95% and 80%, respectively) and 2-year (92% and 80%, respectively) follow-up testing (p < 0.025). In contrast, the likelihood of remaining free of drug intolerance was similar between inducible and noninducible patients at 1 year (72% and 75%, respectively) and 2 years (69% and 65%, respectively). We conclude that antiarrhythmic therapy guided by EPS requires early modification in more than 40% of patients during follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Division of Cardiology, Hartford Hospital.
authors.forename: M R
authors.initials: MR
authors.lastname: Ujhelyi
authors.forename: J R
authors.initials: JR
authors.lastname: Fisher
authors.forename: M S
authors.initials: MS
authors.lastname: Chow
authors.forename: J
authors.initials: J
authors.lastname: Kluger
mesh_terms: D000206:Actuarial Analysis; D000889:Anti-Arrhythmia Agents / Q000009:adverse effects / Q000627:therapeutic use*; D002304:Cardiac Pacing, Artificial; D005500:Follow-Up Studies; D006329:Heart Conduction System / Q000187:drug effects / Q000503:physiopathology*; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D011446:Prospective Studies; D012008:Recurrence; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000188:drug therapy* / Q000453:epidemiology
chemical_list: D000889:Anti-Arrhythmia Agents