Evaluation of the need to modify antiarrhythmic therapy because of drug intolerance or inefficacy in patients evaluated by electrophysiology study.
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)
Ujhelyi
M R
MR
Division of Cardiology, Hartford Hospital.
Fisher
J R
JR
Chow
M S
MS
Kluger
J
J
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
D000889:Anti-Arrhythmia Agents