RESPONSE TO SOTALOL PREDICTS THE RESPONSE TO AMIODARONE DURING SERIALDRUG-TESTING IN PATIENTS WITH SUSTAINED VENTRICULAR-TACHYCARDIA AND CORONARY-ARTERY DISEASE

It was analyzed whether the response to sotalol can predict the respon se to amiodarone as evaluated by programmed ventricular stimulation in 30 patients with coronary artery disease and documented recurrent sus tained ventricular tachycardia (VT). Programmed ventricular stimulatio n was performed using 1 or 2 extrastimuli during sinus rhythm and 4 dr ive cycle lengths at 2 right ventricular sites. If no ventricular tach yarrhythmia was induced, a third extrastimulus was introduced during a paced cycle length of 500 ms. During the control study, VT (mean cycl e length 305 +/- 63 ms) was induced in all patients, and the right ven tricular effective refractory period (during S-1-S-1 = 500 ms) was 223 +/- 12 ms. After sotalol, sustained and nonsustained VT were inducibl e in 22 (73%) and 7 (23%) patients, respectively. One patient did not undergo stimulation on sotalol, because of side effects. After amiodar one, sustained and nonsustained VT were inducible In 23 (71%) and 7 (2 3%) patients, respectively. The mean cycle length of the induced VT wa s prolonged after bath drugs by 17% (p < 0.001). The effective refract ory period was prolonged by 15% (p < 0.001) after sotalol and by 13% ( p < 0.001 compared with baseline study; p = Ns between both drugs) aft er amiodarone. Thus, concordant results (effective or ineffective drug ) between sotalol and amiodarone were found in 26 patients (87%). In c onclusion: (1) The effects of sotalol and amiodarone on the cycle leng th of induced VT and on right ventricular effective refractory period were similar; and (2) inability to suppress VT by amiodarone can be pr edicted from the response to sotalol. Thus, patients who would not res pond to amiodarone can be identified, and therefore, do not have to un dergo a long hospitalization period for loading dose and subsequent wa shout of amiodarone before other nonpharmacologic interventions.