Therapy Assessment for Sustained Ventricular Tachyarrhythmias: How Many Electropharmacological Tests are Appropriate?

Surgery, implantable devices or catheter ablations offer therapeutic choices for the treatment of malignant ventricular tachyarrhythmius (VT) resistant to antiarrhythmic drugs. The number of electropharmacological (EP) tests that should precede consideration of a nonpharmacological therapy has not been defined. We performed serial EP tests in 94 patients with inducible sustained VT until an effective drug was identified or all available drugs had failed to suppress VT induction. With up to 11 tests in individual patients, suppression of VT inducibilify was finally achieved in 66 patients (70%). In 47 of these 66 patients (70%), only one or two tests were necessary to identify an effective regimen. However, in 40%, 28%, 18%, and 9% of the patients still inducible after 2, 3, 4, and 5 drug tests, respectively, an effective agent could be identified during subsequent tests. No critical number of unsuccessful EP tests clearly separated responders and nonresponders to medical therapy. During follow‐up (34 ± 11 months), 14 patients placed on antiarrhythmic drugs predicted to be effective had symptomatic VT recurrence. VT recurrence was unrelated to the type or the number of unsuccessful EP tests preceding identification of the prescribed drug. Extensive EP testing with all available agents might therefore be worthwhile in selected patients. An “appropriate” number of EP studies has to be determined individually for each patient, based on the chance of finding an effective drug during subsequent studies and the risk and benefit of the therapeutic choices.