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Therapy assessment for sustained ventricular tachyarrhythmias: how many electropharmacological tests are appropriate?
W Schoels1, J Brachmann, R Hug
1Department of Cardiology, University of Heidelberg, Federal Republic of Germany.
Abstract:
Surgery, implantable devices or catheter ablations offer therapeutic choices for the treatment of malignant ventricular tachyarrhythmias (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 inducibility 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.
Insights
Electrophysiological (EP) tests help identify effective antiarrhythmic drugs for ventricular tachyarrhythmias (VT). Many patients achieve VT suppression with one to two EP tests, but some require more extensive testing for optimal drug selection.
Area of Science:
- Cardiology
- Electrophysiology
- Pharmacology
Background:
- Malignant ventricular tachyarrhythmias (VT) resistant to antiarrhythmic drugs often require non-pharmacological therapy.
- The optimal number of electrophysiological (EP) tests to guide drug selection before considering alternative therapies remains undefined.
Purpose of the Study:
- To determine the number of EP tests needed to identify effective antiarrhythmic drugs for drug-resistant VT.
- To evaluate the relationship between the number of unsuccessful EP tests and subsequent drug efficacy and VT recurrence.
Main Methods:
- Serial EP tests were conducted in 94 patients with inducible sustained VT until VT suppression or failure of all available drugs.
- Patients were followed for symptomatic VT recurrence after drug therapy was initiated based on EP test results.
Main Results:
- VT inducibility was suppressed in 70% of patients, with 70% of these achieving suppression within one or two EP tests.
- However, effective agents were identified in a significant percentage of patients even after multiple (2-5) unsuccessful tests.
- VT recurrence was not correlated with the number of unsuccessful EP tests prior to identifying an effective drug.
Conclusions:
- Extensive EP testing may be beneficial for selected patients with drug-resistant VT.
- The number of EP studies should be individualized based on the likelihood of finding an effective drug and the risks associated with alternative therapies.