Antiarrhythmic Drug Improve Outcome Study - ADIOS

Description:

The goal of the trial was to determine if effective antiarrhythmic drug therapy guided by EP study improves the outcome of patients with VT/VF compared to patients whose effective pharmacological treatment was discontinued.

Hypothesis:

The primary objective of the randomized, prospective multicenter ADIOS trial was to determine if effective antiarrhythmic drug therapy guided by EP study improves the outcome of patients with VT/VF compared to patients whose effective pharmacological treatment was discontinued.

Study Design

Study Design:

Patients Enrolled: 250

Patient Populations:

Patients were included if they had sustained VT of 30 or more seconds and a suppressed left ventricular ejection fraction (EF)<45%, or if they were successfully resuscitated from VT/VF regardless of their EF. All patients had to have inducible VT or VF and an effective antiarrhythmic drug identified by suppression during EP study. They also had to have an identifiable underlying cardiac disease. Patients were excluded if they had a myocardial infarction less than 4 weeks before the study.

Sixty of 250 patients met the criteria and underwent ICD placement. At baseline, most patients had inducible VT and 30% had VF. Most were males with an EF near 43%. There were no significant differences in baseline variables between patients in the two arms. Researchers tested an average of 1.2 drugs before finding an effective therapy and the drug used most often was sotalol.

Primary Endpoints:

Recurrence of sustained ventricular arrhythmia

Drug/Procedures Used:

Patients were randomized to ICD treatment with (n=31, 52%) or without (n=29, 48%) concomitant antiarrhythmic drug therapy, then followed up every 3 months or at recurrence. Data were evaluated according to an intention-to-treat analysis.

Principal Findings:

Although first recurrence was the primary endpoint, patients in the discontinued therapy group were crossed over, if possible, to the opposing arm by returning the patients to EP-guidedtherapy.

Although continued use of antiarrhythmic drug therapy did not significantly reduce VT/VF recurrences, investigators found a trend to later recurrence of VT/VF episodes during follow-up in this group. After more than 2 years, 35% of patients in the ICD plus drug group had a recurrence at a mean of 12 months, while 45% of patients in the ICD-only arm recurred within a mean of 5±7 months. VT was the most common arrhythmia to recur.

Over the course of the study 8 patients died, the majority from heart failure.

The study was prematurely halted. In designing the study, the investigators assumed a 20% event rate in the group continuing on antiarrhythmic drug therapy and a 50%recurrence rate in the ICD-only group. With the event rate much less than anticipated in the ICD-only group and much greater in the drug therapy arm, the trial was discontinued early.

Interpretation:

The investigators concluded that there is a limited value of serial drug testing in patients with VT/VF and an accepted indication for ICD implantation.

References:

AHA 1997, Clinical Trials, presented by Ellen Hoffmann, MD, University of Munich, Munich, Germany

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Implantable Devices, SCD/Ventricular Arrhythmias, Acute Heart Failure

Keywords: Myocardial Infarction, Recurrence, Tachycardia, Ventricular, Ventricular Fibrillation, Intention to Treat Analysis, Heart Failure, Stroke Volume, Sotalol, Defibrillators, Implantable


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