What were the results of the MUSTT study of implantable cardioverter-defibrillator (ICD) therapy?

Updated: Oct 11, 2019
  • Author: Daniel M Beyerbach, MD, PhD; Chief Editor: Jeffrey N Rottman, MD  more...
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MUSTT, reported in 1999, also showed a survival benefit to ICD therapy. The trial had similar inclusion criteria to MADIT (prior infarct, LVEF ≤40%, nonsustained VT inducible at EPS) and randomized patients to EPS-guided therapy versus no specific antiarrhythmic therapy.

Early in the trial, EPS-guided therapy consisted of antiarrhythmic drug therapy guided by EPS testing, with ICD implantation reserved for patients with ventricular arrhythmias refractory to antiarrhythmic drugs. Later in the trial, ICDs were used earlier in patients who were randomized to the EPS-guided therapy arm of the trial. MUSTT showed a survival benefit in the EPS-guided group. The survival benefit was attributable to the ICD. Patients who were randomized to EPS-guided therapy and treated with antiarrhythmic drugs fared no better or worse than patients assigned to the control arm of the trial. [15]

In MUSTT, a registry was maintained of patients who met the clinical criteria for the study but were noninducible in the electrophysiology laboratory. During follow-up, the survival rate in this group was better than in the inducible patients assigned to the control group but not as good as in inducible patients who received ICDs. Although MUSTT was not designed to determine the optimal treatment in noninducible patients, many have concluded that, in the population studied, EPS testing may be used to stratify high-risk and moderate-risk patients rather than high-risk and low-risk patients. [16, 17]

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