What are the MUSTT-T (Multicenter Unsustained Tachycardia Trial - Treatment) trial criteria for patients with coronary artery disease (CAD) and unsustained ventricular tachycardia (VT)?

MUSTT Trial Inclusion Criteria

The MUSTT (Multicenter Unsustained Tachycardia Trial) enrolled patients with coronary artery disease, left ventricular ejection fraction ≤40%, and asymptomatic nonsustained ventricular tachycardia of ≥3 beats, who then underwent electrophysiologic testing to identify those with inducible sustained VT. 1

Primary Enrollment Criteria

The trial screened 2,202 patients with the following baseline characteristics 1:

• Coronary artery disease (documented prior myocardial infarction or angiographic evidence) 1
• Left ventricular ejection fraction ≤40% (measured by any clinically accurate modality) 1
• Asymptomatic nonsustained ventricular tachycardia consisting of ≥3 consecutive ventricular beats 1, 2
• No prior significant symptomatic ventricular arrhythmias (patients with prior sustained VT or cardiac arrest were excluded) 1

Electrophysiologic Study Requirements

Of the 2,202 enrolled patients, only those with specific EP study findings were randomized 1, 2:

• 704 patients (32%) had inducible sustained ventricular tachycardia during programmed electrical stimulation 1, 2
• These 704 patients with inducible sustained VT were then randomized to either electrophysiologically-guided antiarrhythmic therapy or no antiarrhythmic therapy 1, 2
• The remaining 1,498 patients without inducible sustained VT were followed in a registry but not randomized 2

Additional Clinical Characteristics

The enrolled population had these typical features 1:

• Median age 63-67 years, with only 11% of patients >75 years 1
• Predominantly male (76-92% men, only 8-24% women) 1
• 80% had NYHA Class I or II heart failure symptoms (relatively preserved functional status despite reduced EF) 1
• 56% had prior coronary artery bypass grafting 1
• Mean ejection fraction approximately 0.30 (range 0.23-0.30 across similar trials) 1

Key Exclusions

Patients were excluded if they had 1:

• Poorly controlled diabetes 1
• Prior documented sustained ventricular arrhythmias (symptomatic sustained VT or cardiac arrest) 1
• Medical conditions precluding electrophysiologic testing 1

Clinical Context and Significance

The MUSTT criteria identified a high-risk subset representing only 3.2% of all post-MI survivors, but this population had substantial mortality risk that could be modified with ICD therapy 1. The combination of reduced EF (<40%), nonsustained VT, and inducible sustained VT at EP study proved to be the critical triad for identifying patients who benefited from prophylactic ICD implantation, with a 76% reduction in cardiac arrest or arrhythmic death (relative risk 0.24,95% CI 0.13-0.45, p<0.001) 1, 2.

The trial demonstrated that electrophysiologically-guided antiarrhythmic drug therapy provided no mortality benefit, while ICD therapy in this population significantly reduced sudden cardiac death 2, 3. This finding fundamentally changed clinical practice, establishing that EP-guided ICD implantation—not drug therapy—is the appropriate intervention for patients meeting MUSTT criteria 1.