Objective: To examine the immediate and long-term clinical and prognostic significance of primary ventricular tachycardia, defined as tachycardia of ventricular origin occurring within 48 hours of acute myocardial infarction in patients without hemodynamic compromise (Killip class I).
Design: Prospective cohort study.
Setting: Intensive coronary care units in eight regional, referral, and university hospitals.
Patients: A total of 162 patients with primary ventricular tachycardia, both sustained and nonsustained (study group), and 2578 counterparts without ventricular tachycardia (reference group).
Measurements: In-hospital rates of atrial fibrillation, atrioventricular block, congestive heart failure, cardiogenic shock, and cardiac arrest. In-hospital and 1-year follow-up rates of sudden death, nonsudden cardiac death, and noncardiac death.
Results: The study and reference groups had similar mortality (in-hospital, 6.8% and 9.6%, P greater than 0.2 and at 1 year after discharge, 3.7% and 5.4%, P greater than 0.2, respectively) and in-hospital complication rates (atrioventricular block, 13.0% and 9.7%, P greater than 0.2; cardiogenic shock, 3.7% and 3.0%, P greater than 0.2; cardiac arrest, 1.8% and 4.4%, P greater than 0.2, respectively). Patients with sustained ventricular tachycardia (28 patients) compared with those with nonsustained ventricular tachycardia (134 patients) had higher rates of polymorphic tachycardia (50% compared with 6%, P = 0.001), in-hospital total cardiac mortality (21% compared with 4%, P = 0.003) and sudden-death mortality (14% compared with 2%, P = 0.001); they also showed a trend toward a higher in-hospital mortality than the reference group (21.4% compared with 9.6%, P = 0.15) but had no increased mortality 1 year after discharge (4.6% compared with 5.4%, P greater than 0.2).
Conclusions: As a group, patients with primary ventricular tachycardia do not differ from counterparts without primary ventricular tachycardia in their in-hospital clinical course and 1-year prognosis. Primary sustained ventricular tachycardia is often polymorphic and carries worse in-hospital prognosis than nonsustained tachycardia. However, it does not predict recurrent ventricular tachycardia or increased sudden-death rates during the next year.