Prognostic determinants in hypertrophic cardiomyopathy. Prospective evaluation of a therapeutic strategy based on clinical, Holter, hemodynamic, and electrophysiological findings.

BACKGROUND: Patients with hypertrophic cardiomyopathy (HCM) frequently have arrhythmias and hemodynamic abnormalities and are prone to sudden death and syncope. An important need exists for improved risk stratification and definition of appropriate investigation and therapy. METHODS AND RESULTS: The relation of 31 clinical, Holter, cardiac catheterization, and electrophysiological (EP) variables to subsequent cardiac events in 230 HCM patients was examined by multivariate analysis. Studies were for cardiac arrest (n = 32), syncope (n = 80), presyncope (n = 52), ventricular tachycardia (VT) on Holter (n = 36), a strong family history of sudden death (n = 9), and palpitations (n = 21). Nonsustained VT on Holter was present in 115 patients (50%). Sustained ventricular arrhythmia was induced in 82 patients (36%). Seventeen cardiac events (eight sudden deaths, one cardiac arrest, and eight syncope with defibrillator discharges) occurred during a follow-up of 28 +/- 19 months. The 1-year and 5-year event-free rates were 99% and 79%, respectively. Two variables were significant independent predictors of subsequent events: sustained ventricular arrhythmia induced at EP study (beta, 3.5; p = 0.002) and a history of cardiac arrest or syncope (beta, 2.9; p less than 0.05). Only two of 66 patients without symptoms of impaired consciousness had a cardiac event (3-year event-free rate, 97%). In contrast, nonsustained VT on Holter was associated with a worse prognosis only in patients with symptoms of impaired consciousness: 11 of 79 symptomatic patients with VT on Holter (14%) had events versus only four of 85 symptomatic patients without VT on Holter (5%) (p = 0.057). Notably, none of 51 patients without symptoms of impaired consciousness in whom VT was not induced at EP study had a cardiac event. CONCLUSIONS: In HCM, VT on Holter is of benign prognostic significance in the absence of symptoms of impaired consciousness and inducible VT, and sustained VT induced at EP study, especially when associated with cardiac arrest or syncope, identifies a subgroup at high risk for subsequent cardiac events.