Hypertrophic Cardiomyopathy And Atrial Fibrillation: A Change

Hypertrophic cardiomyopathy was first recognized from pathologic studies in 1958 (1) and subsequently analyzed in detail from hemodynamic (2), echocardiographic (3) and electrophysiologic standpoints (4). It is characterized by a hypertrophied heart with a nondilated left ventricular chamber in the absence of any illness that induces an increased myocardial mass. It is frequently associated with dynamic left ventricular outflow obstruction, mitral regurgitation and left ventricular diastolic dysfunction due to impaired relaxation processes and reduced compliance (5). It is also associated with a relatively high prevalence of supraventricular (11% to 54%) and ventricular (19% to 88%) arrhythmias (6), a significant annual mortality rate (3% to 4%) and an alarming incidence rate of sudden cardiac death (2% annually, accounting for over half of all cardiac deaths in this disease) (7). Interestingly, the major risk factors for mortality in patients with hypertrophic cardiomyopathy are clinically and arrhythmia related and are unrelated to hemodynamic variables. These include younger age at diagnosis «20 years), family history of hypertrophic cardiomyopathy and sudden death, history of syncope, history of severe exertional dyspnea and occurrence of complex ventricular ectopic rhythm and nonsustained ventricular tachycardia, or both (8). Impact of atrial fibrillation. The occurrence of atrial fibrillation in patients with hypertrophic cardiomyopathy has been associated with such marked clinical and hemodynamic deterioration (including acute pulmonary edema, angina, syncope, hypotension and systolic embolization [5]) that it has been assumed to engender a poor prognosis in these patients. Sporadic reports with small numbers of cases seem to confirm this impression (9). Indeed, this assumption has