Patients under evaluation for cardiac transplant surgery were seen for routine psychiatric diagnosis and treatment. Of 35 patients with idiopathic cardiomyopathy, 83% (N = 29) had definite or probable panic disorder. Of 25 patients with postinfarction cardiac failure, rheumatic heart disease, or congenital heart disease, only 16% (N = 4) had definite or probable panic disorder. The authors suggest that autonomic mechanisms may underlie the association of cardiomyopathy and panic disorder and that increased cardiac sympathetic tone or circulating catecholamines may cause myocarditis and cardiomyopathy.