Apical hypertrophic cardiomyopathy (apical HCM) has been believed to be a special type of hypertrophic cardiomyopathy. It usually occurs in middle-aged or elderly men and the prognosis is thought to be good. However, recent reports suggest that approximately 10% of middle-aged patients with apical HCM have cardiac events and poor outcomes. We studied electrocardiograms and echocardiograms, the occurrence of cardiac events, and clinical characteristics in elderly patients with apical HCM (13 men and 7 women, 61 to 95 years old, mean age 74 +/- 7). Three of 20 patients (15%) had cardiac events (sudden death, 1; heart failure, 1; chest pain, 1), 2 had cerebral infarction with atrial fibrillation, and 2 died of non-cardiac causes. There were no differences in age, sex, medication, complications, or in initial values of electrocardiographic or echocardiographic variables between patients who had and did not have cardiac events. However, left ventricular end-systolic dimension (LVEDs) and left atrial diameter at the time of the last evaluation were larger in patients who had cardiac events than in those who did not (26 vs. 34 mm, p = 0.019, 33 vs. 38 mm, p = 0.1325, respectively). These results suggest that the prognosis for patients with apical HCM is not necessarily good, and that enlargement of the LVEDs might be used to predict cardiac events in elderly patients with apical HCM.