Arrhythmias in patients with hypereosinophilia: a comparison of patients with and without Löffler's endomyocardial disease.

About one third of patients with Löffler's endomyocardial disease have abnormal electrocardiograms and some develop arrhythmias and die suddenly. To assess the significance of these findings, continuous ambulatory ECG monitoring was performed for 48 hr on 6 patients with acute or chronic forms of Löffler's endomyocardial disease, and the types and frequencies of arrhythmias were compared with recordings from 6 other patients with equally high blood eosinophil counts who did not have clinically evident cardiac disease. It was hoped that this would show whether arrhythmias were related to high blood eosinophil counts, cardiac injury or other factors. Three of the patients with endomyocardial disease had multiple ventricular extrasystoles with episodes of ventricular arrhythmias and occasional supraventricular arrhythmias which had not been detected with conventional ECGs. These abnormalities did not occur in 2 of the patients with acute endomyocardial lesions who died, nor were they found in patients who did not have congestive cardiac failure or in the control patients. Rhythm disturbances appeared to be most closely related to the development of cardiac failure and they resolved after successful cardiac surgery. Multiple ventricular extrasystoles and arrhythmias occurring in these patients with Löffler's endomyocardial disease are probably due to metabolic changes in the heart associated with cardiac failure and mechanical changes related to valvular dysfunction rather than a direct effect of the eosinophils themselves on the heart.