RESULTS OF BIVENTRICULAR ENDOMYOCARDIAL BIOPSY IN SURVIVORS OF CARDIAC-ARREST WITH APPARENTLY NORMAL HEARTS

Seventeen young patients (10 males and 7 females, aged 14 to 38 years, mean 26.4) with out overt organic heart disease, who had been resuscitated from sudden cardiac arrest and referred to our institution during the period 1984 to 1993 for diagnostic evaluation and electrophysiologic study-guided antiarrhythmic therapy, were studied. Patients underwent noninvasive (electrocardiography, echocardiography [2-dimensional and Doppler], and magnetic resonance imaging) and invasive (left ventricular [LV], right ventricular [RV], and coronary angiography, ergonovine testing, electrophysiologic study, and biventricular endomyocardial biopsy) cardiac studies. Six to 8 biopsy fragments per patient were processed for histology and electron microscopy and read by a pathologist blinded to clinical data. Antiarrhythmic drug testing included amiodarone, propafenone, and metoprolol. A cardioverter-defibrillator was implanted in patients with persistently inducible sustained ventricular tachycardia or ventricular fibrillation. Sequential cardiac biopsy specimens were obtained in patients with active myocarditis undergoing immunosuppressive treatment. Periodic 3-month follow-ups included echocardiography and Holter monitoring. Two groups of patients were distinguished by invasive and noninvasive examinations: group I consisted of 9 patients with entirely normal parameters; group II consisted of 8 patients with structural, nonspecific cardiac abnormalities. In this latter group, mild to moderate dilatation aml hypokinesia of the left ventricle were documented in 4 patients, concentric LV hypertrophy was seen in 3 patients, and RV dysfunction was noted in 1 patient. Histologic examination was abnormal in all patients and revealed specific lesions in 65% of them; LV biopsy specimens allowed a diagnosis in 3 of 7 myocarditic patients with normal RV histology. An active lymphocytic myocarditis was observed in 7 patients, hypertrophic cardiomyopathy in 3 patients, RV dysplasia in 1 patient, and nonspecific cardiomyopathic changes in 6 patients. At 38-month follow-up, the mortality rate was 29% (all deaths were sudden). Biventricular endomyocardial biopsy may identify diagnostic lesions in young survivors of cardiac arrest with apparently normal hearts. In some patients LV biopsies revealed myocarditis when RV biopsies were normal.