[Myocardial dissection in infarction of the right ventricle. Clinical echocardiographic and pathological aspects]

Dissection of the inferior wall of the right ventricle during the acute phase of myocardial infarction with right ventricular involvement is a mechanical complication which has been recently identified, the diagnosis being almost exclusively post-mortem. The authors report the clinical, echocardiographic and pathological features of myocardial dissection in four patients. Between 1985 and 1988, the diagnosis of myocardial dissection was made by echocardiography in 4 patients aged 77 to 80 years, admitted to hospital for an acute inferior wall myocardial infarction. All 4 patients had signs of acute right ventricular failure indicating right ventricular necrosis and a loud systolic murmur at the left sternal border; 2 patients were in shock. The ECG showed signs of inferior wall infarction with, in 2 patients, electrical changes suggestive of right ventricular involvement. Echocardiography showed dissection of the inferior wall of the right ventricle as a pulsatile, echo-free space in the diaphragmatic wall of the right ventricle which appeared to obstruct right ventricular ejection in end systole to a variable degree. The outcome was fatal in all cases with death resulting from refractory myocardial failure. Pathological analysis confirmed biventricular inferior wall infarction also involving the posterior part of the interventricular system, the site of a small tear on the left side which communicated with a neo-cavity dissecting the RV posterior wall. The right coronary artery was totally occluded in all cases. The anatomical lesions were fully concordant with the echocardiographic data: the dissection filled with blood from the left ventricle at each systole creating a pulsatile space in the diaphragmatic wall of the ventricle obstructing ejection.