Right ventricular myocardial infarction diagnosed by 99 m technetium pyrophosphate scintigraphy: clinical course and follow-up.

Out of 178 consecutive patients with acute inferior wall myocardial infarction submitted to technetium-99 m pyrophosphate scintigraphy, 49 (27.5%) were found to have concomitant right ventricular infarction. Gated blood pool scans showed right ventricular abnormalities in 21 out of 26 patients who were submitted to this investigation (right ventricular asynergy: 16 cases; right ventricular dilatation: eight cases; decreased right ventricular ejection fraction: 16 cases). Complications were common in the acute stage. Shock was noted in 19 cases (eight related to bradycardia, three related to relative hypovolaemia and eight instances of true cardiogenic shock). Atrial fibrillation (seven patients), ventricular fibrillation (eight patients) and severe atrioventricular conduction disorders (13 patients) were also frequent. In spite of this, the in-hospital mortality was low: three deaths occurred (6.1%), one from heart failure, two others from posterior septal rupture. All patients were followed up for one year or more. Six additional deaths were noted (three from left cardiac failure, two from recurrent anterior wall infarction and one from massive pulmonary embolism). Clinical assessment, haemodynamic measurements and gated blood pool scans showed significant improvement of right ventricular function with return to normal in those cases with small right ventricular infarcts as judged from technetium-99 m pyrophosphate scintigraphy. In spite of the complications seen in the initial period, patients with a right ventricular infarction have a good overall prognosis and the long-term outcome, primarily determined by the left-sided lesions, is often favourable.