Isolated atrial myocardial infarction: pathological and clinical features in 10 cases.

Isolated myocardial infarction of the atria is a relatively understudied and underestimated entity, rarely diagnosed in life. The pathological and clinical features in 10 cases of acute isolated atrial myocardial infarction are reported. They represent 3.5% of all myocardial necrosis out of a series of 2,704 consecutive autopsies in adults. The right atrium is more frequently involved than the left atrium (9:1). Pulmonary hypertension, with or without coronary arterial narrowing, is the major condition leading to isolated atrial infarction. Congestive heart failure, thromboembolic phenomena, and supraventricular arrhythmias are the most frequent complications of atrial infarction. The electrocardiographic findings are often non-specific and elusive and are not useful to a correct diagnosis. These observations suggest that isolated atrial myocardial infarction is a well-distinct entity with respect to ventricular myocardial infarction, since there are several differences between the 2 diseases in pathogenesis, diagnosis, clinical picture, and prognosis.