[Diagnosis of right atrial infarction by esophageal echocardiography]

Atrial infarction is rare and its ante mortem diagnosis is difficult by electrocardiography. There has been no report concerning the diagnosis of atrial infarction by echocardiography because it is difficult to observe atrial motion by conventional echocardiography. This report deals with a case of probable right atrial infarction diagnosed by esophageal echocardiography. A 50-year-old man was admitted to our hospital under the diagnosis of acute infero-posterior myocardial infarction. Swan-Ganz catheterization data revealed dip and plateau pattern with elevated right atrial pressure suggesting complicated right ventricular infarction. In the esophageal echocardiograms recorded one month later, the motion of the right atrial anterior wall was akinetic and right atrial dimension did not change during both atrial contraction phase and atrial filling phase. These findings suggest impairment of pump function and reservoir function of the right atrium. Amplitudes of the interatrial septum during atrial filling phase and atrial contraction phase were in the lower limit of normal range. Total occlusion of the right coronary artery was proven by coronary arteriography. Hypokinesis of the upper right atrial appendage was suspected by right atriography and maximal right atrial volume was as large as 116 ml. In the right atrial volume curve by cardiac scintigraphy, fractional emptying was as low as 28%. The patient had an uneventful recovery and returned to full-time works, so that pathological diagnosis was not obtained, but the clinical diagnosis of right atrial infarction was strongly suspected by the clinical findings mentioned above. It was concluded that the esophageal echocardiography is mandatory to observe atrial wall motion abnormality whenever atrial infarction is suspected.