Isolated atrial infarction in a patient with single vessel disease of the sinus node artery

Atrial infarction is found in approximately 17 percent of autopsy-proven cases of myocardial infarction, but is a frequently missed clinical diagnosis. The antemortem diagnosis of atrial infarction occurring in the absence of ventricular infarction has not been previously reported. We present a patient with ischemic chest discomfort associated with paroxysmal atrial fibrillation. Electrocardiographic and enzymatic changes were consistent with atrial infarction. Cardiac catheterization demonstrated single vessel critical stenosis at the origin of the sinus node artery. Combined atrial and ventricular infarction occurs frequently and should be considered in the setting of paroxysmal supraventricular arrhythmias occurring early in the course of ventricular myocardial infarction. Lone atrial infarction is a rare but distinct clinical entity. The tetrad of typical ischemic chest discomfort, paroxysmal supraventricular arrhythmia, P-Ta segment shifts, and elevated cardiac enzyme levels without evidence for ventricular infarction strongly suggests isolated atrial infarction.