Diagnostic superiority of continuous‐loop electrocardiographic recording over other testing in a patient with recurrent syncope and underlying coronary artery disease with severe left ventricular dysfunction

Dysrhythmic causes of syncope may elude diagnosis in postinfarction patients despite elaborate testing, including electrophysiologic study. For a correct diagnosis, capture of cardiac rhythm during patient's typical symptoms is crucial. This report describes a patient with coronary artery disease and decreased left ventricular ejection fraction who experienced recurrent syncopal episodes without obvious precipitating factors. The 12-lead electrocardiogram showed left bundle-branch block indicating a possible conduction abnormality as the underlying cause of syncope. Twenty-four-h Holter monitoring exhibited no sinus rhythm or conduction disturbances but revealed a nonsustained run of ventricular tachycardia. Findings at electrophysiologic testing led to a presumptive diagnosis of tachyarrhythmic cause of syncope; however, the correct diagnosis was only made with use of a loop monitor which documented a 15-s sinus pause during a syncopal episode.