Syncope (or loss of consciousness) is one of the most frequent emergency room and hospital diagnoses. Syncope or near-syncope is responsible for 1 percent to 6 percent of hospital admissions and/or emergency room visits. The workup should follow a simple algorithm. The method of evaluating syncope and determining its etiology should consist initially of a history, physical examination, 12-lead ECG, and echocardiogram.
Cardiac syncope primarily consists of arrhythmias of all types: tachycardias (rapid heart rhythms) such as ventricular tachycardia/fibrillation and/or supraventricular tachycardia, and bradyarrhythmias such as heart block, sinus bradycardia, and asystole. If the history, physical examination, and/or electrocardiogram point to a cardiac diagnosis, a cardiac workup may be important, followed by an electrophysiology study.
The electrophysiology study is useful at assessing cardiac conduction and presence of arrhythmias. The results of the study can focus the treatment to drugs, catheter ablation (performed at the time of the electrophysiology study), and device-based therapy (pacemaker or implantable defibrillator).