Near-syncope after exercise

Roy C. Ziegelstein, MD

JAMA. 2004;292:1221-1226.

Syncope and near-syncope are great diagnostic challenges in medicine. On the one hand, the symptom may result from a benign condition and pose little or no threat to health other than that related to falling. On the other hand, syncope or near-syncope can be the manifestation of a serious underlying condition that poses an imminent threat to life. Patients with a cardiac cause of syncope are at far greater risk of dying in the first year after an episode of syncope or near-syncope than individuals with a noncardiac cause. A cardiac cause of syncope should be considered in every patient with syncope or near-syncope, but it is particularly common in older patients or in patients with known structural heart disease, arrhythmia, or certain electrocardiographic abnormalities. Although many diagnostic tests may be helpful in the evaluation of syncope and near-syncope, the history, physical examination, and electrocardiogram pinpoint the cause in many circumstances. Syncope after exercise may be due to left ventricular outflow tract obstruction from aortic stenosis or hypertrophic obstructive cardiomyopathy but can also suggest the diagnosis of postexercise hypotension in which an abnormality in autonomic regulation of vascular tone or heart rate results in vasodilation or bradycardia after moderate-intensity aerobic activity. The patient discussed in this case highlights the importance of the clinical history in the evaluation of this condition, since the diagnosis was revealed as the patient's story was described and eventually acted out.