Exercise-Induced Ventricular Arrhythmia: Initial Presentation of Occult Barlow Syndrome Unmasked by Stress Testing

Barlow syndrome, a form of myxomatous mitral valve prolapse, often presents with nonspecific symptoms and may be missed on resting examination.

A 38-year-old woman presented with recurrent palpitations triggered by stress and poor sleep. Resting physical examination was unremarkable. Exercise stress test (EST) revealed frequent premature ventricular contractions and a midlate systolic apical click postexercise, which were both previously absent at rest. Echocardiography confirmed Barlow syndrome with 7 mm mitral annular disjunction (MAD). Beta-blocker therapy was initiated with symptomatic improvement.

The EST unmasked both electrophysiological and auscultatory abnormalities entirely occult on standard resting evaluation. This case offers a practical diagnostic reference for recognizing latent cardiac diseases in patients with nonspecific symptoms.

EST plays a crucial role in diagnosing atypical Barlow syndrome by unmasking both arrhythmias and characteristic auscultatory findings. Beta-blocker therapy effectively improves symptoms in patients with mitral annular disjunction-associated exercise-induced arrhythmias.