An Unusual Cause of Syncope

Background: Syncope is one of the most common reasons for emergency room visits. Although many cases are due to benign etiologies, identification of patients with serious underlying causes remains challenging.

Case: Ms. N is a 58 year‐old woman with history of hypertension and hyperlipidemia who presented with an episode of loss of consciousness during exercise. Her initial EKG on presentation to the ER showed sinus bradycardia with a right bundle branch block, RBBB, T wave inversions V1‐V5. During stress testing, she had a good exercise tolerance and EKG showed frequent multiform PVCs with mild associated symptoms. On SPECT imaging there was a small fixed inferior apical defect with normal LV wall motion and normal ejection fraction (Figure). Importantly, her right ventricle (RV) was moderate to severely enlarged, prompting a cardiac MR for further evaluation. The MRI findings (Figure) combined with EKG and clinical history confirmed the diagnosis of arrhythmogenic right ventricular dysplasia (ARVD).

Decision Making: On initial evaluation, the etiology for her syncope was unclear. Her EKG was abnormal but was not thought to be significantly changed from her previous studies. Initial cardiac imaging with echocardiogram was non‐diagnostic due to PVCs on the EKG portion. Using SPECT imaging we were able to evaluate both right and left ventricular perfusion and function. The ability to evaluate the right ventricle was critical in the decision to pursue a cardiac MR for a definitive diagnosis of ARVD.

Conclusions: Syncope is a common presenting symptom for patients in the emergency department. The etiology is most commonly due to a benign reason but this clinical case is an excellent example of a rare but life threatening diagnosis that should not be missed.