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Syncope Mediated by Posturally Induced Ventricular Tachycardia
- Emile G. Daoud, MD;
- Rodoljub Dimitrijevic, MD; and
- Fred Morady, MD
- From the University of Michigan Hospital, Ann Arbor, Michigan. Requests for Reprints: Fred Morady, MD, Division of Cardiology B1-F245, University of Michigan Medical Center, 1500 East Medical Center Drive, Ann Arbor, MI 48109-0022. Current Author Addresses: Drs. Daoud and Morady: Division of Cardiology B1-F245, University of Michigan Medical Center, 1500 East Medical Center Drive, Ann Arbor, MI 48109-0022.
In patients without structural heart disease, recurrent orthostatic syncope is often caused by hypovolemia, autonomic insufficiency, or vasodepressor syncope. Only rarely has postural ventricular tachycardia been reported to cause syncope. In this case report, we describe an unusual variant of idiopathic ventricular tachycardia reproducibly triggered by upright posture.
Case Report
A 66-year-old woman with no previous history of cardiac disease or symptomatic arrhythmia began having dyspnea on exertion. Three weeks later, she sought medical attention when she developed severe substernal chest pressure, postural syncope, and near-syncope.
In the emergency department, the patient's supine blood pressure, measured using an arm cuff, was 142/78 mm Hg. Monitoring documented sinus rhythm at 82 beats per minute with episodes of ventricular bigeminy, unifocal couplets, and 10- to 14-beat runs of nonsustained monomorphic ventricular tachycardia. This tachycardia had a right bundle-branch heart block morphology, left-axis deviation, and a cycle length of 280 ms. The electrocardiogram was otherwise normal, with a QTc interval of 410 ms. Electrolyte levels were within normal limits. The patient was treated with lidocaine, heparin, and aspirin. During the subsequent 24 hours, she continued to have short episodes of nonsustained ventricular tachycardia elicited by upright posture. Her systolic blood pressure remained greater than 90 mm Hg during ventricular tachycardia. Creatinine kinase plasma concentrations were not elevated, and …
