Recurrent supine syncope: An unusual manifestation of the neurally mediated faint

Introduction: Syncope occasionally may occur in the supine patient due to severe brady- or tachyarrhythmia. However, recurrent syncope upon assumption of the supine position as a result of a neurally mediated reflex mechanism has not been reported previously. Methods and Results: Two young patients, both of whom had significant systemic illnesses, experienced recurrent episodes of presyncope and/or syncope shortly after assuming the supine position. During ambulatory ECG monitoring, symptoms were provoked only by lying down and were associated with transient bradycardia. Head-up tilt table testing was undertaken as part of the syncope evaluation and was nondiagnostic in both cases. However, both patients exhibited a transient cardioinhibitory response with reproduction of typical symptoms upon return of the table to the supine position ('reverse tilt'). During follow-up (8 and 14 months), both patients improved with pharmacologic treatment (disopyramide in one case and midodrine in the other). Conclusion: Presyncope or syncope upon lying down can be an unusual manifestation of the neurally mediated faint.