Vasovagal Syncope with Bradycardia During Lower Body Negative Pressure in a Heart Transplant Recipient

Abstract

Vasovagal syncope has been ascribed to the vagal excitation and the sympathetic inhibition induced reflexly by mechanical stimulation of receptors in the ventricles. In this case report we describe a vasovagal syncope with bradycardia triggered by a reduction in venous return obtained via mild lower body negative pressure, in a patient with cardiac denervation due to heart transplantation. This suggests that the mechanisms involved in this phenomenon may not exclusively depend on a reflex originating from ventricular receptors. It also suggests that non-neural factors may be involved in the genesis of the bradycardia.

Key Words:

• vasovagal syncope
• heart transplantation
• sympathetic nervous system
• vagal tone
• ventricular receptors