Neurally mediated syncope induced by lung cancer--a case report.

The authors present hemodynamic and autonomic features of recurrent and episodic neurally mediated syncope in a man with lung cancer involving afferent vagus. He revealed extreme hypotension with bradycardia occurring during sitting or standing. A head-up tilt test also induced syncope. However, syncope attacks no longer occurred 2 weeks after admission. Alternatively, the paralyses of the left recurrent laryngeal nerve and the left phrenic nerve developed. It is suggested that the lung cancer involved upper rootlets of the left vagus and caused transient hypersensitivity of baroreceptor function that resulted in neurally mediated syncope.