title: Worsening of vasovagal syncope after beta-blocker therapy.
abstract: Head-up tilt test was done in a 27-year-old man with recurrent syncope of unexplained cause. Severe sinus bradycardia and hypotension accompanied by light-headedness, cold sweating, and nausea occurred at 80 degrees head-up position during 4 micrograms/min isoproterenol infusion. Oral propranolol, 160 mg/d, in four divided doses, effectively prevented the above-mentioned abnormal vasovagal reflexes; diltiazem was only partially effective while disopyramide, aminophylline, or atropine was ineffective in preventing the abnormal vasovagal reflexes induced by head-up tilt with isoproterenol infusion. However, the patient experienced ten episodes of syncope in 2 weeks after he was discharged from the hospital on a regimen of atenolol, 50 mg/d. His symptoms ameliorated immediately after discontinuation of atenolol therapy and he became free of severe symptoms while receiving fludrocortisone. Thus, we have documented a patient with worsening of vasovagal syncope after beta-blocker therapy.
authors.affiliation: Department of Medicine, Chang Gung Memorial Hospital, Chang Gung Medical College, Taipei, Taiwan.
authors.forename: C C
authors.initials: CC
authors.lastname: Wang
authors.forename: S J
authors.initials: SJ
authors.lastname: Yeh
authors.forename: M S
authors.initials: MS
authors.lastname: Wen
authors.forename: F C
authors.initials: FC
authors.lastname: Lin
authors.forename: D
authors.initials: D
authors.lastname: Wu
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000009:adverse effects*; D000328:Adult; D004562:Electrocardiography / Q000187:drug effects; D005438:Fludrocortisone / Q000627:therapeutic use; D006801:Humans; D008297:Male; D011187:Posture; D012008:Recurrence; D013575:Syncope / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy
chemical_list: D000319:Adrenergic beta-Antagonists; D005438:Fludrocortisone