title: Dual chamber pacing for neurally mediated syncope with a prominent cardioinhibitory component.
abstract: The role of cardiac pacing for treatment of recurrent neurally mediated syncope (NMS) remains controversial. We hypothesized that dual chamber pacing in NMS patients with a prominent cardioinhibitory component may be beneficial. Twelve patients (mean age = 37.8+/-17 years, range 15-78 years, 7 men and 5 women) with a mean of 4+/-2.2 episodes of syncope underwent tilt table evaluation. Patients were passively tilted to 70 degrees head-up position for 20 minutes and then returned to the supine position. Isoproterenol was then infused at 1-2 microg/min to increase heart rate by > or = 25% and tilt was repeated. Patients lost consciousness after 16+/-6 minutes of tilt; nine patients had syncope in the baseline state and three during isoproterenol infusion. All patients had at least 5 seconds of asystole with a mean of 9.5+/-4 seconds (range 5-20 s). A dual chamber permanent pacemaker with a special feature allowing heart rate acceleration in response to bradycardia was implanted in all patients. During a mean follow-up of 18.6+/-4.2 months, 11 (92%) of these patients were free of syncope and had negative tilt table test. One (8%) patient had two episodes of syncope. We conclude that dual chamber pacing may be beneficial in patients with NMS with a prominent cardioinhibitory component.
authors.affiliation: Thoracic and Cardiovascular Institute, Department of Internal Medicine, Michigan State University, Lansing 48910, USA.
authors.forename: C P
authors.initials: CP
authors.lastname: Shah
authors.forename: R K
authors.initials: RK
authors.lastname: Thakur
authors.forename: B
authors.initials: B
authors.lastname: Xie
authors.forename: P
authors.initials: P
authors.lastname: Pathak
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D006321:Heart / Q000294:innervation*; D006323:Heart Arrest / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D006801:Humans; D007545:Isoproterenol; D008297:Male; D008875:Middle Aged; D009433:Neural Inhibition / Q000502:physiology*; D010138:Pacemaker, Artificial; D011446:Prospective Studies; D013566:Sympathomimetics; D019462:Syncope, Vasovagal / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D018667:Tilt-Table Test; D016896:Treatment Outcome
chemical_list: D013566:Sympathomimetics; D007545:Isoproterenol