Study of different responses of Head up tilt table testing for Evaluation of Neurocardiogenic syncope

Abstract

Neurocardiogenic syncope is the most common cause of syncope presenting in the out patient setting. It is usually encountered among individuals without an underlying heart disease. Head upright tilt test is a useful method for identifying patients with neurocardiogenic syncope. Heart rate variability gives information about sympathetic-parasympathetic autonomic balance. The aim of the work is: A- evaluation of patients with unexplained syncope + presyncope despite their normal cardiovascular system by head up tilt test. B- Follow up for 6 months for the positive patients to evaluate the medical treatment. This study included two groups: 1- Group I: (the positive group) consisted of 17 patients complaining of syncope + presyncope, 10 females and 7 males. 2- Group II (the negative group) consisted of 3 individuals. (1 female and 2 males). Both groups were subjected to the following: I. Careful medical history and full analysis of their syncopal or Presyncopal spells. II. General examination, pulse rate rhythm and blood pressure during supine and standing. III. Complete clinical examination to assess cardiac state and to exclude neurological problems. IV. Baseline laboratory evaluation, including a complete blood count, blood urea, creatinine, fasting and 2 hours post prandial blood sugar, serum sodium and potassium. V. Electrocardiogram. VI. Electroencephalogram. VII. Ecocardiographic examination. VIII. Head upright tilt test includes 5 consecutive stages: Stage I Patient was tiled to 80 degree for 10 min. without provocation. Sage II Patient was tilted to 80 degree for 10 min. after giving 5 mg isosorbide dinitrate sublingually. Stage III Patient was tilted to 80 degree for 10 min. with IV isopreteronol infusion at 1 microgram/min. Stage IV Patient was tilted to 80 degree for 10 min. with IV isopreteronol infusion at 2 microgram/min. Stage V Patient was tilted to 80 degree for 10 min. with IV isopreteronol infusion at 3 microgram/min. Intravenous cannulation is a must before start of the test, heart rate and rhythm were monitored continuously using a bed side monitor and utilizing lead II as a monitor lead. Non invasive blood pressure measurement was recorded every 2 minutes using automatic blood pressure device, when syncope or presyncope developed the blood pressure was recorded every 30 seconds. The test is considered to be positive if syncope or presyncope associated with hypotensive and/or decreasing of heart rate occurred. The results obtained are: Passive Hut; The test was positive in two patients developed vasodepressor type. No one of the control group developed positive response. Isosorbid Hut: Eleven patients revealed positive test at this stage. Two patients developed mixed response, One patients developed cardio-inhibitory response, and eight patients developed vasodepressor. No one in control group developed positive response. Isoproterenol infusion Hut: The test was positive in four patients, they developed vasodepressor response. In control group, the test was negative.