DURATION OF HEAD UP TILT TEST FOR EVALUATION OF VASOVAGAL SYNCOPE

Objective: To find out the optimum duration of Head up tilt test (HUTT) to produce a positive response in patients with vasovagal syncope. Study Design: Descriptive cross sectional study. Place and Duration of Study: Cardiac Electrophysiology department, Armed Forces Institute of Cardiology/ National Institute of Heart Disease (AFIC/NIHD) Rawalpindi, from Jan 2016 to Dec 2017. Methodology: Record of patients who underwent HUTT during this period was analyzed. The timing of positive vasovagal response was noted. Positive response was further classified as vasodepressor, cardio inhibitory or mixed. Results: 1878 patients participated in the study. 1626 (86.6%) developed a positive response to head up tilt test. 455 (28%) patients showed a positive response during the passive phase while 1171 (72%) patients developed a positive response during the provocation phase with sublingual nitroglycerine. More than 96% patients with positive tilt test had done so within 40 minutes of the test (10 minutes into the drug provocation phase). Conclusion: Majority of positive responses occurred between 10 minute and 30-minute interval in the passive phase, and in the first 10 minute of drug provocation phase. Thus, the drug provocation phase can be shortened to 15 minutes and even up to 10 minutes with slight loss of sensitivity.