Heart Rate Variation in Females Predicts Tilt Test Results

Two protocols for the head-up tilt test (HUTT) are used in our center and in the collaborating centers: (1) passive or prolonged inclination protocol \[40 minutes\], (2) mixed protocol: passive phase \[first 20 minutes\] plus nitrate-provoked phase \[last 20 minutes\], with the use of 1.25 mg sublingual isosorbide dinitrate. All patients are submitted to 10 minutes of rest in the supine position at zero degree before the tilt phase of the HUTT. During this period, HR and systolic (SBP) and diastolic (DBP) measurements are obtained every 2 minutes. After this phase, the table is tilted at an angle of 70° with measurement of SBP / DBP and HR every minute. Patients older than 60 years are routinely investigated for carotid sinus hypersensitivity by carotid sinus massage during the passive phase of the HUTT. The exam is considered positive according to the criteria defined in guidelines.