Head up tilt test (HUTT) or tilt table test is commonly done for the evaluation of neurocardiogenic syncope (vasovagal syncope). Various protocols are followed in different centres. One protocol is as follows: The subject is strapped to the tilt table after venous and arterial access is obtained. Radial arterial access is used for continuous blood pressure monitoring as non-invasive recordings are often inaccurate and difficult to make at the time of syncope. Infusion pump is also set up to give isoprenaline infusion if required. Resuscitation tray and personnel are at hand during the test. ECG, pulsoximetry and invasive blood pressure are monitored through out and the hemodynamic response is also charted. Initial supine phase is for 30 minutes, which is followed by a tilt phase of 20 minutes at an angle of 70 degrees. If syncope does not occur during this period, the table is brought to the supine position for a period of 10 minutes. After that isoprenaline infusion is started at a rate of 1 microgram per minute. The drip is run for 10 minutes with the table tilted to 80 degrees. Still if syncope does not occur within 10 minutes, the table is brought back to the supine position for 10 minutes. The test is repeated at 3 and 5 micrograms per minute of isoprenaline with intervening 10 minutes of supine position, if needed. If there is no syncope, the test is considered negative. Syncope can occur at any of the above stages either with bradycardia, hypotension or both. The first one is called cardioinhibitory, the second one vasodepressor and the third mixed variety.