Head up tilt test (HUTT), also known as HUTT or tilt table test is done to evaluate recurrent episodes of syncope with no other evident cause.
Some facts about Head up tilt test (HUTT):
- Change in heart rate and blood pressure on assuming the erect posture is monitored in Head up tilt test.
- Evaluation of postural orthostatic tachycardia syndrome (POTS) can also be done with HUTT.
- POTS is a condition in which the heart rate increases on standing up.
- Cardioinhibitory response is less common with advancing age as the higher vagal activity in younger age promote more of cardioinhibitory responses..
- Your blood pressure and heart rate is recorded each minute, while you are tilted on a table at varying levels during A HUTT test.
- It help decide whether you will require additional testing to help diagnose your condition.
- A blood pressure cuff on both arms and small electrodes on your chest will be placed to measure the electrical activity of the heart.
Preparation for Head up tilt test (HUTT):
- You can take your prescription medication before the test.
- However, you should not eat or drink anything except a little water for about four hours before the test.
- Usually, an IV is placed into the arm to take blood samples to measure adrenaline.
- Infusion pump is set up in the beginning for delivering medications.
- This pump will be used if needed.
- Blood pressure and ECG, oxygen saturation measured by pulse oximetry are charted at regular intervals during the test
- Resuscitation tray and personnel should be ready during the test.
- Fall and injury is prevented by strapping of the person to the table, if the person faints.
Procedure for Head up tilt test (HUTT):
- The subject is strapped to the tilt table in this pocedure.
- Heart rate and blood pressure monitors connected.
- Although, beat-to-beat finger blood pressure monitoring device is not available always and is more expensive than the usual blood pressure monitoring equipment, it is used ideally as a beat-to-beat change in blood pressure is not provided by usual blood pressure monitoring equipment.
- It may be difficult to use during a syncopal episode.
- The person lies in the supine position for 30 minutes in the first phase of the test which is followed by a tilt phase of 20 minutes at an angle of 70 degrees.
- The tilt table is brought to the horizontal position for 10 minutes if fainting does not occur during the period.
- Isoprenaline infusion, which can increase the heart rate and myocardial contractility, is infused at the starting dose after that and the drip is run for 10 minutes, with the table tilted to 80 degrees.
- The table is brought back to the horizontal position for 10 minutes if syncope does not occur within 10 minutes.
- The test will be repeated at two higher doses of isoprenaline with the interval of 10 minutes in the horizontal position, if needed.
- The test is considered negative if no syncope occurs even with the higher doses of isoprenaline.
- At any of the above stages, syncope can occur with either bradycardia, hypotension or both.
- Cardioinhibitory is the first response, second is vasodepressor and third is mixed variety.