Tilt table testing is used to evaluate syncope, dizziness, recurrent falls, and related symptoms when the initial diagnostic workup has not provided a diagnosis (1). It is specifically used for diagnosing vasovagal syncope, delayed orthostatic hypotension, postural orthostatic tachycardia syndrome, and pseudosyncope and for distinguishing syncope with seizure-like activity from epilepsy.
Tilt table testing produces maximal venous pooling, which can trigger vasovagal (neurocardiogenic) syncope and reproduce the symptoms and signs that accompany it (nausea, light-headedness, pallor, hypotension, bradycardia).
General reference
1. Writing Committee Members, Shen WK, Sheldon RS, et al. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: A report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Heart Rhythm. 2017;14(8):e155-e217. doi:10.1016/j.hrthm.2017.03.004
Procedure for Tilt Table Testing
After an overnight fast, a patient is placed on a motorized table with a foot board at one end and is held in place by straps over the body; an IV line is inserted. After the patient remains supine for 15 minutes, the table is tilted nearly upright to 60 to 80° for up to 45 minutes during which symptoms and vital signs are monitored. IV fluid may be administered to assess response to intravascular volume expansion. Isoproterenol or other medications (such as sublingual nitrates) may be administered to induce symptoms. for up to 45 minutes during which symptoms and vital signs are monitored. IV fluid may be administered to assess response to intravascular volume expansion. Isoproterenol or other medications (such as sublingual nitrates) may be administered to induce symptoms.
This photo shows a patient undergoing a tilt table test. She is monitored with ECG leads and a pulse oximeter. An IV is in place for medication or fluid administration. She is being asked about symptoms by the technician while in the upright position.
AVID PARKER/SCIENCE PHOTO LIBRARY
Contraindications
Relative contraindications include:
Interpretation of Tilt Table Testing
If vasovagal symptoms develop, vasovagal syncope is confirmed. If symptoms do not occur, a medication (eg, isoproterenol) may be given to induce them. (NOTE: If vasovagal symptoms develop, vasovagal syncope is confirmed. If symptoms do not occur, a medication (eg, isoproterenol) may be given to induce them. (NOTE:Isoproterenol should not be used in patients with hypertrophic cardiomyopathy or severe coronary artery disease.Isoproterenol should not be used in patients with hypertrophic cardiomyopathy or severe coronary artery disease.) Sensitivity varies from 25 to 66% depending on the protocol used (1). The false-positive rate is approximately 10% (2).
With vasovagal syncope, heart rate and/or blood pressure may decrease. Some patients have only a decrease in heart rate (cardioinhibitory); others have only a decrease in blood pressure (vasodepressor). Occasionally the bradycardia response is revealed to be high-grade heart block or a bradyasystolic pause in response to increased vagal tone. Other responses that suggest alternative diagnoses include a gradual decrease in systolic and diastolic blood pressure with little change in heart rate (dysautonomic pattern), significant increase in heart rate (> 30 beats/minute in adults or > 40 beats/minute in children and adolescents) with little change in blood pressure (postural orthostatic tachycardia syndrome) (2), and report of syncope with no hemodynamic changes (pseudosyncope).
Interpretation references
1. Forleo C, Guida P, Iacoviello M, et al. Head-up tilt testing for diagnosing vasovagal syncope: a meta-analysis. Int J Cardiol. 2013;168(1):27-35. doi:10.1016/j.ijcard.2012.09.023
2. Sheldon RS, Grubb BP 2nd, Olshansky B, et al. 2015 heart rhythm society expert consensus statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia, and vasovagal syncope. Heart Rhythm. 2015;12(6):e41-e63. doi:10.1016/j.hrthm.2015.03.029
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