Tilt-Table Testing

The tilt-table test is a simple, noninvasive, and informative test first described in 1986 as a diagnostic tool for patients with syncope of unknown origin. ^[1] It is usually performed in hospital electrophysiology departments with the endpoint of reproducing syncope and subsequent appropriate therapy.

The causes of syncope have been divided into 6 major categories, as listed below. ^[2] After a careful history and physical examination, tilt-table testing is particularly helpful in confirmation of the etiology of syncope dysfunction of the autonomic nervous system, encompassing primary or secondary dysautonomias, postural orthostatic tachycardia syndrome (POTS), and vasodepressor or vasovagal syncope. Other venues of investigation, such as a 12-lead electrocardiogram, orthostatic blood pressure readings, Holter/event recording, serum glucose and electrolytes, echocardiography, and psychiatric and/or neurology consultation should be considered prior to tilt-table testing to rule out malignant dysrhythmic, metabolic, cardiac mechanical, or psychological/neurological etiologies of syncope. ^[3]

The 6 major categories of syncopal etiologies  ^[2]

Neurological disorders

• Vertebrobasilar transient ischemic attacks

• Subclavian steal syndrome

• Normal pressure hydrocephalus

• Seizure disorders

Metabolic disorders

• Hypoxia

• Hyperventilation

• Hypoglycemia

Mechanical heart disease

• Aortic stenosis

• Mitral stenosis

• Global ischemia

• Aortic dissection

• Pulmonic dissection

• Obstructive cardiomyopathy

• Left atrial myxoma

• Prosthetic valve dysfunction

• Pulmonary embolus

• Pulmonary hypertension

Cardiac arrhythmias/brady arrhythmias/tachyarrhythmias

• Bradycardia/pauses

• Sinus node dysfunction

• AV conduction disease

Psychiatric disorders

• Panic attacks

• Hysteria

Autonomic Nervous System Dysfunction

• Primary and secondary dysautonomias

• Postural orthostatic tachycardia syndrome (POTS)

• Postural orthostatic hypotension

• Vasodepressor or vasovagal syncope

Consider tilt-table testing in patients with signs or symptoms suggestive of orthostatic hypotension, vasodepressor or vasovagal syncope, postural orthostatic tachycardia, or when other causes of syncope have been eliminated. In general, consider tilt-table testing for patients with the following issues:

• Hypotension (unexplained)

• Tachycardia when standing

• Pallor when upright

• Orthostatic palpitations

• Dizziness (unexplained)

• Lightheadedness

• History of frequent unexplained falls

• History of episodes of fainting or loss of consciousness

The ACC expert consensus document for tilt-table testing including indications was first published in 1996. ^[4] The European Society of Cardiology formed a taskforce to update guidelines for the diagnosis and management of syncope in 2001, which was revised in 2009. ^[3] It includes indications for tilt-table testing with classes of recommendation and levels of evidence (see Table 1).

Table 1. European Society of Cardiology 2009 Indications for Tilt-Table Testing ^[3] (Open Table in a new window)

Contraindications to tilt-table testing include the following: ^[3]

• Coma

• Feeble patient unable to stand

• Lower extremity fractures

• Severe anemia

• Recent stroke (within seven days)

• Recent myocardial infarction

• Severe proximal cerebral or coronary arterial disease

• Critical mitral or aortic stenosis

• Left ventricular outflow tract obstruction

• Hypotensive shock

• Tachyarrhythmias

• Severe metabolic acidosis

• Electrolyte imbalance

• End-stage renal failure

• Severe heart failure

Complication Prevention

Avoid invasive intra-arterial blood pressure monitoring during tilt-table testing because catheterization may provoke a vasovagal reaction. Use a manual sphygmomanometer or digital plethysmography. ^[5]

Generally tilt-table testing is safe, but complications may occur related to decreased perfusion of the heart, including the following:

• Electrocardiographic changes of transient myocardial ischemia with or without angina.

• Vasospasm with isoproterenol administration. ^[6]

• Occasionally, cardiac arrhythmias result in termination of the test, such as advanced atrioventricular block (second or third degree), severe bradycardia or pauses, atrial fibrillation, or tachyarrhythmias.

Complications may also occur related to decreased perfusion of the brain, including the following :

• Seizures from prolonged hypotension (this is a transient phenomenon and not indicative of a seizure disorder)

• Rarely, transient ischemic attacks or strokes occur.

• Transient mental confusion can occur.

• Patients may also experience nonspecific symptoms such as nausea or anxiety.