When is this exam indicated?
It allows to identify the causes of syncope the cause of which is not detected, through traditional diagnostic investigations (electroencephalogram, CT scan of the brain, Holter electrocardiogram, echocardiogram) such as, for example, vasovagal syncopes, often mistakenly categorized as syncopes of dubious epileptic origin, especially among young patients.
Lately the tilting test is also used for the diagnosis of various symptomatic forms of orthostatic hypotension and for some types of dysautonomia.
How is it performed?
It is performed by checking blood pressure values and performing an electrocardiogram on a tilting bed in an almost horizontal position with a slight inclination of the head and feet (clinostatism) and, subsequently, in a horizontal position (passive orthostatism) with bed inclination of 60°.
Blood pressure is continuously recorded and heart rate is monitored. If at the end of a 30-minute recording period the patient does not have syncope, trinitrine, a drug that evokes a response similar to the mechanism involved during vasovagal syncope, is given sublingually. There is a positive response to the test if there is a rapid reduction in blood pressure values associated with, preceded, or followed by a significant reduction in heart rate.
Rapidly returning the patient to a clinostatic position results in abrupt resolution of the syncope.
On the basis of the results, a therapy is defined with the use of pharmacological or dietary and behavioral prescriptions.
The test does not carry any particular risks or serious complications. The test is contraindicated for patients with:
- ischemic heart disease;
- severe valvulopathy;
- significant carotid stenosis.