Syncope is a symptom, defined as a transient, self-limited loss of consciousness, usually leading to falling. Recurrent syncope is a common clinical problem and a significant diagnostic and therapeutic challenge.Vasovagal syncope constitute up to 40% of neurocardiogenic syncope. In vasovagal syncope patients have a transient, self-limited loss of consciousness in caused of sudden fall in blood pressure with or without bradycardia. Head-up tilt testing (HUT) is the basic diagnostic method in the evaluation of patients with vasovagal syncope. Commonly used is the Westminster protocol with 45 minutes of upright posture and with tilt angle of 60° and ECG and blood pressure monitoring. In pathopysiology of vasovagal syncope participates the autonomicnervous system. The disturbances in the of autonomic system can be measured by heart rate variability (HRV). Time and frequency domain analysis of HRV are valuable and reproducible noninvasive method assessing changes in sympathovagal balance in the patients with vasovagal syncope. Many studies documented the relation between heart rate variability and out of HUT.Heart rate variability applied in a valuation of the tilt testing results can disclose the type of reaction leading to event and may identify persons susceptible to recurrent syncope.

Keywords: vasovagal syndrome, head-up tilt testing, Syncope, heart rate variability