Relationship between the arterial compliance and head up tilt testing results in patients with recurrent syncope

Introduction: The orthostatic stress causes many haemodynamic changes in cardiovascularsystem. Similar head-uptilt testing (HUTT) stimulates sympathetic nervous system, which leads to increase of total peripheral resistance and acceleration of the heart rate. These changes in fluence pulse wave shape and pulse pressure with mechanical properties of the arterial system. The arterial compliance describes mechanical properties of the arterial system and pulse pressure is used to desribed the arterial compliance. The aim was to assess the impact of the arterial stiffness, estimated by the pulse pressure (PP), on outcome of HUTT in patients with recurrent syncope. Material and methods: We examined 314 patients (mean age 51+/-18.5 yrs, 42% males) with history of recurrent syncope. PP was estimated using ambulatory blood pressure monitoring (ABPM) device as the arithmetic difference between the systolic(SBP) and the diastolic blood pressure (DBP) measurements. According to magnitude of PP three cut off levels were performed: PP 140mmHg, PP2 50mmHg and PP3 60mmHg. The relationship between magnitude of PP and the outcome of HUTT was analyzed. Results: There were differences between the magnitude of PP and the outcome of HUTT and VASIS response. In the wider PP >= 50mmHg it was found the lost of differences in VASIS response in the passive phase of HUTT. Conclusions: The arterial compliance influences the outcome of HUTT and VASIS respone intilting patients with recurrent syncope. There are disparate VASIS populations related to HUTT’s phase(passive and provocative)and the magnitude of PP.(Clin. Exp. Med. Lett. 2006; 47(3):187-190)

Keywords: Syncope, head-up tilt test, pulse pressure, arterial compliance