Sucu Murat M, Davutoglu Vedat, Akcay Murat, Yiğiter Remzi, Al Behcet
Head-Up Tilt Test and Echocardiography Laboratories, Department of Cardiology, Sahinbey Medical Center, School of Medicine, Gaziantep University, Gaziantep, Turkey.
Pacing Clin Electrophysiol. 2009 Nov;32(11):1417-21. doi: 10.1111/j.1540-8159.2009.02485.x. Epub 2009 Sep 22.
Neurocardiogenic syncope (NCS) is a common clinical problem; however, hemodynamic mechanism is not clearly understood. Aim of the present study was to investigate aortic elastic parameters of patients with NCS provoked by head-up tilt test.
We conducted a prospective study of 40 cases referred to our institution for head-up tilt testing. Group I constituted as 22 patients who developed mixed response and were enrolled for analysis. Hemodynamic data were compared with subjects of negative head-up tilt test (Group II). Aorta-diastolic and aorta-systolic diameters, aortic strain, aortic distensibility, aortic elastic modulus, and aortic stiffness index were calculated from transthoracic echocardiographically derived diameters of thoracic aorta.
Aortic distensibility (mean+/-SD; 2.7+/-1.2 cm2xdyn(-1)x10(-6) vs 4.0+/-1.2 cm2xdyn(-1)x10(-6), P=0.003) and aortic strain index (mean+/-SD; 7.0+/-1.8% vs 8.7+/-2.9%, P=0.042) were lower, and aortic stiffness index (mean+/-SD; 27.6+/-10.9 vs 20.9+/-6.18, P=0.035) and aortic elastic modulus (mean+/-SD; 0.94+/-0.7 cm2xdyn(-1)x10(-6) vs 0.49+/-0.1 cm2xdyn(-1)x10(-6), P=0.009) were higher in patients in Group I compared with those in Group II. There was no difference between two groups for following clinical variables: aorta-diastolic and aorta-systolic diameters, systolic and diastolic blood pressure, pulse pressure, E/A, weight, height, and body mass index.
Findings of this study have shown that elastic properties of aorta are impaired in patients with NCS. The data suggest that increase in aortic stiffness might be one of the determinants responsible for NCS. This proposal of novel link should be confirmed in further studies.
