| Autor: |
Piccirillo G; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Moscucci F; Department of Internal Medicine and Medical Specialties, Policlinico Umberto I, Viale del Policlinico, 00161 Rome, Italy., Di Diego I; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Mezzadri M; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Caltabiano C; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Carnovale M; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Corrao A; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Lospinuso I; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Stefano S; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Scinicariello C; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Giuffrè M; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., De Santis V; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Sciomer S; Department of Clinical and Internal Medicine, Anesthesiology and Cardiovascular Sciences, Policlinico Umberto I, 'Sapienza' University of Rome, Viale del Policlinico, 00161 Rome, Italy., Rossi P; Arrhythmology Unit, Fatebenefratelli Hospital Isola Tiberina-Gemelli Isola, 00186 Rome, Italy., Fiori E; Department of Clinical and Molecular Medicine, Sant'Andrea Hospital, 'Sapienza' University of Rome, 00198 Rome, Italy., Magrì D; Department of Clinical and Molecular Medicine, Sant'Andrea Hospital, 'Sapienza' University of Rome, 00198 Rome, Italy. |
| Abstrakt: |
The head-up/-down tilt test acutely modifies the autonomic nervous system balance throughout a deactivation of the cardiopulmonary reflexes. The present study examines the influence of head-up/-down tilt on a number of ECG segments. A total of 20 healthy subjects underwent a 5 min ECG and noninvasive hemodynamic bio-impedance recording, during free and controlled breathing, lying at (a) 0°; (b) -45°, tilting up at 45°, and tilting up at 90°. Heart rate variability power spectral analysis was obtained throughout some ECG intervals: P-P (P), P-Q (PQ), P e Q (from the end of P to Q wave), Q-R peak (QR intervals), Q-R-S (QRS), Q-T peak (QT p ), Q-T end (QT e ), ST p , ST e , T peak-T end (T e ), and, eventually, the T e P segments (from the end of T to the next P waves). Results: In all study conditions, the Low Frequency/High Frequency PP and LF PP normalized units (nu) were significantly lower than the LF/HF RR and LF RRnu , respectively. Conversely, the HF PP and HF PPnu were significantly higher in all study conditions. ST e , QT p, and QT e were significantly related to the PP and RR intervals, whereas the T wave amplitude was inversely related to the standard deviations of all the myocardial repolarization variables and to the left ventricular end-systolic volume (LVEDV). The T wave amplitude diminished during head-up tilt and significantly correlated with the LVEDV. |
