Selective Beat Averaging to Evaluate Ventricular Repolarization Adaptation to Deconditioning after 5 Days of Head-Down Bed Rest

• Type: Article in International Conference Proceedings Book
• Date: 2012

Authors

Pellegrini, A (Author) Other; Bolea, J (Author) Other; Llamedo Soria, ML (Author) Other; Sotaquira, M (Author) Other; Almeida, R (Author) FCUP; Laguna, P (Author) Other; Vaida, P (Author) Other; Caiani, EG (Author) Other

Conference proceedings International

Title: Computing in Cardiology

Pages: 605-608

39th Computing in Cardiology Conference, CinC 2012

Krakow, 9 September 2012 through 12 September 2012

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Authenticus ID: P-00F-KMQ

Abstract (EN): The study of QT/RR relationship is important for the clinical evaluation of possible risk of ventricular tachyarrhythmia. Our aim was to assess the effects of 5-days of head-down (-6 degrees) bed-rest (HDBR) on ventricular repolarization. High fidelity 12-leads Holter ECG was acquired before (PRE), the last day of HDBR (HDT5), and five days after its conclusion (POST). X,Y,Z leads were derived (inverse Dower matrix) and vectorcardiogram computed. Selective beat averaging applied to the night period resulted in averages preceded by the same stable heart rate (for each 10 msec bin amplitude, in the range 900-1200 msec). For each template (i.e., one for each bin), T-wave maximum amplitude (Tmax), T wave area, R-Tapex and R-Tend were computed. Results (in 8 male volunteers) showed that, compared to PRE, at HDT5 both R-Tapex and R-Tend resulted significantly shortened (-5% and -3%, respectively), together with a decrease in T-wave area (-7%), while Tmax was unchanged. At POST, duration parameters showed a trend towards their control values (-1.5% and -3%, respectively) while amplitude parameters resulted restored. Despite the short-term BR, cardiac adaptation to deconditioning affected ventricular repolarization during the night period.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 4