Effects of long-term exercise on arrhythmogenesis in aged hypertensive rats

• Published in: Computers in biology and medicine Vol. 102; pp. 390 - 395
• Main Authors: Sung, Yen-Ling, Wu, Chih-En, Syu, Jhen-Yang, Kuo, Terry B.J., Li, Jai-Yi, Chen, Chieh-Wen, Weng, Ching-Hui, Hsu, Wei-Hsuan, Chen, Shih-Ann, Hu, Yu-Feng, Lin, Shien-Fong
• Format: Journal Article
• Language: English
• Published: United States Elsevier Ltd 01.11.2018; Elsevier Limited
• Subjects: Action potential; Arrhythmia; Autonomic nervous system; Cardiac arrhythmia; EKG; Electrocardiography; Exercise; Experiments; Fibrillation; Fitness training programs; Heart rate; Heart rate variability; Hypertension; Internal Medicine; Other; Physical activity; Physical training; Rats; Restitution; Rodents; Software; Spontaneously hypertensive rat; Tachycardia; Vagus nerve; Ventricle; Ventricular fibrillation; Ventricular tachycardia; United States > US; Ventricular tachycardia; Spontaneously hypertensive rat; Exercise; Heart rate variability
• ISSN: 0010-4825; 1879-0534; 1879-0534
• DOI: 10.1016/j.compbiomed.2018.08.016

Chronic hypertension is a multifactorial disease that is highly associated with cardiovascular disorders. Physical activity, such as long-term exercise, is advocated as a treatment for hypertension, but the responses of different age groups to long-term exercise are unknown. We used aged spontaneous hypertensive rats (SHRs, 80 weeks old) to test the hypothesis that long-term exercise compensated for deficient autonomic control and reduced susceptibility to ventricular tachycardia (VT) and ventricular fibrillation (VF) in this animal model. The aged SHRs were divided into control and voluntary exercise groups. Ambulatory electrocardiography was recorded for the heart rate variability (HRV) analysis. Programmed stimulation was applied to exposed hearts to induce ventricular arrhythmia in situ. Then, the hearts were isolated for an optical mapping study. The results showed that increased HRV indices were broadly related to vagal dominance in the high-intensity exercise group. Exercise altered the electrical propagation dynamic properties, such as the action potential duration restitution (APDR). Furthermore, the VF inducibility decreased with increased exercise intensity. Taken together, our results suggest that long-term exercise reduces the risk of arrhythmogenesis in aged SHRs through enhanced vagal control and stabilized electrical dynamics. •Vagal dominance was noted in the high-intensity exercise group.•Exercise altered the electrical propagation dynamic properties, such as the action potential duration restitution.•Exercise reduced the risk of arrhythmogenesis in aged hypertensive rats.