A single bout of dynamic treadmill exercise significantly increased the ventricular arrhythmia threshold (Δ+1.95 ± 0.31 min) in conscious hypertensive rats.
Does a single bout of dynamic exercise increase the ventricular arrhythmia threshold in conscious hypertensive rats via the intrinsic adenosine receptor system?
Acute exercise provides cardioprotection against coronary artery occlusion-induced arrhythmias in hypertensive rats via endogenous adenosine production.
Effect estimate: Δ+1.95 ± 0.31 min
Coronary artery occlusion-induced tachyarrhythmias that culminate in ventricular fibrillation are the leading cause of death in developed countries. The intrinsic adenosine receptor system protects the heart from an ischemic insult. Thus the increased functional demands made on the heart during exercise may produce protective adaptations mediated by endogenous adenosine. Therefore, we tested the hypothesis that a single bout of dynamic exercise increases the ventricular arrhythmia threshold (VAT) induced by coronary artery occlusion in conscious hypertensive rats via the intrinsic adenosine receptor system. To test this hypothesis, we recorded the VAT before and on an alternate day after a single bout of dynamic treadmill exercise (12 m/min, 10% grade for 40 min). A single bout of dynamic exercise significantly reduced postexercise arterial pressure (Delta-24 +/- 4 mmHg) and increased VAT (Delta+1.95 +/- 0.31 min). Adenosine receptor blockade with the nonselective adenosine receptor antagonists theophylline or aminophylline (10 mg/kg) attenuated the cardioprotective effects of a single bout of dynamic exercise. Results suggest that strategies that increase myocardial ATP requirements leading to adenosine production provide protection against coronary artery occlusion.
Collins et al. (Sat,) conducted a other in Hypertension. Single bout of dynamic treadmill exercise vs. Baseline (before exercise) was evaluated on Ventricular arrhythmia threshold (VAT) (Δ+1.95 ± 0.31 min). A single bout of dynamic treadmill exercise significantly increased the ventricular arrhythmia threshold (Δ+1.95 ± 0.31 min) in conscious hypertensive rats.