Abstract 740: Statin Prevents Structural and Electrical Atrial Remodeling in Rat Hypertensive Heart Failure Induced by Chronic Inhibition of NO Synthesis
Background: The prevalence of atrial fibrillation (AF) increases in patients with hypertension and heart failure in which endothelial function is impaired. Oxidative stress in atrial tissues is involved in the development of AF. Statins have pleiotropic effects including antioxidant effects. Thus, we developed hypertensive heart failure in rats by the chronic inhibition of NO synthesis and we investigated the role of the statin in atrial remodeling.
Methods and Results: Ten-week-old male Wistar-Kyoto rats were randomly divided into four groups: the control (no treatment), the L-NAME (received L-NAME, an inhibitor of NO synthase, 1 g/L in drinking water), the L-NAME+atorvastatin (L(a low dose)) (5 mg/kg/day) and the L-NAME+atorvastatin (H(a high dose)) (20 mg/kg/day). Chronic inhibition of NO synthesis increased systolic blood pressure (control group: 138±5 mmHg; L-NAME group: 212±8 mmHg L+atorvastatin (L) group: 210±6 seconds , L+atorvastatin (H): 208±6 seconds) and decreased LV dP/dt max/LVSP (control group: 54±3, L-NAME group: 36±8, L+atorvastatin (L) group: 40±3, L+atorvastatin (H) group: 38±6 1/second), whereas co-administration of atorvastatin did not affect them. The sustained duration of AF was always induced by transesophageal burst pacing (The pacing pulse used for induction of AF was rectanglar in shape, of 60V and 6ms-width. The atrium was paced at a cycle length of 12ms (83Hz) for 30seconds) and it was prolonged by L-NAME, which was prevented by atorvastatin in a dose-dependent manner (control: 8.8 ± 1.0 seconds, L-NAME: 20.7 ± 3.0 seconds, L+atorvastatin (L): 12.8 ± 3.2 seconds , L+atorvastatin (H): 8.8 ± 2.6 seconds). The chronic inhibition of NO synthesis increased the extent of fibrosis and markers of oxidative stresses such as proteins modified with 4-hydroxy-trans-2-nonenal and p47phox and rac1 in left atrial tissue, either of which was prevented by atorvastatin.
Conclusion: Atorvastatin attenuates oxidative stresses in atrium and prevents atrial electrical and morphological remodeling in rat hypertensive failing hearts without hemodynamic changes. Statin may be beneficial in patients with coronary heart disease and atrial fibrillation, and may contribute to the prevention of the onset of heart failure.