Abstract
Aldosterone antagonists (AAs) have beneficial effects on ventricular histological and electrical remodeling and improve noradrenaline uptake. Adding an AA to a beta-blocker (BB) further improves cardiac mortality in heart failure patients. We investigated if adjunction of a BB modifies beneficial effects of spironolactone on different parameters of the ventricular remodeling. A severe myocardial infarction (MI) was produced in rats. Three months after surgery, left ventricular (LV) function was assessed by echocardiography. Fifty-five rats with heart failure were then randomized in 5 groups: sham, MI, and MI treated for 4 weeks with spironolactone (10 mg·kg·d), atenolol (1 mg·kg·d), or both. Holter transducers were implanted to record 24-hour ventricular electrical parameters, mean cycle length (RR) and SD of RR. Before killing, invasive left ventricular end diastolic pressure (LVEDP) was recorded. LV samples were used for histological analysis and catecholamine assay. Rats with MI had significantly increased LVEDP (32 ± 3 vs. 14 ± 1 mm Hg), LV, collagen content (5.8% ± 1.4% vs. 3.6% ± 0.7%), ventricular premature complexes (2.5 10 ± 10 vs. 30 ± 13), and decreased meanRR (164 ± 2 vs. 169 ± 1 milliseconds) and SDRR (3.9 ± 0.2 vs. 5.4 ± 0.2 milliseconds) compared with sham. At nonhypotensive doses, spironolactone and atenolol similarly improved LVEDP. Compared with MI, although spironolactone significantly decreased ventricular premature complexes, LV collagen and noradrenaline contents, and improved meanRR and SDRR, atenolol had effects only on meanRR and SDRR. Addition of atenolol to spironolactone further improved spironolactone effects on all these parameters. AA improved, independently of the cardiac function, histological and electrical remodeling after MI. A BB added to an AA did not blunt these beneficial effects; furthermore, it improved these effects related to spironolactone.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
