Atenolol is inferior to metoprolol in improving left ventricular function and preventing ventricular remodeling in dogs with heart failure.
OBJECTIVE
beta-Blockers are standard therapy for patients with heart failure (HF). This study compared the effects of chronic monotherapy with 2 different beta(1)-selective adrenoceptor blockers, namely atenolol and metoprolol succinate, on left ventricular (LV) function and remodeling in dogs with coronary microembolization-induced HF [LV ejection fraction (EF) 30-40%].


METHODS
Twenty HF dogs were randomized to 3 months of therapy with atenolol (50 mg once daily, n = 6), metoprolol succinate (100 mg, once daily, n = 7) or to no therapy (control, n = 7). LV EF and volumes were measured before initiating therapy and after 3 months of therapy. The change (Delta) in EF and volumes between measurements before and after therapy was calculated and compared among study groups.


RESULTS
In controls, EF decreased and end-systolic volume increased. Atenolol prevented the decrease in EF and the increase in ESV. In contrast, metoprolol succinate significantly increased EF and decreased end-systolic volume. DeltaEF was significantly higher and Deltaend-systolic volume significantly lower in metoprolol succinate-treated dogs compared to atenolol-treated dogs (EF: 6.0 +/- 0.86% vs. 0.8 +/- 0.85%, p < 0.05; end-systolic volume: -4.3 +/- 0.81 ml vs. -1 +/- 0.52 ml, p <0.05).


CONCLUSIONS
In HF dogs, chronic therapy with atenolol does not elicit the same LV function and remodeling benefits as those achieved with metoprolol succinate.
Zacà
Valerio
V
Department of Medicine, Division of Cardiovascular Medicine, Henry Ford Heart and Vascular Institute, Detroit, MI 48202, USA.
Rastogi
Sharad
S
Mishra
Sudhish
S
Wang
Mengjun
M
Sharov
Victor G
VG
Gupta
Ramesh C
RC
Goldstein
Sidney
S
Sabbah
Hani N
HN
D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001262:Atenolol / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D004285:Dogs; D004359:Drug Therapy, Combination; D006333:Heart Failure / Q000188:drug therapy*; D008790:Metoprolol / Q000008:administration & dosage / Q000494:pharmacology*; D011897:Random Allocation; D016896:Treatment Outcome; D016277:Ventricular Function, Left / Q000187:drug effects*; D020257:Ventricular Remodeling / Q000187:drug effects*
D000319:Adrenergic beta-Antagonists; D001262:Atenolol; D008790:Metoprolol