The β₃Adrenergic Receptor Antagonist L-748,337 Attenuates Dobutamine-Induced Cardiac Inefficiency While Preserving Inotropy in Anesthetized Pigs

Excessive myocardial oxygen consumption (MVO 2 ) is considered a limitation for catecholamines, termed oxygen cost of contractility. We hypothesize that increased MVO 2 induced by dobutamine is not directly related to contractility but linked to intermediary myocardial metabolism. Furthermore, we hypothesize that selective β 3 adrenergic receptor (β 3 AR) antagonism using L-748,337 prevents this. In an open-chest pig model, using general...