ADRB1 and hydrops fetalis: These results suggest that A) Cl's success in enhancing functional recovery in LVAD-supported patients is unrelated to myocardial size, and reliant on positive EC coupling effects, B) combined β2-AR stimulation +β1-AR blockade is likely to be a safe and beneficial HF therapeutic pharmacological strategy and C) either the strategy of β2-AR stimulation or β1-AR blockade is likely to be superior to that of combined β2-AR stimulation +β1-AR blockade in enhancing functional recovery during LVAD support.