ADRB1 and hydrops fetalis: Notably, Parikh et al. [52] demonstrated in a retrospective analysis of prospectively designed DNA sub-studies from Beta-Blocker Evaluation of Survival Trial (BEST) [53] and Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) trial [54] that enhanced efficacy of bucindolol in heart failure with reduced ejection fraction occurs at high doses for individuals with the ADRB1 Arg389Arg genotype compared with Gly389 carriers.