The discordance in Myf5 expression in porcine versus human failing myocardium could be attributable to multiple factors, including differences in HF dysfunction phenotypes (diastolic versus systolic HF), stage and severity of HF (mid-advanced versus end-stage HF), age at which HF occurs (neonatal versus adult/aged heart), and medication (non-drug for DHF versus multidrug therapy for SHF). The gene discussed is MYF5; the disease is hydrops fetalis.