NPPB and hyperthyroxinemia: Since mechanisms underlying the adverse cardiovascular prognosis associated with RTHβ are unknown, the aim of the present study was to quantify CVD risk and measure plasma NT-proBNP in a large, unselected cohort of adult RTHβ individuals, to determine the relative contributions of atherosclerotic cardiovascular risk and hyperthyroxinemia-associated cardiac dysfunction to the recognized adverse cardiovascular outcomes in this disorder.