GSTM1 and idiopathic dilated cardiomyopathy: As well, two other studies demonstrated reduced cerebral oxygenation (ΔO2 Hb) and perfusion (ΔtHb) using NIRS during exercise and recovery in patients with valvular heart disease or idiopathic dilated cardiomyopathy with reduced left ventricular ejection fraction (<40%) as compared to older aged-matched healthy controls [8, 9].