- Patients with systolic left ventricular dysfunction (left ventricular ejection fraction [LVEF] <50%), mitral or aortic regurgitation of grade 2 or more, aortic or mitral surface <1.5 cm2, severe anemia (blood hemoglobin <9 g/dl), severe chronic obstructive pulmonary disease defined by percent predicted forced expiratory volume in one second <60%, or lung fibrosis were not enrolled in this study.