trial design and enrolment
THORAX, HEART
This study was a bicentered, two‐arm, 1:1 randomized, controlled trial, conducted at following locations: The Department of Cardiac Surgery of the Kerckhoff Heart and Thorax Centre in Bad Nauheim, Germany; the Department of Cardiovascular Surgery at the University Hospital in Giessen, Germany; and the Department of Rehabilitation at the Kerckhoff Clinic in Bad Nauheim, Germany. The study, including informed consent, has been approved by the Ethics Committee of the Justus‐Liebig University Giessen (Ref.: 28/14), complies with the Declaration of Helsinki, and is registered with the German Clinical Trials Register (ID: DRKS00015512). The study protocol was published in advance (Butz et al., The study coordinator screened the patient information on elective cardiac surgery for eligibility criteria. Potential participants received detailed information about the study project. Written informed consent was signed if the patient agreed.Age, sex, education, body mass index, preexisting conditions, and the severity partition for left ventricular ejection fraction (Lang et al., 