We hypothesize that a novel tailor-made cardiac rehabilitation (CR) program for obesity patients (OPTICARE XL) has better outcomes as compared to usual CR regarding parameters of cardiac function as measured by conventional and advanced transthoracic echocardiography. This is an open-label, randomized controlled trial. Inclusion criteria were: patients referred to CR with a body mass index (BMI) ≥30 kg/m2, and age ≥18 years with either coronary artery disease or nonvalvular atrial fibrillation. The experimental group participated in OPTICARE XL and the controls received the usual CR. Subjects randomized to OPTICARE XL received on top of usual CR behavioural therapy for a healthy diet and an active lifestyle for the first 12 weeks. Also, the exercise program was more tailored. Furthermore, a behavioural after-care program was organized with 6 meetings between weeks 13-52. Transthoracic (speckle tracking) echocardiography was performed at baseline and one-year follow-up. A total of 42 patients completed the follow-up, 21 in both groups. There was a mild but statistically significant reduction in weight over time, however, this was comparable between groups. There was no improvement observed in any of the echocardiographic parameters. In conclusion, cardiac function in obesity patients was not improved one-year after a novel tailor-made CR program (OPTICARE XL) as compared to usual CR.