Objective: Advanced age is a risk factor in cardiac surgery contributing significantly to a worse outcome. The reasons are frailty and multimorbidity. In this study, we asked: Is there an aging of the heart which differs from chronological age? Methods: Propensity score matching was performed between 115 seniors ≥ 80 years and 345 juniors < 80 years. After the patients were found to be comparable in terms of cardiac and noncardiac disease and risk profiles, they were further analyzed for cardiac parameters. In addition, the seniors and juniors were compared in terms of cardiac health and postoperative outcome. Furthermore, the patients were subdivided into several age groups (<60 years, 60–69 years, 70–79 years, and >80 years) and compared regarding outcome. Results: The seniors demonstrated significantly lower tricuspid annular plane systolic excursion (TAPSE), significantly more frequent diastolic dysfunction, significantly higher plasma levels of NT-proBNP, and significantly larger left ventricular end-diastolic and end-systolic diameters and left atrial diameters (p< 0.001, respectively). Furthermore, in-hospital mortality and most postoperative complications were significantly higher in seniors compared with juniors. While old cardiac healthy patients showed better outcome than old cardiac aged patients, the outcome from young cardiac aged patients was better than old cardiac aged patients. The outcome and survival deteriorated with increasing life decades. Conclusions: The elderly suffer significantly more from cardiac deterioration, i.e., cardiac aging, and show higher multimorbidity. Mortality risk is significantly higher and they suffer more often from a complicated postoperative course compared to younger patients. Further approaches to prevention and treatment of cardiac aging are needed to address the needs of an aging society.