['Significant evidence shows that elevated heart rate (HR) is an independent risk factor in patients with coronary artery disease (CAD) and influences their prognosis. In addition, patients with chronic obstructive pulmonary disease (COPD) have more frequent episodes of angina and their compliance with heart rate agents, such as beta blockers, is poor. The purpose of the multicenter observational RYTHMOS study was to evaluate the role of heart rate management in the prognosis and quality of life in patients with CAD and COPD.', 'Baseline data from 280 patients, enrolled in 22 hospitals representing all types of hospital and all geographical areas of the country, were analyzed. All patients had either a prior myocardial infarction or angiographically documented CAD, and COPD verified either after spirometry or from a clinical evaluation by pulmonologists.', 'The mean age of the enrolled patients was 71.8 ± 9.3 years, 76% were males, mean body mass index was 28.6 ± 7.9 kg/m2, 76.3% had hypertension, 31% had diabetes mellitus, and 53.5% of them suffered from heart failure. About 31% of the patients had an angina episode the week before the enrollment and the Canadian Cardiovascular Society (CSS) classification was class I, II, III and IV in 55%, 30%, 14% and 1%, respectively. The mean resting HR was 72.5 bpm; 51% of the patients had resting HR>70 bpm and 22% of them had HR80 bpm. Only 52.8% of the study patients were receiving beta-blockade (BB) therapy; they were more likely to have resting HR70 bpm (57.4% vs. 42.7%, p<0.001). 16.4% of the patients were receiving ivabradine and they had a higher initial HR compared to the others (78.5 vs. 71.3, p<0.001). Multivariate analysis showed that diabetes mellitus was independently associated with HR>70 bpm. Patients with resting HR>70 bpm had significantly more frequent angina episodes (p<0.001), were less satisfied with treatment (p<0.001), and had a lower quality of life (p<0.001).'] Is inadequate heart rate control associated with worse quality of life in patients with coronary artery disease and chronic obstructive pulmonary disease . The RYTHMOS study?