A 53-year-old female patient presented for evaluation of a murmur. The examination revealed a 2/6 systolic ejection murmur in the left upper sternal border. Transthoracic echocardiography with color Doppler showed increased blood flow around the apex of the right ventricle. Further imaging revealed the right coronary artery emerging from the pulmonary artery. (
Level of Difficulty: Beginner.
)
SUMMARY The effect of the beta1 selective adrenoceptor blocker, atenolol, on the physiological response to exercise was studied in 12 healthy young men. Oral atenolol (100 mg) and placebo were administered in a randomised double blind crossover fashion an hour and a half before an intermittent multistage cycle ergometer exercise test. At maximal effort oxygen consumption, pulmonary ventilation, carbon dioxide output, and respiratory exchange ratio were not modified by atenolol. In contrast, maximal heart rate and performance time were significantly reduced after atenolol. Nevertheless, because the relation of percentage of maximal oxygen consumption to percentage of maximal heart rate was not changed by atenolol both the absolute and relative oxygen consumption corresponding to 70% and 85%h of the maximal heart rate remained unaltered.These data suggest that recommendations of exercise intensity may be determined on the basis of a calculated percentage of the predetermined maximal heart rate in persons without symptomatic coronary heart disease receiving beta1 selective adrenoceptor blockers.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.