Resting heart rate and measures of effort-related cardiac autonomic dysfunction predict cardiovascular events in asymptomatic type 2 diabetes

BackgroundAutonomic control of the cardiovascular system may be impaired in type 2 diabetes and is associated with increased morbidity and mortality. Parameters obtained during stress testing may reflect early stages of cardiac autonomic dysfunction and provide prognostic information in asymptomatic type 2 diabetes.MethodsWe performed maximal exercise treadmill testing in 594 patients with type 2 diabetes without known coronary heart disease. The prognostic significance of physiological parameters associated with autonomic dysfunction was assessed, including chronotropic incompetence ( 100 beats/minute. Cox proportional hazards analysis was used to determine the association of exercise parameters with a composite outcome of all-cause mortality, myocardial infarction or stroke.ResultsResting heart rate >100 beats/minute was observed in 18% of patients, chronotropic incompetence in 30% and heart rate...