system
Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: BACKGROUND, RESULTS. Meshes: Adenosine A2 Receptor Antagonists, Alabama, Exercise Test, Female, Heart Rate, Humans, Male, Middle Aged, Myocardial Perfusion Imaging, Prevalence, Prognosis, Purines, Pyrazoles, Reproducibility of Results, Risk Assessment, Risk Factors, Sensitivity and Specificity, Stroke Volume, Survival Analysis, Survival Rate, Treatment Outcome, Ventricular Dysfunction, Left.
user
Is a blunted heart rate response to regadenoson an independent prognostic indicator in patients undergoing myocardial perfusion imaging? Context: Regadenoson myocardial perfusion imaging (MPI) is a useful method for risk assessment. We hypothesized that the heart rate response (HRR) to regadenoson carries incremental prognostic information to that derived from perfusion pattern and left ventricular (LV) ejection fraction (EF). The study population included 1,156 (60 ± 13 years, 46% women, 40% diabetes mellitus, 53% chronic kidney disease) patients. During a follow-up period of 22 ± 5 months, 103 patients died (9%). Independent determinants of the HRR included age, gender, race, diabetes mellitus, coronary revascularization, LVEF, use of insulin and aldosterone antagonists. Decreasing HRR was associated with stepwise increase in mortality (log-rank P < .0001). In a Cox proportional model for mortality that adjusted for age, gender, diabetes mellitus, renal disease, and MPI findings, HRR in the lowest quartile was independently associated with fivefold increase in mortality compared to the highest quartile [HR 5.2, 95% CI 2.3-12.0, P < .0001]. Patients with a normal HRR had a relatively low annualized total mortality despite the presence of risk factors. The addition of HRR to traditional MPI findings had a net reclassification improvement of 15%, P = .02.
assistant
A blunted HRR to regadenoson is an independent predictor of poor outcome, adds incremental value to MPI, and helps in better risk stratification. Final Decision: yes