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Chronotropic incompetence, the inability to achieve a target heart rate during exercise stress testing, has been shown to be associated with more extensive coronary atherosclerosis and poorer prognosis. However, few studies have examined the importance of heart rate response during pharmacologic stress testing. In this study, investigators from Egypt and Norway evaluated the clinical, hemodynamic, and echocardiographic variables that contributed to chronotropic incompetence during dobutamine stress echocardiography.
The cohort of 512 patients (mean age, 60; prior MI, 47 percent) not taking beta blockers who underwent dobutamine stress echocardiography (maximum dose, 40 μg/kg/min) either completed the infusion protocol or achieved the target …