Pressure-adjusted Heart Rate by Echocardiography and Mortality in the Cardiac Intensive Care Unit

BACKGROUND:Pressure-adjusted heart rate (HR) (PAHR) provides an integrated assessment of hemodynamic decompensation in critical illness. OBJECTIVES:We aimed to evaluate the association of noninvasively obtained PAHR and mortality in cardiac intensive care unit (CICU) patients. METHODS:This was a retrospective cohort of patients with a transthoracic echocardiogram (TTE) within 24 hours of admission to an academic CICU (2007-2018). HR, right atrial pressure (RAP), and mean arterial pressure (MAP) obtained from the TTE were used to calculate PAHR as RAP · HR/MAP (in beats/min). The primary outcome was in-hospital mortality and secondary outcome was one-year mortality. RESULTS:Among 5,411 patients (median 70.1 years, 38.6% female, 92.4% White), higher PAHR was associated with greater acute illness severity, comorbidities, and critical care therapy utilization. The median PAHR was higher among patients who died while hospitalized (14.3 beats/min vs 6.8 BPM; P < 0.001). Echocardiographic measurements of biventricular function, filling pressures, and cardiac output were worse among those with higher PAHR. In-hospital mortality (adjusted OR: 1.03; 95% CI: 1.01 to 1.05; P = 0.001) and one-year (adjusted HR: 1.03; 95% CI: 1.02-1.04; P < 0.001) mortality increased with each 1 BPM higher PAHR. PAHR had moderate discrimination for in-hospital mortality (C-statistic 0.75). CONCLUSIONS:PAHR is a readily determinable composite measure of cardiovascular status that enhances clinical risk stratification of critically ill patients, performing better than MAP, HR, and Modified Shock Index. Among CICU patients, higher PAHR by TTE was associated with greater mortality.