Abstract

An impaired cardiac output response to exercise is a hallmark of chronic heart failure (HF). We determined the extent to which impedance cardiography (ICG) during exercise in combination with cardiopulmonary exercise test (CPX) responses reclassified risk for adverse events in patients with HF.CPX and ICG were performed in 1,236 consecutive patients (48±15 years) evaluated for HF. Clinical, ICG and CPX variables were acquired at baseline and subjects were followed for the composite outcome of cardiac-related death, hospitalization for worsening HF, cardiac transplantation, and left ventricular assist device (LVAD) implantation. Cox proportional hazards analyses including clinical, non-invasive hemodynamic, and CPX variables were performed to determine their association with the composite endpoint. Net reclassification improvement (NRI) was calculated to quantify the impact of adding hemodynamic responses to a model including established CPX risk markers on reclassifying risk. There were 422 events. Among CPX variables, peak VO2 and indices of ventilatory inefficiency (VE/VCO2 slope, oxygen uptake efficiency slope) were significant predictors of risk for adverse events. Among hemodynamic variables, change in cardiac index, peak cardiac time interval, and peak left cardiac work index were the strongest predictors of risk. Having five impaired CPX and ICG responses to exercise yielded a seven-fold higher risk for adverse events compared to having no abnormal responses. Combining ICG responses to CPX resulted in NRIs ranging between 0.34 to 0.89, attributable to better reclassification of events.Cardiac hemodynamics determined by ICG complement established CPX measures in reclassifying risk among patients with HF.

View details for DOI 10.1016/j.cardfail.2019.08.013

View details for PubMedID 31454685