Cardiac power as predictor of acute myocardial infarction outcomes

Abstract

Introduction: Insufficient reliability and specificity of cardiac output (CO) as widely used parameter for prognosis of acute myocardial infarction (AMI) outcomes led to investigations of alternative parameters such as cardiac power (CP). The aim of this study was to investigate the reliability and specificity of the CP for prognosis of in-hospital mortality using non-invasive impedance cardiography (ICG) and invasive intermittent thermodilution (ITD) techniques. Methods: CO and other hemodynamic indices were evaluated by both ITD and ICG methods in AMI patients, admitted within 12 hours from the onset of pain. CP was evaluated using formula: CP=COxMAP/451. Optimal binning method applying minimal description length principle was used to predict in-hospital mortality. During the period of 2004–2008 years 289 (196 men and 93 women) patients were investigated. Results: CP evaluated non-invasively by ICG on the first day was found as the only valuable prognostic parameter using model entropy method. In-hospital mortality was predicted with a single cut point 0.65 W/m2, sensitivity 100% and specificity 92.2%. Prediction of in-hospital mortality was possible when CO was evaluated using ITD as well. The most significant criteria using minimized entropy model were CP evaluated on the 3rd day (single cut point 0.79 W/m2, sensitivity 84.6%, specificity 100.0%) and CO evaluated also on the 3rd day (single cut point 4.00 L/ min, sensitivity 84.6%, specificity 100.0%). Conclusion: Cardiac power is a reliable predictor of in-hospital mortality after acute myocardial infarction. It could be successfully evaluated using intermittent thermodilution and with sufficient accuracy by means of non-invasive impedance cardiography.