Comparison of changes in ejection fraction to changes in impedance cardiography cardiac index and systolic time ratio.

Ejection fraction (EF) is the most common measure of left ventricular function in patients with heart failure. However, serial measurements of EF are costly and not practical for guiding frequent management decisions. Impedance cardiography (ICG) provides noninvasive hemodynamic measures with proven validity. The purpose of this study was to assess how changes in ICG parameters compared with changes in EF in heart failure subjects enrolled in a comprehensive outpatient management program. Retrospective chart review identified 13 subjects with two sets of paired echocardiography and ICG measurements (before and after treatment in an outpatient heart failure clinic setting). Mean age was 69+/-11 years, etiology was 54% ischemic heart disease, and mean New York Heart Association class was 2.5+/-0.5. The mean time between pre- and posttreatment EF measurements was 198+/-161 days. Changes in cardiac index and systolic time ratio by ICG were compared with changes in EF by echocardiography. From entry to final measurement, mean EF improved 9%+/-13%. Seven (54%) subjects had >5% improvement in EF, three (23%) had >5% decrease, and three had <5% change. Changes in ICG cardiac index and systolic time ratio were highly correlated with changes in EF (0.85, -0.73). ICG may be a practical, reliable, and cost-effective method of monitoring left ventricular function and guiding management decisions.

[1]  R. Heethaar,et al.  A Comparison of Bioimpedance and Echocardiography in Measuring Systolic Heart Function in Cardiac Patients , 1999, Annals of the New York Academy of Sciences.

[2]  G. Fonarow,et al.  Impact of a comprehensive heart failure management program on hospital readmission and functional status of patients with advanced heart failure. , 1997, Journal of the American College of Cardiology.

[3]  B. Greenberg,et al.  Reproducibility of impedance cardiography hemodynamic measures in clinically stable heart failure patients. , 2000, Congestive heart failure.

[4]  H. Boudoulas,et al.  Systolic time intervals. , 1990, European heart journal.

[5]  W. Shoemaker,et al.  Systolic and diastolic time intervals in the critically ill patient , 1991, Critical care medicine.

[6]  N. Albert,et al.  Equivalence of bioimpedance and thermodilution in measuring cardiac output and index in patients with advanced, decompensated chronic heart failure hospitalized in critical care , 2003 .

[7]  M. Drazner,et al.  Comparison of impedance cardiography with invasive hemodynamic measurements in patients with heart failure secondary to ischemic or nonischemic cardiomyopathy. , 2002, The American journal of cardiology.

[8]  P J Lynch,et al.  Comparison and reproducibility of visual echocardiographic and quantitative radionuclide left ventricular ejection fractions. , 1996, The American journal of cardiology.

[9]  C. Yancy,et al.  Noninvasive hemodynamic monitoring in heart failure: utilization of impedance cardiography. , 2003, Congestive heart failure.