Measurement of haemodynamic response during exercise test by impedance cardiography method in patients with coronary artery disease

Abstract

Left ventricular dysfunction was detected by bioimpedance measurement in patients with coronary artery disease during exercise bicycle test. The impedance cardiography gave the opportunity to monitor haemodynamic trends parameters. The aim of the study was to evaluate the haemodynamic changes during an exercise test in patients after coronary artery revascularisation. Material and Methods: 30 consecutive patients (age 60±9 y.) included into the cardiac rehabilitation program were divided into 2 groups; EF<50% (6 patients) and EF>50% (24 patients). Routine bicycle exercise tolerance test (EET) was performed simultaneously with four-electrode impedance cardiogram. ECG, blood pressure, Thoracic Impedance and the first derivative dz/dt were recorded. Stroke volume (SV), cardiac output, contractility indices (HI, ACCI), vascular peripheral resistance were calculated for each cardiac evolution. Trends of the parameters were analysed. Results: In patients with EF<50% the 3 SV trend patterns were observed. SV decreased 1.5 minute before the exercise time limit in 2 patients. SV was in the same level in 2 and increased slowly only during the first two steps in 2 ones. The contractility indices (HI, ACCI) had the similar trends. In patients with EF>50% the SV trends increased to the time limit of the test. Conclusion: The haemodynamic response in patients with low Ejection Fraction was different than in the ones with EF>50%. © Springer-Verlag 2007.