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

Abstract

Left ventricular dysfunction was detected by bio- impedance measurement in patients with coronary artery disease during exercise bicycle test. The impedance cardiogra- phy gave the opportunity to monitor haemodynamic trends parameters. The aim of the study was to evaluate the haemo- dynamic changes during an exercise test in patients after coro- nary artery revascularisation. Material and Methods: 30 con- secutive patients (age 60±9 y.) included into the cardiac rehabilitation program were divided into 2 groups; EF 50% (24 patients). Routine bicycle exer- cise tolerance test (EET) was performed simultaneously with four-electrode impedance cardiogram. ECG, blood pressure, Thoracic Impedance and the first derivative dz/dt were re- corded. Stroke volume (SV), cardiac output, contractility indi- ces (HI, ACCI), vascular peripheral resistance were calculated for each cardiac evolution. Trends of the parameters were analysed. Results: 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%. Impedance cardiography is a noninvasive technique used to estimate stroke volume and contractility indices in hu- mans. Cardiac rehabilitation is based on the heart rhythm frequency, oxygen consumption and clinical status in pa- tients with coronary artery diseases. The patient's work capacity differs in patients after myocardial infarction or invasive therapy of coronary artery diseases or artificial valve replacement compare to the healthy ones. The limit of work load has been described by empirical formula be- fore rehabilitation. Rehabilitation of the patients who has had a myocardial infarction requires the assessment of exist- ing myocardial competence and the potential to the further recovery (1). The patients should be protected against risk of cardiovascular complications during physical exercise. It is necessary to know the response of the patient's cardio-