Holter-type impedance cardiography device. A system for continuous and non-invasive monitoring of cardiac haemodynamics.

Impedance cardiography (ICG) enables the non-invasive, reproducible, beat-to-beat estimation of stroke volume (SV) changes, and the measurement of the absolute values of the ejection time (ET) and pre-ejection period (PEP), which allows the indirect evaluation of cardiac contractility. The miniaturised, Holter-type impedance cardiography device with built-in one channel of ECG called ReoMonitor, was constructed. The system allows the long-term, beat-to-beat, automatic evaluation of SV, ET, PEP and heart rate. The measurements obtained by ReoMonitor were verified using on echocardiographic method in supine and tilted positions. A high correlation coefficient (r=0.83) was calculated between the measurements collected using both methods. Speech or vigorous movement distinctly lowered the percentage of properly recognised cardiac cycles (during daytime: 20-80%, during the night: 75-90%). However, during exercise testing on a cycloergometer the quality of recordings was good. The following clinical applications of a system are presented: a) evaluation of hemodynamical abnormalities caused by arrhythmia events, b) vasovagal syncope diagnosis, and c) optimisation of atrio-ventricular delay during dual-chamber pacing.