Vol 14, No 2 (2007)
Review Article
Published online: 2007-03-08
Impedance cardiography: A valuable method of evaluating haemodynamic parameters
Cardiol J 2007;14(2):115-126.
Abstract
This year marks 40 years since the technique was designed of measuring and monitoring the
basic haemodynamic parameters in humans by means of impedance cardiography (ICG), also
known as "impedance plethysmography of the chest", "electrical bioimpedance of the chest" or
"reocardiography". The method makes it possible to denote stroke volume and cardiac output.
It also enables the factors to be assessed that influence the following: preload (measurement of
thoracic fluid content), afterload (measurement of systemic vascular resistance), the systemic
vascular resistance index, contractibility (measurement of the acceleration index), the velocity
index, the pre-ejection period, left ventricular ejection time, systolic time ratio and heart rate.
Advances in hardware and software, including digital signal tooling and new algorithms,
have certainly improved the quality of the results obtained. The accuracy and repeatability of
the results have been confirmed in comparative studies with results obtained through invasive
methods and echocardiography. Not only are haemodynamic changes monitored by means of
ICG in intensive care units, in operating theatres and at haemodialysis stations, but repeated
measurements also provide haemodynamic information during the treatment of patients with
hypertension and heart failure and pregnant women with cardiological problems and gestosis.
A single ICG investigation makes a great contribution to the basic information available about
the circulatory system, which is helpful in the initial evaluation of patients in a severe general
condition (for example in the admission room), and also makes it possible to make a swift
diagnosis of the cause of complaints such as dyspnoea and hypotonia. A particular application
of ICG is the assessment of haemodynamic parameters during the programming of atrioventricular
and CRT pacemakers. Besides these uses, ICG is a valuable investigative tool. It is
defect-free and does not have pulmonary artery pressure monitoring limitations. Moreover, it
is not as time-consuming as echocardiography and the examination can be performed by
trained technicians or nurses. (Cardiol J 2007; 14: 115-126)
Keywords: impedance cardiographyelectrical bioimpedance of the chestreocardiographycardiac outputhaemodynamicsnon-invasive diagnostics