The use of impedance cardiography in heart failure.

The suitability of the impedance cardiograph for studying patients with cardiac failure in a District General Hospital was assessed over a 12-month period. Over 200 recordings were made from 60 patients. Stroke volume, using the derived formulation of Kubicek and his colleagues, and the Heather Index (a measure of cardiac contractility) were calculated in each case. Serial recordings provided an objective assessment of the efficacy of treatment. An abnormal diastolic O wave was found in the majority of patients. This may indicate an excessive accumulation of blood in the thorax as a result of myocardial dysfunction.