Cardiac mechanical performance in circulatory shock: a critical review of methods and results

The article reviews studies which have focused upon the changes in cardiac contractile behavior induced by shock states. The major hypothesis tested experimentally was that cardiac contractility is depressed by shock states. The conclusions drawn by the cited articles are diverse, equally divided between confirming and rejecting the above hypothesis. The thesis of this article is that these diverse conclusions may have been caused by the limitations of the methods employed to assess cardiac contractility. The concepts of cardiac function curves, cardiac work and efficiency, parameters of shortening and the analysis of the end systolic pressure volume relationship (EES) are examined for their suitability to determine changes in cardiac contractility during shock states. Only the EES methodology appears to be able to assess cardiac contractility in shock states due to its insensitivity to altered conditions of cardiac contraction.