ABSTRACT
Suga and Sagawa reported in the early 1970s that measurements of left ventricular pressure-volume (PV) relationships over a range of volume loads enabled separation of the effects of preload, afterload, and contractility on cardiac performance. The end-systolic pressure-volume relationship was found to be a relatively load-insensitive index of contractile state. Ventricular diastolic properties could be similarly characterized in terms of pressure-volume relationships. This chapter focuses on a method of measuring ventricular PV relationships continuously in patients with preload changes induced by transient inferior vena cava (IVC) occlusion with a balloon occluder catheter. It also focuses on five groups of patients including normals, patients with hypertrophic cardiomyopathy, patients with dilated cardiomyopathy, and patients with ischemic heart disease with and without ventricular aneuysms. To measure PV relationships, the IVC balloon was rapidly inflated by 20 to 30 ml of carbon dioxide. The balloon was deflated in 6 to 7 s, when there was no further decrement in volume or pressure.
