Evidence for Existence of Intramyocardial Steal

Abstract

Intramyocardial steal is defined as a process in which blood flow is diverted away from one area of the myocardium to another or away from the heart altogether. There are three potential causes of coronary steal syndrome: 1) congenital or acquired anatomic coronary malformations, 2) coronary atherosclerotic obstructive disease, and 3) vasoactive pharmacologic interventions. There is angiographic and physiologic data to support the existence of coronary steals in patients with congenital coronary artery disease, (Talner et al, 1965) as well as iatrogenic coronary steals (Pierach et al, 1971 and Barman et al, 1973). Evidence for the presence of coronary steals in exercised patients with ischemic heart disease (IHD) (Maseri et al, 1974 and Robertson et al, 1976) or pharmacologically induced steals in patients with IHD (Wilcken et al, 1971 and Utley et al, 1975) is scant and controversial (Rowe 1970). A reason for the controversy in this area is that indirect methods have been used to demonstrate coronary steals. The present report documents changes in directly measured myocardial oxygen tension that can be explained by the existence of a coronary steal phenomena.