The Regional Myocardial Flow–Function Relationship

Abstract

This pioneering article was the first to quantitatively relate regional myocardial blood flow (microspheres) to regional contractile function (sonomicrometry). Regional flow and function were more or less proportionately reduced during acute ischemia in conscious dogs. The notion that myocardial ischemia arises from an imbalance between oxygen demand and supply goes originally back to the characterization of hemodynamic determinants of myocardial oxygen consumption in the whole heart and the observation that decreases or increases, respectively, in heart rate or ventricular function decrease or increase, respectively, the severity of ischemic injury.1 However, myocardial ischemia is in most instances a regional event. It was not until into the 1970s that experimental techniques became available to measure myocardial blood flow and contractile function on a regional level, notably the microsphere technique2 and sonomicrometry.3 Stephen Vatner in his classic article4 was the first to use both techniques simultaneously and quantitatively relate subendocardial segment shortening to subendocardial blood flow. He characterized the flow–function relationship as exponential during acute coronary stenosis in conscious dogs, with a more steep and almost linear part at more severe stenosis. Admittedly, the measurements were restricted to only the subendocardial layer, and segment …