Coronary blood flow measurement by the Kety-Schmidt method using antipyrine

The Kety-Schmidt method of measuring coronary blood flow using radioactive iodoantipyrine as the indicator has been used in man after cardiopulmonary bypass and other states. However, the validity of this method has not been established. We found the method to be both precise and accurate in measuring left ventricular coronary flow in normal dogs. The highest precision of coronary blood flow measurement by this method was obtained by using only the successive 15 or 30 sec coronary sinus and arterial samples that gave the best exponential fit. This usually fell within the first 3 min of antipyrine infusion.