A modified platinum electrode method for cardiac diagnosis.

devices originally described by Clark and Bargeron1 in 1959 provide a simple, rapid and reproducible means of detecting and localizing intracardiac shunts. Their clinical application has been well documented in the past five years.25 This paper will describe a modification of the platinum electrode and its application and a modification of the method of hydrogen gas administration. The advantages of these modifications will be discussed. The potentiometric electrode: Clark and Bargeron1 applied the classic hydrogen reference electrode principle to the measurement of gaseous hydrogen concentration in the blood. Platinum electrodes coated with platinic chloride (platinized) were found to produce potentials up to 300 my with reference to a silver skin electrode upon exposure to blood containing hydrogen gas. These potentials exceed the normal cardiac potential and can be measured and recorded by conventional DC amplifiers and recording devices. This electrode provides a sensitive method for the recognition of both left-to-right and right-to-left intracardiac shunts. In the detection of left-to-right shunts, inspired hydrogen gas is dissolved in blood as it passes through the lung to enter the left heart. From there, part of the hydrogen-containing blood then enters the right heart through the defect *From the Latter-day Saints Hospital. and activates the platinized platinum electrode positioned there earlier than would occur in the normal individual. The potential developed is in the range of 100 my and the appearance time is usually less than one second after hydrogen dose administration. In the detection of right-to-left shunts, Clark et al.2 injected hydrogen-saturated saline into the right heart and monitored for hydrogen in the aorta with the platin-ized platinum electrode. This technique is based on the observation that hydrogen is completely cleared from intravenously injected hydrogen-saturated saline as it passes through the normally ventilated lungs. Incidentally , it was observed that a platinized platinum electrode also develops a recorda-ble potential in the presence of sodium as-corbate. Hence ascorbic acid can be used as an indicator for right-to-left shunts with the platinized potentiometric electrode and can also be used for verification of the function of the detecting electrode. Polarographic electrode: The platinum electrode is referred to as a polarographic electrode whenever it is polarized as either a cathode or an anode and must, therefore , be distinguished from the potentio-metric electrode method. The polarograph-ic cathode is a familiar instrument to the biologist for measuring oxygen whereas the polarographic anode is a more recent de-velopment3 and …