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The maximal rate of rise of the left ventricular pressure is now commonly determined in many catheterization laboratories and has achieved wide use as a relatively simple index of contractility.~ 1 Further, there is a highly suggestive correlation between the intensity of the first heart sound and the speed of left ventricular contraCtion.2, 3Gleason and Braunwald' have stressed that the Telco intracardiac manometer should be used to determine the left ventricular dpldt, because of its high frequency response, and in order to avoid the frequent artifacts related to motion of the catheter within the heart. We have found that this instrument will produce excellent recordings, but the extremely high replacement cost of the catheter limits its use. The catheter manometer system usually used in cardiac catheterization can also be used to obtain excellent recordings, if care is taken in placing the catheter in the left ventricular chamber, so that it is reasonably free of motion.A study of the first derivative of the left ventricle, aorta and brachial artery, in patients undergoing diagnostic cardiac catheterization, was undertaken in order to compare these different parameters and to determine their usefulness. METHODSForty-seven patients underwent diagnostic right and left heart catheterizations. Rheumatic heart disease was present in most of the patients studied. Four patients were investigated for benign murmurs and were subsequently found to be free of any cardiac abnormality.Catheterization of the left ventricle was performed either by the Seldinger technique or by retrograde catheterization through a brachial arteriotomy. The rate of change (dpldt) of the left ventricular pressure and the aortic pressure was recorded through a catheter manometer system utilizing a RC differentiating circuit. Measurements were made only when the pressure curves showed an undistorted wave form. A Cournand needle was placed into the opposite brachial artery. For high-fidelity tracings, the needle was directly connected to a Statham P23Db pressure transducer. The first derivative of the brachial artery pressure could then be computed by a RC differentiating circuit. RESULTSComplete data on all 47 patients are presented in table 1. The rate of rise of the left ventricular pressure in the 4 normal patients was from 1615 to

SUMMARYIn 6 patients with pulmonary edema, the intravenous administration of phentolamine at a rate of 0.3mg./min. resulted in a rapid alleviation of symptoms and signs.In one patient with severe left ventricular failure a complete hemodynamic study was possible and the infusion of phentolamine produced a striking improvement in the measured hemodynamic functions.Phentolamine may prove to be a valuable and effective drug for the treatment of patients in pulmonary edema due to left ventricular failure. Additional Indexing Words:Congestive heart failure Inotropic drug T AYLOR and his co-workers1)-3) have investigated the hemodynamic effects in man of the acute intravenous injection of 5mg. of phentolamine and of the intravenous infusion of phentolamine at a rate of 2mg./min. for 10min. Both methods of administration produced an increase in the heart rate and cardiac output and a decrease in the systemic arterial pressure and systemic vascular resistance. They postulated that the decrease in the peripheral resistance produced a reflex increase in the cardiac output. Evans, Smulyan, and Eich4) made a similar observation and came to a similar conclusion. Measurements of the force of contraction using a strain gauge arch, or of the speed of contraction employing the left ventricular dp/dt, were not, however, utilized by these workers. On the other hand, Goodman and Gilman5) state that phentolamine given intravenously produces vasodilatation and cardiac stimulation and that blood pressure response depends upon the relative contribution of these two effects. The vasodilatation is due primarily to a direct action on vascular smooth muscle, although, with higher doses, alpha adrenergic blockade may also be involved.