Steady-state cardiac output determination during combined right and left heart catheterization.

Interpretation of the meaning of a mean diastolic atrioventricular gradient or a mean systolic ventricular-great vessel gradient requires simultaneous determination of the level of the gradient, the heart rate, and the cardiac output. The feasibility of steady-state Fick principle cardiac output determination during combined right and left heart catheterization is investigated. LEFT heart catheterization1-8 is a natural outgrowth of the development of mitral and aortic valve surgery and the resultant necessity for accurate preoperative evaluation of left-sided cardiac hemodynamics. Such evaluation requires simultaneous determination of valve gradient (systolic gradient for the aortic valve; diastolic gradient for the mitral valve), flow across the valve (cardiac output in the absence of valvular insufficien-cy), and heart rate. The first and third variables are readily determined during left heart catheterization. The purpose of this paper is to investigate the feasibility of steady-state cardiac output determination by the Fick principle, at rest and during exercise , in the course of combined right and left heart catheterization. METHODS AND MATERIAL Twenty-four comparisons of cardiac output at rest were performed in 23 patients, 11 women and 8 men with mitral valve disease, and 4 men with aortic valve disease. Right heart catheteriza-tion was performed, supine, in the usual manner, in the basal postabsorptive state, via a cutdown in the antecubital area. Brachial artery cannula-grant from the Heart Association of Greater Miami. 60 tion and open-circuit determination of oxygen consumption permitted calculation of cardiac output , generally in duplicate or triplicate. Left heart catheterization was then carried out in the prone position by a modification of the posterior percutaneous puncture technic of Fisher.' Two no.-17, thin-walled, 7-inch needles were inserted into the left atrium; polyethylene catheters were passed through the needles, one into the left atrium, and the other into the left ventricle. The needles were then removed over the catheters, leaving the latter in situ. The patient was then rotated back into the supine position. After a suitable rest period to permit restoration of the steady state, repeat cardiac output determinations were performed at rest, singly or in duplicate. Ten comparisons of cardiac output during exercise were performed in 9 patients, 3 women and 5 men with mitral valve disease, and 1 man with aortic stenosis. All 9 are included in the above group of 23 patients. Exercise cardiac outputs during right heart catheterization alone were generally obtained in duplicate or triplicate before the commencement of left …