Two types of intraventricular pressure difference within the left ventricle of man are described. The first type was encountered in eight consecutive patients with muscular subaortic stenosis in whom the outflow tract pressure distal to the stenosis was low and equal to the aortic systolic pressure, whereas all ventricular pressures proximal to the stenosis, including that just inside the mitral valve (the initial inflow tract pressure) were high. The second type was encountered in five of 10 patients with nonobstructive cardiomyopathy when a cardiac catheter was advanced to the left ventricular wall where it became entrapped or imbedded in cardiac muscle in systole and recorded a high ventricular pressure that was believed to reflect subendocardial intramyocardial tissue pressure. In this second type of intraventricular pressure difference, the initial inflow tract pressure, as well as all truly intracavitary pressures, were low and equal to the aortic systolic pressure. By defining two types of intraventricular pressure difference, the recent controversy as to the nature of such pressure differences in man may be resolved, and the obstructive nature of muscular subaortic stenosis reaffirmed.
Left heart catheterization in man has assumed increasing importance with the rapid advances in cardiac surgery for lesions of the left side of the heart.Zimmerman, Scott, and Becker (1950) were the first to perform left ventricular catheterization, passing a catheter in retrograde fashion from aorta to left ventricle.Subsequently the transbronchial (Facquet et al., 1952; Allison and Linden, 1953), transthoracic (Bjork, Malmstrom, and Uggla, 1953), suprasternal (Radner, 1954), and direct ventricular puncture (Brock, Milstein, and Ross, 1956) techniques have been used widely; but each has certain disadvantages (Morrow, Braunwald, and Ross, 1960).Ross (1959) and Cope (1959) almost simultaneously described the transseptal technique of left heart catheterization.Cope (1959) was the first to apply this technique in man.Ross, Braunwald, and Morrow (1960) have described the original transseptal technique in detail.Subsequently the improved and modified transseptal technique of Brockenbrough, Braunwald, and Ross (1962) has been described and has gained wide acceptance.This report describes our experience in combining this improved trans- septal technique with the retrograde technique of left ventricular catheterization.This represents a combination of the newest and oldest methods of left heart catheterization, a combination that permits a complete assessment of both stenosis and regurgitation at aortic and mitral valves, in- cluding hemodynamic, angiographic, and dye dilution studies, and overcomes some of the limita- tions encountered using either technique alone.Right heart catheterization may be combined easily with this procedure.One of the distinct advantages is the fact that both the transseptal and retrograde catheters can be introduced percutaneously from the right groin.McIntosh et al. (1961) have previously reported the combination of retrograde left ventricular catheterization with the original Ross technique of transseptal left atrial catheterization for the assessment of mitral valve disease.The combination of techniques described here is particularly suited for the assessment of lesions obstructing left ventricular outflow, as well as for the assessment of mitral valve disease. THE COMBINED TECHNIQUEPercutaneous Retrograde Aortic Catheterization.After local anesthetic has been injected into the right groin, a retrograde aortic cathetert is introduced into the right femoral artery by the catheter replacement technique (Seldinger, 1953).This catheter is then advanced to the ascending aorta and its tip positioned at the aortic valve.This part of the procedure is performed first, as this catheter then accurately locates the aorta for reference during transseptal left heart catheterization.
Amyl nitrite was administered on two occasions to a patient with muscular subaortic stenosis, to ascertain if selective peripheral vasodilatation would affect the degree of obstruction to left ventricular outflow in this condition. On each occasion there was a marked increase in the systolic pressure gradient across the left ventricular outflow tract prior to the onset of reflex tachycardia. Following the second amyl nitrite inhalation, the systolic cross-sectional area of the left ventricular outflow tract decreased to 1.0 sq. cm., from the control value of 2.6 sq. cm. It is believed that the increased degree of muscular subaortic stenosis, following peripheral vasodilatation, could be secondary to a decrease in the systolic size of the whole left ventricle, or to a selective decrease in the physical size of the left ventricular outflow tract.
Because a great majority of patients with chronic complete heart block have bilateral bundle-branch lesions, it becomes important to recognize earlier degrees of bilateral bundle-branch block. The H-V interval in the His bundle electrogram during unilateral bundle-branch block reflects the conduction primarily through the contralateral bundle branch, and thus the His bundle electrogram in bundle-branch block (BBB) provides information regarding the functional status of the contralateral bundle branch in addition to helping in the localization of defects elsewhere in the conduction system. His bundle electrograms were obtained in 20 patients with BBB and 13 patients without BBB. The following results were obtained from this study: (1) Prolonged P-R interval in the absence of BBB indicated delayed conduction through the A-V node. (2) Prolonged P-R interval in the presence of BBB indicated delayed conduction through the contralateral bundle branch or through the A-V node, or both. (3) Delayed conduction through the contralateral bundle branch in BBB occurred in the presence of a normal P-R interval and could only be detected by demonstrating a prolonged H-V time in the His recording. (4) In alternating BBB the His recording clearly demonstrated that the changing P-R interval was related to varying conduction through the bundle branches. (5) Finally, it has been demonstrated that the Wenckebach (Mobitz type I) type of decremental conduction can occur in the bundle branches or Purkinje system as well as in the A-V node. It is concluded that His bundle electrograms provide valuable information concerning the nature and management of conduction disturbances in patients with bundle-branch disease.
