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Echocardiographic and hemodynamic studies were obtained in 42 consecutive patients undergoing aortic valve replacement for isolated aortic stenosis. Concentric left ventricular (LV) wall thickening, the most common preoperative abnormality, occurred in 95% of patients. LV dilation with reduced fractional shortening was noted in approximately 25% of patients but was severe in only one patient. Six months after operation, LV wall thickness had decreased on average but had not returned to normal and fractional shortening was unchanged. Repeat measurements in 13 patients an average of 37 months after operation were unchanged compared with measurements made 6 months after operation. When patients were subdivided into those with LV dilatation and those without, we found that patients with dilated ventricles preoperatively had a greater decrease in LV internal dimension and mass than those without preoperative dilatation. The patient data also were examined for possible association with mortality. One operative (2%) and five late cardiac (13%) deaths occurred. No preoperative or 6-month postoperative echocardiographic or hemodynamic measurement was strongly associated with these deaths, nor were any late deaths due to congestive heart failure. Compared with preoperative measurements in symptomatic patients who were operated for isolated aortic regurgitation, patients with aortic stenosis had smaller left ventricles with less depression of systolic function, as well as less aortic root and left atrial dilatation. Our data do not support the concept that the aortic valve should be replaced before the onset of symptoms to prevent irreversible LV damage in patients with isolated aortic stenosis.

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Nitroglycerin reduces elevated left ventricular filling and pulmonary arterial pressures in resting patients with rheumatic valve disease and reduces symptoms when given over long periods to patients with primary myocardial disease. To determine whether nitroglycerin may prove effective therapeutically in ambulatory patients with heart valve disease, its effects on hemodynamics and exercise capacity were studied in 11 severely symptomatic adults who were already receiving optimal treatment with digitalis and diuretic agents. Seven had predominant mitral valve disease, one had predominant aortic insufficiency and three had equally severe mitral and aortic valve disease. Maximal exercise capacity was assessed with graded treadmill exercise after placebo and after nitroglycerin (0.5 mg sublingually) administered in random sequence to each patient. Exercise capacity (exercise time to limiting fatigue or dyspnea) increased from a mean of 8.3 minutes after placebo to 9.8 minutes after nitroglycerin (P less than 0.005). Eight patients were studied hemodynamically during further intense treadmill exercise. Pulmonary arterial pressure was significantly lower (P less than 0.05) after nitroglycerin than after placebo (mean 44 versus 56 mm Hg), but cardiac output was greater after nitroglycerin (5.0 versus 4.6 liters/min, P less than 0.005). Thus, nitroglycerin appears to increase exericse tolerance and improve the hemodynamic response to exercise in patients with heart valve disease and may be valuable in the long-term pharmacologic therapy of such patients.

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This study summarizes the results in 26 patients of triple valve replacement (TVR) performed between 1967-1975. The first ten patients (group I) received all-mechanical valves, but the last 16 (group II) received porcine xenograft atrioventricular and porcine or mechanical aortic valves. Preoperatively, all patients were functional class II or IV with pulmonary arterial and venous hypertension. Early mortality was 30% group I and 18.8% group II; late mortality has been 30% group I and 6.3% group II. Total operative and bypass time, and duration of postoperative respiratory support was less (P less than 0.025) in group II than in group I. Postoperative catheterization performed in 16 of 26 patients demonstrated significant reduction (P less than 0.05) in pulmonary arterial and venous hypertension, and aortic and mitral gradients in group II. There have been no late complications or valve malfunctions in group II. An improvement of at least two functional classes was seen in 4/6 group I and 12/13 group II operative survivors. The results of TVR with porcine xenografts compare favorably with those of all-mechanical replacements and deserve further evaluation.

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To test the hypothesis that the ventricular septum moves during systole toward the center of the ventricular mass (so that the end-diastolic position of the septum within the heart should determine both the direction and the magnitude of septal motion during systole), echocardiograms from patients with several different hemodynamic burdens were analyzed. A linear relation was noted between the end-diastolic intracardiac position of the ventricular septum and the direction and magnitude of systolic septal motion in 1) forty three patients with an atrial septal defect )regression coefficient r = 0.80), 2) fourteen patients with other causes of right ventricular volume overload (r = 0.82), 3) nineteen patients with left ventricular volume overload (r = 0.74), 4) ten patients with right ventricular pressure overload (r = 0.93), 5) ten patients with left ventricular pressure overload (r = 0.80), 6) twenty-eight normal subjects (r = 0.82). We conclude that, in the presence of normal ventricular activation and contraction, the direction and magnitude of sepatal motion during systole is determined by the intracardiac position of the septum at enddiastole.

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In an attempt to define quantitatively the relation between left atrial size and atrial fibrillation, echocardiography was used to study 85 patients with isolated mitral valve disease, 50 patients with isolated aortic valve disease, and 130 patients with asymmetric septal hypertrophy. In all three groups of patients, atrial fibrillation was rare when left atrial dimension was below 44 mm (3 of 117 or 3%) but common when this dimension exceeded 40 mm (80 of 148 or 54%). In addition, when left atrial dimension exceeds 45 mm, cardioversion, while initially successful, is unlikely to produce sinus rhythm that can be maintained at least six months. These data suggest that left atrial size is an important factor in the development of atrial fibrillation and in determining the long term result of cardioversion. The pathophysiologic mechansim most consistent with this is that a chronic hemodynamic burden initially produces left atrial enlargement which in turn predisposes to atrial fibrillation. Only prospective studies will determine definitively whether these observations will be useful in decisions concerning prophylactic anticoagulation and elective cardioversion.

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Since July, 1970, 111 patients have undergone mitral and/or tricuspid valve replacement with a glutaraldehyde-fixed porcine xenograft mounted on a flexible stent; 41 of these patients also had aortic valve replacement with a Starr-Edwards or Bjork-Shiley valve, and 85 patients presently are alive. Cumulative follow-up totals 2,060 months, with 16 patients followed more than 4 years. Anticoagulants have not been administered postoperatively, and one patient has had a systemic embolus. Postoperative hemodynamic assessments have been carried out in 54 patients, and in either the mitral or tricuspid position the valve was shown to have good hydraulic function. Significant mitral regurgitation, secondary to prosthetic dysfunction, occurred in one patient 56 months following implantation. Progressive prosthetic stenosis has not occurred, and hemolysis or anemia of clinical significance has not been observed as a consequence of the use of the use of the xenograft. To date, these clinical and hemodynamic data indicate that the glutaraldehyde-fixed xenograft, mounted on a flexible stent, is the prosthesis of choice for mitral and tricuspid valve replacement.

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The long-term durability of saphenous vein bypass grafts and their effect on existing intrinsic coronary artery disease remain ill defined. Therefore, sequential catheterization studies were performed in patients selected for study solely on the basis of documentation of a patent graft at an earlier study performed three to nine months postoperatively; at that time 29 patent grafts were demonstrated in 20 patients. Fifteen to 36 months postoperatively (average 22 months), 27 grafts were unchanged, 1 manifested minimal luminal irregularities and 1 was occluded. In one additional patient, studied 4 months and 4 1/2 years postoperatively, the graft was widely patent and had good distal runoff at the second study. Sequential coronary arteriograms revealed that progression of disease to complete occlusion occurred in 24 percent of vessels with severe lesions proximal to a patent graft, whereas progression of disease distal to a graft anastomosis was uncommon. Of 25 vessels not receiving grafts, disease progressed in 5 (20 percent). Grafts that are patent 3 months after operation appear to remain patent for at least 2 to 3 years, and their presence does not unduly accelerate the disease process involving the native coronary arteries.

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The electrocardiographic response to exercise was compared with the results of coronary angiography in 89 patients with Type II hyperlipoproteinemia who had previous myocardial infarction or typical angina or both (43 patients)(Group A), "atypical angina" (16 patients)(Group B)or positive electrocardiographic response to exercise without other evidence of cardiac disease (30 patients)(Group C). Thirty-nine of 43 in Group A had greater than or equal to 50 per cent stenosis, and 26 (67%) of these 39 had negative exercise tests. In Group B, five of the 16 had greater than or equal to 50% stenosis, and three had positive exercise tests (one patient had a false-positive test). In Group C, eleven of 30(37%) had greater than or equal to 50% stenosis; however, nine (30%) had minor stenosis (less than or equal to 50%), and 10(33%) normal coronary arteries. The diagnostic usefulness of exercise electrocardiography is limited. False-negative responses are frequent in patients with clinically suspected coronary disease, and false-positive responses frequent in asymptomatic patients.

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The results of operative treatment in 83 patients with idiopathic hypertrophic subaortic stenosis (IHSS) are described. Most patients with the disease are asymptomatic, or derive satisfactory symptomatic improvement from nonoperative therapy: administration of propranolol, exerice limitation, control of arrhythmia, etc. Operation is required, however, in 10-15% of patients, those who remain severely symptomatic after nonoperative treatment or who become refractory to it. Operation relieves symptoms in IHSS by relieving obstruction to left ventricular outflow, and for a patient to be considered an operative candidate severe obstruction must be documented at left heart catheterization either under resting conditions or after provocative interventions. All 83 patients were severely incapacitated--58 in Class III and 24 in Class IV. Seventy had obstruction at rest (average gradient 96 mm Hg), and 13 had only provocable obstruction. At operation the hypertrophic interventricular septum was exposed via an aortotomy, and a vertical bar of muscle was resected between parallel myotomy incisions. There were six operative deaths (7%); no patient has died since 1970. Seven patients have died late after operation, five of them from causes unrelated to their heart disease or the operation. All surviving patients describe symptomatic improvement. Fifty-two patients with obstruction at rest preoperatively (average gradient 95 mm Hg) have been studied postoperatively: no resting gradient was evident in 47, while in the remaining five the gradient was less than 25 mm Hg. Recurrence of obstruction has never been observed at late catheterization (21 pts) or late echocardiographic examination (37 pts). Obstruction could not be provoked postoperatively in ten of the 11 patients who had large gradients only with the Valsalva maneuver or isoproterenol administration preoperatively. Obstructed and provocable obstructed patients had similar symptomatic improvement after operation. A variety of rhythm and conduction abnormalities were observed both pre and postoperatively, and these are described in detail. The results of operation in these 83 patients with IHSS demonstrate that gratifying symptomatic and hemodynamic improvement uniformly follows left ventriculomyotomy and myectomy. Relief of obstruction and amelioration of symptoms have proved to be long-lasting during postoperative observation periods extending to 14 years. Continued application of the operative procedure in properly selected patients appears to be indicated.

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A patient is described in whom right coronary artery dissection occurred 48 hours after coronary angiography. Successful operative treatment consisted of immediate saphenous vein bypass grafting and ligation of the proximal coronary artery. Several aspects of the case are characteristic of this pathological entity as reported in the literature and suggest principles of surgical management.

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This report describes a new method based on roentgen videodensitometry for the measurement of left ventricular ejection fraction in man. The net forward ejection fraction (NFEF) is calculated directly from the formula NFEF=1-exp(-.693/N), where N is the number of cardiac cycles necessary for half of the injected contrast material to be washed out of the left ventricle. The derivation of this formula is presented, and the technique is validated by comparison with washout curves from a Lucite model of the heart and with simultaneous angiographically determined left ventricular ejection fractions in man. The videodensitometry technique offers the following advantages over the conventional volume technique: (1) only a small amount of contrast material is required; (2) ectopic beats are uncommon during the washout phase when measurements are made; (3) the ejection fraction measured is an average of several cardiac cycles; and (4) dependence upon operator interpretation is minimized. Furthermore, given adequate mixing within the chamber, NFEF should be independent of ventricular geometry. Thus, NFEF of the unusually shaped left ventricle can be readily determined.

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