Robert D. Leachman

Myocardial bridges: A review

LTHOUGH it has long been recognized that the coronary arteries and their main branches are normally positioned subepicardially, the anatomical literature since 1737 has occasionally mentioned an exception to this rule. Sometimes a coronary artery tunnels under a “bridge” of superficial myocardial fibers for a short distance. To quote Reymann’s’ original report, in Latin: “arteria coronaria sinistra . . . sub ortu arteriae pulmonaris frequenter se subducit pone stratum extimum fibrarum cordis iisque tegitur” (the left coronary artery. . . under the origin of the pulmonary artery, frequently becomes submerged under a thin layer of cardiac fibers and then resurfaces). Only during the last few years, since the first angiographic description of myocardial bridges in vivo by Portsmann et al.’ in 1960, has the clinical significance of this entity been discussed. Whereas the majority of specialists remain uncommitted, a few claim that myocardial bridges exert an ischemic effect on the myocardium and warrant surgical resection in selected cases.

Early and Late Mortality of Patients Undergoing Aortic Valve Replacement After Previous Coronary Artery Bypass Graft Surgery

BACKGROUND In a small number of patients who undergo coronary artery bypass graft surgery (CABG), a hemodynamically significant aortic valve lesion requiring aortic valve replacement (AVR) develops as they grow older. In a limited number of studies in small patient groups, high mortality has been shown in patients undergoing AVR after CABG. We undertook this study to determine the mortality risk factors for patients who undergo AVR after CABG procedures. METHODS AND RESULTS The outcome of 104 patients treated at our institution between January 1983 and December 1993 was retrospectively reviewed. The initial surgery was CABG in all patients. The patient population included 86 men (83%) and 18 women (17%); their mean age was 67 years. Overall, 70% of patients had congestive heart failure, and 96% had multivessel coronary artery disease. The diagnosis was aortic stenosis in 68% of patients, aortic insufficiency in 16%, and combined aortic stenosis and aortic insufficiency in 16%. Postoperative complications included worsening congestive heart failure (35%), perioperative myocardial infarction (13%), and bleeding (28%). The early mortality was 14%, and the late mortality was 17% (mean follow-up, 35 months). The risk factors for early mortality were number of diseased vessels (P = .028), renal failure (0.000), and prior myocardial infarction (P = .028). A perioperative predictor of early mortality was cardiopulmonary bypass time (P = .000). The risk factors for late mortality included preoperative diabetes mellitus (P = .007), postoperative acute respiratory distress syndrome (P = .011), and ventricular arrhythmias (P = .0001). The survival at 1, 5, and 10 years was 96%, 75%, and 49%, respectively. CONCLUSIONS Risk factors were identified for early and late mortality in patients undergoing AVR after previous CABG. Although early morbidity and mortality were high, the longterm outcome of the survivors was favorable.

Diverticulum or aneurysm of left ventricle

Two cases of abnormalities in development of the left ventricular wall (left ventricular aneurysm or diverticulum) are presented. In 1 case the defect was an isolated finding in an otherwise asymptomatic child. In the second, the malformation was associated with midline thoracoabdominal defects in a middle-aged man. Both patients had the diagnosis confirmed by cardiac catheterization and angiography and underwent successful surgical correction of the abnormality. The clinical, angiographic and pathologic characteristics of congenital diverticulum and aneurysm of the heart are reviewed, and an attempt is made to clarify the concept of congenital aneurysm and diverticulum of the heart.

Surgical repair of atrial septal defect in patients over 60 years of age. Long-term results.

In order to evaluate results of surgical repair of secundum atrial septal defect (ASD) in patients 60 years of age or older, a review was made of 16 patients who had undergone such operation between January 1964 and December 1974. Before operation eight patients were in functional classification III (New York Heart Association), seven were in class 11, and one was in class 1. Twelve patients had a left-to-right shunt greater than 3:1. Pulmonary artery systolic pressure was greater than 40 mm Hg in 12 patients and greater than 60 mm Hg in five. Four patients had documented paradoxical emboli and were being treated with Coumadin. Before operation all patients but one were receiving digoxin.Repair was accomplished by direct suture in two patients and Dacron patch graft in 14. No deaths occurred during the postoperative period. Postoperatively, ten patients were in class I, five in class II, and one remained in class III. The hospital stay ranged from eight to 20 days (average 11 days). Two patients died one year and another (at the age of 77) five years after surgery. The remaining 13 patients are alive and well three months to 11 years after surgery.We conclude that repair of secundum ASD in patients over the age of 60 is safe, has low morbidity, and produces considerable clinical improvement.

Association of ostium secundum atrial septal defects with mitral valve prolapse

Severe prolapse of the mitral valve leaflets was seen at left ventricular angiography in 16 of 92 patients with a secundum type atrial septal defect studied prospectively from 1970 to 1974. The patients were aged 15 to 69 years; angioplasty or mitral valve replacement was carried out in nine. In 9 of 122 patients aged 15 to 55 years who were operated on for closure of a secundum type atrial septal defect between 1956 and 1969, mitral regurgitation due to prolapse but with intact chordae tendineae was seen at operation. In three of these patients chordal rupture was seen at a second operation 2 to 6 years later. The outlook in the syndrome of mitral valve prolapse may be less benign than is usually believed.

Response of the transplanted, denervated human heart to cardiovascular drugs.

Abstract The action of 3 of the most commonly used inotropic agents was studied in the human transplanted heart. Digoxin increased the first derivative of the right or left ventricular pressure curve ( dp dt ) in 2 patients. The cardiac output was increased in a patient with latent heart failure but remained unchanged in another with normal cardiac function. Digoxin did not appear to produce atrioventricular (A-V) nodal blockade in 2 patients with atrial flutter or fibrillation. Isoproterenol effected a marked rise in cardiac index and stroke index as well as in right ventricular dp dt in a patient who was in the terminal phase of rejection. Glucagon produced a marked increase in cardiac output and index, stroke index and left ventricular dp dt in a patient who was already digitalized. From these actions it is concluded that digoxin produces a positive inotropic effect in patients with cardiac transplants, without affecting the A-V nodal refractory period. Isoproterenol and glucagon both exert a positive chronotropic and inotropic effect. All 3 drugs exert a direct action on the transplanted denervated heart, in accord with previous observations on experimental animals.

Morphologic Findings in Human Cardiac Allografts

Morphologic findings in human cardiac allografts from 13 patients are presented. In the acutely rejected cardiac allograft there was a cellular infiltrate consisting of large lymphocytes and varying numbers of polymorphonuclear leukocytes, eosinophils, and histiocytes in the myocardium and arterial intima. The coronary arteries frequently exhibited degeneration, acidophilia, and vacuolation of the tunica media. In the cases with chronic cardiac allograft rejection there was obliterative fibrous thickening of the arterial intima with medial necrosis. Focal areas of myocardial necrosis and fibrosis were present along with a myocardial infiltrate of mononuclear cells. In most patients who died of causes other than rejection, there was evidence of an immunologic response. Rejection has not been regarded as an “all or none” phenomenon. There was indication in this series that survival was related to histocompatibility.

Early systolic closure of the aortic valve in patients with hypertrophic subaortic stenosis and discrete subaortic stenosis: Correlation with preoperative and postoperative hemodynamics

Patterns of motion of the aortic valve were analyzed with echocardiography in 9 patients with discrete subaortic stenosis and 31 patients with idiopathic hypertrophic subaortic stenosis, 22 with and 9 without a resting intraventricular pressure gradient. The intention was to determine whether the early systolic closure of the aortic valve was a sensitive indicator of a resting pressure gradient across the left ventricular outflow tract. All 9 patients with discrete subaortic stenosis and the 22 patients with idiopathic hypertrophic subaortic stenosis with a resting pressure gradient showed early systolic closure of the aortic valve; however, the 9 patients without a resting gradient had normal motion of the aortic valve. Measured values for O-ESC (the interval from the opening point of the aortic valve to the point of early systolic closure of the aortic valve) in 9 patients with discrete subaortic stenosis and in 22 with idiopathic hypertrophic subaortic stenosis averaged 0.05 ± 0.01 (standard deviation) second and 0.14 ± 0.04 second for each group, respectively (P < 0.01). Twelve patients with idiopathic hypertrophic subaortic stenosis underwent operation to alleviate left ventricular outflow tract obstruction. In eight of these patients the resting pressure gradient was completely abolished and early systolic closure of the aortic valve was no longer present. The results indicate that in idiopathic hypertrophic subaortic stenosis, early systolic closure of the aortic valve is recorded only when there is a significant intraventricular pressure gradient at rest. The time of occurrence of early systolic closure differentiated patients with discrete subaortic stenosis from those with idiopathic hypertrophic subaortic stenosis in all observations.

Supravalvular mitral stenosis associated with tetralogy of Fallot

The association of tetralogy of Fallot with supravalvular mitral stenosis is a rare anomaly that has been reported only once previously. The difficulty of preoperative diagnosis is emphasized. Although left-sided obstructive lesions in association with tetralogy of Fallot are rare, their recognition is imperative since these are surgically correctable anomalies and potentially lethal, as proved in this case and the one previously reported.

Correlations of systolic time intervals and radionuclide angiography at rest and during exercise

Systolic time intervals (STI) were correlated with radionuclide angiography studies (RAS) in 57 patients at rest, during maximal semisitting bicycle exercise, and at 4 minutes following the cessation of exercise. Eleven were judged as being free of coronary artery disease (group 1), while 14 had coronary artery disease without (group 2A), and 27 (group 2B) with a previous transmural myocardial infarction. For RAS, resting radionuclide ejection fraction (REF), the changes in REF and end-systolic volume, and the development of a wall motion abnormality at peak exercise were each highly correlated with the presence of coronary disease (p less than 0.001). The accuracy of STI parameters in predicting the presence of coronary disease was poor (less than 60%). Changes in end-diastolic volume (EDV) correlated significantly with PEP/LVET and LVET1 changes following exercise. Moreover, patients with an abnormal (greater than 25%) increase in EDV at peak exercise had a greater increase in LVET1 in the postexercise period (p less than 0.01). We conclude that STI is not accurate enough a predictor of coronary disease or left ventricular function to serve as a useful screening test. Changes in STI parameters appear to be more related to changes in ventricular volume than to ventricular function.