Floppy mitral valve and ventricular septal defect: an anatomic study.

Eighteen percent of heart specimens with isolated ventricular septal defect also had a floppy mitral valve. There was no statistical difference in the incidence of floppy mitral valve in the three age groups considered (less than 1 year, 1 to 16 years and 17 to 91 years). In no patient was a floppy mitral valve considered to be the cause of death. Complications of floppy mitral valve (ruptured chordae tendineae, bacterial endocarditis, mitral regurgitation and fibrin deposits at the mitral valve-left atrial angle) occurred at approximately the same frequency as that reported in autopsy studies of isolated floppy mitral valve. In the specimens with floppy mitral valve and ventricular septal defect, 63% also had floppiness of the tricuspid valve, 16% of the pulmonary valve and 5% of the aortic valve. The anatomic basis for floppy mitral valve was considered to be spongiosal invasion and disruption of the fibrosa of the valve leaflet. In this study, spongiosal invasion of the fibrosa was fully developed by 3 months of age and there was no evidence that the incidence or severity of spongiosal invasion increased between the ages of 3 months and 88 years. These data suggest that the floppy mitral valve is a congenital lesion that reaches full anatomic expression in infancy. No evidence was found that ventricular septal defect and floppy mitral valve share a common etiology.

Predictive value of lung biopsy in ventricular septal defect: long-term follow-up.

Although the Heath-Edwards classification has been used for more than 25 years to evaluate pulmonary vascular changes, its potential to predict the long-term course after successful ventricular septal defect closure has not been proved. Operative lung biopsy slides obtained at the time of closure from 57 infants and children who had been among the first survivors (between 1954 and 1960) of such surgery were graded in blinded fashion according to the Heath-Edwards classification system, and the resultant biopsy grade of each was compared with the eventual long-term outcome of each child. In 53 (93%) of the 57 cases, the Heath-Edwards system correlated well with long-term clinical or hemodynamic status of the patient. Grade IV changes were predictive of a usually fatal outcome, while grade I and II changes were generally benign. Death from pulmonary vascular disease occurred, however, in four children whose operative lung biopsy had been classified as either grade I or II, indicating that the focal nature of the higher Heath-Edwards grades, or human error, must be considered when this classification system is employed.

Myoglobin facilitated oxygen diffusion maintains mechanical function of mammalian cardiac muscle.

Myoglobin, an intracellular iron containing protein that binds oxygen reversibly, has been shown in model systems to facilitate the diffusion of oxygen and thereby maintain the mechanical function of exercising canine skeletal muscle and of hypoxic benthic fish hearts. Since no such role has yet been established for mammalian cardiac muscle small diameter (less than or equal to 0.70 mm) isolated kitten papillary muscles were stimulated at 24 X min-1 under isometric conditions in a physiological bath maintained at 30 degrees C with an oxygen tension of approximately equal to 450 mm Hg (59.8 kPa) to obtain a level of oxygenation just adequate to meet the metabolic needs of the muscles, as confirmed experimentally. Myoglobin was inactivated by adding 2 X 10(-3) mol X litre-1 sodium nitrite to the bath to abolish the facilitated diffusion of oxygen in the presence or absence of glycolytic blockade by 10(-4) mol X litre-1 sodium iodoacetate. This resulted in a 22(8)% (with blockade) or 10(3)% (without blockade) decrease (p less than 0.05) in the maximal rate of relaxation (-dT/dtmax) of the papillary muscles. Since the depression in mechanical function was reversible by increasing the bath oxygen tension to approximately equal to 600 mm Hg (79.8 kPa) it is concluded that the myoglobin facilitated diffusion of oxygen plays a role in maintaining the mechanical function of mammalian cardiac muscle under normal conditions. Furthermore, the maximal rate of relaxation of cardiac muscle is a sensitive indicator of the presence of hypoxia.

Changes in regional myocardial blood flow and variable development of hypertrophy after aortic banding in puppies.

Supravalvar aortic banding was performed in 6 to 12 week puppies. Sixteen animals were studied 7.3 (3.5 to 10) months later, closed-chested under morphine-chloralose, catheters being positioned in the great vessels and heart, including the left atrium for microsphere injection. Compared with 11 controls, eight dogs developed biventricular hypertrophy, four isolated left ventricular hypertrophy and four had no hypertrophy. The left ventricular systolic pressure was similar (P greater than 0.05) in these 3 banded groups (mean, 30 +/- 2 [SEM] kPa, [222 +/- 16 mmHg], n = 16). The left ventricle was divided into three coronal slices with approximately 59 samples being taken from subendocardial, midwall, and subepicardial layers and additional samples from the atria and right ventricle for regional myocardial flow measurement. As left ventricular hypertrophy increased, the subendocardial/subepicardial flow ratio decreased (r = -0.8). Heterogeneity of left ventricular regional myocardial flow, including a base-to-apex decrease in flow, present in controls, was markedly reduced in the banded dogs. Analysis of variance was found to be the most sensitive test for detecting left ventricular perfusion abnormalities since in banded dogs without hypertrophy, total and regional subendocardial/subepicardial flow ratios were not significantly different from control values, whereas the subendocardial circumferential flow pattern determined by analysis of variance was significantly different from control in these dogs (P less than 0.05).

Cardiac complications in children with systemic lupus erythematosus.

Two patients had cardiac complications of childhood onset systemic lupus erythematosus (SLE). A 14-year-old boy had extramural and intramural coronary arteritis demonstrated by angiography. The signs and symptoms of myocardial ischemia improved dramatically when corticosteroid dose and immunosuppression were increased. A 20-year-old woman had had SLE for 18 years and had functionally significant mitral stenosis and regurgitation. Calcification of the mitral valve was observed on echocardiography. Corticosteroid treatment has controlled the renal manifestations of SLE. Cardiac complications of SLE are now a significant clinical problems.

Gross and histologic anatomy of total anomalous pulmonary venous connections.

Among 49 heart specimens with total anomalous pulmonary venous connection (TAPVC), obstruction to pulmonary venous flow was present in all 13 cases with TAPVC below the diaphragm and in 53% of 36 cases with TAPVC above the diaphragm. Obstruction was produced by extrinsic pressures on the vein, intrinsic narrowing of the vein, or both. The histology of the narrowed veins was extremely variable, ranging from atrophy of the vein wall to hypertrophy of intima, media-adventitia, or both. Balloon dilation of narrowed veins was performed in 3 cases, without clinical or anatomic evidence of success.

Isolated cleft mitral valve: a variety of congenital mitral regurgitation identified by 2-dimensional echocardiography.

Nine children with isolated cleft mitral valve, aged 1 day to 12 years, were studied. The electrocardiogram showed a normal QRS axis in 5 subjects. Cardiac catheterization was performed in 4 patients and demonstrated severe mitral insufficiency in 3 but failed to clearly demonstrate a cleft mitral valve or gooseneck deformity. The mitral cleft was confirmed at operation in 2 patients. Two-dimensional echocardiography demonstrated a cleft dividing the anterior mitral leaflet into 2 portions in each patient. The mitral anulus was normally positioned and the atrioventricular septum present. Atrial and ventricular septa were intact. Features similar to anatomic studies such as accessory chordae and thickening of the edges of the cleft with increasing age were also seen. Two-dimensional echocardiography is the only method available to reliably diagnose isolated cleft of the mitral valve.

Cor triatriatum: study of 20 cases.

Twenty cases of cor triatriatum are reported. The diagnosis was confirmed by necropsy in 16 cases and at the time of operation in 4. The lesion occurred as an isolated anomaly in 7 cases; in 13, other associated cardiac anomalies were present. Three anatomic types of cor triatriatum were identified in the cases studied at necropsy: diaphragmatic (10 cases), hourglass (3) and tubular (3). The diaphragmatic type was also present in all four cases in which the diagnosis was confirmed at operation. Associated anomalies were found in five cases of the diaphragmatic type and in each case of the hourglass of tubular types. In isolated cor triatriatum the clinical findings were characteristic of pulmonary venous and arterial hypertension. In two cases, one with a communication between the right atrium and the accessory left atrial chamber and one with partial anomalous pulmonary venous connection associated with cor triatriatum, the clinical findings suggested a large left to right shunt with pulmonary arterial hypertension. The clinical findings varied in the cases with associated anomalies, and it was difficult to determine the cause of disturbance of the circulation.

Causes of sudden unexpected cardiac death in the first two decades of life.

Sudden, unexpected cardiac death in the age group 1 to 21 years usually is due to myocarditis, hypertrophic cardiomyopathy, aortic valvar stenosis, and coronary arterial abnormalities. The hearts of 70 patients <21 years of age who died suddenly were reviewed. Twenty patients were <1 year of age and 50 were 1 to 21 years old. The cardiac findings were compared with those in 68 age-matched controls with known cardiac disease who did not die suddenly. Significant cardiac abnormalities were present in 13 (65%) of the 20 infants; 10 (50%) had anomalies of the aortic origin of the coronary arteries. Among the 50 older patients, cardiac abnormalities were found in 40 (80%), among whom coronary arterial anomalies existed in 12 (24%). Anomalies of aortic origin more frequently involved the left main than the right coronary artery in both groups.

Transcatheter closure of patent ductus arteriosus in piglets.

To better determine the risks of transcatheter closure of a patent ductus arteriosus (PDA), a model of PDA was made in newborn piglets by using 5- to 7-mm angioplasty catheters to dilate the probe PDA. This maneuver resulted in a permanent PDA in most piglets. Four to 6 weeks later PDA closure was attempted using the Rashkind PDA occluder. Twelve such procedures were attempted, using clean but nonsterile technique. Nine of 12 PDAs were successfully closed. Two failures were the result of inability to successfully traverse the PDA. This problem was solved by using a long sheath to position the device properly. Four complications occurred, all related to device release: left pulmonary artery embolization in 1 case, femoral artery embolization in 1, torn pulmonic valve cusp in 1 and lodgment of a prosthesis on a pulmonic valve cusp. Two successfully implanted devices were infected at necropsy. This study demonstrates the value of a piglet model in testing transcatheter PDA occlusion devices, the importance of sterile technique in such procedures, the hazards of device retrieval through the right heart and the feasibility of transcatheter PDA closure.

Pulmonary arterial aneurysm. A pathologic study of five cases.

Five cases are described in which noninflammatory pulmonary arterial aneurysmal disease existed. In each case, severe pulmonary hypertension had been present. In one (woman, age 50 years), the pulmonary hypertension was of the primary type, while in each of the others, congenital heart disease was an underlying condition (atrial septal defect in three cases; each woman, age range 35 to 56 years) and complete transposition in the remaining case (boy, age ten). In one case with atrial septal defect, saccular aneurysm involving each major pulmonary arterial branch was considered to have resulted from atherosclerotic disease. In each of the remaining cases, cystic medial necrosis was present, and the aneurysmal disease was the result of laceration of a major pulmonary arterial segment. In one of the cases with atrial septal defect, the laceration was recent and extended through the full thickness of the pulmonary trunk in a circumferential manner. In the remaining three cases, lacerations were usually old and had not extended through the full thickness of the involved arterial segments. Saccular aneurysm formation (usually multiple) had resulted from weakness of the wall as a result of laceration and retraction of tissue.

Silent unilateral pulmonary venous obstruction. Occurrence after surgical correction of transposition of the great arteries.

An 11-year-old girl was found to have completely obstructed left pulmonary veins eight years following corrective surgery for transposition of the great arteries. The patient was acyanotic and asymptomatic. Retrograde flow of arterial blood from the affected left lung accounted for an angiographic appearance that mimicked occlusion of the left pulmonary artery and resulted from a failure of systemic venous development. Pulmonary venous anatomy could only be demonstrated by pulmonary arterial wedge angiographic studies. This experience emphasizes that complete unilateral pulmonary venous obstruction may occur in an asymptomatic patient and underlines the importance of investigating pulmonary venous anatomy in any patient with gross inequality of the distribution of pulmonary blood flow.

Accessory flaplike tissue causing ventricular outflow obstruction.

In three cases, two in children and one in a young adult, ventricular outflow obstruction was caused by a valvelike flap of accessory endocardial tissue. The angiocardiographic feature was that of a narrow radiolucent, crescent-shaped or linear filling defect corresponding to the site of obstruction. Resection of the accessory tissue was performed in each case at the time of correction of associated conditions. In one case (a woman 20 years of age) the obstructing membrane was in the outflow tract of the right ventricle, and a ventricular septal defect was associated. In each of the other two cases the outflow tract of the left ventricle was the site of obstruction. In one (a 14-month-old boy), an ostium primum type of atrial septal defect and cleft mitral valve were associated; in the remaining case (a 7-year-old boy) complete transposition and ventricular septal defect were also present. In the latter case a Mustard procedure was performed and was followed by death. Successful results were obtained in the first two patients.

Recurrent myxosarcoma of left atrium.

The surgical treatment of cardiac myxosarcoma is reviewed with emphasis placed on palliative response to radiation therapy. A case of primary myxosarcoma of the left atrium in a 16-year-old girl is presented. The tumor was surgically removed in October, 1967. Recurrently myxosarcoma was removed in August, 1968, at which time involvement of the pulmonary veins and the pericardium was noted. Subsequent to postoperative radiation therapy, the patient remained symptom-free for more than three years. Death occurred 4 1/2 years after the original operation from local and systemic recurrence of the tumor.

Pulmonary arteriopexy to relieve tracheobronchial compression by dilated pulmonary arteries.

Adequate treatment of pulmonary artery compression of the tracheobronchial tree requires a high index of suspicion for the diagnosis, precise localization of the sites of airway compromise by bronchoscopy, and accurate identification of the anatomy of the obstructing vascular structures. Surgical correction of this vascular anomaly to relieve airway compression is necessary in many infants and should be performed promptly. Pulmonary artery plication, arteriopexy, or aneurysmorrhaphy is well tolerated and can be dramatically successful in improving airway patency.

Tracheobronchial compression in acyanotic congenital heart disease.

Children with acyanotic congenital heart disease frequently develop respiratory difficulties such as atelectasis, pneumonia, or infantile lobar emphysema. In some cases, the cause of the respiratory difficulty is compression of the tracheobronchial tree by hypertensive dilated pulmonary arteries, since this type of heart disease frequently demonstrates large left-to-right intracardiac shunts. Sites of predilection for compression include the left main bronchus, the left upper lobe bronchus, the junction of the right bronchus intermedius and right middle lobe bronchus, and the left side of the distal trachea. Cardiac anomalies which predispose to this type of compression include ventricular septal defect, patent ductus arteriosus, interruption of the aortic arch, and tetralogy of Fallot. Pulmonary arteriopexy may relieve the tracheobronchial compression.

Anisodamine increases blood flow to the retina-choroid and protects retinal and pancreatic cells against lipid peroxidation.

This study investigated the effect of anisodamine (2 and 5 mg/kg i.v.) on ocular and systemic blood flow distribution in awake lambs using the radioactive microsphere technique. In separate in vitro studies, the effects of anisodamine (at final concentrations of 0.01 to 2.5 mg/ml) were determined on arachidonic acid, alloxan and ultraviolet radiation-induced lipid peroxidation of isolated retinal cells from rabbits and on alloxan-induced lipid peroxidation of hamster pancreatic islet beta cells. Malondialdehyde production was used as an index of lipid peroxidation and measured by the thiobarbituric acid method. Anisodamine preferentially increased blood flow and oxygen delivery to the retina-choroid and iris-ciliary body of the eye by 50-100%. Anisodamine significantly attenuated lipid peroxidation in retinal cells induced by ultraviolet radiation, alloxan and arachidonic acid by 17-50% and protected pancreatic beta cells against alloxan-induced lipid peroxidation. These properties may, in part, account for the beneficial effect of anisodamine in certain patients with diabetes.