Myocardial ischemia in infants. Its role in three common congenital cardiac anomalies

Cerebral arteriovenous malformation in neonates. The role of myocardial ischemia

Ischemic myocardial damage was identified as a complicating feature in the clinical course of 12 newborn infants who died in congestive failure with cerebral arteriovenous malformation. Electrocardiograms of 11 patients showed signs of chamber hypertrophy and T wave and ST segment features of varying degree compatible with ischemia or infarction. Histological evidence of myocardial necrosis or infarction was detected in seven of the ten infants from whom autopsy material was still available.

Development and regression of increased ventricular mass

This report deals with increased cardiac mass in the light of the following variables: normal ventricular growth (embryo, fetus, neonate and child), the response to work loads (hemodynamic stress) and hypoxia, the cell responses of hyperplasia (increase in cell number), hypertrophy (increase in cell size) and the type of cell (muscle or connective tissue), the age or maturity of the myocardium at the time the hemodynamic or hypoxic stress is imposed, and the biochemistry, ultrastructure and functional morphology (modeling) of the ventricles in response to volume or pressure overload. The desirable physiologic adaptations to work loads are characterized, and the transition from physiologic to pathologic states is examined, comparing and contrasting increased ventricular mass in patients and in trained athletes. Regression of increased ventricular mass is then discussed, first at the cell level (hypertrophy/hyperplasia; muscle cell/connective tissue cell), then at the organ level. The requirements for maintaining or establishing normal ventricular function after removal of overload are reviewed, together with such variables as the type and duration of preoperative hemodynamic stress, the right versus the left ventricle and the relative rates of contractile protein synthesis and degradation.

Surgical management of coarctation of aorta with ventricular septal defect. Multivariate analysis

Optimal management of coarctation with ventricular septal defect is difficult. Should one treat the coarctation, the ventricular septal defect, or both? This dilemma was investigated by reviewing 39 successive patients, aged less than 4 months, undergoing coarctation repair without pulmonary artery banding. Twelve hospital deaths occurred. Ventricular septal defect size was graded "blind" according to preoperative angiocardiographic and haemodynamic findings. Of 14 patients classified as having a large ventricular septal defect, necropsy and operative findings in eight showed defects 7 to 12 mm in diameter. Factors associated univariately with significantly increased mortality were young age, raised atrial and ventricular end-diastolic pressures, low weight, high admission blood urea, preoperative ventilation, and a large ventricular septal defect. All but the last two were also closely associated with each other. A jack-knifed discriminant function based upon ventricular septal defect size, blood urea, pulmonary venous oxygen content, and inferior caval oxygen saturation correctly predicted outcome in 78.9% of patients. Combinations of these four giving a probability greater than 0.9 of survival were rare with blood ureas above 8 mmol/litre. Raised blood urea was associated with low descending aortic pressure and subsequent dialysis. Only patients with a large ventricular septal defect stand to benefit from pulmonary artery banding at initial operation. Preoperative treatment to increase renal blood flow (prostaglandins, dopamine) may improve overall survival.

Sarcomere relaxation and ischaemic myocardial injury

Material from hearts known to have had recent myocardial infarction and biopsies of dog hearts subjected to an experimental procedure producing ischaemic injury, were examined by polarising microscopy. A technique which depends on the relaxation of sarcomeres on ischaemic areas of myocardia was used and assessed for its value in the diagnosis of early myocardial infarction. We found no statistically significant difference in sarcomere lengths in ischaemic and control heart muscle in man. The dog study failed to show changes with a study period of up to 2 h after ligation. We do not support the suggestion that sarcomere length is a useful measurement in the demonstration of early myocardial ischaemic injury in man.

Ventricular septal defect due to septal infarction after repair of tetralogy of fallot

A case is reported of ventricular septal defect resulting from septal infarction following repair of a tetralogy of Fallot. The infarct probably resulted from division of a septal coronary artery during resection of the hypertrophied infundibulum. The superficial position of the septal artery on the right side of the septum in tetralogy makes it surprising that this complication has not been previously reported.

Infantile cardiomyopathy with histiocytoid change in cardiac muscle cells. Report of six patients

Clinical and pathologic findings are presented in 14 patients (six newly reported, eight described previously), all children ranging in age from 6 to 24 months, with a clinicopathologic syndrome termed "infantile cardiomyopathy with histiocytoid change in cardiac muscle cells." This syndrome is manifested clinically by severe, eventually fatal cardiac arrhythmias, and is characterized pathologically by cardiac hypertrophy and by a distinctive type of focal degeneration of the muscle cells, which lose their myofibrils, undergo marked mitochondrial hyperplasia, become rounded in shape and enlarged, and resemble histiocytes. Evidence is presented to support the conclusions that these manifestations are those of a cardiomyopathy, that cardiac hypertrophy precedes the onset of the clinical features, that the focal degeneration is likely to be a cause rather than a consequence of the arrhythmias, and that the latter develop only in the late stages of the disorder. The etiology of this cardiomyopathy remains unclear.

Ultrastructure of crista supraventricularis muscle in patients with congenital heart diseases associated with right ventricular outflow tract obstruction

Ultrastructural studies were made of operatively resected crista supraventricularis muscle in 59 patients with congenital heart diseases, or whom 54 had obstruction to right ventricular outflow. Relationships of anatomic diagnosis, age, peripheral arterial oxygen saturation (PAO2), peak right ventricular systolic pressure gradient and right ventricular end-diastolic pressure (RVEDP) to hypertrophic changes, abnormalities of cellular and myofibrillar orientation, and degenerative alterations were determined. Changes directly related to hypertrophy were: cell diameters greater than 20 mu, irregular cell shape, lobulated nuclei, multiple intercalated discs, dilated T tubules, abnormal Z bands, and increased numbers of ribosomes. Abnormalities of cellular or myofibrillar orientation were focal in distribution and occurred in 12 patients, most of whom had elevated RVEDP, decreased PAO2, markedly enlarged cells, and interstitial fibrosis. Interstitial fibrosis was prominent in 19 patients and was associated with cellular hypertrophy, elevation of RVEDP, and increased age of the patients. Degenerative changes (myofibrillar lysis, abnormally small mitochondria, myelin figure formation, and proliferation of sarcoplasmic reticulum in cardiac muscle cells ocurred in six patients and correlated with increased age, decreased PAO2, and elevated RVEDP. Mitochondria containing glycogen deposits were present in 17 patients, most of whom had decreased PAO2. The variability of morphologic manifestations of chronic cardiac hypertrophy and the relationships of hypertrophic changes to orientation abnormalities and degenerative alterations are discussed.

Pediatric congenital cardiac becomes a postoperative adult. The changing population of congenital heart disease

The following commentary on the changing population of congenital heart disease will deal with: incidence and survival patterns—an overview; effects of diagnostic and surgical interventions on survival patterns—changing population; ultimate goals and aspirations—what are we trying to accomplish?; types of surgical intervention—desirability of primary anatomic repair in infancy; and the problem of residua—setting the stage for future research.

Postductal coarctation of aorta causing myocardial ischaemia and heart failure in first week of life

Two infants with isolated postductal coarctation of the aorta who developed heart failure in the first week of life are reported. Possible factors contributing to symptomatology from this anomaly in the newborn period are discussed. In these two infants there was some evidence that left ventricular myocardial necrosis was an important factor.

Total anomalous pulmonary venous drainage in infants. I. Clinical and hemodynamic findings, methods, and results of operation in 37 cases

Thirty-seven infants with total anomalous pulmonary venous drainage have been operated upon at The Hospital for Sick Children, Great Ormond Street, London, with 13 survivors. Most were rapidly deteriorating when admitted. Cardiac catheterization, angiography, and operation were urgently undertaken to achieve the maximum salvage. Physical examination, plain radiography, and electrocardiography were insufficient for accurate diagnosis. Survival was closely related to the degree of pulmonary hypertension, which was dependent on the type of anomalous venous drainage and the presence of pulmonary venous obstruction. The prognosis was good for patients over 3 months of age, especially those without pulmonary venous obstruction, provided that they arrived in the hospital in reasonable condition. The best survival rate, nine of 11 cases, was achieved in those patients between 3 and 12 months of age with supracardiac drainage.

Arrhythmias in children with pulmonary stenosis

Arrhythmias have been recorded in association with congenital pulmonary stenosis. Of six patients who had arrhythmias before operation, anatomical conduction defects were present in two and the arrhythmias persisted after operation. In four, the arrhythmic episodes have not been recorded after operation. No specific causative factors were evident in the pre-operative group. Acute and often fatal arrhythmias have occurred in the early post-operative period. High risk patients were those with cyanosis, high right ventricular pressure (in excess of 175 mm. Hg), and gross right ventricular hypertrophy. There is evidence to suggest that these arrhythmias develop in association with myocardial ischaemia.

Myocardial infarction in a neonate

Extensive myocardial infarction developed in a neonate, apparently as a result of paradoxical embolism from the ductus venosus. It is suggested that in instances of myocardial infarction in the very young this vessel should be examined as a possible source of the embolus.