Abraham M. Rudolph

The natural history of ventricular septal defects in infancy

Abstract Sixty-two infants with ventricular septal defects were first catheterized under 1 year of age and followed up for one to five years; 40 were recatheterized. Thirty-six infants were born in the Bronx Municipal Hospital Center or Lincoln Hospital (local group). These patients were unselected, in that the decision to catheterize them was based only on the clinical diagnosis of a ventricular septal defect and not on an assessment of its size or the presence of symptoms. As far as we know, these infants include most if not all of the children born with ventricular septal defects in these hospitals during the period of study. With this assumption, the incidence of ventricular septal defects per 1,000 live births was 0.94 for full term infants, 4.51 for premature infants, and 1.35 for the whole group. Twenty-six other infants were referred from other hospitals or doctors (referred group), and, compared to the local group, they had larger defects, were more often in congestive heart failure and were more often catheterized after 6 months of age. In the whole series, 31 of 62 had congestive heart failure. This began before 6 months of age in all and occurred much earlier in premature than in full term infants. In the local group, spontaneous functional closure of the ventricular septal defect took place in 13 of 36 (36%); this was proved by recatheterization in 10 and autopsy in 1. Marked decrease in size of the defect took place in another 10 (28%). In the referred group (26 cases) there were 2 (8%) spontaneous closures and 7 (27%) reductions in defect size. For the whole series, 52 per cent of the patients had defects which were known to have closed or become smaller; 32 per cent were doing well clinically (most were not recatheterized so that some of these defects might have become smaller); and only 16 per cent of the infants were seriously affected by their lesions. Complete closure occurred between 7 and 12 months of age, most often when the defect was small, but it could occur with large defects. Decrease in defect size, however, occurred as frequently with large as with small defects, and was found in many children with congestive heart failure and pulmonary arterial hypertension. The 10 infants with large ventricular septal defects who did not do well included 4 who had pulmonary arterial banding for severe, uncontrolled congestive heart failure (2 died); 1 premature baby who died at 6 weeks of age with severe congestive heart failure; and 5 with a very high pulmonary vascular resistance. One of these 5 had a high pulmonary vascular resistance when 1 month old, and this did not change significantly at 5 and 13 months of age. The other 4, however, had low pulmonary vascular resistance when first catheterized at 3, 6, 6 and 11 months of age, respectively, and significant rises of resistance to pathologic levels when recatheterized at 9, 15, 26 and 40 months of age, respectively. This suggests that a rise in pulmonary vascular resistance in infancy is not rare when the ventricular septal defect is big and that, even in these children, the pulmonary vascular resistance does not usually persist at the high level present at birth but first falls post natally to normal levels before rising. These 5 infants all had large left to right shunts, high left atrial pressures and marked pulmonary arterial hypertension. In 3 out of the 4 whose pulmonary vascular resistances rose after the first catheterization, there were no distinctive clinical indications of this rise which was detected only at recatheterization. The other child had increasing right ventricular hypertrophy on the electrocardiogram. From these findings we suggest that, since in infancy spontaneous closure or reduction in size of the ventricular septal defect is so common, most infants should be treated conservatively in the hope that spontaneous improvement will occur. If the defect is very big and the child is in severe congestive heart failure which cannot be well controlled, then surgical closure of the defect or banding of the pulmonary artery should be done. If, however, the defect is big but congestive heart failure can be controlled medically, then the infant should be followed up with the hope that spontaneous improvement will occur. Whether clinical improvement occurs or not, the infant should be recatheterized six to nine months after the initial catheterization to determine if a rise in pulmonary vascular resistance has occurred; if it has then surgery should be advised.

Effects of angiographic contrast media on cardiac function

Abstract Alterations in cardiovascular dynamics after intravenous administration of angiographic media suggested that these effects might be due to the high sodium concentration of these agents. Experiments were performed on dog heart-lung preparations and intact dogs. Stroke volume, ventricular, atrial and arterial pressures, and serum osmolarity were measured. Responses were recorded to (1) conventional angiographic agents containing 2,000 to 2,500 milliosmols/ liter, (2) angiographic agents containing the same base but no sodium, (3) hypertonic glucose solutions and (4) hypertonic sodium solutions of equivalent osmolar concentrations. After injection of hyperosmolar sodium chloride or sodium-containing angiographic agents into the aortic root or left ventricle, left ventricular end-diastolic, left atrial and pulmonary arterial pressures increased and myocardial contractile force decreased for 10 to 15 minutes. Injection of hypertonic glucose solutions or angiographic agents containing no sodium produced no significant cardiovascular changes. Total serum osmolarity was similar after administration of each agent. These studies demonstrate that administration of hypertonic sodium solutions produces significant transient alterations in cardiovascular function and that it is one mechanism for changes observed with sodium-containing angiographic agents.

Hemodynamic basis for clinical manifestations of patent ductus arteriosus

Abstract A prosthesis made of silicone rubber has been developed for insertion between the aorta and pulmonary artery of dogs. The size of the communication can be controlled in the closed-chest, unanesthetized animal. The hemodynamic effects of complete acute opening and closing of the shunt have been studied in 35 dogs. The basic hemodynamic changes are related to a decrease in systemic vascular resistance, an increase in pulmonary blood flow, and direct transmission of aortic pressure to the pulmonary artery. When the shunt is opened, there is an immediate decrease in aortic and left ventricular systolic pressure, a rise in pulmonary arterial, left atrial, and left ventricular end-diastolic pressure, an increased stroke volume, and an increased heart rate. A systolic gradient between the left ventricle and the aorta frequently develops when the shunt is opened, and is probably related to the high stroke volume which occurs. The pulmonary arterial pressure tracing shows a triphasic contour when the shunt is open; left ventricular ejection is slightly prolonged, but the right ventricular ejection period is markedly reduced. This explains the paradoxical splitting of the second sound, which is also observed in some patients with patent ductus arteriosus. Systemic blood flow is moderately reduced, but pulmonary blood flow is increased about twofold. Pulmonary diastolic blood flow is markedly increased, so that peripheral pulmonary blood flow becomes much more continuous. During diastole, blood flows perferentially into the low-resistance shunt and pulmonary vascular system, and a marked backflow during diastole occurs in the descending aorta distal to the shunt. The animals varied in their ability to tolerate the shunt. After the initial responses, some dogs showed a gradual increase in aortic stroke volume and left ventricular systolic pressure, and tolerated the shunt well. Others developed a “failure response” that was characterized by a continuing fall in aortic stroke volume and left ventricular systolic pressure, with a rise in left ventricular end-diastolic, left atrial, and pulmonary arterial pressures.

Epinephrine in the Treatment of Cardiac Failure due to Shunts

A technic for establishing a controlledaorto-pulmonary shunt in closed-chest, spontaneously breathing dogs has been developed. Wide opening of the shunt is well tolerated in some animals, but others develop acute left ventricular failure. Administration of sympathetic blocking agents may induce a failure response on opening the shunt, in an animal that previously tolerated it well.Epinephrine infusion during the control period consistently prevented cardiac failure when the shunt was widely opened. Epinephrine was also capable of reversing the failure, if rapidly infused before left ventricular systolic pressure had dropped to extremely low levels. It was also effective in countering the adverse effects of sympathetic blocking agents. The optimal rate of infusion was found to be 0.5 to 1.5 &mgr;g./Kg./min. of epinephrine hydrochloride.A constant infusion of epinephrine hydrochloride was administered to three infants with large left-to-right shunts who had failed to respond to intensive decongestive measures, and who manifested severe cardiac failure with severe pulmonary edema. Marked clinical improvement resulted, and anesthesia and surgery were well tolerated while the infusion was continued.Epinephrine should be administered with a constant infusion apparatus to avoid induction of ventricular ectopic beats due to overdosage. Its use is reserved, at present, for the management of the desperately sick infant with acute left ventricular failure due to systemic-pulmonary shunts.

Anomalous left coronary artery arising from the pulmonary artery with large left-to-right shunt in infancy

Anomalous origin of the left coronary artery from the pulmonary artery has been separated into the “infantile” type with poor collateral circulation and early death due to myocardial infarction and the “adult” type in which there is well-developed collateral circulation and long survival. That this classification cannot be held too rigidly is demonstrated by the patient described, who developed a myocardial infarct in spite of the presence of a large collateral circulation.

Chapter 15: Complications Occurring in Infants and Children

ous complication occurring before the catheter was inserted into the vascular system, during the course of the procedure, or after the child had been returned to the ward. Frequently, cyanosis developed or a marked increase in existing cyanosis occurred. The actual cause of this syndrome was not always apparent, but several etiologic factors could be identified. Those patients in whom the circulatory and respiratory depression was initiated by a cardiac arrhythmia are not included in this discussion but are presented in the sections on infants and children in the discussion of arrhythmias (Chapter 5).

Arteriotomy and local circulation in children: The value of oscillometry

The effects of arteriotomy on the local circulation were studied in 25 patients at varying intervals following cardiac catheterization. Manual palpation of the peripheral pulses provided only a fair index of the flow through the incised artery, whereas oscillometric examination (a significantly more sensitive method) indicated that arterial flow had been compromised in all patients who had brachial arteriotomies and in 83 per cent of patients who had femoral arteriotomies. Despite signifcant reduction in major arterial flow, examination of the digital pulse indicated that perfusion of the limb was unaltered in these children, probably because adequate collateral circulation had been established. These studies stress the importance of using objective methods for examining the arterial circulation in children, and the need for establishing standard oscillometric indices for the pediatric age group.