Norman S. Talner

Fetal echocardiography: A tool for evaluation of in utero cardiac arrhythmias and monitoring of in utero therapy: Analysis of 71 patients*

Fetal echocardiographic studies were performed in 71 patients referred for evaluation of cardiac rhythm disturbances at 24 to 40 weeks gestation. After 2-dimensional echocardiographic study of cardiac structure was performed, M-mode echocardiograms were analyzed for measurement of cardiac rate, atrioventricular contraction sequence, atrioventricular valve motion, and duration of postectopic pauses. Arrhythmias were diagnosed in 59 patients. In 34 patients with isolated ectopic beats, the arrhythmia resolved during later pregnancy in 26 or within the first 5 days of life in 8. Six patients had mild sinus bradycardia and 8 had frequent sinus pauses; all 14 had resolution of the arrhythmia during pregnancy. Sustained arrhythmias occurred in 11 patients. Deaths occurred when there was associated fetal congestive heart failure (hydrops fetalis), structural heart disease, or both. M-mode echocardiography diagnosed supraventricular tachycardia in 3 fetuses. The echocardiogram was used thereafter for monitoring transplacental digoxin therapy.

Vasomotor responses in the hind limbs of foetal and new-born lambs to asphyxia and aortic chemoreceptor stimulation.

1. Hind limb blood flow was measured in lambs of from 91 days gestation (delivered by Caesarean section) to 1 month after birth (term is about 147 days), under chloralose anaesthesia. Vascular resistance/100 g wet wt. increased progressively with age. There was reflex femoral vascular tone from the earliest age studied, as shown by vasodilatation on cutting the sciatic nerve.

Early Extubation Following Pediatric Cardiothoracic Operation: A Viable Alternative

A protocol is presented that facilitates early extubation following pediatric cardiothoracic operations. A total of 197 consecutive patients were managed according to this protocol. Fifty percent of the patients were less than 3 years old. Cardiopulmonary bypass was required in 113 (57%) of the surgical procedures. Extubation immediately following the surgical procedure was accomplished in 142 (72%) of the patients. Pulmonary complications occurred in 8 of these 142 patients (6%) and in 10 (18%) of the 55 patients requiring postoperative mechanical ventilation. Of the patients having early extubation, 5 (4%) required reintubation. One death in this group was unrelated to pulmonary function. There were 16 deaths among the 55 patients managed with mechanical ventilation. Carefully conducted early extubation provided specific advantages over routine postoperative mechanical ventilation. Modern techniques of anesthesia and surgical repair of congenital heart disease can decrease the requirement for postoperative mechanical ventilation and the potential for related complications.

Physiologic Effects of Increasing Hemoglobin Concentration in Left-to-Right Shunting in Infants with Ventricular Septal Defects

We studied the acute effects of increasing hemoglobin concentration and hematocrit on the pulmonary and systemic circulations of nine infants with large left-to-right shunts. After isovolemic exchange transfusion, which was designed to raise hemoglobin but keep blood volume constant, a consistent rise in systemic and pulmonary vascular resistances occurred. This rise was comparable to those previously found in isolated circulations showing a linear relation between hematocrit and loge of the vascular resistance. These changes in resistance were accompanied by decreases in systemic and pulmonary blood flow and a marked decline in left-to-right shunt. Despite the decrease in systemic blood flow, there was no decline in systemic oxygen transport, and there may have been a marginal decrease in left ventricular stroke work. These observations help explain why the newborn with a large ventricular septal defect and a high hemoglobin concentration does not have clinical signs of a large left-to-right shunt, and also suggest that the postnatal decline in hematocrit has a substantial role in the normal fall in pulmonary vascular resistance after birth.

Repair of Aortic Coarctation in the First Three Months of Life: Immediate and Long-Term Results

The optimum surgical procedure for treatment of coarctation of the aorta in the neonatal period remains controversial. To assess immediate and long-term results of using primarily the subclavian flap angioplasty procedure (SFA), we reviewed our initial 5-year experience. The average follow-up was 6 years. From 1977 to 1981, 25 infants under 3 months of age (1 to 86 days, mean 21) required emergency surgery for repair of coarctation of the aorta. Three groups of patients were identified. Group I consisted of 10 patients with or without patent ductus arteriosus. In group II, 10 patients had coarctation association with one or multiple ventricular septal defects (VSDs) without other congenital defects. In group III, 5 patients had coarctation associated with more complex congenital heart lesions. Twenty-three SFAs and two patch aortoplasties were performed. No patient with isolated VSD was banded. All patients except one in group III with an associated atrioventricular canal survived initial hospitalizations. Four late deaths occurred, all in patients with associated complex heart defects. There were three recurrent coarctations requiring surgery or balloon angioplasty (12%)--one in each group, with a total rate of 0.77 recurrences per 100 patient-months. SFA for coarctation in the neonatal period is a safe and effective operation with a low initial mortality (4%, 0-19%, 70% confidence limits) well tolerated in this group of ill patients. Long-term outcome is primarily related to the presence of associated complex congenital defects. Infants with VSD associated with coarctation did not require pulmonary artery banding unless primary intracardiac repair was not feasible.(ABSTRACT TRUNCATED AT 250 WORDS)

EXPERIMENTAL CARDIAC HYPERTROPHY: CONCENTRATIONS OF RNA IN THE VENTRICLES.

Banding of the aorta or pulmonary artery in puppies produces a selectively increased concentration of RNA in the ventricle with the increased hemodynamic load as compared to the opposite side or to normal hearts. The increase in concentration of RNA following distortion of the myocardial cell may represent a fundamental response of growth and the system described mayserve as a useful model for its study.

Echocardiographic assessment of the severity of aortic stenosis in children and adolescents.

The magnitude of ventricular hypertrophy in response to afterloading is determined by wall stress, with wall thickness increasing in proportion to ventricular load until systolic wall stress is normalized. With use of echocardiographic measurements of left ventricular end-systolic wall thickness (Ws) and cavity transverse dimension (Ds), the pressure constant k was calculated in 16 patients without left heart obstruction according to the formula k = P-Ds/Ws. The mean value for k was 225 +/- 6.7 (standard deviation) mm Hg. From this value, left ventricular pressure was estimated in 13 patients with aortic stenosis aged 4 to 17 years using the formula P = k-Ws/Ds. No subject had evidence of cardiac failure. Peak systolic aortic pressure difference (delta P) was calculated by subtracting cuff-measured brachial arterial peak systolic pressure from the estimated left ventricular pressure. Excellent correlation was obtained between the estimated delta P and that found at cardiac catheterization (r = 0.89). In two patients, echocardiographic data predicted significant obstruction in the presence of normal electrocardiographic, vectorcardiographic and vector lead tracings. Echocardiography offers a noninvasive method for estimating the severity of aortic stenosis, in the absence of myocardial failure; it appears to be more sensitive than other currently employed techniques.

Myocardial damage following transthoracic direct current countershock in newborn piglets

SummaryThe effect of transthoracic direct current countershock on the myocardium of 21 newborn piglets was studied. Myocardial damage was quantified by measuring the myocardial uptake of technetium-99m pyrophosphate injected 24 hours after countershock.Substantial myocardial damage occurred in animals given greater than 150 joules/kg but not at lower energy doses. Damage occurred in both ventricular free walls, but more frequently in the right ventricle. The epicardial half of the myocardium was more severely affected than the endocardial half. The relationship between myocardial damage and total countershock energy dose was well modeled by an exponential function.Transthoracic direct current countershock appears unlikely to cause myocardial damage in newborn piglets unless greatly elevated energy doses are employed.

CIRCULATORY BYPASS OF THE RIGHT SIDE OF THE HEART. VI. SHUNT BETWEEN SUPERIOR VENA CAVA AND DISTAL RIGHT PULMONARY ARTERY; REPORT OF CLINICAL APPLICATION IN THIRTY-EIGHT CASES.

IT HAS been more than 10 years since our first successful anastomosis of the side of the superior vena cava to the distal end of the right pulmonary artery in a dog. The dog is still alive, in fact is robust and leading an active life in a domestic environment. In the 10 years following, several hundred experimental anastomoses have been performed. Results of these have been reported recently.2 From this experimental work it has become evident that partial bypass with the superior vena cava is preferable to that with the inferior vena cava. Total right heart bypass has never resulted in prolonged survival in animals and probably is not practical in man. More than 6 years have elapsed since our first successful superior vena cava-pulmonary artery anastomosis in a patient.3 Since operation, the patient, a 7-year-old boy with transposition of the great vessels and pulmonary stenosis, has been free from complaints, except for a mild cyanosis increasing on vigorous exercise, and has been leading a normal life. The cava-pulmonary artery anastomosis has been used in 3S patients in our clinic. All patients had severe malformation of the right side of the heart for which no established corrective procedure was available. It is the purpose of this present paper to report the postoperative results and show our progress with the clinical application of the procedure, not to offer a definitive evaluation that must

Accessory Mitral Valve Tissue Causing Left Ventricular Outflow Obstruction (Two-Dimensional Echocardiographic Diagnosis and Surgical Approach)

Accessory mitral valve tissue, a rare cause of left ventricular outflow tract obstruction, can be difficult to diagnose preoperatively and confusing even at surgery. The reported case illustrates how preoperative evaluation can be made using two-dimensional echocardiography combined with Doppler flow analysis. The intraoperative technique for removing the accessory tissue without causing damage to the native mitral valve is discussed.