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Biomedical subjects

C S Kleinman

Publications and source records attributed to C S Kleinman.

At least 91 records · Page 5Linked to original sources

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.

Anti-Arrhythmia Agents↗

Ultrasonic evaluation of the fetal human heart.

The fetal echocardiogram has demonstrated its utility for visualizing the fetal human heart during the second and third trimesters of pregnancy. The potential utility of the technique for establishing accurate anatomic diagnoses of major congenital cardiac malformations has been established. These data have been utilized to counsel prospective parents and formulate management plans for the remainder of pregnancy and the intrapartum and immediate postpartum periods. Diagnoses have been established as early as the 16th to 18th week of gestation, raising in some cases the moral and ethical question of termination of pregnancy.

Arrhythmias, Cardiac↗

Prenatal diagnosis of a human pseudoacardiac anomaly.

A unique case is presented of dichorionic-diamnionic twins, one of which contained a primitive heart arrested at an early stage of development and which resembled in many other respects a classic case of acardia. Lack of vascular anastomoses, the dichorionic nature of the twins, and ultrasonic evidence of independent heart rates suggest that the primary pathogenesis in acardia may be cardiac dysmorphogenesis rather than reversal of vascular flow. Ultrasonography and fetal echocardiography proved useful in delineating many of the features of the amorphous twin before delivery.

Abnormalities, Multiple↗

Fetal echocardiography. II. The diagnosis and significance of a pericardial effusion in the fetus using real-time--directed M-mode ultrasound.

By means of real-time--directed M-mode ultrasound, the hearts of normal and abnormal fetuses were evaluated for evidence of a pericardial effusion. Because of its limited potential space, the pericardial sac appears to become distended with fluid prior to ultrasound evidence of ascites, pleural effusions, or soft tissue edema. Fetal echocardiography, therefore, appears to be useful in the assessment of fetuses at risk for developing hydrops.

Adult↗

Fetal echocardiography. I. Normal anatomy as determined by real-time--directed M-mode ultrasound.

With current ultrasound technology, it is now possible to obtain accurate real-time and M-mode information from the fetal heart with the use of real-time--directed M-mode echocardiography. With this method, the M-mode cursor is directed to the fetal cardiac structures of interest while the image is obtained in the real-time mode. This enables M-mode echocardiograms to be obtained in an accurate, reproducible manner. The most useful imaging planes for cardiac evaluation are the long axis four-chamber plane, the short axis plane through the atrioventricular valves, and the short axis plane through the aortic and pulmonic outflow tracts. Once normal fetal cardiac anatomy is understood, structural defects and/or alterations of function can be evaluated accurately antenatally.

Echocardiography↗

Fetal echocardiography for evaluation of in utero congestive heart failure.

Thirteen fetuses with nonimmune hydrops (22 to 39 weeks of gestation) were evaluated with two-dimensional and M-mode echocardiography. Ten fetuses had cardiovascular abnormalities resulting in heart failure, and three had noncardiac causes of hydrops. In three cases, hydrops was caused by supraventricular tachycardia. One of these fetuses responded to cardioversion at birth, another responded to transplacental digoxin therapy, and the third died with atrial flutter and high-grade atrioventricular block before delivery. There were no cases of "idiopathic" hydrops. Our results show that fetal echocardiography is useful in determining cardiac causes of in utero heart failure resulting in hydrops fetalis. The fetal echocardiogram may also be used in monitoring transplacental therapy of heart failure.

Adolescent↗

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.

Blood Circulation↗

Patch reconstruction of the right ventricular outflow tract with pulmonary valve insertion.

Although pulmonary regurgitation is generally well tolerated, reconstruction of the right ventricular outflow tract and insertion of a pulmonary valve are indicated in some patients. This procedure was performed in 12 patients, ages 1 1/2-17 years (mean 10 years). Seven had tetralogy of Fallot; of these, one underwent primary repair with Glenn shunt takedown and six underwent repeat operations after previous repairs. Of these six, the major indication for reoperation was right ventricular outflow tract obstruction in four, tricuspid and pulmonary regurgitation in one, and a residual ventricular septal defect and patent shunt in one. Three had absent pulmonary valve syndrome and two had pulmonary atresia. There were no early complications or deaths in this series during a mean follow-up of 28 months. Repeat cardiac catheterization was performed in eight patients and revealed that the preoperative right ventricular-pulmonary artery gradient was reduced from 58 +/- 25 mm Hg to 11.6 +/- 7 mm Hg at rest postoperatively and was located at the level of the valve. This gradient increased with exercise or isoproterenol infusion to 31 +/- 9 mm Hg. Our experience suggests that right ventricular outflow tract reconstruction with porcine valve insertion can be safely performed with good hemodynamic results. This technique allows insertion of a larger porcine valve and avoids kinking and compression of a conduit behind the sternum.

Adolescent↗

Prenatal echocardiography.

Congenital cardiac defects are not common, but their serious consequences make early detection and treatment essential. In developing a set of workable criteria for selective screening of serious abnormalities, the authors used commercially available ultrasound equipment in more than 500 high-risk pregnancies. Possible future applications include elucidation of causes of fetal cardiac defects.

Echocardiography↗

A radiographic and echocardiographic approach to cyanotic congenital heart disease.

An updated, systematic approach to the diagnosis of cyanosis in the infant or child has been presented. It involves the use of clinical data (to establish the presence of cyanosis), radiographic information (to assess lung parenchyma, pulmonary vascularity, and certain key, border-forming, cardiac structures), and M-mode and cross-sectional echocardiographic data (the source of detailed intracardiac anatomic information). Specific radiographic and echocardiographic features of the 10 most common cyanotic congenital heart lesions have been presented. Using this approach, one should be able to diagnose accurately the cyanotic infant or child. Further planning for cardiac catheterization and angiocardiography can then be accomplished with an informed and rational point of view.

Adolescent↗

Echocardiographic studies of the human fetus: prenatal diagnosis of congenital heart disease and cardiac dysrhythmias.

During obstetrical ultrasound examinations, 200 M-mode and 35 real-time two-dimensional echocardiographic studies were performed on 180 fetuses of high-risk pregnancies. Fetal gestational ages ranged from 18 to 41 weeks. M-mode "sweeps" demonstrating mitral- and septal-aortic fibrous continuity were obtained in 115 studies. Paradoxic septal motion in 50 fetuses suggested relarive right ventricular volume loading. Congenital cardiac malformations were accurately diagnosed in a 34-week fetus with pulmonary atresia and hypoplastic right ventricle and in a 28-week fetus with a univentricular heart. Congenital complete atrioventricular block was diagnosed in a 28-week fetus and atrial flutter with variable atrioventricular block was diagnosed in a 38-week fetus. The use of echocardiographic studies to evaluate cardiac structure and rhythm in utero assists in counseling prospective parents and in planning postnatal management for their offspring.

Arrhythmias, Cardiac↗

Autoregulation of cerebral blood flow in fetuses with congenital heart disease: the brain sparing effect.

Fetuses with congenital heart disease (CHD) have circulatory abnormalities that may compromise cerebral oxygen delivery. We believe that some CHD fetuses with decreased cerebral oxygen supply have autoregulation of blood flow that enhances cerebral perfusion (brain sparing). We hypothesize that cerebral autoregulation occurs in CHD fetuses, and the degree of autoregulation is dependent on the specific CHD and correlates with intrauterine head circumferences. CHD fetuses were compared to normal fetuses. Data included cardiac diagnosis, cerebral and umbilical artery Doppler, head circumference, weight, and gestational age. The cerebral-to-placental resistance ratio (CPR) was assessed as a measure of cerebral autoregulation. CPR = cerebral/umbilical resistance index (RI) and RI = systolic-diastolic/systolic velocity (normal CPR > 1). CPR > 1 was found in 95% of normal vs 44% of CHD fetuses. The incidence of CPR < 1 was greatest in hypoplastic left or right heart fetuses. Compared to normal, cerebral RI was decreased in CHD fetuses. The CPR vs gestational age relationship, and the relationship among weight, head circumference, and CPR differed across normal and CHD fetuses. Fetuses > 2 kg with CHD and a CPR < 1 had smaller head circumferences than normal. Brain sparing occurs in CHD fetuses. Fetuses with single ventricular physiology are most affected. Inadequate cerebral flow in CHD fetuses, despite autoregulation, may alter brain growth.

Blood Flow Velocity↗