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Biomedical subjects

W W Pinsky

Publications and source records attributed to W W Pinsky.

51 records · Page 3Linked to original sources
PubMed1979

Dosage of digoxin in premature infants.

The pharmacokinetics and pharmacodynamics of digoxin in premature infants was studied. During maintenance therapy, after a total digitalizing dose of 30 microgram/kg, the measured digoxin level was related inversely to body weight at birth and to estimated gestational age. The serum digoxin levels found in the immature and smaller infants were two to three times the values usually reported to be toxic in older children. Based on these findings, a second group of premature infants was digitalized with 20 microgram/kg; in this group, the serum digoxin levels were below the toxic range, irrespective of gestational age or birth weight. The cardiac effects of digoxin, i.e., shortened left ventricular pre-ejection period and ejection time as determined by echocardiography, were similar in the two groups. For both groups, the half-life of digoxin in the serum was twice that reported for term infants and children. Since digitalis effect is obtained with lower dose and serum concentration, we recommend that this dose be used in premature infants.

Birth Weight↗
PubMed1979

Permanent changes of ventricular contractility and compliance in chronic volume overload.

Left ventricular volume overload (LVVO) has been created in 18 dogs by anastomosing a Dacron conduit between the infrarenal abdominal aorta and inferior vena cava. The dogs previously were instrumented so that in the awake state LV pressure, systemic arterial pressure, LV dP/dt, myocardial segment length and excursion, and coronary and renal artery velocities could be monitored. The animals were stressed with separate infusions of alpha-adrenergic and beta-adrenergic agonists. Both at rest and with stress, over a 12-wk period, preejection, ejection, and contractility indices decreased. Left ventricular compliance decreased as exemplified by the increased ratio of end-diastolic pressure to end-diastolic length. The shunt was ablated in 7 dogs, and monitoring in conjuction with alpha- and beta-adrenergic stress foan additional 12 wk demonstrated an initial improvement in the previous indices. However, the amelioration plateaued and values similar to the control state were not attained. This suggests that potentially permanent alterations in ventricular function and compliance have occurred.

Adrenergic alpha-Agonists↗
PubMed1979

Myocardial depression after elective ischemic arrest. Subcellular biochemistry and prevention.

The hemodynamic and cardiac biochemical effects of global ischemic arrest during cardiopulmonary bypass (CPB) were studied in 54 animals and compared to seven animals without ischemic arrest. Ischemic arrest alone reduced the first derivative of left ventricular force of contraction (LV dF/dt) to 52 percent of control 10 minutes after resuming function and to 64 percent after 1 hour of reperfusion. Cardiac output was depressed to 52 percent of control after 10 minutes of reperfusion, and to 74 percent of control after 60 minutes of reperfusion. In six animals, moderate hypothermia (26 degrees C.) resulted in no protection of cardiac function from ischemic arrest, whereas profound hypothermia to 18 degrees C. resulted in values of LV dF/dt and cardiac output nearly equivalent to the CPB control group (no arrest). A continuous infusion of a hyperkalemic hypothermic solution slightly improved the degree of protection over hypothermia alone. The sarcoplasmic reticulum (SR) isolated from hearts which had undergone 60 minutes of ischemic arrest bound significantly less calcium when the isolation was done after 10 minutes of reperfusion as well as when it was done after 60 minutes of reperfusion. The time to spontaneous release of calcium from the SR also was significantly longer. Moderate hypothermia did not result in improved SR function, whereas deep hypothermia induced by local cooling or by hypothermic potassium infusion retained SR function at normal levels. Oxidative phosphorylation of mitochondria isolated after 60 minutes of reperfusion was also depressed. The mitochondrial respiration rate after normothermic ischemic arrest was 155 natoms of oxygen per minutes versus 237 natoms for the hypothermic hyperkalemic group. Respiratory control index was 5.5 for the normothermic group versus 9.4 for the hypothermic group. It is concluded that hypothermia, whether effected by surface cooling or by hypothermic potassium infusion, allowed full recovery of hemodynamic and biochemical functions within 1 hour of reperfusion.

Animals↗
PubMed1978

The absent pulmonary valve syndrome. Considerations of management.

The absent pulmonary valve syndrome consists of a severely hypoplastic pulmonary valve with anular stenosis, aneurysmal dilatation of the main pulmonary artery with one or both pulmonary branches also dilated, and a ventricular septal defect. From 1955 to 1975, 15 patients were seen at Texas Children's Hospital with this syndrome. Although anatomically similar to tetralogy of Fallot, the most significant symptoms during early infancy were secondary to bronchial compression resulting from the dilated pulmonary arteries and enlarged left atrium. Intracardiac repair performed on two infants at four months of age failed to ameliorate the respiratory symptoms and both died. Seven patients from 2.3 to 16 years of age were operated upon, with one late postoperative death. Five other patients have not yet received surgical intervention. We recommend vigorous continual respiratory therapy for for infants and small children and intracardiac repair in older children since repair in infancy does not relieve respiratory symptoms. We do not recommend a prosthetic pulmonary valve unless there is persistently elevated main pulmonary artery pressure.

Emphysema↗
PubMed1978

Anomalous origin of left coronary artery from the pulmonary artery with ventricular septal defect.

Only two cases have been reported previously of the association of ventricular septal defect (VSD) with anomalous origin of the left coronary artery (ALCA) arising from the pulmonary artery. The purpose of this paper is to present two additional cases, to describe the pathophysiology, and to emphasize how the clinical course of this combination of defects differs from that of isolated ALCA. Patients with both of these anomalies present in infancy with manifestations only of a large left-right ventricular shunt and pulmonary hypertension. Initially the ALCA is well perfused from the high pressure in the pulmonary artery. In these instances in which the pulmonary artery pressure subsequently decreased because of spontaneous reduction in size of the VSD, the left coronary arterial system became less well perfused. Because of this decreased perfusion in association with the left ventricular myocardial stress initially caused by volume overload, myocardial ischemia and ultimately infarction occurred. Early identification and repair of the anatomic abnormality could prevent irreversible myocardial damage.

Coronary Vessel Anomalies↗
PubMed1978

Anomalous origin of circumflex coronary artery from right pulmonary artery: report of a rare anomaly.

A heretofore unreported anomaly of the coronary arteries in which a large circumflex artery arises from the pulmonary artery is described. The circumflex coronary artery in an 8-year-old girl was filled in a retrograde fashion via collaterals from a dominant left anterior descending coronary artery, and the right coronary artery was small and nondominant. Successful surgical correction of this defect was performed by use of total cardiopulmonary bypass and cardioplegic arrest. The orifice of the anomalous vessel and detached from the right pulmonary artery and implanted into the posterolateral aspect of the ascending aorta. Cardiopulmonary bypass with cardioplegic arrest is recommended for reconstruction of coronary arterial anomalies with abnormal sites of origin.

Aorta↗
PubMed1976

Subclavian-coronary artery anastomosis in infancy for the Bland-White-Garland syndrome: a three-year and five-year follow-up.

Two infants, 4 months and 8 months of age, with anomalous origin of the left coronary artery, underwent direct anastomosis of the left subclavian artery to the left coronary artery. In the patient operated upon at 4 months of age, the anastomosis proved to be patent by angiographic study 3 years postoperatively. However, in the patient operated upon at 8 months of age, the study 5 years postoperatively revaled clinically unsuspected occlusion at the anastomosis site. After operation, both patients symptomatically improved. The heart size decreased on radiograms, the left ventricular ejection fraction improved, and the electrocardiographic abnormality resolved to a great extent. Since the preferred treatment for this abnormality and the ideal age for operation are yet to be established, long-term angiographic follow-up of all such surgically treated patients is needed. An advantage of the subclavian-coronary artery anastomosis is its applicability in the infant.

Angiocardiography↗
PubMedDate not supplied

Cardiopulmonary performance during exercise in patients with repaired tetralogy of Fallot with absent pulmonary valve.

In patients with tetralogy of Fallot and absent pulmonary valve, the dilated pulmonary arteries sometimes result in bronchial compression and pulmonary symptoms due to airway obstruction, recurrent pulmonary infection, and development of bronchiectasis. After complete intracardiac repair, residual pulmonary disease may be expected to result in impaired cardiopulmonary performance during exercise. To assess this hypothesis, nine patients with tetralogy of Fallot and absent pulmonary valve underwent exercise testing and were compared to 38 patients with tetralogy of Fallot repaired using a transannular patch. All patients were exercised to maximum volition using a 1 minute incremental treadmill protocol with monitoring of pulmonary functions and expired gases. Maximal heart rate, maximal oxygen consumption, oxygen consumption at anaerobic threshold, and maximal respiratory exchange ratio were similar for the two groups. There was no significant difference for ventilation and gas exchange parameters at rest or at maximal exercise, and values for both groups were below the predicted normal for healthy subjects. Breathing reserve, however, did tend to be somewhat lower in the group with tetralogy of Fallot with absent pulmonary valve. In summary, despite significant preoperative symptoms, cardiopulmonary performance during exercise in patients with tetralogy of Fallot and absent pulmonary valve is similar to patients with tetralogy of Fallot repaired with a transannular patch.

Adolescent↗
PubMedDate not supplied

False-negative findings in pericardial effusion using M-mode echocardiography.

M-mode echocardiography in a 3-year-old patient with suspected pericardial effusion was negative for the presence of an effusion. A subsequent 2-dimensional echocardiogram demonstrated a large effusion lateral to the right atrium and right ventricle. The reasons for the false-negative M-mode echocardiogram and a discussion of the literature are presented.

Child, Preschool↗
PubMedDate not supplied

Atrial natriuretic factor and sympathetic nervous output in response to volume shifts in the immature canine circulation.

This study evaluated the immature circulation's response to acute shifts in intravascular volume with respect to atrial natriuretic factor and plasma catecholamines. Serial measurements were performed on thirteen beagle puppies during volume expansion with a saline and albumin solution followed by volume contraction with furosemide. Atrial natriuretic factor correlated with right (r = .73, p less than 0.001) and left (r = .62, p less than 0.001) atrial pressures and increased to much greater levels than previously reported for mature animals. Simultaneously, 10 puppies had a progressive decrease in plasma norepinephrine over the 60-minute infusion (p less than 0.05) while two puppies demonstrated a marked increase between the 30- and 60-minute samples. Furosemide increased urine output and reversed the hormonal changes caused by volume expansion. Thus a greatly augmented output of atrial natriuretic factor occurs in the immature canine circulation in response to increased atrial and pulmonary pressures, while sympathetic output remains unchanged or falls with increasing intravascular volume until a critical decrease in cardiac output triggers a catecholamine surge.

Aging↗