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Biomedical subjects

R V Lucas

Publications and source records attributed to R V Lucas.

At least 37 records · Page 2Linked to original sources
PubMed1983

Floppy mitral valve and ventricular septal defect: an anatomic study.

Eighteen percent of heart specimens with isolated ventricular septal defect also had a floppy mitral valve. There was no statistical difference in the incidence of floppy mitral valve in the three age groups considered (less than 1 year, 1 to 16 years and 17 to 91 years). In no patient was a floppy mitral valve considered to be the cause of death. Complications of floppy mitral valve (ruptured chordae tendineae, bacterial endocarditis, mitral regurgitation and fibrin deposits at the mitral valve-left atrial angle) occurred at approximately the same frequency as that reported in autopsy studies of isolated floppy mitral valve. In the specimens with floppy mitral valve and ventricular septal defect, 63% also had floppiness of the tricuspid valve, 16% of the pulmonary valve and 5% of the aortic valve. The anatomic basis for floppy mitral valve was considered to be spongiosal invasion and disruption of the fibrosa of the valve leaflet. In this study, spongiosal invasion of the fibrosa was fully developed by 3 months of age and there was no evidence that the incidence or severity of spongiosal invasion increased between the ages of 3 months and 88 years. These data suggest that the floppy mitral valve is a congenital lesion that reaches full anatomic expression in infancy. No evidence was found that ventricular septal defect and floppy mitral valve share a common etiology.

Adolescent↗
PubMed1983

Cardiac complications in children with systemic lupus erythematosus.

Two patients had cardiac complications of childhood onset systemic lupus erythematosus (SLE). A 14-year-old boy had extramural and intramural coronary arteritis demonstrated by angiography. The signs and symptoms of myocardial ischemia improved dramatically when corticosteroid dose and immunosuppression were increased. A 20-year-old woman had had SLE for 18 years and had functionally significant mitral stenosis and regurgitation. Calcification of the mitral valve was observed on echocardiography. Corticosteroid treatment has controlled the renal manifestations of SLE. Cardiac complications of SLE are now a significant clinical problems.

Adolescent↗
PubMed1982

Progressive cardiac conduction defect and cardiomyopathy in siblings with syncope.

Three siblings evaluated for syncope were found to have left bundle-branch block. Progression to complete heart block occurred in all. Pacemaker implantation eliminated syncopal epidoses in each case. Echocardiographic manifestations of cardiomyopathy were present in each child despite normal roentgenographic heart size. Careful family study identified no other affected members with conduction defects. These children area believed to represent a form of familial cardiomyopathy in which clinical manifestations of cardiac conduction system disease predominate.

Bundle-Branch Block↗
PubMed1982

Aortic valvular atresia. Associated cardiovascular anomalies.

The pathological anatomy of 109 specimens of aortic valvular atresia was reviewed for the purpose of identifying the cardiovascular anomalies associated with that condition. We found the most commonly associated anomaly to be coarctation of the aorta, which was present in 71 percent of our cases and judged to be hemodynamic significance in one-third of the involved cases. Other associated anomalies, in order of decreasing frequency, were mitral atresia, anomalous systemic and pulmonary venous connections, abnormalities of branching of the aortic arch, and ventricular septal defect. The study demonstrated that aortic atresia is associated with a significant incidence of other cardiovascular anomalies. Additional anomalies, when present, may complicate emerging attempts at surgical correction of this condition.

Aorta↗
PubMed1982

Rest and exercise hemodynamics after the Fontan procedure.

Sixteen consecutive patients (12 with tricuspid atresia) underwent a Fontan procedure, with no operative deaths. There were three late deaths. Eleven of the survivors were electively catheterized 4-25 months postoperatively. Rest and exercise hemodynamics were measured in five patients, and resting hemodynamics alone were measured in three. All exercised patients were New York Heart Association class I Cardiac index was low at rest (2.3 +/- 0.61/min/m2) and during exercise (4.9 +/- 1.11/min/m2) due to a low stroke index both at rest (28 ml) and exercise (35 ml). Accordingly, mixed venous oxygen saturations were decreased (66% at rest and 31% during exercise). These values are significantly lower than those at rest and during exercise from 23 control patients of similar age and size. Heart rates, pulmonary vascular resistances, and left ventricular filling pressures appeared normal both at rest and during exercise. High right atrial pressure at rest (15 mm Hg) was associated with minimal conduit gradient (2 mm Hg). However, exercise increased the mean conduit gradient to 8 mm Hg, demonstrating significant functional conduit obstruction. As expected, the cardiovascular response to exercise is abnormal after the Fontan procedure, even in asymptomatic patients. This abnormal response may be exacerbated by conduit obstruction, and conduit obstruction may not be apparent during resting studies.

Adolescent↗
PubMed1981

Changes in regional myocardial blood flow and variable development of hypertrophy after aortic banding in puppies.

Supravalvar aortic banding was performed in 6 to 12 week puppies. Sixteen animals were studied 7.3 (3.5 to 10) months later, closed-chested under morphine-chloralose, catheters being positioned in the great vessels and heart, including the left atrium for microsphere injection. Compared with 11 controls, eight dogs developed biventricular hypertrophy, four isolated left ventricular hypertrophy and four had no hypertrophy. The left ventricular systolic pressure was similar (P greater than 0.05) in these 3 banded groups (mean, 30 +/- 2 [SEM] kPa, [222 +/- 16 mmHg], n = 16). The left ventricle was divided into three coronal slices with approximately 59 samples being taken from subendocardial, midwall, and subepicardial layers and additional samples from the atria and right ventricle for regional myocardial flow measurement. As left ventricular hypertrophy increased, the subendocardial/subepicardial flow ratio decreased (r = -0.8). Heterogeneity of left ventricular regional myocardial flow, including a base-to-apex decrease in flow, present in controls, was markedly reduced in the banded dogs. Analysis of variance was found to be the most sensitive test for detecting left ventricular perfusion abnormalities since in banded dogs without hypertrophy, total and regional subendocardial/subepicardial flow ratios were not significantly different from control values, whereas the subendocardial circumferential flow pattern determined by analysis of variance was significantly different from control in these dogs (P less than 0.05).

Animals↗
PubMed1981

Postoperative hemodynamics in children with polytetrafluoroethylene shunts.

Twenty-two consecutive infants and children underwent aortopulmonary shunt operations with polytetrafluoroethylene grafts. Thirteen infants younger than 6 months of age (group I) received 14 grafts (4--5 mm in diameter, 0.5--2.5 cm long). Two shunts became obstructed, including kinking in the single 2.5-cm graft. Eight of the nine long-term survivors had pulmonary artery pressures measured a mean of 14 months postoperatively. In all infants, pulmonary resistance was normal and mean pulmonary artery pressure was less than or equal to 20 mm Hg, except in the infant with a 5-mm graft. In nine children 7 months to 15 years of age (group 2), the rate of graft occlusion was higher (five of nine). There was no evidence of pulmonary artery distortion secondary to shunt placement in either group. On late follow-up, blood hemoglobins were less than 20 g% as late as 30 months of age; acceptable palliation may be expected until at least 2 years of age and 12 kg in weight are reached. We conclude that short, 4-mm-diameter polytetrafluoroethylene grafts provide good palliation in infants with cyanotic congenital heart disease, with minimal risks from pulmonary hypertension or pulmonary artery distortion. Such grafts are less successful in older children, and should only be considered when other forms of surgical relief are not feasible.

Adolescent↗
PubMed1980

Myocardial perfusion abnormalities in carbon monoxide poisoned dogs.

The effect of carbon monoxide inhalation on the regional distribution of right and left ventricular myocardial blood flow was studied in 12 closed-chest anesthetized dogs. Dogs were exposed to a nonhypoxic mixture of oxygen (21-40%) and carbon monoxide (1.5-2.0%) for 10 min. Myocardial blood flow was measured (15 micron radionuclide-labeled spheres) during control conditions, and 10 and 60 min following discontinuation of carbon monoxide corresponding to carboxyhemoglobin levels (COHb) of 41.6 +/- 2.8 and 26.5 +/- 1.6% (mean +/- SE), respectively. At COHb level of 26.5%, right and left ventricular blood flows were increased to approximately 1.8-1.9 times the control values (1.06 +/- 0.10 vs 0.64 +/- 0.08 mL/min per gram and 1.72 +/- 0.12 vs. 0.91 +/- 0.07 mL/min per gram, respectively, P less than 0.002). At a COHb level of 41.6%, both right and left ventricular vascular beds were maximally or near maximally dilated as right ventricular and left ventricular myocardial blood flow values were increased approximately fivefold. The right and left ventricular subendocardial-subepicardial flow ratios were reduced at both COHb levels (P less than 0.05). Thus, in addition to the global myocardial hypoxia that occurs following elevation of the COHb level, relative subendocardial underperfusion is a component of carbon monoxide poisoning in the intact dog.

Animals↗
PubMed1980

Accessory flaplike tissue causing ventricular outflow obstruction.

In three cases, two in children and one in a young adult, ventricular outflow obstruction was caused by a valvelike flap of accessory endocardial tissue. The angiocardiographic feature was that of a narrow radiolucent, crescent-shaped or linear filling defect corresponding to the site of obstruction. Resection of the accessory tissue was performed in each case at the time of correction of associated conditions. In one case (a woman 20 years of age) the obstructing membrane was in the outflow tract of the right ventricle, and a ventricular septal defect was associated. In each of the other two cases the outflow tract of the left ventricle was the site of obstruction. In one (a 14-month-old boy), an ostium primum type of atrial septal defect and cleft mitral valve were associated; in the remaining case (a 7-year-old boy) complete transposition and ventricular septal defect were also present. In the latter case a Mustard procedure was performed and was followed by death. Successful results were obtained in the first two patients.

Adult↗
PubMed1979

Postoperative haemodynamics in tetralogy of Fallot. A study of 132 children.

Our study was undertaken to determine the type, incidence, and functional significance of residual anomalies in patients who have undergone corrective repair for tetralogy of Fallot. We reviewed data from cardiac catheterisations performed on 132 survivors. A significant residual ventricular septal defect was present in only 12 patients. Resting right ventricular systolic pressure was less than 80 mmHg in 100 patients and ranged from 80 to 150 mmHg in the other 32 patients. Thirty-five patients were studied both at rest and during supine exercise. In most patients, the relation between oxygen consumption and cardiac output was normal during exercise. The stroke index and right ventricular end-diastolic pressure at rest and on exercise were compared in 34 patients. Seventeen showed a normal response to exercise. In the other 17 patients, right ventricular end-diastolic pressure rose on exercise; in 5 of these the stroke index fell during exercise, indicating abnormal myocardial response. Our studies indicate the frequent occurrence of residual abnormalities, even in patients who appear asymptomatic, after total correction of tetralogy of Fallot.

Adolescent↗
PubMed1978

Silent unilateral pulmonary venous obstruction. Occurrence after surgical correction of transposition of the great arteries.

An 11-year-old girl was found to have completely obstructed left pulmonary veins eight years following corrective surgery for transposition of the great arteries. The patient was acyanotic and asymptomatic. Retrograde flow of arterial blood from the affected left lung accounted for an angiographic appearance that mimicked occlusion of the left pulmonary artery and resulted from a failure of systemic venous development. Pulmonary venous anatomy could only be demonstrated by pulmonary arterial wedge angiographic studies. This experience emphasizes that complete unilateral pulmonary venous obstruction may occur in an asymptomatic patient and underlines the importance of investigating pulmonary venous anatomy in any patient with gross inequality of the distribution of pulmonary blood flow.

Blood Pressure↗
PubMed1975

Cor triatriatum: study of 20 cases.

Twenty cases of cor triatriatum are reported. The diagnosis was confirmed by necropsy in 16 cases and at the time of operation in 4. The lesion occurred as an isolated anomaly in 7 cases; in 13, other associated cardiac anomalies were present. Three anatomic types of cor triatriatum were identified in the cases studied at necropsy: diaphragmatic (10 cases), hourglass (3) and tubular (3). The diaphragmatic type was also present in all four cases in which the diagnosis was confirmed at operation. Associated anomalies were found in five cases of the diaphragmatic type and in each case of the hourglass of tubular types. In isolated cor triatriatum the clinical findings were characteristic of pulmonary venous and arterial hypertension. In two cases, one with a communication between the right atrium and the accessory left atrial chamber and one with partial anomalous pulmonary venous connection associated with cor triatriatum, the clinical findings suggested a large left to right shunt with pulmonary arterial hypertension. The clinical findings varied in the cases with associated anomalies, and it was difficult to determine the cause of disturbance of the circulation.

Adolescent↗
PubMed1975

Patent ductus arteriosus complicating respiratory distress syndrome.

PDA was diagnosed in 76 (19%) of 396 patients with RDS. Evidence of excessive pulmonary blood flow and CHF developed in 15 (20%). CHF was not recognized prior to 10 days of age in any patient. All 15 with CHF were initially managed medically. Seven improved; three died of other causes. Five patients who failed medical management were surgically treated; all survived operation, but only two were improved.

Autopsy↗
PubMed1975

Recurrent myxosarcoma of left atrium.

The surgical treatment of cardiac myxosarcoma is reviewed with emphasis placed on palliative response to radiation therapy. A case of primary myxosarcoma of the left atrium in a 16-year-old girl is presented. The tumor was surgically removed in October, 1967. Recurrently myxosarcoma was removed in August, 1968, at which time involvement of the pulmonary veins and the pericardium was noted. Subsequent to postoperative radiation therapy, the patient remained symptom-free for more than three years. Death occurred 4 1/2 years after the original operation from local and systemic recurrence of the tumor.

Adolescent↗