Biomedical subjects
Publications and source records attributed to M J Tyrrell.
Isolated anomalous drainage of the right superior caval vein to the left atrium is a very rare cause of cyanosis in the newborn. Herein, the cross-sectional echocardiography and colour Doppler findings of this malformation are described.
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An 11-year-old girl who underwent Mustard's operation for complete transposition of the great arteries in infancy, developed Mobitz type II second-degree AV block 8 1/2 years later. A transvenous, active fixation left ventricular lead was inserted and connected to a rate responsive pacemaker. Two years later the lead dislodged due to the child's growth. A new active fixation electrode was positioned in the left ventricle below the pulmonary valve, leaving an electrode loop in the ventricle. Such an approach may prevent lead dislodgement due to growth after intraatrial repair for transposition of the great arteries, but regular radiological or echocardiographic follow-up of lead position is recommended in these patients.
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We report on the occurrence of cerebrovascular accidents as a possible complication of balloon angioplasty in children. The first patient underwent balloon angioplasty for aortic stenosis and subsequently developed a right temporoparietal infarct in the vascular territory of the right middle cerebral artery. The second patient developed a right temporoparietal infarct also in the vascular territory of the right middle cerebral artery following balloon angioplasty of native coarctation of the aorta. This experience suggests that, in addition to the previously reported complications of balloon angioplasty, the occurrence of a potential cerebrovascular accident must be considered in the risk-benefit analysis of this procedure.
Two children with left ventricular outflow tract obstruction due to myocardial hypertrophy received oral disopyramide as a negative inotrope. Both showed rapid improvement in clinical signs and by echo Doppler examination. Nearly complete abolition of severe left ventricular outflow tract obstruction was documented in each case. This experience may prompt further application of disopyramide as a therapeutic agent to relieve dynamic muscular subaortic obstruction in children.
A 9-year-old boy with an endocardial cushion defect who had skull erosion as well as widening of the diploe is described. This was accompanied by thickening of the tables, "hair-on-end" striations in the skull, and cortical thinning and medullary cavity expansion in the femora. The skull erosion is attributed to venous distension and increased blood volume. The finding of skull erosion in cyanotic congenital heart disease has not been reported before.
Colour Doppler flow imaging (CD) is a well-established method of assessing valvular and congenital disease of the heart. The technique has proven useful intraoperatively in patients undergoing valve repair or replacement or intracardiac reconstruction. In 21 patients with various cardiac anomalies, colour Doppler flow imaging was used intraoperatively, before cardiac cannulation and again after cardiopulmonary bypass. Previously undisclosed features were demonstrated preoperatively in two patients and important residual defects after cardiopulmonary bypass in three others. Adequacy of valve replacement was confirmed in four patients and small leaks in ventricular septal defect patches were shown in another three. The procedure facilitated repair of complex cardiac fistulas in two patients. There were no apparent complications from CD. As intracardiac repairs become more complex, the role of intraoperative CD will expand.
A two-year-old child dying of pulmonary hypertension and cor pulmonale secondary to bronchopulmonary dysplasia, was demonstrated to have reactive pulmonary hypertension in response to 100% oxygen and isoproterenol infusion. In an attempt to find an oral medication to maintain pulmonary vasodilatation, experimental trials were done using hydralazine, salbutamol, nifedipine and diltiazem. Cardiac index, pulmonary and systemic vascular resistances and intrapulmonary shunts were monitored during the trials. Hydralazine, salbutamol and nifedipine were ineffective. Diltiazem 2.0 mg given every 6 h resulted in a profound and sustained decrease in pulmonary pressures and resistance, and a reversal of the cor pulmonale.
Nine children and 1 adolescent with anomalous left coronary artery from the pulmonary trunk (ALCA) were studied between 1970 and 1982. Serial angiographic and hemodynamic data are compared with the clinical course. Four patients had separate conus coronary arteries with a major contribution to collateral flow. Eight patients survived various surgical procedures with 1 late death, 1 awaits operation, and 1 died in infancy. The authors' data show a significant potential for improvement in left ventricular function as shown by an increase in LV ejection fraction on medical therapy alone (5/6 patients), including all 4 with separate conus coronary arteries. The authors conclude that medical treatment alone may be indicated for a time in selected patients with ALCA, and a subgroup with a separate conus coronary artery may have a more favorable natural history.
Mitral valve replacement was performed in two critically ill neonates with severe mitral stenosis and regurgitation. Both patients had coexisting severe aortic stenosis previously treated by transventricular aortic valve dilatation. Preoperative echocardiography showed a mitral annulus measuring between 11 and 12 mm in diameter--too small for any of the commercially available free-standing valve prostheses. Accordingly, the porcine valve from a commercially available 12-mm external-valved conduit was removed and sutured into position. The function of the valve was satisfactory in both cases and cardiopulmonary bypass was discontinued easily with a good cardiac output established in both. Both patients died--one at 20 h and one 36 h after surgery. In each case, the immediate cause of death was acute bleeding secondary to preexisting hepatic failure and depletion of coagulation factors. At autopsy, both prostheses had been correctly placed and were competent. Left ventricular outflow tract obstruction secondary to strut imposition was not evident. Both patients were very ill preoperatively. Although neither patient survived mitral valve replacement, we were encouraged by the relative hemodynamic improvement in the immediate postoperative period. We believe that prosthetic valve replacement could become a viable therapy for the neonate with severe mitral valve abnormalities.
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The thoracoomphalopagus conjoined twins comprise 75% of all conjoined twins. In the assessment of the organ systems of the twins, the cardiovascular system is important since union of this system in the twins has occurred in 75% of the cases. Of the five cases reported here, two had separate hearts and vessels with a common pericardium only. Two twins were joined at the right atrial level. The fifth pair were connected at both atrial and ventricular levels. It has been suggested that the presence of two separate QRS complexes in the ECG indicates complete separation of the two hearts. Case 4 shows that even in the presence of atrial union, the existence of an atrioventricular block in one twin may produce a very slow heart rate, while the other twin may have a normal rate that will not influence the ventricular rate of the other. In our experience, angiocardiography has been the most useful diagnostic procedure.
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The diagnosis, angiographic evaluation and surgical treatment by aortocoronary vein bypass are described in a 3(1/2)-year-old girl with anomalous origin of the left coronary artery from the pulmonary artery. The anomaly had resulted in cardiac dilatation, diminished left ventricular contractility, an aneurysm of the left ventricular free wall and mitral regurgitation.At the postoperative cardiac catheterization the graft was demonstrated to be patent, but a significant proportion of the flow to the left coronary artery was derived from anastomotic connections with the right coronary artery. The most striking evidence of improvement was obtained from the left ventricular volume studies which showed that the end systoiic volume had decreased from 85 to 49 ml./m.(2) with an increase in ejection fraction from 0.39 to 0.62, suggesting enhanced left ventricular contractility after surgery.The patient continues to do well and is free from symptoms.
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