Michael Tynan

Transcatheter embolization in the treatment of coronary artery fistulas

Seven patients with a coronary artery fistula underwent percutaneous transcatheter embolization (five were male and two female; the age range was 2 to 67 years [median 17]). Three patients were symptomatic. The left to right shunt ranged from 1.6 to 2.6:1. In six patients, the fistula was an isolated congenital anomaly; in one, it was acquired. The fistula arose from branches of the left (n = 5) and right (n = 2) coronary arteries and drained to the right ventricle (n = 2), right atrium (n = 2), coronary sinus (n = 1), pulmonary artery (n = 1) and a bronchial artery (n = 1). Different embolization techniques were used to occlude eight feeding arteries. The embolization materials included a detachable balloon (n = 3), coaxial embolization with platinum microcoils (n = 3), a combination of detachable balloon and microcoil (n = 1) and standard steel coils (n = 1). Satisfactory occlusion was achieved in six patients. In one case, the valve of the detachable balloon was damaged, resulting in early balloon deflation and a residual fistula. There were no associated complications in any patient. Follow-up investigation by Doppler ultrasound or coronary angiography 4 months to 4 years later showed that permanent occlusion was achieved in all six patients in whom embolization was initially successful. Transcatheter embolization should be considered the treatment of choice for coronary artery fistulas.

Nomenclature and classification of congenital heart disease.

At present there is no universally accepted nomenclature for congenital cardiac malformations. Much of the controversy results from failure to distinguish the structural connections of the heart from the morphology and spatial relations of its components. The confusion is compounded by an abundance of individual definitions, many of them speculative. The present article proposes a totally descriptive nomenclature. It describes in turn the connections of the cardiac segments, their morphology, their relations, and additional anomalies in any segment. Each step in the segmental approach is discrete. The overall effect is to force a succinct and comprehensive description of any cardiac malformation, no matter how complex.

Balloon dilatation of the aortic valve in the fetus: a report of two cases.

Because they had irreversible damage to the left ventricular myocardium none of 12 patients with critical aortic stenosis diagnosed prenatally survived after postnatal treatment. This experience prompted three attempts at intrauterine balloon dilatation of the aortic valve in two fetuses with this condition. On each attempt the balloon catheter was successfully delivered to the left ventricle. In the first fetus the aortic valve was not crossed and the fetus died the next day. In the second fetus the balloon was correctly positioned across the aortic valve and inflated in the valve ring. After delivery, a further balloon angioplasty was performed; this relieved the stenosis but the patient died five weeks later from persisting left ventricular dysfunction related to endocardial fibroelastosis. Balloon angioplasty is feasible in fetal life but the prognosis depends on the ability of the relief of stenosis to limit, prevent, or allow regression of left ventricular damage before delivery.

Prenatal screening for congenital heart disease

Routine ultrasound examination of the fetus is already established in most obstetric units in Britain. A simple method was devised to evaluate one section of the fetal heart systematically. Examination of this section, the four chamber view, may readily be incorporated into routine obstetric screening. Severe cardiac abnormalities detectable in this view occur in two per 1000 pregnancies. For six years the department of paediatric cardiology at Guys Hospital, London, served as a referral centre for fetal echocardiography. As teaching became more widespread an increasing proportion of cases of cardiac anomaly were referred because the obstetrician suspected abnormality on examination of the four chamber view. Currently 80% of detected abnormalities are referred for this reason. Further extension and organisation of teaching might result in most severe cardiac malformations being detected in early prenatal life.

M-mode echocardiography in the developing human fetus.

The M-mode echocardiogram can be obtained in the developing human fetus from around the 16th week of gestation until term. Errors in interpretation of the M-mode echocardiogram can be avoided by concurrent two dimensional fetal cardiac examination. The pattern of motion of the mitral, tricuspid, aortic, and pulmonary valves and ventricular wall motion can be studied. Motion of the foramen ovale flap, which is characteristic in fetal life, can also be observed. Using the M-mode tracing, measurement data for six variables were made and growth charts constructed. The variables recorded were septal and left ventricular wall thickness, right and left ventricular internal dimension in diastole, aortic root dimension, and left atrial internal dimension. The measurements were made in normal pregnancies where the fetal heart was structurally normal. Confidence limits for each measurement were derived for gestational ages between 16 and 39 weeks.

Sequential segmental analysis of congenital heart disease.

1 Department of Paediatrics, Cardiothoracic Institute, Brompton Hospital, London, England; 2 Department of Pathology, Wilhelmina Gasthuis, University of Amsterdam, The Netherlands; 3 Department of Cardiology, Hospital for Sick Children, Toronto, Canada; 4 Thoracic Unit, Hospital for Sick Children, London, England; 5 Department of Pediatric Cardiology, Centro Ramon y Cajal, Madrid, Spain; 6 Institute of Child Health, University of Liverpool, Royal Liverpool Childrens Hospital, Liverpool, England; and 7 Department of Paediatrics, Guys Hospital, London, England

Evaluation of fetal arrhythmias by echocardiography.

The normal fetal heart shows variation in rate and rhythm. Twenty three cases that fell outside the normal patterns of variation of heart rate and rhythm were evaluated by echocardiography. Ten showed atrial or ventricular extrasystoles and these were not associated with perinatal morbidity or mortality. Seven cases showed complete heart block, two in association with structural cardiac abnormality. Six cases were of supraventricular tachycardia, five of which were successfully treated and one was delivered prematurely. It was possible to diagnose accurately the type of arrhythmia using the M-mode echocardiogram to compare the relation between atrial and ventricular contraction. Cross-sectional echocardiography allowed identification of associated structural abnormalities. Recognition that an arrhythmia is present and appropriate prenatal treatment if this is indicated will avoid unnecessary operative or premature deliveries.

Fetal complete heart block.

In a series of over 6000 patients referred for fetal echocardiography during an eight year period, 37 fetuses were found to have complete heart block. There were 16 cases of isolated heart block and 21 cases associated with structural heart disease. All mothers of fetuses with isolated complete heart block had evidence of circulating syndrome Sjögren A antibody (Ro). Only one mother had clinical evidence of connective tissue disease. In the 21 cases associated with structural heart disease there were 17 cases of atrioventricular septal defect, one case of secundum atrial and perimembranous ventricular septal defects, two cases of tetralogy of Fallot, and one case of pulmonary stenosis. All fetuses with atrioventricular septal defects and complete heart block had left atrial isomerism. Additional abnormalities of the great arteries were often found in this group; these were double outlet right ventricle, transposition of the great arteries, pulmonary atresia, coarctation of aorta, and stenosis of the pulmonary or aortic valves. Intrauterine congestive heart failure was a feature of four cases in the group with isolated complete heart block and 11 cases of the group with associated structural heart disease. The outcome in the fetuses with isolated complete heart block was better than in those with heart disease: 12 of the 16 fetuses are alive, two of them have a pacemaker. But only three of the group of 21 fetuses with cardiac malformation are alive, and two of them have a pacemaker.

Doppler echocardiographic evaluation of the normal human fetal heart.

Pulsed wave Doppler estimates of blood flow velocity were made across the mitral, tricuspid, aortic, and pulmonary valves in a series of 120 normal fetuses (gestational age 16-36 weeks). In 36 of these the data were obtained in all four sites. The maximum and mean velocities were calculated for each valve and these values were plotted against gestational age. There was little change in these values throughout pregnancy. The orifice dimensions of the valves were measured by cross sectional echocardiography. At all ages the tricuspid orifice was larger than the mitral and the pulmonary orifice was larger than the aortic. The blood flow values for each valve were derived from the product of the mean velocity and the valve orifice dimensions. The output of the right ventricle was usually, but not always, greater than that of the left ventricle. Combined ventricular output increased from approximately 50 ml/min at 18 weeks to 1200 ml/min at term. Despite limitations in the accuracy of the technique these results form a useful basis for the analysis of blood flow in the normal fetus and for the interpretation of abnormal Doppler findings in prenatal life.

The natural history of the hypoplastic left heart syndrome

In a fetus, examined initially at 22 weeks gestation, we identified the echocardiographic features of a dilated, hypertrophied and poorly contracting left ventricle. The presumptive diagnosis was critical aortic stenosis. Subsequent scans at 32 weeks and at term showed that the left ventricle had not grown since the first study such that the left ventricle had developed the appearance of a hypoplastic and densely echogenic chamber. Thus, in some forms of the hypoplastic left heart syndrome, the left ventricle can be of normal size or even dilated in early pregnancy. This may mean that the more subtle sign of poor left ventricular contraction could be overlooked in a routine four-chamber view obstetric scan.