A 64-element phased-array echocardiographic transducer mounted on a sliding carriage was used transthoracically in 11 patients with subaortic obstruction caused by various different morphological substrates. The transducer is moved in a plane from the outflow tract to the apex of the heart in steps of 0.5 to 1.3 mm and records a tomographic slice of the heart at each step. Parallel images are recorded at a frame rate of 25–30 images per second and triggered to heart rate and respiration. A complete cardiac cycle is recorded at each level. The images are digitized and stored in the image-processing computer, which reconstructs the anatomic structures of the heart in a three-dimensional format by means of different gray-scales. Good quality echocardiographic pictures were obtained in 10 of the 11 patients and three-dimensional reconstructions were possible in those 10 patients. The technique is able to display the heart in real-time in any desired plane, and in up to five planes simultaneously, without the need to change the position of the transducer on the chest. Thus the best views with which to display the substrate of subaortic stenosis could be selected. The left ventricular outflow tract could also be displayed in a view similiar to the one obtained by the surgeon during operative procedures for resection of the subaortic stenosis through an incision in the aortic root. Image acquisition took three to five minutes, and three-dimensional reconstruction of various cardiac structures took 20–90 minutes. Display of the subaortic area in three-dimensional format may enhance our understanding of cardiac anatomy and identify the different morphological lesions in the left ventricular outflow tract which cause subaortic obstruction.

Coronary angiograms were analyzed in 29 children after heart transplantation. Age at transplantation was one month to 14 years (mean 4.5 years) with follow-up from five months to six years (mean 2.9 years). Immunosuppression was based on cyclosporine and azathioprine; six patients also received maintenance steroids. Coronary angiograms were obtained after giving an intracoronary arterial bolus of nitroglycerin to avoid spasm. Coronary angiograms showed stenoses, luminal irregularities, loss of luminal diameter and obliteration of branches, and one example of myocardial bridging. The review of angiographic recordings in some patients showed a loss of normal motion of coronary arteries which, instead, appeared rigid. No abnormalities were seen in eight patients (28%). Coronary arterial changes were present between six months and four years after transplantation in 15 patients (52%). Isolated loss of normal motion of the coronary arteries was present in six patients (20%). The separate analysis of 15 patients who underwent more than one coronary angiogram showed a progression of lesions in eight cases. Coronary arterial disease is a frequent complication of heart transplantation in children and there is a progression of lesions in a large proportion of patients. Since there is no satisfactory therapy for this complication, heart transplantation should be reserved for children having no other reasonable therapeutic option.

The embryonic heart and vascular bed interact dynamically to support rapid growth of the embryo during cardiovascular development. Pressure-volume relations define ventricular function during alterations in loading conditions. We analyzed these relationships in the embryonic heart in order to define ventricular function and the response of the ventricle and vascular bed to acute changes in preload. We simultaneously measured ventricular pressure and recorded 60 video images per second in n≥6 stage 16, 18 and 21 white Leghorn chick embryos at baseline and during the infusion of 1–2 microliters of physiologic buffer into the venous sinus (sinus venosus). Ventricular tetany was then induced with the topical application of 2 Molar sodium chloride. Video fields were traced for ventricular pressure and epicardial cross-sectional area. Cross-sectional area was converted to volume assuming ellipsoid geometry, and cavity volume was calculated as total volume minus wall volume derived from the tetanized heart. We defined end-diastole at the onset of ventricular contraction and end-systole at maximum pressure/volume ratio. Stroke volume increased linearly with end-diastolic volume. End-diastolic pressure-volume relations were positive and linear, and end-systolic pressure-volume relations were curvilinear downward. Arterial elastance decreased with growth of the embryo and with volume infusion. Pressure-volume loop area, an index of consumption of energy, doubled between the embryonic stages. Thus, embryonic ventricular pressure-volume relations define diastolic and systolic function at rest and in response to altered preload.

Catheter ablation of an accessory atrioventricular pathway using 500 kHz radiofrequency current was attempted in 53 children and young adolescents less than 16 years of age (mean 9.3±4.1 years) who were referred for treatment of symptomatic supraventricular tachycardia. Thirty children had the Wolff-Parkinson-White syndrome and 23 had tachyarrhythmias related to an accessory pathway conducting only in retrograde fashion. Of the latter, seven were found to have the permanent form of junctional reciprocating tachycardia, which had resulted in depressed left ventricular function in four. Ablation of left-sided accessory pathways was usually attempted utilizing an arterial approach to the annulus of the mitral valve, while the venous route to the atrial aspect of the tricuspid valvar annulus was chosen for right-sided accessory connections. To reduce invasiveness and the duration of the procedure, a technique with a solitary catheter was attempted in 20 children with the Wolff-Parkinson-White syndrome, regardless of the anatomical site of the accessory pathway. Ablation of 54 of 56 accessory connections was achieved in 51 patients (96% success) with a median of six applications of radiofrequency current. The sessions were completed within 3.4±2.2 hours, with a median exposure to radiation of 31.1 minutes. During a 10-month period of follow- up, no patient required antiarrhythmic medication, and 51 children (96%) were completely free of any symptoms related to arrhythmias. Left ventricular function returned to normal in the four children with tachycardia-induced cardiomyopathy. Except for a patient with an arterial thrombotic occlusion, no serious complications were encountered. Catheter ablation using radiofrequency current is a highly effective and safe curative approach for treating young patients with supraventricular tachycardias mediated by accessory pathways. The use of fewer catheters of smaller size is feasible and advisable in this cohort of patients.

In order to understand some of the cellular mechanisms of interaction in secondary pulmonary vaso-occlusive disease, we studied 21 lung biopsies from patients with different types of congenital cardiac defects. Their ages ranged from four to 248 months (mean 71.5 months; median 41 months). Changes in the cytoskeleton and extracellular matrix were assessed in the arterial wall. Immunostaining was applied to formalin-fixed, paraffin- embedded tissue, using antibodies to muscle-specific actin, vimentin and fibronectin in supra-optimal dilution. The staining for muscle-specific actin in the medial layer revealed a heterogenous pattern, with areas exhibiting low or absent labelling, reflecting a process of dedifferentiation of the smooth muscle cells in those segments. Within intimal proliferative lesions, the expression of muscle-specific actin was variable, being weak in some lesions and strong in those showing concentrically arranged intimal smooth muscle cells, suggesting a reversion of the migrated cells to the contractile phenotype. The endothelial cells of arteries from cases presenting severe qualitative lesions exhibited strong expression of vimentin, reflecting their heightened regenerative activity and/or their necessity to maintain their shape. The expression of fibronectin was greater in the predominantly cellular lesions of the intima when compared to the fibrotic lesions, indicating the role of that matrix glycoprotein in cellular migration and in replicative processes.

A total of 80 patients, diagnosed by echocardiography as having ventricular septal defect with aortic valvar prolapse, underwent cardiac catheterization and surgery. Echocardiographic and angiographic results were compared with surgical findings. The ventricular septal defects as observed during surgery were found to be doubly committed and subarterial in 49 (61%), muscular outlet in 10 (13%), and perimembranous in 21(26%). The location had been erroneously categorized by echocardiography and angiography in 12 (15%) and in 15 (19%) patients, respectively. Prolapse of the right coronary leaflet of the aortic valve, as documented by echocardiography, was confirmed by angiography in all but two cases. Prolapse of the noncoronary leaflet was detected by both imaging modalities in three patients. Prolapse of the right coronary and noncoronary leaflets was observed at surgery in 49 and three patients, respectively. The mean size of the ventricular septal defect, when measured by echocardiography, was significantly smaller than that found following surgical measurements (3.3±1.3 vs 8.4±3.8 mm, p<0.001). Our study showed that the ventricular septal defect was erroneously classified in the presence of prolapse of the aortic valve in 15% and 19% of our cases by echocardiography and angiography, respectively. The herniated sinus of Valsalva forming the “roof” of the ventricular septal defect probably redirected the jet across the defect to cause the errors in interpretation. Echocardiography, nevertheless, is as reliable as angiography in our hands in the follow-up of patients with ventricular septal defect opening to the outlet of the right ventricle.

The descending aorta appears small relative to unusually large pulmonary arteries in infants with atrioventricular septal defects. To determine whether this discrepancy in great arterial size influences the outcome after repair of atrioventricular septal defects, we reviewed our experience with 34 infants younger than one-year-old undergoing primary repair. There were four early deaths (11.8%), one in 16 patients with normal chromosomes (6.3%), and three of 18 with Down's syndrome (16.7%). There was no difference between survivors and non-survivors in terms of either the size of the aorta at the level of the diaphragm (descending aortic index, 149±34 versus 139±46 mm2/m2), the pulmonary arterial index (675±170 versus 745±182 mm2/m2), or the ratio of the descending aorta to the pulmonary trunk arterial (4.85±1.6 versus 5.93±2.8). Compared with survivors, non-survivors had higher ratios of vascular resistance (0.48±0.42 versus 0.23±0.14, p<0.05), and tended to have larger preoperative cardiothoracic ratios (0.63±0.05 versus 0.55±0.08, p=0.12) Compared to patients with normal chromosomes, the patients with Down's syndrome tended to have smaller descending aortas (140±34 versus 159±34 mm2/m2, p=0.12), higher ratios of vascular resistance (0.32±0.2 versus 0.18±0.1, p=0.08), and higher mean pulmonary arterial pressures (47±11 versus 39±18 mm Hg, p=0.12), suggesting that pulmonary vascular obstructive disease may be more severe in patients with Down's syndrome. The size of the descending aorta and pulmonary arteries do not influence outcome after repair of atrioventricular septal defect in infants.

We describe three children with chronic renal failure who developed mitral obstructive disease over a period when maintained on hemodialysis. The development and progression of the mitral disease was documented by cardiac catheterization in one child and by Doppler echocardiography in the other two children. These three patients had the lowest body weight among the 16 children undergoing chronic dialysis who were examined cardiologically in our hospital. Autopsy in one child who died from heart failure revealed marked thickening of the leaflets and subvalvar apparatus of the mitral valve with severe obliteration of the intercordal spaces. We found no sign of calcification at the mitral annulus nor at the attachments of the leaflets of the aortic valve, and no Ashoff bodies. We attempted percutaneous catheter balloon valvoplasty in one child which permitted successful renal transplantation after failure of an initial transplantation because of severe pulmonary venous congestion. We conclude that mitral obstructive disease could be a complication of long-term hemodialysis for chronic renal failure. Catheter intervention may serve to release the obstruction, although the procedure is not curative.

Four patients with the phenotypic characteristics of Noonan's syndrome presented in infancy with a suspected cardiac defect. The cardiac segmental connections were normal. All four were diagnosed to have valvar pulmonary stenosis by cross-sectional echocardiography, the valve being typically thickened and dysplastic as expected for the syndrome. In addition, all had hypertrophic cardiomyopathy and evidence for important abnormalities of the other cardiac valves. Two of the four patients died following cardiac surgery. Of the other two, one child died during interventional catheterization and another died while awaiting cardiac surgery. The cardiac abnormalities, confirmed at postmortem, were dysplastic pulmonary valve with stenosis (four patients), dysplastic aortic valve (three patients), supravalvar aortic stenosis (one patient), small and dysplastic tricuspid and mitral valves (four patients), hypertrophic obstructive cardiomyopathy affecting both ventricles, with asymmetric septal hypertrophy (four patients), atrial septal defect within the oval fossa (one patient). In addition to the usually described abnormalities of the pulmonary valve and ventricular myocardium, the patients described showed a wide spectrum of valvar dysplasia which has received little attention in the past. If these patients do indeed have Noonan's syndrome, and the evidence supports this contention, then these findings support the hypothesis of a more generalized disorder in the development of the ventricles and valves in the syndrome, which has a variable expression. They also stress the need to look carefully for abnormalities of valves other than the pulmonary valve in patients who present with symptoms in infanscy.

Syncope has never been described as the presenting symptom of divided left atrium (cor triatriatum sinistrum). We have now encountered this mode of presentation in an otherwise asymptomatic patient. An upright tilt test elicited syncope prior to surgical correction, but failed to induce any symptom, even subsequent to infusion of isoproterenol, after surgery.

A heart is described in which there was a solitary arterial trunk that exited from the heart astride a large perimembranous ventricular septal defect, with the pulmonary arterial supply originating entirely from collaterals from the descending aorta. There was no evidence of either hilar pulmonary arteries or an atretic pulmonary trunk. The morphology of the ventricular outlet component, with absence of the outlet septum supports the description of this heart as solitary arterial trunk, rather than tetralogy of Fallot with pulmonary atresia.

We report a two-year-old boy with a rare combination of tetralogy of Fallot and aortic coarctation. The obstruction in this patient had an hourglass-like configuration, with a pressure difference of 15 mm Hg. There was a right aortic arch, bilateral brachiocephalic arteries, and persistent left superior caval vein. Percutaneous transluminal balloon angioplasty was performed to lower the resistance to the left ventricular ejection, considered a risk factor for subsequent corrective surgery of tetralogy. Six months later, he underwent combined repair of tetralogy of Fallot and coarctectomy with end-to-end anastomosis, thus avoiding the future potential for restenosis. During surgery, a ligament was found extending from the right subclavian artery to the distal side of the coarctation. The perioperative course was uneventful, indicating the success of the preoperative balloon angioplasty. We speculate that the embryogenesis of the coarctation could be related to an abnormal involution of the aortic arches.

We report a 12-year-old boy with hypertrophic cardiomyopathy presenting with syncope. His electrocardiogram showed first-degree atrioventricular block, complete right bundle branch block, conduction delay in the anterior fascicle of the left bundle branch, and intermittent complete atrioventricular block. We detected hypertrophic cardiomyopathy in the mother. The relationship between the diseases is discussed, and interpreted in the light of previous descriptions.

A simple technique is described with which to relieve postoperative compression of the heart. Although delayed sternal closure has conventionally been used to deal with postoperative compression, this maneuver always exposes the patient to the risk of infection. We have recently employed a simple method of sternal traction when there are signs of compression on temporary sternal closure. One or two couples of sutures in the sternum are used supported by bags of saline. This simple and effective method is applicable to patients, but especially to infants and neonates, without worrying about overindications.

A case is presented of a 3.5-year-old boy with aorto-left ventricular tunnel. A diagnosis of isolated aortic regurgitation had been made at the age of 11 months following cardiac catheterization with selective left ventricular angiography and aortography. The correct diagnosis was established 2.5 years later following cross-sectional echocardiographic examination combined with color Doppler investigation.

Aneurysmal dilatation is a rare malformation of the arterial duct. Successful repair of this anomaly was achieved in a five-day-old neonate, using deep hypothermia and circulatory arrest. Of the cases of aneurysm of the arterial duct reported in the English literature, only seven have been treated surgically with success.

Editor's Note: This discussion is extracted from a lecture and has been minimally edited to maintain the style which we think maintains the spirit as well as the educational content. It is primarily included to offer trainees an introduction to the history and physiology encountered in this evolving specialty. We invite your comments.