The arterial switch operation has become the standard of surgical repair for total correction of complete transposition (concordant atrioventricular and discordant ventriculoarterial connections). A standard nomenclature for classification of the numerous anatomic relationships the coronary arteries may assume, however, has yet to be universally adopted. Inconsistent use of varied nomenclatures remain an obstacle to effective communication between physicians and surgeons. In this review we offer a unified nomenclature incorporating five important relationships: the configuration of the sinuses; their location; the configuration of the arterial orifices; the pattern of branching of the major coronary arteries; and the course of each artery.

Balloon dilation was attempted in seven symptomatic patients with congenital mitral stenosis aged 7.6±5.3 years. Of the five patients with typical mitral stenosis, four underwent successful dilation with decrease of the mean left atrial pressure and the gradient across the mitral valve and increases in the area of the valve of 127±43 and 85±16%, respectively, as demonstrated hemodynamically or by Doppler echocardiography. In the patient in whom the procedure was unsuccessful, a small child with recurrent pulmonary edema, death occurred during the procedure as a consequence of vasovagal reaction. In the other two patients, one with a parachute-like mitral valve and the other with Shone's syndrome, severe pulmonary hypertension and reversal of the shunt through a patent arterial duct, it was not possible to dilate the valve. In the patient with Shone's syndrome, nonetheless, palliation was achieved by balloon angioplasty of the aortic coarctation and by creation of an atrial septal defect. The patients undergoing dilation remained symptom-free during follow-up and mantained the increase in valvar area as judged by Doppler studies and, in one patient, also by cardiac catheterization. A residual atrial septal defect closed spontaneously in three patients. We conclude that balloon dilation of congenital mitral stenosis is an effective alternative to surgery in patients with typical mitral stenosis. Cross-sectional echocardiography plays an important role in defining valvar morphology and selection of patients. The procedure is not without risk, especially in very sick patients but satisfactory results are long-lasting.

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.

The size of the coronary arteries parallels the ventricular mass, thus it may be abnormal in complete transposition beyond infancy and could be influenced by the arterial switch operation. To investigate this possibility, we measured the diameters of the right, left main trunk, anterior descending, and circumflex coronary arteries before and three to seven years (mean 4.8) after the arterial switch operation in 17 patients with a “normal” distribution of the coronary arteries (so-called Shaher type 1). The values were compared with 18 controls who had Kawasaki disease with no apparent coronary arterial disease. The right, left anterior descending, and circumflex arteries were smaller than control values before the operation. The post-/preoperative ratios of the diameter were 1.16±0.11 for the right coronary artery, 1.18±0.16 for the left main trunk, 1.20±0.18 for the left anterior descending artery, and 1.22±0.26 for the circumflex artery. There were no significant differences among these values. After surgery, the right coronary artery was larger, but the left coronary arteries were smaller in the patients than in the controls: 2.5±0.3 vs 2.0±0.2 mm for the right coronary artery; 2.4±0.3 vs 2.7±0.1 mm for the left main trunk; 1.9±0.2 vs 2.4±0.2 mm for the left anterior descending artery; 1.6±0.4 vs 2.2±0.5 mm for the circumflex artery, respectively. The posterior descending coronary artery originated from the right coronary artery in all patients. The total cross-sectional area of the right coronary, left anterior descending, and circumflex arteries was 9.7±2.4 mm2 in the patients, and 11.8±2.9 mm2 in the controls (p>O. 1), suggesting that the increased size of the right coronary artery compensates for the small left coronary arteries. We conclude that the arterial system in complete transposition, with a large right coronary artery and small left coronary system, remains smaller than normal even at midterm follow-up after anatomic repair despite normalization of left ventricular volume and muscle mass.

In 38 children with aortic coarctation between the age of three weeks and 16 years, 44 balloon dilation procedures were attempted. At initial catheterization (n=38), the mean gradient dropped from 49.6±21.2 mm Hg prior to dilation, to 15.3±15.8 mm Hg after the procedure (p>0.05). Twenty-six patients were recatheterized 3–24 months after the initial procedure. The mean gradient remained low at 12.7±15.2 mm Hg (range 0–64). Six of the 26 (23%) patients required a second dilation because of significant recoarctation. This proved successful in four, but in two patients, the second dilation failed, and they were referred for elective surgery. Thus, good overall results were obtained in 24 of the 26 (92.3%) patients undergoing reinvestigation following balloon dilation. Complications included requirements for blood transfusion in 9/44 (20%), chest pain during balloon inflation in 3/44 (6.8%), rupture of the balloon in 3/44 (6.8%), and femoral arterial thrombectomy in 3/44 (6.8%). At a mean clinical follow-up of 21 months, 21% of the patients had a weaker femoral pulse on the side used for balloon dilation, while 21% had mild hypertension measured in the arms despite the absence of a significant gradient. One patient (2.6%) developed an aortic aneurysm as a complication of the procedure. We conclude that balloon dilation is a safe and effective procedure in the majority of the patients with native aortic coarctation.

The Constitution of the United States of Mexico, in its Article Number 4, provides for the right to health care. The government's National Health Program was created to comply with this mandate. This program comprises a National Health Care System. This system has three branches. The first one is Social Security, which encompasses 50% of the population of Mexico—namely 45 million affiliates. Out of this popu lation, 10 million are under the “Instituto Mexicano del Seguro Social-Solidaridad.”This program is financed by federal resources, is self-managed by the “Instituto Mexicano del Seguro Social” and provides health care to the general population (basically farmers). The rest of the population that receives benefits from the Social Security System includes employees, blue-collar workers (affiliated with the “Instituto Mexicano del Seguro Social“), federal and state-government workers (who receive benefit from “Instituto de Seguridad Social de los Trabajadores al Servicio del Estado”) and the military personnel (who are affiliated with the “Instituto de Seguridad Social de las Fuerzas Armadas”). These institutes are jointly financed by employers, the state, and the workers.The payment percentage is established depending on the worker's income. For state workers and armed forces it represents 2% of the income of the employee and another 2% is paid by the state; those depending on die Instituto Mexicano del Seguro Social pay 3.5% of their salary and 8.4% is paid by die employer.

A 29-year-old man, with a diagnosis of congenitally corrected transposition (discordant atrioventricular and ventriculoarterial connections) with associated multiple ventricular septal defects, mild pulmonary valvar stenosis and Ebstein's malformation of a stenotic left-sided morphologically tricuspid valve, died after closure of the ventricular septal defect and insertion of a valved homograft conduit between the morphologically left ventricle and the pulmonary trunk. Death occurred because of failure to appreciate the bizarre and rather stenotic anomaly of the morphologically tricuspid valve, in which the anterosuperior leaflet divided the morphologically right ventricle into an inlet portion and a smaller outlet portion. After closure of the ventricular septal defects, this ventricle could no longer support the systemic circulation. We discuss the natural history and the reasons for the erroneous interpretation of the echocardiographic images of the left-sided tricuspid valve.

Dissection of a pulmonary arterial aneurysm due to underlying pulmonary hypertension from congenital heart disease is uniformly fatal, but fortunately rare. Two such cases are presented, along with review of 24 other known cases published in the literature. Clinical presentation, guidelines tomanagement, and possible surgical intervention in the acutely dissecting patient are discussed.

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.

This study reviews the results of the surgical management of 154 cases of ruptured aneurysm of the sinus of Valsalva. Of the patients0 73% were male, with an average age of 28 years. An associated ventricular septal defect was found in 40% and 23% had aortic valvar regurgitation. The aneurysms originated from the right coronary sinus in 79% and from the non-coronary sinus in the remainders. The aneurysms ruptured into the right ventricle in 73%, into the right atrium in 27% and into the left ventricle in less than 1%. Operative mortality was 4.5%. Long-term follow-up was achieved in 80% of patients, with a mean duration of 5.7 years and a range from two months to 29 years. Preoperative aortic regurgitation and preoperative functional class (NYHA III or IV) were both predictive of a worse long-term outcome. The optimal surgical approach was closure of the distal end of the fistula by direct suture together with reinforcement of the aortic sinus with a Dacron patch.

Summary Between June 1988 and December 1992, six patients with dominant left and rudimentary right ventricles underwent orthoterminal correction with a modified Fontan operation in which the atriums were neoseptated using a flap constructed from the right atrial wali. Four patients had anomalous systemic venous connections. The operations were performed under direct caval cannulation, standard cardiopulmonary bypass, moderate hypothermia and cardioplegic arrest. After opening the right atrium with a longitudinal incision, the atrial septum was completely resected and the coronary sinus was cut back. The upper wall of the right atrial incision was brought down in such a way that the pulmonary venous atrium was drained into the dominant ventricle via the right-sided or common atrioventricular valve. This was followed by direct connection of the right atrium with its anterior wall reconstructed with pericardium to the pulmonary arteries. In one patient, a left superior caval vein draining to the left atrium was divided and anastomosed to left pulmonary artery. One patient died on the 12th postoperative day with pulmonary infection and sepsis, though he had no hemodynamic problem, and another died on the sixth day due to high pulmonary vascular resistance. The remaining four patients are progressing well at a mean of 23.4 months postoperatively with functional capacity of NYHA I-IT and sinus rhythm. Echocardiographic and angiocardiographic examinations during follow-up showed unobstructed pulmonary and systemic venous pathways in all. This modification of the Fontan operation seems a good alternative technique which creates a contractile left atrium with large enough dimensions and an unobstructed pathway for pulmonary venous flow.

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 distribution of axial velocities in the pulmonary artery must be determined to describe accurately the flow in the pulmonary artery. Previous studies in our laboratory have demonstrated the complexity of the velocity profile in the pulmonary trunk and the branch pulmonary arteries with normal and altered pulmonary blood flow. These findings have demonstrated a skewed, parabolic mean velocity profile in the pulmonary trunk under normal hemodynamic conditions. To determine the effect of left-to-right intracardiac shunting on the distribution of axial velocities in the pulmonary artery, an animal model of atrial and ventricular shunting was used. In both models, the distribution of mean axial velocities remained skewed and parabolic with the higher mean velocities recorded toward the anterior wall.

Over the last 30 years, 94 episodes of infectious endocarditis have been identified in 86 children seen at the Children's Hospital of Pittsburgh. In most of these children no precipitating event could be documented. There was no change in underlying cardiac anomalies over the three decades of this study, and left ventricular outflow tract obstruction, ventricular septal defect and tetralogy of Fallot were the most common anomalies. Streptococci and staphylococci were the most common infecting organisms, and there was a slight increase in the percentage of streptococci in the last decade. Cardiovascular damage occurred in about one-third of the cases, and aortic regurgitation was most common. Mitral regurgitation was also an important complication, as was the development of an aortic aneurysm. Important systemic and pulmonary emboli were rare. Surgical intervention was necessary in one-fifth of the children. Valvar replacement was the most common procedure done. The mortality rate declined markedly over the period of the study, dropping from 36% in the first decade to 8% in the last.

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.

Between February 1980 and February 1992, 28 children (17 males and 11 females) were treated for endocarditis on congenital cardiac lesions, most commonly the mitral valve (32%). Their ages ranged between four months and 14 years (mean 8.2 years). The most common infecting organism (in 25% of patients) was Staphylococcus aureus. Patients were divided into two groups. In the first, made up of eight patients, cardiac surgery was undertaken within one week of the start of antibiotic therapy. The second group of 20 patients was further divided into a group of seven patients who underwent surgery during the initial, active stage of endocarditis because of failure of medical management and a group of 13 patients who initially received antibiotic therapy alone. In this last group, three infections with the same organism recurred within two months and surgical intervention was necessary in the active phase of the recurrence. Subsequently, surgery for “healed” endocarditis was undertaken in three more patients. Mortality in the 21 patients undergoing surgery was 19%—one of eight (12.5%) in those undergoing surgery within one week of starting treatment and two of 10 in the remaining patients. Overall, three patients (15%) died from those in whom surgery was not undertaken within one week of the start of treatment. There were also fewer pre- and postoperative complications as well as a lower mortality rate in those undergoing early surgery. We conclude that early surgical intervention, in our hands, is the most appropriate management for endocarditis in congenital cardiac lesions.

We examined the effectiveness of the application of ice water to the face during metronome-controlled respiration (15 breaths per minute) for vagalstimulation. We also examined the importance of basal vagal tone and sympathovagal interaction in determining the individual response to the stimulation. Fifty-three boys, aged 12 and 13, were included in this study. Vagal tone and sympathovagal interaction were assessed by power spectral analysis of the variability of the RR interval (heart rate). Basal heart rate, high frequency power, and low-to-high frequency power ratios were 81 ± 13(58–110 beats/min), 791 ± 1061(56–4161 m.sec2) and 1.08±1.22 (0.04–4.85) during controlled respiration. After application of ice water, 23 children developed frequent nodal escape beats due to severe sinus bradycardia. Minimum heart rate, high frequency power, and low to high power ratios changed to 42± 12 (19–72 beats/min), 1890±1882 (211–7258 m.sec2) and 0.64±0.43 (0.12–1.46). The increased ratio of high frequency power, maximum decrement in heart rate, and its percent after stimulation were 5.44±5.62 (0.63–24.26), 39±14 (10–81 beats/mm) and 47±15 (16–81%), respectively. The increased ratio of high frequency power was correlated with basal logarithmic high frequency power (r=−0.60, p=O.0004). Maximum heart rate decrement was correlated with basal logarithmic high frequency power (r=−0.60, p=O.OO18) and low-to-high frequency power ratio (r=0.27, p=O.O4). We conclude that application of ice water to the faceduring controlled respiration induces powerful vagal stimulation and bradycardia similar to, or even greater than, facial immersion in cold water. There is wide variability of individual response which can be explained by the magnitude of absolute basal vagal tone.

Twenty cases of aortopulmonary window are reported with special reference to some unusual modes of presentation and hemodynamics. Patients over 15 years of age accounted for 35% of the group. This delayed presentation may relate to referral patterns and socioeconomic conditions prevalent in India. Curiously, this elderly subset had two modes of presentation—either as large left-to-right shunts with low pulmonary vascular resistance (71.4%), or as Eisenmenger's syndrome (28.6%). The reasons for the low pulmonary vascular resistance in the majority of these older patients remain unclear. The echocardiographic features of these defects can be missed in presence of significant associated cardiac lesions. A careful search should, therefore, be made for an additional aortopulmonary window in all cases with evidence of intercirculatory shunting.

Twenty-six patients requiring palliation for the tetralogy of Fallot were treated by balloon dilation. The mean age at dilation was 8.5 months (range 0.5−20.6) and the mean weight 6.7 kg (range 2.6−10.7). Successful dilation was achieved in 25 patients. The mean ratio of the balloon to the diameter of the pulmonary outflow tract was 1.6 (range 1.2−2.0). The aortic oxygen saturation increased from mean±SD of 80±12.4% before to 91±4.3% after dilation (p<0.05). The pulmonary arterial oxygen saturation rose from 64±10.7% to 80±7.7% (p<0.05). Transient hypotension and arterial desaturation were noted in 19 patients during inflation of the balloon. One patient had a cardiac arrest prior to dilation and died afterwards. Seven patients had cyanotic spells related to the procedure. Attempts to cross the pulmonary valve resulted in infundibular perforation by the guide wire in one patient. Of the 24 survivors who initially had successful dilation procedures, three have needed a Blalock-Taussig shunt. Palliation without a shunt was achieved in the remaining 21 patients. In 12 patients, repeat angiography, 2.5−20 months (mean 9.1) after dilation, showed an increase in the diameter of the outflow tract from 7.1±2.1 mm before to 9.5±2.0 mm after dilation (p<0.05). Diameters of the pulmonary arteries increased from 6.3±2.2 mm on the right and 6.8±1.9 mm on the left before to 9.2±2.2 mm and 9.3±2.5 mm respectively after dilation (p<0.05 for both branches). Surgical correction has been achieved in 22 patients, 21 of these 2−22 months after balloon dilation and the other patient 20 months after construction of a shunt. At operation, the leaflets of the pulmonary valve were noted to be torn in five patients. In 12 patients, there was extensive scarring of the infundibulum. Balloon dilation of the right ventricular outflow tract achieves adequate palliation and may result in an increase in the diameter of the pulmonary valve and branches of the pulmonary trunk. It should be considered as an alternative to shunt procedures in children with tetralogy of Fallot.