The development of newer, load-independent indices of contractility has not substantially reduced general clinical reliance on ejection fraction and shortening fraction to detect abnormalities of contractility, in spite of common understanding of the preload and afterload dependence of percent fiber shortening. The more widespread application of sensitive indices of contractility has been impeded in part by complex methods of acquisition and analysis of data as well as uncertainty concerning the clinical importance of the additional derived information. Substantial recent experience with analysis of stress-shortening and stress-velocity, nonetheless, demonstrates that physiologically meaningful indices of afterload, preload, and contractility can be obtained noninvasively without hemodynamic interventions. There is extensive theoretical and experimental basis for these methods, and the limitations are similar to other global indices of myocardial mechanics. The superiority of methods which allow distinction between contractile abnormalities and abnormal load are particularly important when altered ventricular loading conditions are a prominent feature of the disease state. Several clinical situations have been identified for which analysis of stress-shortening and stress-velocity demonstrates that assessment by fiber shortening alone has resulted in misrepresentation of myocardial status. The clinical utility of assessment of ventricular function is considerably enhanced when the relative contribution of load and contractile performance is determined.

The effect of enalapril, an inhibitor of angiotensin converting enzyme, was studied in 35 infants and children with congestive heart failure associated either with residual mitral or aortic regurgitation following intracardiac repair (24 patients) or with dilated cardiomyopathy (11 patients). Enalapril, at an average dose of 0.24 ±0.10 mg/kg, reduced the concentration of angiotensin II in the serum from 115 ± 67 pg/ml to 60 + 30 pg/ml and increased plasma renin activity from 25 + 24 ng/ml/hr to 45 ± 37 ng/ml/hr. There was a significant decrease in hepatomegaly, cardiothoracic ratio, heart rate and blood pressure in both groups of patients. Left ventricular end-diastolic dimension as evaluated by cross-sectional echocardiography, also decreased, whereas fractional shortening and systolic time intervals improved in both groups of patients. Adverse effects were noted in only one infant with postoperative mitral regurgitation who developed renal failure with oliguria, increase of blood urea nitrogen and serum creatinine. Renal function improved dramatically after discontinuation of enalapril. Hyperkalemia (>5mEq/ 1) was observed in four patients, three of whom were receiving spironolactone. Our results showed that enalapril is effective in improving hemodynamics in the relatively short-term treatment of infants and children with congestive heart failure due to postoperative volume overload or dilated cardiomyopathy. These conditions are poorly controlled with conventional medical therapy.

Our purpose was to study serially, measurements which relate to right ventricular events, using echocardiography and Doppler in full term neonates for the first three weeks after birth. Echocardiographic and pulsed Doppler studies were performed for 21 newborns during the first 36 hours of life, and subsequent serial studies were performed in the second (n=21) and third (n=14) weeks of life. Evaluation included measurement of right isovolumic relaxation time and peak E and A velocities across the tricuspid valve. Pulmonary velocities were studied for evidence of patency of the arterial duct, and to determine acceleration in the pulmonary trunk. Mean right isovolumic relaxation time decreased significantly from 68±9 ms to 39 ± 14 ms (p<0.001) between the first and second week. Mean tricuspid peak E increased significantly between the second (48 ± 7 cm/s) and the third week of life (62 ± 8 cm/s; p<0.001). Mean peak A wave velocity did not change significantly during the time of study. The pulmonary arterial acceleration time increased from the initial measurement (68 ± 10 ms) to the second week (85 ± 9 ms; p<0.001). Changes in right isovolumic relaxation time were significantly related to the changes in the pulmonary arterial acceleration time (r=0.63, p=0.0001), suggesting a significant influence of afterload on diastolic events. These data demonstrate the normal progression of some measures of early right ventricular diastolic function.

Two infants, aged eight days and four months, with tetralogy of Fallot and absence of the leaflets of the pulmonary valve, presented with acute respiratory distress and congestive heart failure. Primary repair was performed using a cryopreserved pulmonary arterial homograft. Both infants survived and are doing well three and two years later. A review of the surgical procedures attempted in this symptomatic group of patients is presented together with a discussion of the pathophysiology of this defect.

To assess whether paradoxical (systolic anterior) motion of the interventricular septum is a true abnormality of septal contraction caused by right ventricular volume overload, we examined the regional pattern of left ventricular contraction in 20 patients with an atrial septal defect within the oval fossa using a fixed and floating reference system of analysis of wall motion. The patients, with a median age of 6.8 (3.5–13.4) years, had a Qp/Qs ratio of 3.5:1 (1.2:1–8:1). They were studied by cross-sectional echocardiography four days (3–5) before and 14.5 (3–67) days after surgical closure of the atrial septal defect. The postoperative Qp/Qs ratio was 1.1:1 (0.9:1–2:1). Regional wall motion of the left ventricle was analyzed in the parasternal short axis view at the level of the mitral valve and papillary muscles as well as in the apical four-chamber view. The endocardium was digitized manually in end-systolic and end-diastolic frames. The center of mass of this figure was calculated and connected to an outside reference point in the right ventricle. With the floating system, both centers of mass and the reference lines were superimposed, thus correcting for movement of the heart inside the thorax. With the fixed system,both end-diastolic and end-systolic frames were measured separately without correcting for movement of the heart. The left ventricle was divided in eight segments in a clockwise fashion and regional change in area was measured and compared to 40 normal age matched controls. With the floating system, left ventricular regional wall motion was normal in all patients before and after closure of the atrial septal defect and, thus, was not influenced by the change in right ventricular volume load. With the fixed system, both before and after surgical closure of the atrial septal defect, left ventricular regional wall motion was reduced in the two segments representing the basilar and middle portion of the interventricular septum. The floating system of analysis of left ventricular regional wall motion has the ability to correct for movement of the heart, which makes the supposed “abnormal” systolic anterior motion in right ventricular volume overload, a condition prevalent in patients with atrial septal defect, disappear. Thus, we conclude that the so-called paradoxical septal motion in atrial defect is an artifact. This may be caused by an increased motion of the heart but is unrelated to the volume load of the right ventricle.

Although noninvasive estimation of the ratio of pulmonary to systemic flow by measuring the cross-sectional areas of the pulmonary and aortic valves and the respective time integrals of the velocity of blood is widely used to determine the amount of shunting in patients with left-to-right shunts, few data exist concerning interobserver variability. We assessed such variability of shunt calculations derived from Doppler echocardiography in 10 children aged six (3.5–11) years with an isolated atrial septal defect within the oval fossa. The ratio of flows was calculated by measuring stroke volumes over the pulmonary trunk and the aorta immediately before and at an average of seven days (5–11) following surgical closure of the atrial septal defect. Two independent observers measured the cross-sectional areas of the aortic and pulmonary orifices and the velocity time integrals and calculated the size of the shunt from these data. All measurements were performed five times, and the mean of these five measurements was calculated and compared for analysis. Before surgery, observer I had measured a ratio of pulmonary to systemic flow of 3.8 (2.1–6.2) and observer II of 3.5 (1.9–5). The mean interobserver difference in terms of the size of the shunt was 1.1 (or 30%). After surgery, observer I measured a ratio of 1.3 (0.8–1.7) and observer II of 1.1 (0.7–1.6). The cross-sectional area of the pulmonary valve was measured as 3.6 (2.6–4.9) cm2 and 3.4 (2.3–5.8) cm2 respectively, with a mean interobserver difference of 0.8 cm2 or 23%. For the velocity time integrals across the pulmonary trunk, the mean interobserver difference was 13% (4–38) before and 16% (0–55) after surgery. The respective variability for the aortic velocity time integrals was 11 % (4–46) before and 9% (0.5–23) after surgery. The variability of measurements of maximal flow velocity across the pulmonary trunk was 15% (4–38) before and 18% (1–77) after surgery. The respective variability for the aortic flow velocity was 11 % (2–28) before and 9% (4–23) after surgery. A paired t-test showed no significant differences for all parameters assessed. The difficulty of reproducing measurements of the pulmonary valve is an important factor affecting interobserver variability. The magnitude of interobserver difference was significantly related to the cross-sectional area of the pulmonary trunk (r=0.84; p<0.02). The interobserver variability may be considerable, and is large enough to influence clinical decisions. Thus, we conclude that a decision regarding need for surgery cannot be based solely on calculation of the shunt derived only from Doppler measurements in patients with isolated atrial septal defects within the oval fossa.

Five previously reported cases have established the combination of a small right ventricle (sometimes with Uhl's anomaly), imperforate tricuspid valve with fibrotic tensor apparatus, congenital absence of the pulmonary valve, and an intact interventricular septum with muscular subaortic stenosis as a rare variant of tricuspid atresia. In this study of three new autopsy cases, we additionally identified Ebstein's malformation of the imperforate tricuspid valve, partial Uhl's anomaly, regional dysplasia of right ventricular myocardium and thinning of the interventricular septum by intramyocardial sinusoids from the right ventricle. All three new cases had epicardial anomalies of the right coronary artery—a fistula to right ventricle, ostial stenosis and proximal arterial hypoplasia. Sinusoidal connections from the right ventricle to the right coronary artery and to the sclerotic left anterior descending artery were identified in serial sections of the right ventricle and septum. Myofiber disarray, with thick walled intramyocardial arteries and sinusoids from left ventricle, involved the bulging subaortic interventricular septum. These studies are consistent with the hypothesis that defective development of the the right ventricle, along with its blood supply and associated atrioventricular and arterial valves, may underlie this unusual form of congenital heart disease.

Right ventricular dominance was observed in 22 (6.6%) out of 332 patients with atrioventricular septal defects. Their mean age was 2.24 ± 2.73 months. Chromosomal anomalies were seen in only three patients (Down's syndrome in two and trisomy nine in one). Seventeen patients underwent surgical treatment. A pulmonary artery banding was performed in eight of them with one long-term survivor who underwent a successful staged orthoterminal repair. A Norwood-type of palliation was attempted in four without success. Biventricular repair was performed in four additional patients with two mid-term survivors, in one of whom the patch used for closure of the atrial septal defect was fenestrated. One patient underwent successful heart transplantation at seven months of age. Pathophysiological problems and surgical options are discussed.

The use of intraoperative echocardiography with Doppler color flow imaging has acquired increased popularity for early assessment of efficacy of repair of congenital heart defects soon after discontinuance of cardiopulmonary bypass. This technology has been found useful also for evaluating the anatomy of the lesion prior to repair. Furthermore, with the use of color flow mapping, additional anomalies, such as patent arterial duct or multiple ventricular septal defects, which might have been overlooked during the initial examination, can be easily diagnosed. Moreover, intraoperative echocardiography provides the quickest and most sensitive method for a surgeon to look for residual atrioventricular valves regurgitation and/or residual atrial or ventricular septal defects as well as for depressed ventricular contractility. Previous studies1–4 have discussed specifically the applicability of intraoperative color flow imaging during the repair of atrioventricular septal defect with a common atrioventricular orifice using both epicardial and transesophageal methodology. Routine intraoperative echocardiography with Doppler color flow imaging has been used since March 1987 at Duke University Medical Center during repair of congenital heart defects. Our aim was to confirm the preoperative dignosis and to assess the quality of repair soon after discontinuance of cardiopulmonary bypass. Our overall experience now includes 612 patients of whom 239 or 39% were less than one year of age at the time of repair. This indicates our tendency to undertake early correction regardless of the age of patients and of the severity of the lesion.

The arterial supply to the lungs in cases with tetralogy of Fallot with pulmonary atresia or critical pulmonary stenosis is mostly via the arterial duct or else by collateral arteries arising directly or indirectly from the aorta. Nine anatomical specimens with collateral arteries were studied by blunt dissection to determine the arterial supply to each pulmonary segment. The precise supply varied from case to case but, overall, nearly two-thirds of the pulmonary segments were connected to the central pulmonary arteries. A quarter were supplied exclusively by systemic-to-pulmonary collateral arteries, with the remainder having a dual supply. Coexistence of ductal connections and systemic-to-pulmonary collateral arteries was seen in one case. Anastomoses between vessels of different origins were observed up to the segmental level in eight of the nine cases. In four cases, the anastomoses formed arterial rings. The extent of pulmonary parenchyma supplied by arteries from different sources and the presence of arterial anastomoses in these malformations have implications on the planning of surgical repair.

Two patients are described with sudden death as the first presenting symptom of Kawasaki disease. The first patient died of cardiac tamponade as a result of rupture of a coronary arterial aneurysm at the age of three months and nineteen days. The second patient, one and half years old, developed acute myocardial infarction secondary to coronary arterial aneurysm and thrombosis. The true nature of their underlying disease was realized only after postmortem examination. Their clinical signs and symptoms of Kawasaki disease might be so mild as to escape recognition. A high index of suspicion should be exercised by the clinician in order not to miss this condition, especially in places where Kawasaki disease is uncommon.

Using combined epicardial echocardiography and high-fidelity intraventricular pressure recordings, the acute effects of transition to a Fontan circulation were studied in 10 patients. Measurements were made before and after cardiopulmonary bypass. The Fontan operation had no significant effect on load-dependent indices, or on a load independent index (Vmax) of ventricular systolic function. Large changes were observed in ventricular geometry. Maximum and minimum cavity dimensions were reduced, while maximum and minimum thicknesses of the posterior wall were increased.While simultaneous Doppler/intraventricular pressure measurements suggested that the compliance of the ventricle was unchanged, the pattern of atrioventricular flow changed from predominantly early diastolic (E wave) to predominantly atrial systolic (A wave) as a result of surgery in four patients. The time constant of ventricular relaxation was prolonged in all patients and five developed Doppler echocardiographic evidence of incoordinate relaxation of the ventricle, with intraventricular flow occurring during isovolumic relaxation. Thus, the Fontan operation causes acute hypertrophy of the systemic ventricle due to a sudden reduction in ventricular preload in the presence of a maintained shortening fraction. While global ventricular diastolic compliance may be unchanged by the operative procedure, filling of the ventricle during early diastole is altered as a result of incoordinate relaxation and a prolonged time constant of ventricular relaxation.

Surgical banding of the pulmonary artery in patients with transposition of the great arteries leads to a rapid increase of the left ventricular mass. The purpose of this animal experiment was to induce ventricular systolic hypertension in the “subpulmonary ventriclerdquo; by intravascular obstruction to pulmonary flow. The first experiment was performed in an anesthetized animal with an open thorax. A balloon-tipped catheter was introduced into the femoral vein and advanced to the pulmonary artery. The balloon was positioned in the pulmonary trunk and was progressively inflated until a systemic pressure was achieved in the “pulmonary ventricle”. This was accomplished within 40 minutes without a significant reduction in cardiac output, which was continuously monitored by an electromagnetic flowprobe. In the second experiment an analogous procedure was performed in a closed chest, awake, spontaneously breathing animal. The catheter was maintained in proper place for 24 hours. Subsequent macroscopic examination of the heart demonstrated a remarkable increase in the ventricular mass. The results of this preliminary experiment demonstrate the possibility for creating “intraluminal pulmonary banding”. The potential advantages of this technique are the nonsurgical approach and the ability to adjust the grade of obstruction to pulmonary flow.

The use of an obstructing balloon catheter positioned in the outflow tract of the pulmonary ventricle may be an alternative method for the adaptation of the left ventricle to an increased afterload prior to an arterial switch procedure in patients with complete transposition requiring a two-stage approach. We tested this approach in an acute hemodynamic study in a piglet model. Seven piglets were anesthetized with halothane and ventilated at FiO2 1.0. Through a median sternotomy, the great vessels were exposed. The right ventricular pressure and the aortic blood pressure were recorded using microtip manometers, cardiac output was measured by an electromagnetic flow probe on the ascending aorta. A 6F or 7F Berman angiographic catheter was placed in the lumen of the pulmonary artery and the balloon inflated to decrease cardiac output no more than 30%. The hemodynamic changes observed after balloon inflation included an 100% increase in systolic right ventricular pressure (control vs balloon inflation (mean±SE) 20.4 ± 1.5 mm Hg vs 46.6 ± 4 mm Hg, p<0.001), a slight reduction in systolic aortic pressure (75.5 ± 3.8 mm Hg vs 65.0 ± 5.8 mm Hg; p<0.05), and a reduction in cardiac output by 30% (1.1 ± 0.081/min vs 0.8 ±0.08 1/min, p<0.01). The systolic right ventricular to aortic pressure ratio was increased from 0.27 ± 0.02 to 0.69 ± 0.08, p<0.001. This study shows that a balloon catheter may be useful in creating systolic hypertension in the pulmonary ventricle in patients with complete transposition requiring a two-stage approach.

Obstruction to the pulmonary venous return is a frequent associated anomaly in patients with isomerism of the right atrial appendages. Yet, preoperative diagnosis by means of either cross-sectional echocardiography or cardiac catheterization can be intriguing. Indeed, the presence of two morphologically right lungs reduce considerably the size of window for precordial echocardiography. Also, in the presence of severe pulmonary stenosis or atresia, it can be difficult at cardiac catheterization to enter the pulmonary trunk. In these patients, construction of a systemic-to-pulmonary artery anastomosis will almost inevitably result in pulmonary edema. Between May 1984 and December 1988, five patients with isomerism of the right atrial appendages, severely decreased pulmonary blood flow and concealed obstruction to the pulmonary venous return were admitted to our hospital. A modified Blalock Taussig shunt by interposition of a polytetrafluoroethylene prosthesis was performed in each patients and all of them developed pulmonary edema. Three patients died despite appropriate medical treatment. The remaining two patients were successfully treated by banding of the Blalock shunt. This was performed in the first patient at the time of the initial surgery, when prior to closure of chest, pulmonary edema became manifest. The second patient who developed pulmonary edema early postoperatively, underwent cardiac catheterization to confirm the clinical diagnosis of obstruction to the pulmonary venous return. Reduction of blood flow through the Blalock shunt with resolution of edema was initially achieved by means of a partially occluding balloon catheter. Pulmonary edema recurred one week later because of rupture of the balloon and the patient eventually underwent a successful banding of the Blalock shunt through a left thoracotomy. We conclude that preoperative assessment of the pulmonary venous return is mandatory in patients with right isomerism and reduced pulmonary blood flow. Construction of a modified Blalock-Taussig shunt in the presence of concealed obstruction to the pulmonary venous return will almost inevitably cause pulmonary edema. Banding of the Blalock shunt can be successful, as observed in our experience, for the management of this serious complication.

The feasibility and efficacy of radiofrequency catheter ablation of medically resistant supraventricular tachycardia is a promising technique with applications in the pediatric age group. The limitations of this procedure in the pediatric population, however, have yet to be delineated. We herein report a case of incessant reentrant supraventricular tachycardia in a two month old infant which was resistant to pharmacologic therapy, yet successfully treated by radiofrequency catheter ablation.