Congenital heart block: development of late-onset cardiomyopathy, a previously underappreciated sequela.

OBJECTIVE: We report 16 infants with complete congenital heart block (CHB) who developed late-onset dilated cardiomyopathy despite early institution of cardiac pacing. BACKGROUND: Isolated CHB has an excellent prognosis following pacemaker implantation. Most early deaths result from delayed initiation of pacing therapy or hemodynamic abnormalities associated with congenital heart defects. METHODS: A multi-institutional study was performed to identify common clinical features and possible risk factors associated with late-onset dilated cardiomyopathy in patients born with congenital CHB. RESULTS: Congenital heart block was diagnosed in utero in 12 patients and at birth in four patients. Ten of 16 patients had serologic findings consistent with neonatal lupus syndrome (NLS). A pericardial effusion was evident on fetal ultrasound in six patients. In utero determination of left ventricular (LV) function was normal in all. Following birth, one infant exhibited a rash consistent with NLS and two had elevated hepatic transaminases and transient thrombocytopenia. In the early postnatal period, LV function was normal in 15 patients (shortening fraction [SF] = 34 +/- 7%) and was decreased in one (SF = 20%). A cardiac pacemaker was implanted during the first two weeks of life in 15 patients and at seven months in one patient. Left ventricular function significantly decreased during follow-up (14 days to 9.3 years, SF = 9% +/- 5%). Twelve of 16 patients developed congestive heart failure before age 24 months. Myocardial biopsy revealed hypertrophy in 11 patients, interstitial fibrosis in 11 patients, and myocyte degeneration in two patients. Clinical status during follow-up was guarded: four patients died from congestive heart failure; seven required cardiac transplantation; one was awaiting cardiac transplantation; and four exhibited recovery of SF (31 +/- 2%). CONCLUSIONS: Despite early institution of cardiac pacing, some infants with CHB develop LV cardiomyopathy. Patients with CHB require close follow-up not only of their cardiac rate and rhythm, but also ventricular function.

Cervical aortic arch with aneurysm formation.

Two pediatric cases of cervical aortic arch with aneurysm formation are reported. Only female patients with cervical aortic arch have developed aneurysms, which may influence risk counseling of such patients.

Treatment of transposition of the great arteries.

Today, the arterial switch operation is the treatment of choice for patients with transposition of the great arteries. Midterm follow-up confirms the initial hopes for good systemic ventricular function and lack of arrhythmias. A two-stage operation can be performed in patients seen after 1 month of age or in subjects who have had an atrial switch operation and with late systemic dysfunction. Increasing experience with the arterial switch operation has led to its successful use in more complex lesions. Increased mortality and morbidity after the atrial switch operation has been confirmed, with decreased cardiac output, baffle obstruction, and arrhythmias. In some cases interventional catheterization is useful. In patients with corrected transposition of the great arteries who have associated malformations, the poor midterm results seen with the classical surgical repair make the combined atrial and arterial switch an interesting option.

Recent advances in the diagnosis and treatment of coarctation of the aorta.

Although it has been the topic of intense medical and surgical attention for over 50 years, coarctation of the aorta continues to be a major cause of cardiovascular morbidity and mortality in infants and children. Refinements in established diagnostic modalities--primarily fetal, transesophageal, and intravascular echocardiography--have improved pre- and post-treatment assessments. Aggressive and early intervention, whether by surgery, catheter, or both, have been shown to increase initial success; the results of long-term follow-up are yet to be determined. The best possible outcome requires prompt recognition and effective treatment directed at immediate gradient relief, which will hopefully prevent or reduce the known late and long-term sequelae.

Pulsed Doppler echocardiographic and color flow imaging detection of retrograde filling of anomalous left coronary artery from the pulmonary artery.

We report a case in which pulsed wave Doppler echocardiography and color flow imaging of blood flow direction in an anomalous coronary artery from the pulmonary artery assisted in the correct diagnosis and confirmed the adequacy of the surgical correction. Low-velocity color scales were used to show retrograde filling of the left coronary artery before surgery and antegrade filling of the left coronary artery after surgery. Detecting direction of blood flow in coronary arteries should increase the accuracy of the noninvasive diagnosis of anomalous left coronary artery from the pulmonary artery.

Use of the postductal PaO2 as a predictor of pulmonary vascular hypoplasia in infants with congenital diaphragmatic hernia.

Infants with congenital diaphragmatic hernia (CDH) demonstrate a wide range of anatomic and physiologic abnormalities that result in decreased pulmonary perfusion. We have used the patients' ability to achieve at least one postductal PaO2 greater than 100 torr while on maximal ventilation with 100% oxygen during the first 24 hours of life as the clinical marker to identify the degree of pulmonary perfusion. Patients were grouped as follows: group 1 had at least one postductal PaO2 greater than 100 torr, and group 2 patients never had a postductal PaO2 above 100 torr. To see if this classification did reflect pulmonary vascular abnormalities, we compared the pulmonary arteriograms of these two groups of CDH infants for size of the main pulmonary arteries (PAs), size of the lungs, and degree of peripheral vascular obstructive disease (PVO). Infants in group 2 had significantly smaller ipsilateral and contralateral main PAs, as well as smaller ipsilateral lungs with more severe PVO. We propose the postductal PaO2 as the clinical marker for identification of the degree of pulmonary perfusion.

Midterm results after the arterial switch operation for transposition of the great arteries with intact ventricular septum: clinical, hemodynamic, echocardiographic, and electrophysiologic data.

Although the short-term results of atrial level repair of transposition of the great arteries (TGA) are satisfactory, longer follow-up has disclosed a significant incidence of systemic right ventricular dysfunction and rhythm disturbances. The arterial switch operation (ASO) may represent a major improvement by restoring the left ventricle as the systemic ventricle and avoiding extensive atrial surgery. We have prospectively evaluated 49 consecutive survivors of ASO for TGA with intact ventricular septum (IVS) by clinical examination, echocardiography, cardiac catheterization, ambulatory electrocardiographic monitoring, and invasive electrophysiologic studies. The mean length of follow-up has been 29 +/- 14 (SD) months after surgery. All children are currently asymptomatic and on no medications. Severe supravalvular pulmonary stenosis (greater than 60 mm Hg) was present in five children, all of whom have undergone reoperation. No patient has severe supravalvular aortic obstruction. Mild degrees of supravalvular pulmonary or aortic obstruction have not progressed. Seven children (14%) have trivial or mild aortic regurgitation. Two children have proximal occlusion of the left anterior descending coronary artery with adequate retrograde collateral perfusion. One child had an electrocardiographic pattern of inferior myocardial infarction without evidence of ventricular dysfunction. Systemic (left) ventricular function is normal as measured by end-diastolic pressure (mean 7 +/- 6 mm Hg), ejection fraction (mean 68 +/- 6%), end-diastolic volume (mean 101 +/- 22% of predicted normal), and cardiac index (mean 4.7 +/- 1.3 liters/min/m2). Only one patient has sinus node dysfunction. There have been no late deaths. These early results are encouraging. We conclude that the arterial switch operation is currently the procedure of choice for neonates with TGA and IVS.

Late results in patients with tetralogy of Fallot repaired during infancy.

Between 1973 and 1985, 220 infants (age 1 day to 18 months, mean = 7 months) underwent repair of tetralogy of Fallot (TOF) or TOF/pulmonary atresia with 17 early deaths. Follow-up status was ascertained for 184 of 203 survivors (91%) at a postoperative interval of 2 to 185 months (mean = 60 months). Significant residual hemodynamic lesions included ventricular septal defect in three, and right ventricular outflow gradient in excess of 40 mm Hg in 24. Reoperation or interventional catheter procedures were performed in 31 of 184 (17%) patients. All postoperative electrocardiograms were reviewed; only two of 184 patients had ventricular ectopy on any tracing. Holter data from 41 patients revealed one with sinus node dysfunction, 12 with Lown grade 1 ectopy, and one with Lown grade 2 or greater. Conduction defects, evaluated by electrocardiographic and electrophysiologic measurements, were not different from those reported for TOF patients undergoing repair at later ages. No study patient received antiarrhythmic medication, although one required a pacemaker for sinus node dysfunction. There were three late deaths, all unrelated to arrhythmia. TOF repair in infancy appears to be associated with an acceptable hemodynamic outcome, and a low incidence of ventricular ectopy and sudden death at 5 year follow-up.

Dual balloon technique for valvuloplasty of aortic stenosis in adults.

A dual balloon technique was studied in 16 patients with aortic stenosis in whom results with a single balloon (up to 20 mm, 5.5 cm or 25 mm, 3.0 cm in diameter and length, respectively) were judged to be suboptimal. Dual balloon valvuloplasty was performed using 2 balloons advanced and inflated simultaneously across the stenotic aortic valve orifice. For the group as a whole, the average peak transvalvular gradient was reduced from 79 +/- 8 to 57 +/- 7 mm Hg (mean +/- standard error) using a single balloon (p less than 0.0005), and reduced further to 36 +/- 4 mm Hg using dual balloons (p less than 0.0005 compared with single balloon results). Similarly, calculated aortic valve orifice area was increased from 0.45 +/- 0.04 to 0.57 +/- 0.05 cm2 using a single balloon (p less than 0.0005), and further increased to 0.77 +/- 0.06 cm2 using dual balloons (p less than 0.0005). Dual balloon dilation caused no complications directly attributable to the use of 2 balloons, including no exacerbation of aortic regurgitation. These results suggest that dual balloon valvuloplasty is safe and efficacious in selected patients with aortic stenosis.

Mechanism of aortic balloon valvuloplasty: fracture of valvular calcific deposits.

Balloon valvuloplasty has been shown to acutely reduce the hemodynamic and symptomatic severity of calcific aortic stenosis. The mechanism by which this improvement is accomplished is not known. At necropsy, three patients who died after hemodynamically successful aortic balloon valvuloplasty were found to have aortic valve calcific deposits fractured at one or more sites. These findings suggest that fracture of leaflet calcium represents the basis for successful aortic balloon valvuloplasty.

Cardiovascular findings in adolescent inpatients with anorexia nervosa.

Left ventricular function, resting electrocardiograms, and Holter recordings were systematically examined in 25 consecutively hospitalized, seriously ill, emaciated adolescents with anorexia nervosa. We failed to observe serious arrhythmias, abnormal prolongation of QT interval, conduction abnormalities, or depression in left ventricular systolic function.

Treatment of calcific aortic stenosis by balloon valvuloplasty.

Recent reports have established the feasibility of using balloon valvuloplasty to reduce left ventricular outflow tract obstruction due to a calcified aortic valve. The present study summarizes experiences with this technique in 9 patients (7 women, 2 men, mean age 78 years) in whom balloon valvuloplasty was used to treat calcific aortic stenosis. Peak aortic valve gradient (mm Hg) decreased from 68 +/- 8 (mean +/- standard error of the mean) before valvuloplasty to 35 +/- 5 after valvuloplasty (p = 0.003). Mean aortic valve gradient decreased from 57 +/- 7 before valvuloplasty to 30 +/- 5 after valvuloplasty (p = 0.006). Calculated aortic valve area increased from 0.42 +/- 0.04 to 0.81 +/- 0.06 cm2 (p = 0.005). Balloon valvuloplasty failed to diminish aortic valve obstruction in only 1 patient who, at subsequent surgery, had a congenitally bicuspid aortic valve. Significant aortic regurgitation was not observed in any of the 9 patients after valvuloplasty. One patient did have a highly focal, presumably embolic, brain stem infarct during the procedure. Femoral arterial blood loss, related to wire-guided exchange of balloon catheters too large for a 12Fr introducer sheath, was minimized by direct arterial exposure in 8 of the 9 patients. Thus, these findings confirm the efficacy of balloon valvuloplasty for the treatment of calcific aortic stenosis. The procedure, however, is not without hazard.

In vitro analysis of mechanisms of balloon valvuloplasty of stenotic mitral valves.

Preliminary reports indicate that percutaneous balloon valvuloplasty is efficacious for treatment of mitral stenosis. The present study was designed to evaluate whether anatomic features of stenotic mitral valves in older adults affect the efficacy of balloon valvuloplasty and to determine the mechanism by which increased orifice area is accomplished. Fifteen mitral valves excised intact at the time of mitral valve replacement from patients with no more than 2+/4+ mitral a regurgitation were selected for study. Balloon valvuloplasty was performed using a sequence of dilation catheters with balloons 18 to 25 mm in inflated diameter. Mitral valve area, measured with a conical valve sizer, increased from 0.71 +/- 0.06 cm2 (mean +/- standard error of the mean) to 1.77 +/- 0.19 cm2 (p less than 0.0001) after valvuloplasty, resulting in an increase in calculated orifice area of 185 +/- 27% (range 34 to 407%). The increase in calculated orifice area correlated inversely with orifice area before valvuloplasty (r = -0.57; p = 0.026), but was unrelated to extent of calcific deposits on the prevalvuloplasty x-ray of the excised mitral valve. Gross examination together with x-ray analysis after valvuloplasty revealed that the mechanism of balloon valvuloplasty in each case involved commissural splitting, including splits through heavily calcified commissures, without grossly apparent detachment of tissue fragments. These findings suggest that balloon valvuloplasty augments the functional mitral valve orifice area in a manner analogous to standard surgical commissurotomy, and balloon valvuloplasty is likely to be efficacious for a wide spectrum of adult mitral valvular stenosis, including severe stenosis with extensive calcific deposits.

Cor triatriatum associated with partial anomalous pulmonary venous connection to the coronary sinus: echocardiographic and angiocardiographic features.

An infant girl is described who had cor triatriatum and partial anomalous pulmonary venous connection of the left pulmonary veins to the coronary sinus, the first report of this combination of lesions. The infant also had a Dandy-Walker malformation and multiple facial and intrathoracic hemangiomas. The cardiac diagnosis was made by two-dimensional echocardiography. Cardiac catheterization and angiography confirmed the findings and also demonstrated a persistent left superior vena cava draining to the coronary sinus. The infant underwent successful surgical repair. Partial anomalous pulmonary venous connection and left superior vena cava not infrequently are associated with cor triatriatum. Although two-dimensional echocardiography is sensitive for the detection of cor triatriatum, preoperative cardiac catheterization is necessary to identify unequivocally systemic and pulmonary venous connections.

Results of the Senning operation for transposition of the great arteries with intact ventricular septum in neonates.

In spite of an adequate balloon atrial septostomy, some neonates (less than 28 days of age) with transposition of the great arteries and intact ventricular septum (TGA, IVS) remain hypoxemic and acidotic and require operative treatment. Our entire experience with the Senning operation in neonates with TGA, IVS is reviewed. From March 1978 to March 1983 there were 104 infants who underwent the Senning operation for TGA, IVS. Of these, 19 were neonates (18%). The mean age at operation was 12 days (2 to 24) and mean weight was 3.52 kg (3 to 4.38). Two died early (10%) and one died late (5%). The last 16 are alive and well. Causes of early mortality were sepsis and severe obstruction of the superior vena cava. The cause of late mortality was severe pulmonary venous obstruction. Among the 16 survivors, postoperative courses, both early and late, have been remarkably benign. Ten patients have undergone postoperative cardiac catheterization (mean follow up 17 months). Two (12%) had severe pulmonary venous obstruction (one diagnosed by two-dimensional echocardiography), but both were successfully repaired. Atrial shunt was noted in two patients (12%), one of which underwent elective repair. Five infants have dynamic subvalvular pulmonary stenosis of various gradients (9 to 93 mm Hg). One infant has mild tricuspid regurgitation. There are no cases of superior vena caval obstruction or right ventricular dysfunction. Twenty-four hour electrocardiographic monitoring (mean follow-up 25 months) showed predominant normal sinus rhythm in 15 infants and predominant junctional rhythm in one.(ABSTRACT TRUNCATED AT 250 WORDS)

Sudden death in infants with chaotic atrial rhythm.

In four cases of chaotic atrial rhythm in infancy, three infants died, two unexpectedly. Chaotic atrial rhythm may be associated with a relatively high mortality in the first year of life.

Cardiac rhythm after the Mustard operation for complete transposition of the great arteries.

The Mustard operation corrects the effects of congenital transposition of the great arteries by creating an intraarterial baffle to direct pulmonary venous blood to the tricuspid orifice and systemic venous blood to the mitral orifice. To identify the long-term effects of this procedure, we followed 372 patients with complete transposition of the great arteries who survived the Mustard operation for at least three months. The mean follow-up period was 4.5 years (range, 0.4 to 15.9); the mean age at operation was 2.0 years. Mean resting heart rates were consistently lower than those for age-matched normal children. Seventy-six per cent of the patients had sinus rhythm during the year of operation--a figure that decreased to 57 per cent by the end of the eighth postoperative year. Twenty-five patients died during the follow-up period, nine suddenly. Life-table analysis revealed a cumulative survival rate of 91 per cent for 11 years and 71 per cent for 15 years after the operation. No strong risk factor for sudden unexpected death identified. This study demonstrates that extended survival among patients with transposition can be expected after the Mustard operation. However, over time there is a decreasing prevalence of normal sinus rhythm in survivors, as well as a small risk of sudden death.

Myocardial monovalent cation transport during the quinidine-digoxin interaction in dogs.

To study the relationship of the serum digoxin concentration to the digoxin effect on monovalent cation transport during the quinidine-digoxin interaction, we used radiolabeled rubidium to measure monovalent cation active transport in myocardial biopsy samples from dogs. In a preliminary study, we showed that quinidine did not affect rubidium uptake by myocardial samples from intact dogs. Then, we studied four groups, each consisting of 13 dogs, which received either saline, low dose digoxin, high dose digoxin, or low dose digoxin plus quinidine treatment. In these groups of dogs, the following steady state serum digoxin concentrations were achieved: saline-treated, 0 ng/ml; low dose digoxin, 1.2 +/- 0.2 ng/ml (mean +/- SD); high dose digoxin, 2.4 +/- 0.4 ng/ml; and low-dose digoxin plus quinidine treated, 2.3 +/- 1.1 ng/ml. Compared to control values, rubidium uptake was decreased by 17% in dogs treated with low dose digoxin (P less than 0.05) and by 38% in dogs treated with high dose digoxin (P less than 0.01 vs. saline-treated, P less than 0.01 vs. low dose digoxin). Although low dose digoxin plus quinidine-treated dogs had the same mean serum digoxin concentration as the high dose digoxin-treated dogs, rubidium uptake in low dose digoxin plus quinidine-treated dogs was decreased by only 17% compared to control (P less than 0.05 vs. saline-treated, (P less than 0.01 vs. high dose digoxin). During the quinidine-digoxin interaction in the intact dog, the reduction in myocardial rubidium uptake is less than expected from the increase in serum digoxin concentration.