Wendy J. Wolf

Atrial septal aneurysms in infants and children

Interatrial septal aneurysm (IASA) has been detected with increasing frequency since the advent of two-dimensional echocardiography (2DE). In this study, we investigated the prevalence, characteristics, and predisposing factors in IASA formation in 724 infants, children, and adolescents undergoing 2DE. Among this group, 12 patients had an IASA (prevalence = 1.7%). Eleven of the 12 patients had abnormal atrial hemodynamics as a result of either structural heart disease or significant supraventricular dysrhythmias. Follow-up 2DE performed in 10 of 12 patients, 1 to 48 months (mean 16.5 months) after the initial diagnosis, demonstrated diminution or resolution of the IASAs in those patients who had normal hemodynamics following surgical or spontaneous closure of their intracardiac defect, or medical control of their dysrhythmias. In contrast, IASAs became more prominent in those patients with persistent hemodynamic abnormalities. The high prevalence rate and subsequent involution of many IASAs in infants suggest that in the presence of abnormal atrial hemodynamics, the neonatal atrial septum may be prone to aneurysm formation because of inherent structural weaknesses of the neonatal septal tissue. In the absence of continued hemodynamic stress., the majority of these IASAs in infants resolve with maturational changes in the septum and normal cardiac growth.

Diagnostic features and pitfalls in the two-dimensional echocardiographic evaluation of a child with cor triatriatum

SummaryTwo-dimensional echocardiography has been successfully used to diagnose cor triatriatum in adults and children, and surgical referral of these patients has been undertaken without preceding cardiac catheterization and angiography. A child with cor triatriatum demonstrated by two-dimensional echocardiography was directly referred for surgical resection. Despite thorough preoperative echocardiographic examination and direct intraoperative inspection of the posterior left atrial chamber, partial anomalous right pulmonary venous drainage was not diagnosed until the postoperative period. The failure to detect this uncommon associated anomaly underscores the limitations of relying on two-dimensional echocardiography as the sole preoperative method of evaluation.

Left ventricular bands (false tendons): Echocardiographic and angiocardiographic delineation in children

Left ventricular bands were prospectively identified in 31 of 218 (14.2%) children undergoing an initial two-dimensional echocardiogram for suspected or known cardiac disease. Left ventricular bands usually coursed from the midportion of the interventricular septum to the free wall of the left ventricle. Most of the bands were detected in the apical four-chamber view. In 7 of 31, an hourglass configuration of the left ventricular cavity was noted. Diagnostic left ventricular angiography was performed in 9 of 31 patients, and in seven of nine the band was delineated. The echocardiographic and angiographic findings in children with left ventricular bands are discussed and the literature is reviewed.

Is there a thyrotoxic cardiomyopathy in children

We measured left ventricular ejection fraction by radionuclide angiocardiography at rest and during graded exercise in eight thyrotoxic children. Five patients were reassessed after return to a clinically euthyroid state. In the thyrotoxic state the left ventricular ejection fraction was 69% +/- 8% at rest, and increased normally by 7% to 10% during exercise in four patients but did not change significantly or decreased by as much as 8% in the other four patients. The change in left ventricular ejection fraction during exercise correlated inversely with serum concentrations of thyroxine (r = -0.82, P less than 0.02) and triiodothyronine (r = -0.88, P less than 0.01). A comparison between patients who had normal left ventricular response to exercise with those who had abnormal response while thyrotoxic failed to uncover any significant differences between their resting ejection fractions or resting and exercise heart rates and systolic blood pressures. Three abnormal and two normal responders were reassessed after return to a clinically euthyroid state. The left ventricular ejection was 64% +/- 6% at rest, and increased during exercise in all patients. Our study suggests that thyrotoxicosis causes diminished left ventricular reserve (compensated functional cardiomyopathy) in some patients, but appears to be reversible. Severity of thyrotoxicosis, as measured by thyroid hormone blood levels, may be a determining factor in the development of functional cardiomyopathy.

Fetal cardiovascular and catecholamine responses to hypoxemia after chemical sympathectomy.

Summary: Chemical sympathectomy was performed in fetal lambs in utero by daily intravenous administration of 6-hydroxydopamine (6HD) until a total dose of 60-70 mg/kg was reached. The completeness of adrenergic denervation was confirmed by the absence of any cardiovascular response to tyramine infusion. Baseline plasma catecholamine concentrations in normoxemic, sympathectomized fetuses were slightly higher than controls but the differences were not statistically significant. The concentration of norepinephrine (NE) was 313 ± 73 pg/ml after 6HD administration compared with 259 ± 25 pg/ml in control animals. Similarly, the concentration of epinephrine (E) was 39 ± 15 pg/ml (6HD) versus 21 ± 4 pg/ml (control). These mildly elevated catecholamine levels were accompanied by a small but significant increase in resting blood pressure (BP) (P < 0.05). Heart rate (HR), however, was no different from control. Hypoxemia induced a marked increase in plasma catecholamines in control animals (NE, 2416 ± 419 pg/ml and E, 2017 ± 749 pg/ml) along with hypertension and bradycardia. Sympathectomized fetuses maintained a profound NE response to hypoxemia (NE, 1550 ± 261 pg/ml) but a significant reduction in peak E response was observed (E, 244 ± 42 pg/ml, P < 0.05). HR and BP responses to hypoxemia were generally similar to control animals though there appeared to be a brief 1-3-min lag period between the nadir of the bradycardia and the peak of the BP response. We conclude that the generalized chemical sympathectomy after 6HD administration in the fetal lamb in utero is useful in evaluating the interaction of the autonomic nervous system and adrenal medullary function on the regulation of the fetal cardiovascular system.

Echo Doppler detection of external compression of the vertical vein causing obstruction in total anomalous pulmonary venous connection

External obstruction of the pulmonary venous return was detected by two-dimensional (2-D) and pulsed Doppler echocardiography and was confirmed by angiography and at surgery in two infants with isolated supracardiac total anomalous pulmonary venous connection (TAPVC) to the left vertical vein. In both infants, the left vertical vein ascended behind the left pulmonary artery and anterior to the left main stem bronchus. This arrangement produces mechanical obstruction to both vertical vein flow and pulmonary venous drainage. Early detection and surgical correction of obstructed pulmonary venous return are necessary to prevent severe right-sided heart failure and death. Doppler echocardiography is recommended when evaluating infants with TAPVC for possible anatomic or mechanical obstruction to pulmonary venous return.

Absent right atrioventricular connexion with the left atrium connected to the morphologically right ventricle, a right-sided rudimentary left ventricle, and right juxtaposition of the atrial appendages: documentation by angiography and cross-sectional echocardiography

In this report, a 12-hr-old male infant was demonstrated to have the absent connexion variant of right atrioventricular valve atresia with the left atrium connected to the morphologically right ventricle with a right-sided rudimentary left ventricle. The aorta arose from the right ventricle and there was pulmonary atresia, the pulmonary circulation being duct-dependent. In addition there was right juxtaposition of the atrial appendages. The definitive cross-sectional echocardiographic and angiographic findings are presented.

Echocardiographic detection of a left atrial thrombus in an infant with complex congenital heart disease

revealed only a trace of mitral insufficiency and tricuspid insufficiency. The capability of a chronic supraventricular tachycardia inducing cardiomyopathy has been reported. These cases were present in children or in adolescents, with the oldest patient being 14. To our knowledge, this is the first reported case in an adult. In the initial studies, the main therapy was surgical intervention, with subsequent resolution and normalizing of function. The next cases were pediatric patients whose myocardial function improved after medical therapy. Our case reveals changing echocardiographic findings consistent with the development of a congestive cardiomyopathy and valvular insufficiency secondary to a supraventricular arrhythmia, and subsequent medical treatment eliminating this. The initial echocardiogram was done when supraventricular tachycardia was at a lower rate. As the tachycardia became more consistent and had a faster rate, a congestive cardiomyopathy developed. The patient had been treated with prednisone for her acute exacerbation, with tapering dosages. The possibility of a steroid causing the myopathy was considered. However, the patient was on a larger prednisone dose when her first echocardiogram was done than during the second echocardiogram, and she continued to be maintained on prednisone. Subsequent therapy with amiodarone corrected the arrhythmia and within 1 year the patient showed marked improvement of left ventricular function. The Doppler study (although not quantitative) appears to show decreasing regurgitation that accompanied the resolution of the dilatation of the ventricles. This shows that cardiomyopathy can occur in the adult as well as in the adolescent population secondary to tachycardias, and that the condition may cause vaIvular dysfunction. This also demonstrates the time course of the occurrence and resolution of the cardiomyopathy. The treatment of the tachycardia should be aggressive, including experimental drugs, surgical or catheher ablation, or other mechanisms. With successful therapy, the cardiomyopathy and valvular dysfunction may resolve.

87 LEFT VENTRICULAR FALSE TENDONS (BANDS): ECHOCARDIOGRAPHIC AND ANGIOCARDIOGRAPHIC DELINEATION

Left ventricular false tendons have been demonstrated by two-dimensional echocardiography in adults (5%) and children (61%). After identifying 3 children with left ventricular false tendons and mitral stenosis, a prospective study was designed. Over a 4 month period, 62 children underwent complete two-dimensional echocardiographic exam for either suspected heart disease or pericardial effusion. Ages ranged between 1 day and 18 years. In 7 children, a single left ventricular false tendon was identified in the apical 4 chamber view. The diagnoses included congenital heart disease (5), cardiomyopathy (1) and functional murmur (1). The left ventricular false tendon usually extended from the left ventricular apical free-wall to the mid portion of the interventricular septum. Left ventricular angiography was performed in 6 children (including the 3 prior to the prospective study). In 5 of 6, a fine radiolucent line was seen towards the apex of the left ventricle after careful review, confirming the echocardiographic finding. No left ventricular outflow tract obstruction was detected by pressure recordings in these 6 patients.Left ventricular false tendons were identified in 11% of children by two-dimensional echocardiography and were successfully detected during left ventricular angiography. Left ventricular false tendons appear to have a benign course and should not be mistaken for structures that can produce left ventricular outflow tract obstruction.

HIS-PURKINJE ELECTROPHYSIOLOGICAL CHARACTERISTICS IN CHILDREN WITH HEART DEFECTS

Refractory periods (RP) of the atrium, atrioventricular (A-V) node and of the right ventricle have been determined with the atrial extrastimulus (AES) technique in children with and without heart defects (HD). Limited data is available on the RP of the HIS-Purkinje (HP) network in children with preoperative (preop) and postoperative (postop) HD. Electrophysiologic studies (EPS) were performed in 49 children with various preop and postop HD. Ages ranged between 2 and 20 years. EPS consisted in determining sinus node recovery times; atrial and A-V nodal RP. AES was coupled to sinus rhythm and to 1 or 2 paced cycle lengths. The relative (R) RPHP was determined in 18/49 (37%) patients (10 preop and 8 postop). Only 2/18 had prolonged H-V interval at rest. During AES coupled to sinus rhythm the RRPHP ranged between 270-530 msec. During AES coupled to atrial pacing the RRPHP ranged between 250-470 msec. These values did not differ significantly between the preop and postop patients. The RRPHP decreased when the cycle length was shortened. The effective (E) RPHP and the RRP of the His-bundle (HB) were only determined in 4/49 patients.In conclusion, the RRPHP did not differ significantly between the preop and postop patients and, therefore, it is a functional electrophysiological characteristic of HP system; and it was more easily elucidated than the ERPHP and RRPHB.