Ductus arteriosus aneurysm presenting as pulmonary artery obstruction: diagnosis and management.

The occurrence of pulmonary artery obstruction in an 8 day old infant as a complication of an aneurysm of a nonpatent ductus arteriosus is reported, together with the echocardiographic and angiographic findings. To relieve the obstruction, the aneurysm and an intrapulmonary thrombus were successfully removed with the use of cardiopulmonary bypass when the infant was 3 months old.

Pulsed Doppler and two-dimensional echocardiographic findings in aortico-left ventricular tunnel.

Two-dimensional echocardiography was used to make the anatomic diagnosis of aortico-left ventricular tunnel in a 1 day old infant. Pulsed Doppler echocardiography allowed directional flow to be determined within the tunnel. The findings were confirmed by cardiac catheterization and by direct visualization at the time of surgical repair. Aortic valve insufficiency was excluded before and after surgery using pulsed Doppler echocardiography. The anatomy and physiology of aortico-left ventricular tunnel can thus be documented using noninvasive techniques.

Effect of physical training on exercise performance of children following surgical repair of congenital heart disease.

The effect of physical training on the exercise performance of 26 patients following surgical repair of tetralogy of Fallot (16 patients) and ventricular septal defect (ten patients) was evaluated. Base line exercise testing was performed on a bicycle ergometer using the technique of Godfrey. Patients were placed on a six-week alternate day submaximal interval home exercise program of varying duration and intensity. Work loads at 50%, 60%, and 70% maximum oxygen consumption were selected to maintain heart rates between 130 and 160 beats per minute. Subjects completed an average of 18 of the possible 21 training sessions (range 11 to 21). A 25% improvement (p less than .001) was noted in maximum work capacity (747 to 935 km). Sixty-five percent of the patients performed at less than expected maximum work capacity prior to training, but only 31% performed at less than expected maximum work capacity after training. Repeat testing at work loads of one-third, one-half, and two-thirds the original maximum work capacity revealed improved aerobic efficiency as manifested by significantly decreased oxygen consumption and heart rate at each level of work. No significant difference was noted in maximum oxygen consumption. It is concluded that physical training can improve the exercise performance of patients after surgical repair, permitting the individuals to function at levels of activity at, or closely approaching, normal.

Aerobic capacity, obesity, and atherosclerotic risk factors in male adolescents.

Correlations between aerobic capacity, obesity, and atherosclerotic risk factors were evaluated in adolescents with low-to-moderate levels of physical fitness. Subjects with higher levels of fitness had a more favorable risk profile with decreased body mass index, lower systolic and diastolic blood pressure and plasma triglyceride levels, and higher plasma high-density lipoprotein-cholesterol levels. Simple linear regression analysis revealed an association between body mass index and blood pressure, plasma triglyceride and plasma high-density lipoprotein-cholesterol. The level of aerobic fitness as determined by exercise duration was also associated with the same atherosclerotic risk factors. However, multiple linear regression analysis demonstrated that body mass index provided the largest explanation, by those variables examined, of the interindividual variance in blood pressure, plasma triglyceride, and high-density lipoprotein-cholesterol. Aerobic fitness contributed only minimally to the variation in these risk factors. These findings suggest that if aerobic conditioning is used to modify atherosclerotic risk factors, it should be accompanied by a reduction in weight in adolescents with low-to-moderate levels of physical fitness.

Oral hydralazine in patients with pulmonary vascular disease secondary to congenital heart disease.

Two patients with pulmonary vascular obstructive disease secondary to congenital heart disease were evaluated hemodynamically before and during oral hydralazine therapy. Both patients were assessed postoperatively and had no significant residual shunts. Pulmonary vascular resistance failed to decrease, and an increase in pulmonary arterial pressure occurred because of increased cardiac output secondary to systemic arteriolar dilatation. These responses were sufficiently consistent to warrant a warning against the use of oral hydralazine except under controlled conditions in patients with secondary pulmonary vascular obstructive disease.

Great vein and right atrial thrombosis in critically ill infants and children with central venous lines.

We performed a retrospective review of echocardiographic data files of infants and children hospitalized in the Newborn and Pediatric Intensive Care Units. Echocardiograms were examined to detect the presence and evolution of great vein and right atrial thrombosis in patients with central venous lines. Thirty-seven patients were identified over a five-year period. Echocardiograms were performed, not routinely, but in response to specific indications including catheter malfunction, thrombocytopenia, persistent chylothorax, bacterial or fungal sepsis, and superior vena cava syndrome. Fifteen of 37 patients died, 13 of them during the hospitalization in which the thrombus was discovered. Thrombolytic agents and surgery were used to treat selected patients, with mixed results. Two of the 22 survivors have significant disability related to the thrombus or complications arising from it. We conclude that great vein and/or right atrial thrombosis is a common complication of central venous catheterization in small infants and children; moreover, the morbidity and mortality relating to this complication is substantial.

Blood pressure response to exercise in children following the subclavian flap procedure for coarctation of the aorta.

Eight patients who underwent repair of coarctation of the aorta as infants (mean age 4.6 months) by the subclavian flap procedure were evaluated by dynamic exercise. Their mean age at the time of exercise testing was 4.6 years. Resting upper to lower limb systolic blood pressure gradients were similar in the patients and control subjects (mean 17 +/- 12 and 2 +/- 14 mm Hg) (p greater than 0.05). Mean resting systolic blood pressures in the upper limb were 121 +/- 10 mm Hg in the patients and 107 +/- 14 mm Hg in the volunteers (p greater than 0.05). The mean gradient between the upper and lower limbs was 13 +/- 19 mm Hg in the patients on dynamic exercise testing. No patient became pathologically hypertensive in the upper limbs during dynamic exercise. These results indicate that the subclavian flap procedure is an effective form of treatment for the symptomatic infant with coarctation of the aorta and can be expected to result in a low incidence of subclinical residual obstruction or restenosis.

Noninvasive assessment of cardiopulmonary function in critically ill infants and children.

Echocardiography and Doppler echocardiography allow for the accurate noninvasive assessment of cardiac structure and function. Two-dimensional echocardiography accurately demonstrates both normal and abnormal intracardiac and great vessel anatomy and assists in differentiating cardiac from noncardiac causes of respiratory distress. M-mode echocardiography allows for documentation of cardiac chamber size and left ventricular function. Doppler echocardiography is used to measure cardiac output, assess AV and semilunar valve function, detect abnormal flow patterns within the heart and great vessels, and assist in the assessment of pulmonary artery pressures. This article discusses the uses of all these modalities as they apply to the critically ill infant and child.

Evaluation of the pediatric surgical patient with congenital heart disease.

Children with cardiac disease who undergo noncardiac surgical procedures may encounter risks beyond those usually associated with surgical procedures. In this article, several complicating factors seen in children with heart disease are discussed, including arrhythmias, cyanosis, congestive heart failure, pulmonary hypertension, and subacute bacterial endocarditis.

Cardiac hypertrophy associated with ACTH therapy for childhood seizure disorder.

Hypertrophic cardiomyopathy is a newly recognized, potentially fatal complication of ACTH therapy. We report the clinical, echocardiographic, and pathologic findings of an infant who was treated with ACTH for seizure disorder and subsequently developed severe systemic hypertension. Echocardiography revealed marked cardiac hypertrophy with disproportionate septal hypertrophy. Decreasing the dose of ACTH reduced the systemic blood pressure, but the cardiac hypertrophy progressed and the child subsequently died. Children who develop hypertension during ACTH therapy should be considered at risk for hypertrophic cardiomyopathy and should undergo routine echocardiographic evaluation.

Hypertrophic cardiomyopathy in the adolescent.

Hypertrophic cardiomyopathy is the more accurate term for the condition also known as idiopathic hypertrophic subaortic stenosis, asymmetric septal hypertrophy or hypertrophic obstructive cardiomyopathy. Although an uncommon condition in the adolescent, its importance lies in the fact that it is hereditary, sometimes difficult to diagnose clinically, and may be associated with sudden death - especially during or after exertion. All patients with a systolic murmur at the left sternal border should be made to stand, squat and perform a Valsalva maneuver while being auscultated. Since hypertrophic cardiomyopathy is associated with a dynamic intraventricular gradient, the murmur will change in character and intensity during these maneuvers. An electrocardiogram and echocardiogram is indicated if there is any suspicion of the diagnosis. Patients with hypertrophic cardiomyopathy should be prohibited from participating in competitive sports or performing strenuous activities even in the absence of a significant intracavitary gradient. They should be placed on high-dose beta-blockers and followed closely. Follow-up should include the use of Holter monitoring to exclude the presence of arrhythmias. Supraventricular or ventricular arrhythmias should be treated aggressively since they may be associated with sudden death. Family members or first-degree relatives should be screened by echocardiography for the condition and the patient informed of the genetic nature of the disease. The condition needs to be differentiated from the 'athlete's heart' which may present with a murmur and electrocardiographic and echocardiographic evidence of left ventricular hypertrophy, since the latter condition is considered physiologic and not an indication to discontinue an athlete's activities.

Intussusception in haemophilia: a case report.

A case of intussusception in a haemophilic boy is described. The presumed cause was an intramural haematoma, which resulted in an ileocolic intussuception. This appears to be the first reported case which has been reduced by barium enema. It is suggested that this method, together with factor VIII replacement therapy as soon as possible after the development of symptoms, is the treatment of choice.

Effect of resistive training on plasma lipid and lipoprotein levels in male adolescents.

We studied fourteen 14 to 17-year old male adolescents before and after a 9-week resistive exercise program and compared the changes in lipid and lipoprotein profiles with those in 14 non-exercising control subjects. Studies included determination of weight, body mass index (weight for height2), percent body fat, blood pressure and resting heart rate, maximum heart rate and maximum oxygen consumption, and plasma lipids and lipoproteins. No significant differences were present between the two groups before training except that percent body fat was lower in the control subjects. After training, low-density lipoprotein cholesterol in the exercising subjects decreased from 120 +/- 15 to 95 +/- 13 mg/dL (P less than 0.001), high-density lipoprotein cholesterol increased from 35 +/- 12 to 45 +/- 8 mg/dL (P less than 0.01), and high-density lipoprotein cholesterol/total cholesterol ratio increased from 0.2 +/- 0.06 to 0.27 +/- 0.05 (P less than 0.001). Control subjects showed a significant increase in weight (P less than 0.01) and body mass index (P less than 0.01) and a decrease in maximum heart rate (P less than 0.01) at the end of the 9 weeks. Adjustment for body mass index resulted in no alteration in the favorable response of the lipoprotein profile. No change occurred in body composition or maximum oxygen consumption with training. These findings indicate that resistive training is associated with a favorable alteration in the lipoprotein profile in adolescent males.

Inotropic responsiveness of the heart in catecholamine cardiomyopathy.

Inotropic responsiveness to norepinephrine (NE) or Ca2+ was studied in 15 rabbits with catecholamine cardiomyopathy (CM) and the results were compared with 11 controls. The former group was prepared by infusing NE (2 micrograms/min/kg) for 90 minutes, 2 to 3 days prior to study, and injury was confirmed and quantified histologically. Comparison of NE dose-response curves relating percent increase of left ventricular (LV) dP/dt max to NE dose in six controls and 10 CM hearts revealed significant depression of CM contractility. Responses to graded infusions of Ca2+ were also determined in five controls and in five CM animals. With the increases in serum Ca2+ identical in the two groups, the percent increases in dP/dt max were less in CM hearts. Further, NE dose-response curves obtained during continuous CaCl2 infusion were sharply attenuated in CM hearts and initial LV end-diastolic pressure (LVEDP) in the CM hearts was considerably higher than in the controls. It is concluded that inotropic sensitivity to NE is reduced in CM hearts. This cannot be ascribed to altered beta-receptors alone, because responsiveness to Ca2+ was also reduced. Myocardial damage was indicated by histology and elevated LVEDP. Moreover, the normalized percent data suggest tht the remaining viable fibers in the CM hearts were functioning subnormally and thus reduced performance was not due solely to the decreased number of contracting units.

Myocardial responses to alpha-adrenoceptor stimulation with methoxamine hydrochloride in lambs.

This study was undertaken to evaluate the effects of methoxamine on left ventricular performance, coronary blood flow (CBF), and myocardial oxygen consumption (MVO2) in lambs. Measurement of maximum rate of rise of left ventricular pressure (LV dP/dtmax), left ventricular end-diastolic pressure (LVEDP), CBF, and MVO2 were made in nine lambs using a hemodynamically controlled preparation. The lambs were given atropine sulfate (1 mg), tetraethylammonium chloride (100 mg), and practolol (4 mg/kg) to provide parasympathetic, ganglionic, and beta-adrenergic blockades. Aortic pressure and blood flow and heart rate were held constant in each lamb. Dose-related increases in LV dP/dtmax and decreases in LVEDP were observed after progressively larger doses of methoxamine ranging from 0.4 to 6.0 mg/kg were given. These positive inotropic responses were eliminated by giving phentolamine (2 mg/kg). CBF, myocardial O2 extraction, and MVO2 did not change significantly. A positive inotropic action of methoxamine was also demonstrated in five additional animals by obtaining ventricular function curves. Initially the mean stroke volume at LVEDP 10 cmH2O (SV10) was 4.11 +/- 0.16 (SE) ml. This value increased to 5.09 +/- 0.28 ml after methoxamine (P less than 0.01). After phentolamine, SV 10 fell to 4.37 +/- 0.08 ml (P less than 0.05). These observations support the hypothesis that alpha-adrenergic receptors are present and mediate a substantial positive inotropic action on neonatal lamb myocardium.

Hemodynamic effects of ketamine in children undergoing cardiac catheterization.

Ketamine is used to supplement sedation during cardiac catheterization. We studied ketamine-induced circulatory changes in 28 acyanotic children (18 of whom had left-to-right shunts), aged 4-161 months (mean, 33 months). Oxygen consumption (VO2) was measured continuously. In the 18 patients with shunts, the pulmonary to systemic flow ratio fell slightly (2.3 +/- 1.1 to 1.8 +/- 0.4, p less than 0.05). In all patients, the ratio of pulmonary (PVR) to systemic vascular resistance (SVR) rose from 0.16 +/- 0.09 to 0.28 +/- 0.21, p less than 0.001. Ketamine increases VO2, heart rate, cardiac output, and pulmonary arterial pressure (PAP). The rise in PAP is more consistent than the rise in PVR; resistance changes were greatest in patients with elevated resting PVR (r = 0.54). Caution should be used in administering ketamine to selected subjects; moreover, ketamine can confuse interpretation of cardiac catheterization data, especially if VO2 is assumed and not measured.

Enhanced sensitivity of diabetic hearts to alpha-adrenoceptor stimulation.

Inotropic responses to alpha-adrenergic stimulation with methoxamine were compared in 12 normal (N) and 12 diabetic (Db) lambs. Diabetes was produced by giving alloxan monohydrate (150 mg/kg iv). Measurements of maximal rate of rise of left ventricular pressure (dP/dtmax), left ventricular end-diastolic pressure (LVEDP), coronary flow, and myocardial O2 consumption were made simultaneously in hemodynamically controlled preparations. All animals were subjected to ganglionic blockade (tetraethylammonium chloride, 100 mg) and beta1-adrenergic blockade (practolol, 4 mg/kg). Methoxamine was given in incremental doses ranging from 0.4 to 6.0 mg/kg. dP/dtmax increased progressively to 126 +/- 4% of initial values in N. However, the increase was twice as large (150 +/- 4%) in the diabetics (P less than 0.005). LVEDP fell in both groups. These changes were abolished by phentolamine (2 mg/kg). Inotropic responses to methoxamine in lambs 2 and 3 wk after induction of diabetes did not differ from those with acute (2 days) diabetes. Dose-response curves obtained by infusing Ca2+ (2-8 mg X min-1 X kg-1) were identical in N and Db. It is concluded that lamb myocardium possesses an alpha-adrenergic receptor system that is stimulated by methoxamine in a dose-dependent manner and blocked by phentolamine. Db hearts are supersensitive to alpha-receptor activation. The mechanistic basis for this latter finding has not been examined but may relate to altered receptor density or nucleotide regulation.

Significant pulmonary valve incompetence following oversize balloon pulmonary valveplasty in small infants: A long-term follow-up study.

Oversized dilatation balloons are recommended for relief of valvar pulmonic stenosis in infants and children during cardiac catheterization. Little information exists about the long-term outcome of this practice. Six of 107 consecutive patients undergoing balloon pulmonary valveplasty developed increasing pulmonary valve incompetence during follow-up periods of 0.5-10 years (mean, 7.2 years). Secondary right ventricular dilatation prompted insertion of a bioprosthetic pulmonary valve in one patient 6.8 years after intervention; valve replacement is pending in two additional patients, 4.3 and 10 years after intervention, respectively; and the three remaining subjects are thought likely to require valve replacement during childhood. The six reported subjects differ from the pulmonary valveplasty group as a whole in that they are younger (median age, 3 days vs. 11 months), had a higher degree of obstruction (right/left ventricular systolic pressure ratio prior to valveplasty 1.28 vs. 0.92), and underwent dilatation with relatively oversized balloons (balloon diameter to pulmonary valve annulus ratio 1.44 vs. 1.08). The balloon diameter to valve annulus ratio did not exceed 1.5 in any subject. Caution is advised in the use of oversized dilatation balloons in neonates or young infants with severe or critical pulmonic stenosis. Long-term consequences of substantial pulmonary valve incompetence outweigh, in our opinion, the limited gradient relief achieved with smaller balloons, sometimes requiring a second dilatation of the valve at an older age and larger size. Cathet. Cardiovasc. Intervent. 48:61-65, 1999.

Carbohydrate metabolism in isolated, working newborn pig heart.

Metabolic activity of the newborn pig heart was observed by means of a preparation that allowed isolated hearts to perform a physiologic work load. A 10-min period of retrograde aortic perfusion was followed by 60 min of recirculating perfusion in which bicarbonate buffer was infused into the right atrium and ejected from both ventricles at measured pressures and flow rates. The buffer was supplemented with either glucose (10 mM), lactate (20 mM), or pyruvate (20 mM), or was unsupplemented. Pressure development and ventricular outputs were stable through 60 min of perfusion with glucose, pyruvate, or lactate supplementation. Myocardial high-energy phosphate and glycogen contents were also stable. In hearts perfused without substrate supplementation, mechanical performance deteriorated after 30 min. Rates of substrate uptake and oxygen consumption indicated that either glucose, lactate, or pyruvate could serve as a primary source of metabolic energy. Minimal lactate production was observed when either glucose or pyruvate were present. These findings indicate that, despite recent emergence from the relatively hypoxic intrauterine environment, the well-oxygenated newborn pig heart did not depend on anaerobic metabolism of glucose for energy production at physiologic work loads.

Vessel-sparing technique for coil occlusion of the very small patent ductus arteriosus.

A technique is described for coil occlusion of the small patent ductus arteriosus through a 4 French arterial catheter. The need for a 5 French sheath and catheter to stabilize the 3 French size delivery catheter system is obviated. The method is proposed as a way to minimize arterial vascular injury in the small patient undergoing transcatheter occlusion of the small ductus.