Robert D. Ross

Grading the severity of congestive heart failure in infants

SummaryTo determine which variables most accurately define congestive heart failure (CHF) in infants, 41 patients (median age 2.5 months) were graded by four pediatric cardiologists for the presence and severity of CHF based on the following variables: amount of formula consumed per feeding, feeding time, history of diaphoresis or tachypnea, growth parameters, respiratory and heart rates, respiratory pattern, perfusion, presence of edema, diastolic filling sounds, and hepatomegaly. There were 19 patients graded as having no CHF, nine as mild, seven moderate, and six severe CHF. The most sensitive and specific variables (p<0.0001) for the presence of CHF were a history of <3.5 oz/feed, respiratory rate >50/min, an abnormal respiratory pattern, diastolic filling sounds, and hepatomegaly. Moderate to severe CHF was present when patients took <3 oz/feed or >40 min/feed, had and abnormal respiratory pattern with a resting respiratory rate >60/min, and had a diastolic filling sound and moderate hepatomegaly. Severe CHF was accompanied by a heart rate >170/min, decreased perfusion, and severe hepatomegaly. Thus, the grading of the severity of CHF in infants should include an accurate description of these historical and clinical variables.

Plasma norepinephrine levels in infants and children with congestive heart failure

To characterize the sympathetic nervous system response to congestive heart failure (CHF) in infants and children, plasma catecholamine levels were measured in 102 subjects undergoing routine cardiac catheterization (mean age 3.3 years, range 0.1 to 14.7), including 61 with left-to-right shunts. Plasma norepinephrine levels were significantly higher (p less than 0.0001) in children with CHF than in those without CHF. A highly significant association (p less than 0.0001) was found between the level of plasma norepinephrine and severity of CHF symptoms. This relation was found for CHF secondary to lesions producing a left-to-right shunt and CHF resulting from primary myocardial dysfunction. In congenital lesions with a left-to-right shunt, plasma norepinephrine levels correlated well with size of the shunt (Qp/Qs) (r = 0.75, p less than 0.001) and degree of pulmonary arterial hypertension (r = 0.70, p less than 0.001). Elevation of plasma norepinephrine concentrations in infants and children are seen with severe CHF regardless of its origin.

Spontaneous regression of cardiac rhabdomyoma

Abstract Multiple cardiac rhabdomyomas in a neonate with tuberous sclerosis were first described by Von Recklinghausen in 1862. These hamartomas are the cardiac tumors most frequently encountered during infancy and childhood. Rhabdomyomas account for 45% of primary heart tumors in children and represent 53% of primary benign childhood cardiac tumors. 1 Approximately 30% of patients with tuberous sclerosis have cardiac rhabdomyomas. 2 Their natural history is unclear because most reviews on this subject are based on autopsy data. The prognosis for cardiac rhabdomyomas is believed to be grim because of reported fatality rates of 53% by the first week of life and 78% by 1 year of age. 2,3 With widespread use of echocardiography in pediatrics during the last 2 decades, it has become clear that rhabdomyomas result in a wide spectrum of clinical manifestations, ranging from a total absence of symptoms to intrauterine or sudden postnatal death. Also reported are hydrops fetalis, dysrhythmias, inflow or outflow obstruction, congestive heart failure and possibly cerebral embolization. Histologic examination of these masses in 1923 was suggestive of spontaneous regression. 4 Isolated clinical reports of spontaneous regression have recently appeared. 5 We now describe a series of 5 infants with tuberous sclerosis who had close documentation of the size of their 13 tumors.

Relation of elevated plasma endothelin in congenital heart disease to increased pulmonary blood flow

Endothelin-1 (ET), a potent vasoconstrictor peptide, has been found to be elevated in children with pulmonary hypertension associated with congenital heart defects. To evaluate the effect of pulmonary blood flow on ET concentrations, 5 ml blood samples were obtained peripherally at cardiac catheterization from 35 patients, ages 0.13 to 17 years (median 2). Plasma was extracted and ET measured by radioimmunoassay. Patients were classified into 2 groups based on the presence (group A) or absence (group B) of increased pulmonary blood flow defined as a Qp/Qs > or = 1.5. When the 13 patients (37%) in group A were compared with the 22 patients (63%) in group B there were no significant differences in age, cardiac index, or pulmonary and systemic resistances. ET concentrations were significantly higher in group A patients (median 3.25, range 0 to 16.5 vs median 0, range 0 to 6.35 pg/ml; p < or = 0.05). Pulmonary blood flow and pulmonary artery pressure were also higher in group A patients (p < or = 0.01). When patients within group A were subdivided into those with and without pulmonary hypertension, no difference was present in their ET concentrations (mean/SD: 4.4/4.3 vs 4.0/6.4 pg/ml, p = NS). Thus, ET is elevated in patients with congenital heart disease associated with left-to-right shunts and it appears that this increase is related to increased pulmonary blood flow independent of pulmonary artery pressure.

Presentation, Diagnosis, and Medical Management of Heart Failure in Children: Canadian Cardiovascular Society Guidelines

Pediatric heart failure (HF) is an important cause of morbidity and mortality in childhood. This article presents guidelines for the recognition, diagnosis, and early medical management of HF in infancy, childhood, and adolescence. The guidelines are intended to assist practitioners in office-based or emergency room practice, who encounter children with undiagnosed heart disease and symptoms of possible HF, rather than those who have already received surgical palliation. The guidelines have been developed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology, and are accompanied by practical Recommendations for their application in the clinical setting, supplemented by online material. This work does not include Recommendations for advanced management involving ventricular assist devices, or other device therapies.

Coronary Sinus Ostial Atresia With Persistent Left Superior Vena Cava

BACKGROUND Atresia of the coronary sinus orifice with a persistent left superior vena cava is an intrinsically benign cardiac anomaly with important surgical implications. METHODS THe medical records of 5 patients with atresia of the coronary sinus orifice with a persistent left superior vena cava were reviewed retrospectively, and a computer search of the world literature describing this cardiac malformation was undertaken. RESULTS The 5 patients ranged in age from 9 months to 5 years. In 2, the diagnosis was made preoperatively by angiocardiography, and in 3, the abnormality was found incidentally at the time of cardiotomy for repair of associated congenital heart disease. Four of the 5 patients underwent repair of associated cardiac lesions. During operation, care was taken to avoid disruption of left superior vena cava flow to prevent coronary venous obstruction. All patients survived and are doing well at follow-up. CONCLUSIONS Atresia of the coronary sinus orifice with persistent left superior vena cava is, in itself, a benign anomaly without physiologic consequence. However, the recognition of this lesion during repair of associated cardiac lesions is of vital importance to the cardiac surgeon. Interruption of this sole route of coronary venous drainage can potentially lead to myocardial ischemia and necrosis.

Augmented norepinephrine and renin output in response to maximal exercise in hypertensive coarctectomy patients

To evaluate a possible neural or renal contribution to the hypertension that occurs in some patients following coarctation of aorta repair, 35 patients underwent graded bicycle exercise with serial measurements of plasma norepinephrine concentrations and plasma renin activity. Sixteen patients with coarctectomy who had systolic or diastolic hypertension at peak exercise were compared with 19 normotensive patients with coarctectomy. The average time interval between coarctation repair and study was significantly longer (p less than 0.05) in the hypertensive group than in the normotensive patients (12.8 +/- 4.8 versus 8.7 +/- 2.2 years). The heart rate response to exercise was similar for both patient groups. The systolic blood pressure in the hypertensive group was higher than in the normotensive group at rest in the supine and upright positions and at 5 minutes of recovery, in addition to peak exercise, and the diastolic blood pressure was increased at peak exercise. Plasma norepinephrine concentrations were significantly higher at peak exercise and during recovery in the hypertensive group than in the normotensive patients. Plasma renin activity was also significantly higher in the hypertensive group at peak exercise. These data suggest that patients with coarctectomy who have a hypertensive response to exercise have an augmented sympathetic nervous system output and increased plasma renin activity that may lead to peripheral vasoconstriction at peak exercise and that may contribute to the development of their hypertension.

Sequence mapping of transfer RNA chemical modifications by liquid chromatography tandem mass spectrometry.

Mass spectrometry is a powerful analytical tool for identifying and characterizing structural modifications to the four canonical bases in RNA, information that is lost when using techniques such as PCR for RNA analysis. Here we described an updated method for sequence mapping of modified nucleosides in transfer RNA. This modification mapping approach utilizes knowledge of the modified nucleosides present in the sample along with the genome-derived tRNA sequence to readily locate modifications site-specifically in the tRNA sequence. The experimental approach involves isolation of the tRNA of interest followed by separate enzymatic digestion to nucleosides and oligonucleotides. Both samples are analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) and the data sets are then combined to yield the modification profile of the tRNA. Data analysis is facilitated by the use of unmodified sequence exclusion lists and new developments in software that can automate MS/MS spectral annotation. The method is illustrated using tRNA-Asn isolated from Thermus thermophilus.

Activity of the renin-angiotensin-aldosterone and sympathetic nervous system and their relation to hemodynamic and clinical abnormalities in infants with left-to-right shunts

We studied neurohormonal, clinical and invasively measured hemodynamic data of 47 infants with left-to-right shunts and varying degrees of congestive failure. When referred to a clinical heart failure score, plasma renin activities (r=0.71) and norepinephrine levels (r=0.43) are significantly increased. Arterial hypotension seems to be the hemodynamic trigger of renin release (r=-0.72), but not decreased systemic cardiac index (r=-0.43), the magnitude of the left-to-right shunt (r=0.33) or a reduced ejection fraction (r=0.12). These data indicate neurohormonal activation in infants with left-to-right shunts with preserved myocardial function is similar to the activation in adults with heart failure secondary to myocardial pump failure. These findings have to be considered for optimal medical treatment of these infants with angiotensin-converting enzyme inhibitors or beta-blockers.

Myocardial Performance and Perfusion During Exercise in Patients with Coronary-Artery Disease Caused by Kawasaki Disease

For a study of the natural history of coronary artery lesions after Kawasaki disease and their effect on myocardial blood flow reserve with exercise, five such patients underwent exercise testing on a bicycle. Oxygen consumption, carbon dioxide production, minute ventilation, and electrocardiograms were monitored continuously. Thallium-201 scintigraphy was performed for all patients. One patient stopped exercise before exhaustion of cardiovascular reserve but had no evidence of myocardial perfusion abnormalities. Four patients terminated exercise because of exhaustion of cardiovascular reserve; one had normal cardiovascular reserve and thallium scintiscans, but the remaining patients had diminished cardiovascular reserve. Thallium scintigrams showed myocardial ischemia in two and infarction in one. No patient had exercise-induced electrocardiographic changes. These results indicate that patients with residual coronary artery lesions after Kawasaki disease frequently have reduced cardiovascular reserve during exercise. The addition of thallium scintigraphy and metabolic measurements to exercise testing improved the detection of exercise-induced abnormalities of myocardial perfusion.