André Davignon

Normal ECG standards for infants and children

SummaryNormal ECG values were determined using computer-assisted measurement of the ECGs of 2,141 white children aged 0 to 16 years divided into 12 age groups.These values are plotted on graphs containing the second, fifth, 25th, 50th, 75th, 95th, and 98th percentiles for each age group. This provides a convenient, fast, and practical method for comparing the values found in a given ECG with those found in a normal population, taking into account the evolution of ECG patterns with age.

Predictive factors for spontaneous closure of atrial septal defects diagnosed in the first 3 months of life

OBJECTIVES To establish the rate of spontaneous closure of atrial septal defects diagnosed before age 3 months, 101 infants (mean age 26 days) with an interatrial shunt confirmed by Doppler echocardiography were followed up for an average of 265 +/- 190 days. BACKGROUND Even if interatrial shunts in the newborn are frequently encountered, little is known about their natural history. METHODS Defect diameter on two-dimensional echocardiography and width of color flow jet were measured in the subcostal view. Right and left ventricular diameters and atrial septal curvature were also studied. Kaplan-Meier curves were obtained to predict age of spontaneous closure in relation to initial defect diameter. RESULTS There was no significant correlation between the diameter of the atrial septal defect and right ventricular/left ventricular ratio or type of septal curvature (vertical or concave toward the left atrium). The classic predominance of girls over boys was observed only for defects > 5 mm. An overall rate of spontaneous closure of 87% was observed. Frequency and timing of closure were inversely correlated to atrial septal defect diameter: closure occurred in 100% (32 of 32) of defects in group 1 (diameter < 3 mm), 87% of defects (39 of 45) in group 2 (diameter 3 to 5 mm), 80% of defects (16 of 20) in group 3 (diameter 5 to 8 mm). Spontaneous closure did not occur in four patients of group 4 (defect > or = 8 mm) during an average follow-up interval of 417 days (range 294 to 597 days). CONCLUSIONS These results suggest that infants with an atrial septal defect < 3 mm need not be followed up as 100% of these defects will be closed by age 18 months; those with a defect 3 to 5 or 5 to 8 mm should be evaluated by the end of the 12th and the 15th month, respectively, when > 80% of these defects will be closed. An atrial septal defect with a diameter > or = 8 mm may have little chance of closing spontaneously and the possibility of surgical correction should be considered. Defects < 3 mm probably do not constitute a cardiac malformation in light of their natural evolution and gender distribution.

Frequency and prognosis of arrhythmias after operative Correction of tetralogy of fallot

Two hundred twenty-four consecutive patients operated on for tetralogy of Fallot were followed from 1 to 28 years (mean 11). Mean age at surgery was 5.3 years (range 1 to 14). Postoperative right ventricular systolic pressure was 60 mm Hg in 19 of 213 patients (9%). Fourteen patients (6%) had ventricular premature complexes on surface electrocardiograms. Seventy-nine patients underwent treadmill exercise tests, and ventricular premature complexes were induced in 17 (22%). Twenty-four-hour ambulatory monitoring in 92 patients demonstrated significant ventricular arrhythmias (greater than or equal to grade 2 of the Lown classification) in 41 (45%). The frequency of ventricular arrhythmias correlated with length of follow-up and duration of cardiopulmonary bypass. No correlation was found with age at surgery, postoperative right ventricular systolic pressure and importance of conduction defects on electrocardiogram. There were no sudden or unexpected deaths during follow-up.

The Influence of Heart Rate and Age on the Systolic and Diastolic Time Intervals in Children

The systolic time intervals have been measured in 76 normal children, aged 1 month to 15 years, from simultaneous recordings of the electrocardiogram, phonocardiogram and carotid arterial pulse or apexcardiogram (left or right). Four different statistical methods were applied to study the separate influence of heart rate (HR) and age on these intervals. Left ventricular ejection time (LVET) had a highly significant correlation with HR but none with age. Age alone had a slight but significant influence on pre-ejection period (PEP) and isometric contraction time (ICT). Electromechanical systole (Q-II) varied directly with age and inversely with HR. Right and left total mechanical systole (TMSR, TMSL) and left isometric relaxation time (IRTL) were inversely related to HR, while right electromechanical delay varied only with age. Q to first sound interval (Q-I), interval from onset of contraction to first sound on left and right apexcardiogram (ClL, ClR) and left electromechanical delay (EMDL) were found to be constant values. PEP/LVET (0.313, SD 0.05) and TMSL/LVET (1.546, SD 0.128) were not significantly correlated with HR nor age. Regression equations and mean values are presented to permit rapid estimation of predicted normal values in children. The ratios TMSL/LVET and PEP/LVET being unaffected by age or HR, are suggested as practical indices of myocardial function in children.

VENTRICULAR ARRHYTHMIAS AFTER CORRECTION OF VENTRICULAR SEPTAL DEFECTS : IMPORTANCE OF SURGICAL APPROACH

To compare the prevalence of conduction disturbances and ventricular arrhythmias in cases of postoperative ventricular septal defect, 100 patients (50 with repair by right atriotomy, group 1; and 50 with repair by right ventriculotomy, group 2) underwent complete evaluation including an electrocardiogram (ECG) and 24 h ambulatory ECG monitoring. The two groups were comparable except for a shorter follow-up duration (7 +/- 3 versus 12.4 +/- 7 years) and a younger age at evaluation (12.4 +/- 5 versus 16.9 +/- 7 years) in group 1. Complete right bundle branch block was less frequent in group 1 than in group 2 (20% versus 50%, p less than 0.05) but three of the four patients with complete atrioventricular (AV) block detected on ambulatory monitoring were in group 1. Six patients had significant supraventricular arrhythmias, all well tolerated. Ambulatory monitoring revealed significant ventricular arrhythmias (modified Lown grade 2 or higher) in 39 patients, with a lower prevalence in group 1 (30% versus 48%, p = 0.05). No correlation was found between prevalence of ventricular arrhythmias and right ventricular systolic pressure, cardiopulmonary bypass duration, presence of a synthetic patch, previous pulmonary artery banding, presence of complete right bundle branch block and cardiomegaly on chest X-ray film. Prevalence of ventricular arrhythmias increased with follow-up duration, age at evaluation and age at surgery. These were always well tolerated and did not warrant treatment. Thus, right atriotomy reduces the prevalence of right bundle branch block but does not prevent late AV block. Ventricular arrhythmias are frequent after surgical closure of ventricular septal defect whatever the surgical approach and their prevalence is not statistically different from that in postoperative tetralogy of Fallot.(ABSTRACT TRUNCATED AT 250 WORDS)

Captopril in infants for congestive heart failure secondary to a large ventricular left-to-right shunt

Abstract Vasodilators have been used for many years in the treatment of cardiac failure of adult patients with cardiomyopathy, mitral regurgitation or coronary artery disease. More recently, they have been used in children with similar problems.1,2 Their use in infants with ventricular left-to-right shunts was suggested a few years ago3 but did not gain wide acceptance. One of the reasons could be the difficulty of finding a safe and reliable systemic vasodilator that could be administered orally in infants. This study investigates the ability of captopril, a selective systemic vasodilator, to reduce ventricular leftto-right shunting and assesses the global hemodynamic status of infants receiving the drug.

Surgical Treatment of Partial Anomalous Pulmonary Venous Drainage A Long-Term Follow-up Study

Fourteen children who had been operated on for partial anomalous pulmonary venous return from the right lung to the vena cava or right atrium have been submitted to a follow-up study 1 to 9 years after surgery. This included clinical, hemodynamic, and angiographic data. All patients were doing well and had normal exercise tolerance at the time of follow-up examination. Electrocardiograms and chest roentgenograms had returned to normal in 10 and were improved in three. Hemodynamic and angiographic data demonstrated perfect correction in eight. Of the remaining six, three had an obstructed superior vena cava (SVC) with collateral pathways to a persistent left superior vena cava in two and to the inferior vena cava in one. Three had significant pressure gradients between the SVC and the right atrium, two with a small right-to-left shunt from the SVC to the left atrium, and one with an additional small left-to-right shunt. None had obstruction to the pulmonary venous return. These complications occurred exclusively in cases in which at least one anomalous vein drained high into the superior vena cava. Enlargement of the SVC with a patch of pericardium gave good results in three patients with this type of anomalous drainage but did not prevent obstruction or severe narrowing of the SVC in two other cases. It is concluded that the present corrective technics are not adequate for cases in which an anomalous vein drains high in the SVC, especially in the presence of a left superior vena cava.

Cardiovascular responses to dynamic submaximal exercise in children previously treated with anthracycline

This study assessed the long-term (5-year) outcome of pediatric low-dose anthracycline therapy on the circulatory response to moderate exercise. Thirteen patients (13 +/- 4 years old) and 15 age-matched control subjects completed a maximal cycle ergometer protocol as well as two 5-minute cycling tests at 33% and 66% maximal oxygen uptake (V(O2)max) for determination of cardiac index (carbon dioxide rebreathing). V(O2)max was lower in patients than in control subjects (1.3 +/- 0.5 L/min vs 2.3 +/- 0.6 L/min) (p< 0.05). Smaller relative increases in cardiac index for similar increases in relative exercise intensities were found in patients (33% V(O2)max, 73% vs 116%; 66% V(O2)max, 115% vs 192%), as a result of smaller increases in stroke index from rest (33% V(O2)max, 33% vs 54%; 66% V(O2)max, 33% vs 69%; p< 0.05). Similarly, despite normal resting systolic function, patients exhibited a lower stroke index and higher heart rate for any given value of oxygen uptake (milliliters per minute per square meter). Children who had survived cancer exhibited stroke index impairment during exercise similar in intensity to that of recreational activities or play, attesting to a limited inotropic reserve.

Subxiphoid two-dimensional echocardiographic diagnosis of double-chambered right ventricle.

The echocardiographic features of 14 patients with double-chambered right ventricle are presented. Diagnosis was confirmed in 13 patients at cardiac catheterization and in one at necropsy. The ultrasonic diagnosis was based on the visualization in subxiphoid short-axis view of an anomalous muscle bundle at the lower margin of the right ventricular infundibulum; this structure was present in diastole and systole and the distal portion of infundibulum was wide and free of obstruction. Associated lesions were very frequent (especially ventricular septal defects, present in 13 patients). Subxiphoid two-dimensional echocardiography is an easy, reliable, noninvasive means of assessing this disease in infants and children.

Evolution of QRS-T relationship from birth to adolescence in Frank-lead orthogonal electrocardiograms of 1492 normal children.

Patterns of evolution of QRS-T relationship were investigated by determining statistical distributions of QRS and STT integral vectors and the ventricular gradient vector in 1492 normal children divided into 12 age groups from birth to the age of 16 years. From birth to the age of 4 days, the ventricular gradient vector shifts posteriorly and to the left due to posterior shift of the STT integral vector and an increase in the spatial angle between QRS and STT integral vectors to a mean value of 103 degrees. These early neonatal changes in QRS-T relationship probably reflect the sudden reduction of hemodynamic load and the subsequent postnatal atrophy of the right ventricle while the left ventricular load slowly increases. The magnitude of the ventricular gradient vector increases from age 3 weeks until about 7 years. The increase appears to be related to a gradual increase in the magnitude of the QRS and STT integral vectors and a drastic decrease in the spatial angle between them. The spatial angle between QRS and STT integral vectors reaches it minimum (22 degrees) in the age group 1.5--4.5 years, suggesting that at that age the average direction of ventricular excitation and repolarization wavefronts are nearly opposite to each other. In addition to the shifting balance between the left and right ventricular hemodynamic load, other factors, such as the maturation of the sympathetic nervous system, may be important in determining spatial gradients in the duration of action potentials, thus influencing the relationship between ventricular excitation and repolarization.