Lewis P. Scott

Aortic Valve Atresia: A New Classification Based on Necropsy Study of 73 Cases

Certain clinical and morphologic observations are described in 73 necropsy patients with aortic valve atresia. The mean age at death was 5 days; 80 percent died during the first week of life, and 70 percent were boys. Of the 73 patients, 69 (95 percent) had a hypoplastic left ventricle with intact ventricular septum and either an atretic (25 patients) or hypoplastic (44 patients) mitral valve. The other four patients had a well developed left ventricle with one or more defects in the ventricular septum and either an atretic (one patient) or well developed (three patients) mitral valve. Review of previous reports on aortic valve atresia disclosed that a well developed left ventricle or ventricular septal defect in association with absence of the aortic valve was extremely rare. A new classification for aortic valve atresia is presented based on the status of the ventricular septum, which in turn appears to determine the size of the left ventricular cavity. The predilection for male subjects for all types of aortic valve disease, including atresia, is emphasized.

Left ventricular false tendons in children: Prevalence as detected by 2-dimensional echocardiography and clinical significance

During a 28-month period, consecutive 2-dimensional echocardiograms were reviewed to determine the prevalence of left ventricular (LV) false tendons, their associated anomalies and clinical significance. LV false tendons were found in 31 (0.8%) of 3,847 consecutive 2-dimensional echocardiograms. Of 31 LV false tendons, 30 passed longitudinally from papillary muscle to septum and 1 went from free wall to free wall. The 31 patients were aged 1 day to 15 years. Associated heart disease, most often ventricular septal defect, bicuspid aortic valve and coarctation of the aorta, was present in 48%, of whom 73% were girls. Of those without heart disease, 69% were boys. In patients with heart disease, precordial murmurs were due to the underlying cardiac anomaly. Of those without heart disease, 15 of 16 (94%) had a precordial murmur, usually of the Stills type over the lower left sternal border. Four of 31 (13%), 1 with and 3 without heart disease, had unifocal premature ventricular contractions that were rate-dependent in the 2 patients undergoing stress testing. LV false tendons appear to occur in 0.8% of pediatric patients and usually are accompanied by a Stills type innocent murmur if unassociated with heart disease. Some LV false tendons are associated with rate-dependent premature ventricular contractions.

Anticoagulation therapy in children with mechanical prosthetic cardiac valves

From 1980 through 1984, 28 children younger than 19 years (mean 7.9) underwent cardiac valve replacement with 30 mechanical prostheses. Patients were followed for a total of 471 months (mean 15.7) and received either warfarin (mean 0.16 mg/kg/day) or acetylsalicylic acid and dipyridamole (mean 6.1 and 1.9 mg/kg/day, respectively) as thromboembolism prophylaxis. The frequency and incidence of thromboembolism and hemorrhage were compared. Warfarin-treated patients were at increased risk of hemorrhage (5 of 20 [25%], or 22 per 100 patient-years, vs 0 of 10 [0%], or 0 per 100 patient-years, p less than 0.05). Three of the 5 hemorrhagic episodes were mild, and in no case was hemorrhage life-threatening. Patients who did not receive warfarin had a greater risk of thromboembolism (2 of 10 [20%], or 12 per 100 patient-years, vs 0 of 20 [0%], or 0 per 100 patient-years, p less than 0.05). Both episodes of thromboembolism were life-threatening and necessitated emergency valve replacement. Although warfarin is associated with greater risk of hemorrhage than is acetylsalicylic acid and dipyridamole, warfarin is better than antiplatelet drugs in thromboembolism prophylaxis and is indicated for anticoagulation therapy in children with mechanical cardiac prostheses.

Electrophysiologic studies after Mustard's operation for d-transposition of the great vessels

Abstract Electrophysiologic studies were performed in 16 patients after Mustards operation for d-transposition of the great vessels. Standard 12 lead electrocardiograms showed the following rhythms: “sinus” (10 patients), junctional (4 patients), atrial flutter (1 patient) and alternating sinus and junctional (1 patient). Overdrive atrial stimulation was used to determine sinus nodal recovery time in the 16 patients. Atrial and atrioventricular (A-V) nodal effective refractory periods were determined in 12 patients utilizing the atrial extrastimulus technique. Twenty-four hour Holter electrocardiographic monitoring was performed in 15 patients. Ten (63 percent) of the 16 patients had abnormal sinus nodal recovery time. The atrial effective refractory period was prolonged in 4 (33 percent) of the 12 patients in whom it was measured. All 12 patients had a normal A-V nodal effective refractory period. Previously undetected arrhythmias were found in all patients when the 24 hour Holter electrocardiogram was compared with the standard electrocardiogram. Atropine shortened the sinus nodal recovery time, atrial effective refractory period and A-V nodal effective refractory period in all patients studied. One patient, whose junctional pacemaker was first to recover after termination of atrial pacing, had conversion to sinus rhythm and normal sinus nodal recovery time after administration of atropine. This study indicates (1) that a diseased sinus node and interrupted atrial pathways are involved in the genesis of arrhythmias after Mustards operation, and (2) that adequate evaluation of arrhythmias in patients after this operation requires not only the standard electrocardiogram, but also a 24 hour Holter monitor, His bundle electrograms and determination of sinus nodal recovery time and atrial and A-V nodal effective refractory periods.

Isolated partial anomalous pulmonary venous drainage associated with pulmonary vascular obstructive disease

Five patients with partial anomalous pulmonary venous drainage with intact atrial septum are described. In two patients, pulmonary arterial hypertension and pulmonary vascular disease developed. Both had one or more right pulmonary veins draining anomalously to the right superior vena cava. It is postulated that a combination of increased pulmonary blood flow and reflex pulmonary vascular changes contributes to the production of pulmonary vascular obstructive disease.

Acute bacterial percarditis in children: Report of 25 cases

Twenty-five patients, aged 5 months to 14 years, with acute bacterial pericarditis are reported. Thirteen (52 per cent) of the patients died. The presenting symptoms, associated illness and physical findings, bacteriology, and response to therapy are reviewed. Optimum therapy consists of intravenous administration of specific antibiotics combined with surgical drainage; 90 per cent of our patients treated in this fashion survived. Antibiotic therapy alone is usually inadequate, especially in the presence of significant effusion, and among our patients only three of 10 patients so treated survived. One patient developed constrictive pericarditis 1 month after the initial attack with meningococcal pericarditis and required pericardectomy.

The double-chambered right ventricle: A diagnostic and operative pitfall∗

Abstract Four patients with a double-chambered right ventricle due to an anomalous muscle band low in the body of the ventricle have been presented. None of them had ventricular septal defects, but 2 had stenosis or atresia of the pulmonary valve and intricate involvement of the chordal attachments of the tricuspid valve with the obstructing mass. The cases presented with loud stenotic systolic murmurs best heard at the lower left sternal border and suggestive of ventricular septal defect or infundibular stenosis, or both. Right atrial and ventricular hypertrophy were shown by chest roentgenograms and electrocardiograms. It has been stressed that cardiac catheterization with meticulous exploration of the pulmonary artery and outflow and inflow tracts of the right ventricle will show a sudden rise in pressure low in the body of the right ventricle just distal to the tricuspid valve. Cineangiograms should then delineate the site of the obstruction as being due to a wedge of muscle extending from the apex of the right ventricle towards the crista supraventricularis. Pulmonic valvular stenosis and a ventricular septal defect should be ruled in or out by appropriate means. Surgery should be performed by utilizing cardiopulmonary bypass. Careful exploration of the ventricular septum is necessary in all cases to rule out the presence of a hidden ventricular septal defect and to prevent inadvertent closure of the orifice of the obstructing ring. Adequate excision of the muscle band should then be performed. It must be recognized that the muscle mass may be intimately attached to the chordae tendineae of the tricuspid valve. It is the difficult task of the surgeon to attempt to relieve the obstruction without severely damaging the valve.

Systemic artery—pulmonary vein fistulas: Congenital and acquired left to left shunt

Abstract Fistulas from systemic arteries to the pulmonary vein may be congenital or acquired. Hemodynamically significant left to left shunts are associated with a continuous murmur, bounding peripheral pulses and left ventricular enlargement. Clinically they may be indistinguishable from left to right shunts into the pulmonary artery. Atypical location of the continuous murmur, lack of evidence of increased pulmonary flow and evidence of localized lesions in pulmonary parenchyma should lead to a suspicion that a left to left shunt is present. At cardiac catheterization left to left shunts are not associated with increased oxygen saturation in the pulmonary artery and may be clearly outlined with the use of arteriography. Two cases are presented, 1 representing a congenital and the other an acquired left to left shunt.

Small left atrium and change in contour of the ventricular septum in total anomalous pulmonary venous connection: A morphometric analysis of 22 infant hearts

Morphometric measurements of 22 hearts with total anomalous pulmonary venous connection (TAPVC) were compared with measurements of 8 matched control specimens without heart disease. Each of the TAPVC specimens had a shorter left atrium, smaller left atrial surface area and larger diameter of the fossa ovalis. In addition to increased length of the right ventricle and larger circumferences for tricuspid and pulmonary valve anuli, the left ventricular contour of the ventricular septum was flat or convex in 18 of the 22 hearts; the septum was significantly longer than normal in these specimens and wider at its midportion. Because mitral and aortic valve anuli were normal in circumference, the data suggest that left ventricular volume is not decreased despite change in ventricular shape.

Single ventricle with truncus arteriosus in siblings

Abstract Single ventricle and truncus arteriosus (TA) are relatively uncommon congenital cardiac defects. Keith et al. 1.2 reported these lesions to occur, respectively, in 1.1% and 0.4% of children with congenital cardiac defects. The occurrence of TA with a single left ventricle (LV) often has been theorized as a developmental stage but not previously described. This report describes siblings with the unique association of single LV with rudimentary right ventricular (RV) outflow chamber, TA type I, ostium primum atrial septal defect (ASD), and common atrioventricular (AV) valve.