The pathology of hypertensive pulmonary vascular disease; a description of six grades of structural changes in the pulmonary arteries with special reference to congenital cardiac septal defects

Progressive histologic changes occur in the pulmonary arteries and arterioles, as a complication of chronically elevated pulmonary arterial blood pressure, in patients with congenital septal defects of the heart. This progression is so stereotyped as to allow a division of the structural effects into 6 grades. The histologic features of each grade are described in detail in this communication. These results afford a basis for comparing the magnitude of these changes to the clinical findings.

The electrocardiogram in ventricular septal defect

One hundred and nineteen cases of ventricular septal defect in infancy and childhood have been reviewed, with special reference to the electrocardiogram. The changes in the electrocardiogram were related to the hemodynamics found at cardiac catheterization, and particularly the pulmonary to systemic blood flow ratios, pulmonary artery pressures, and oximetry. They were also studied in relation to the groups of cases that obviously had a low pulmonary vascular resistance with or without diastolic loading of the left ventricle. Survival of a patient following closure of the defect with a drop in pulmonary artery pressure was also taken as a sign that the pulmonary vascular resistance was not excessive. The patients with clinical and hemodynamic evidence of a high pulmonary vascular resistance were also evaluated in relation to the electrocardiogram.

The information obtained from the electrocardiogram may be graded according to degree of severity: (a) normal electrocardiogram, (b) left ventricular loading, (c) combined loading, (d) isolated right ventricular loading. These groups may be further graded depending on the diminishing number of signs listed below. 1-7 A detailed review of these four groups in relation to the following criteria may allow one to identify a low or only moderately raised pulmonary vascular resistance, or one that is sufficiently moderate to permit successful corrective surgery in the pediatric age group: 1. An R in V 6 over 20 mm. 2. A Q in V 6 of 4 mm. or over. 3. An S in V 1 over 25 mm. 4. A Q in V 6 of 2 mm. or more when associated with evidence of right ventricular loading. 5. An axis of less than 90°. 6. Counterclockwise vector. 7. Broad notched P waves in standard leads I or II, with late inversion in V 1 .

As a rule, several of these criteria occur together, but even if only one of them is present, one may conclude that the pulmonary vascular resistance is not excessive. Further support to this conclusion is evident if any of the above 7 items are accompanied by one or more of the following: (x) a pulmonary blood flow that is twice systemic, (y) an absence of reversal of flow through the defect either at rest or with exercise, (z) an age under 7 years.

Among the 119 infants and children with ventricular septal defect, over 90 per cent appeared to have a sufficiently low pulmonary vascular resistance to be operable provided the surgical technic is adequate and provided complete heart block does not occur.

Age appears to be an important factor in assessing the likelihood of success at surgery. Only an exceptional case shows hemodynamic findings indicating inoperability before the age of 7 years.

During the first year of life many cases of ventricular septal defect have signs of left ventricular loading appear or increase, suggesting a favorable trend in the pulmonary vascular resistance. Until surgical technic makes operation more readily feasible in infancy, the optimum age of correction would appear to be between 2 and 7 years.

Endocardial cushion defect. Preoperative and postoperative survey

Preoperative and postoperative data on 44 patients with endocardial defect, 32 with the incomplete and 12 with the Complete form are presented. Nineteen per cent of the incomplete form died with per cent of the deaths occurring early and 9.5 per cent late. The mortality rate for the complete form was 75 per cent.

Late follow-up results were evaluated in 28 patients 1 to 2½ years following surgery. Catheterization data in nine of 10 and clinical observations in 18 indicated no residual shunt. One patient showed questionable evidence of a left-to-right shunt by cardiac catheterization. Evidence of mitral regurgitation was present in seven (25 per cent) of the survivors. Short chordae attaching the closed cleft margin of the mitral leaflet to the ventricular septum rendered the valve incompetent in nine of 12 autopsied specimens. Surgical exploration of the underside of the cleft margins for such chordae is recommended. No evidence of residual tricuspid regurgitation was found.

Ventricular septal defect with patent ductus arteriosus. A clinical and hemodynamic study

Twenty-two patients with the combined lesions of ventricular septal defect and patent ductus arteriosus, proved at cardiac catheterization, are reviewed in detail in regard to their clinical profile, hemodynamic data, and indications for, and results of, surgical repair.

The incidence of this combination of lesions is not so uncommon as would be anticipated by the paucity of the reports in the medical literature. The diagnosis of both lesions is important for management and surgical technic.

The striking findings by physical examination are the gross undernourishment and the wide pulse pressure in the great majority. Almost all have harsh systolic murmurs along the mid left sternal border and only 2 had continuous Gibson murmurs. Consequently, auscultation is of little help in delineating the presence of an associated patent ductus arteriosus.

The electrocardiogram is of minor importance in the diagnosis of this combination of lesions. Roentgenograms in the majority show features common to either lesion alone although the frequency with which left atrial enlargement is found appears to be greater in this combination of lesions.

Careful hemodynamic studies are crucial in the diagnosis of these 2 lesions. At the ductal level passage of the catheter establishes the diagnosis, or an increase in oxygen saturation greater than 5 per cent in comparison to the right ventricular blood strongly suggests the presence of a patent ductus arteriosus. The great majority of the ventricular septal defects were diagnosed by an increase in the oxygen saturation of 10 per cent or greater at the ventricular level. Almost all had pulmonary artery hypertension.

Thirteen patients had surgical intervention; 9 had only closure of the patent ductus arteriosus alone and 4 had complete repair of the lesions. In the former group there were 2 deaths and 2 improved significantly. In the latter group there were 2 surgical deaths and 2 were markedly improved. The 2 surgical deaths appear to be directly related to the massive hemorrhage through the unsuspected patent ductus arteriosus while on cardiac bypass and the subsequent technical difficulty of closing both defects from an anterior thoracotomy.

The relationship of calculated pulmonary vascular resistance to surgical closure of the defects is discussed.

It is suggested that if the patent ductus arteriosus is diagnosed on the basis of a typical machinery murmur, correction of this lesion is indicated, irrespective of the associated ventricular defect. If, on the other hand, the clinical picture is suggestive of a ventricular defect alone and the presence of the combination of lesions is discovered only at catheterization, then simultaneous correction of the 2 lesions is recommended. In small infants in whom the combined operation is particularly difficult at the present time, a preliminary trial of medical management is recommended; only if this fails to accomplish the expected result should division of the ductus be undertaken.

A histopathologic study of the atrioventricular communications in two hearts with the Wolff-Parkinson-White syndrome

The atrioventricular communications and the AV node, bundle, and bundle branches of two cases with the WPW syndrome were studied histologically. One case was that of chronic Chagas' myocarditis and the other possible chronic Chagas' myocarditis.

Accessory muscular communications in the right atrioventricular junction were found in one heart, and no communications outside the conduction system in the other.

Inflammatory changes were found in the conduction system of both hearts.

The literature of the anatomic changes in hearts with the WPW syndrome, and that with the presence of accessory atrioventricular muscular communications without the WPW syndrome are reviewed.

From the study of the literature and of our two cases, it appears that some cases of the WPW syndrome are associated with accessory communications and others are not, and accessory communications may be present without this syndrome. Of the four cases with this syndrome, however, in which a thorough study has been made of all possible conduction pathways, three showed accessory communications. On the other hand, inflamatory changes in the pre-atrioventricular nodal area, AV node, bundle and bundle branches have been found in many cases of the WPW syndrome.

It is thus clear that an anatomic base has as yet not been established for the WPW syndrome. It is possible that a different mechanism may be responsible in different cases. The high incidence of inflammation of the conduction system in the studied cases makes accelerated conduction an attractive hypothesis, where no accessory bundles have been found. More correlative histologic and clinical work needs to be performed in this field.

Coronary embolism following repair of a ventricular septal defect

A unique cause of coronary embolism is described: open-heart surgery for correction of a ventricular septal defect.

Auscultatory findings in patients with a small ventricular septal defect

The auscultatory and phonocardiographic findings were analyzed in 21 cases of small ventricular septal defect. Eleven patients had identical right ventricular and pulmonary artery systolic pressures, whereas in nine a minimal systolic gradient across the infundibulum of the right ventricle was demonstrated. One half of the patients, with or without an infundibular gradient, had a pansystolic plateau-shaped murmur. Several patients, mostly those with an infundibular gradient, had a distinct diamond-shaped murmur. A few children showed an early systolic decrescendo murmur. Appreciable, even wide splitting of the second sound with inspiratory widening, was demonstrated. It is proposed that a sharp differentation between "ejection" and "regurgitant" systolic murmurs may be difficult under certain circumstances. Furthermore, it is suggested that the definition of an "innocent" or "functional" murmur may depend on the sensitivity of the diagnostic methods used.