Cineangiocardiographic Demonstration of the Diastolic Snap in Constrictive Pericarditis

In constrictive pericarditis, a dense, pericardial scar restricts the action of the heart. Although this dense fibrous tissue is the result of an inflammatory process, in many cases the specific etiologic agent is never discovered. Often there is no evidence in the past history of pericarditis, pleuritis, or pneumonia, and the patient may be completely asymptomatic until symptoms caused by abnormal cardiac function appear. Constrictive pericarditis is essentially a disease of youth, although it may occur beyond middle age. Most of the proved cases have been reported between the ages of ten and forty years (4). Because of the serious, disabling nature of the disease, which can often be treated surgically with dramatic results, an accurate diagnosis is particularly important. The roentgenologic abnormalities have been well described but are of limited value because the findings are variable and nonspecific. The classic description of a “small, quiet heart” notwithstanding, the cardiothoracic ratio may be normal, slightly enlarged, or grossly enlarged (9). There may be pleural thickening or pericardial adhesions. Because of the elevated venous pressure, the shadow of the superior vena cava and azygos veins may be enlarged. By physiologic measurement there is always pulmonary venous hypertension (16), but pulmonary edema is rare. Pericardial calcifications occur in 30 per cent of the cases (4). Fluoroscopic examination of the heart may reveal decreased puisations. This finding will be observed in any disease of the myocardium with ventricular dilatation and a normal or decreased stroke volume. When the ventricles are large and the cardiac output normal or diminished, the relative changes in the end-diastolic and end-systolic volumes are small, resulting in decreased pulsations. When the heart size is normal, the fluoroscopic observation of diminished pulsations is far more significant. Although it is well known that cardiac pulsations may be decreased in this disease, there are few reports of the fluoroscopic observation of other types of abnormal movement of the heart. In contrast, the electrokymographic findings have been well described (8, 12). The electrokymograph (EKY), an instrument described by Renny and Boone (10), converts changes in x-ray intensity to an amplified electric current. The subject is exposed to an x-ray beam which strikes a small fluoroscopic screen, and the light emitted is converted to electrical energy. Changes in density are represented by changes in the electric current which are then recorded. The x-ray beam passes through a small slit placed within the border movement of the heart. In diastole the movement of the heart border laterally is represented by the upstroke of the EKY. The downstroke records the medial border movement of the heart in systole.