A family is described in which the mother and three of seven children had atrial myxoma. The mother had biatrial myxoma; surgical treatment resulted in massive intraoperative embolization and death. Surgery was sucessful in two sons with left atrial myxoma and systemic arterial embolization. A third son had calcified right atrial myxoma with destruction of the tricuspid valve and episodes of syncope and pulmonary embolism; surgery including valve replacement, was successful. The mother's father and a brother had died suddenly without a definite diagnosis. The family data are consistent with dominant transmission. The possibility of finding affected relatives should be borne in mind when studying patients with atrial myxoma.

Atrial myxoma in a family.

A fourth case is presented of propagation of Wilms' tumor to the right atrium through the inferior vena cava. Ultrasonic examination of the heart was diagnostic of the tumor and the diagnosis was confirmed by angiographic studies and surgical exploration. This report provides the first echocardiographic description of a right atrial tumor in a child.

Echocardiographic diagnosis of right atrial extension of Wilms' tumor.

In the course of the evaluation of five patients with left atrial myxoma, it was noted that the movement of the myxoma was related to specific changes in left atrial hemodynamics. Prolapsing tumors, Type I, move from the left ventricle to the left atrium in early systole and from the left atrium to the left ventricle in early diastole, thereby causing prominent c and v waves accompanied by a rapid y descent. Nonprolapsing tumors, Type II, remain in the left atrium during the entire cardiac cycle, impeding flow across the mitral valve. In these latter cases, the y descent is slow and indistinguishable from that caused by mitral valvular stenosis. The cineangiocardiograms and echocardiograms corroborate these two types of hemodynamic observations. The particular value of direct echocardiographic examination of the left atrium prior to cardiac catheterization was evident in two of the three patients with nonprolapsing tumors. Since the hemodynamic pattern of nonprolapsing left atrial myxoma resembles that of mitral valvular stenosis, it is stressed that echocardiography should have an important place in precatheterization assessment of patients with mitral valve disease. If left atrial myxoma is suspected clinically or on the basis of echocardiographic findings, regardless of the pressure curve contours, transseptal cardiac catheterization should be avoided and the left atrium visualized by pulmonary angiography levophase.

Hemodynamic features of prolapsing and nonprolapsing left atrial myxoma.

In patients with prolapsing right atrial myxoma, paradoxical ventricular septal motion and right chamber dilatation have been observed. The abnormal septal motion has been ascribed to concomitant severe tricuspid regurgitation. Frame-by-frame analysis of echo-Doppler tracings in one case allows an alternative explanation: the septal motion abnormality and the hepatic vein flow pattern are mainly due to hemodynamic effects of tumor movements during the cardiac cycle.

Misleading Echo-Doppler Findings in Prolapsing Right Atrial Myxoma

An experimental model of a prolapsing left atrial tumor mass has been utilized In dogs to study the hemodynamic events of the cardiac cycle and the cineangiographic and echocardiographic manifestations of this condition. The characteristic ventricular notch has been correlated with the timing of the expulsion of the simulated tumor mass from the left ventricle to the left atrium. The early notch seen with small simulated tumors delays aortic ejection by 0.02 to 0.03 second and results in abbreviated aortic ejection time and minimal distortion of the E-F slope of anterior mitral leaflet motion in the echocardiogram. Larger masses lead to late ventricular notching, transiently interrupt aortic flow and may displace the anterior mitral leaflet until It impinges on the interventricular septum in mid-diastole and at the onset of systole. A transient systolic Increment of coronary flow is observed after expulsion of the tumor from the left ventricle into the left atrium. There is an echo-free interval immediately after opening of the mitral valve, indicating that tumor motion lags perceptibly behind the initial blood flow through the mitral orifice. The sudden expulsion of the mass from the ventricle to the atrium early in systole represents an in vivo example of the quick release phenomenon.

Ira J. Gelb

Papers

Simulated left atrial tumor: A hemodynamic, echocardiographic and cineangiographic study