[Dissecting aneurysm of the aorta with rupture in the right atrium].

Rupture of the false sac in dissecting aortic aneurysm commonly occurs into the pericardial sac with an immediately fatal outcome (Hirst, Johns, and Kime, 1958). It is well known that should re-entry be established the immediate prognosis is not so grave as used to be thought, though death occurs later from heart failure due to aortic incompetence or hypertensive heart disease (Shennan, 1934). Dissection of the false sac back to the aortic root itself is common and rupture most frequently occurs into the pericardium (Gore and Seiwert, 1952). More rarely rupture into a cardiac chamber occurs. The right ventricle may be entered, a left-to-right shunt being established and, theoretically at least, this is amenable to surgical repair. This is more common with rupture of a sinus of Valsalva rather than a true dissection (Oram and East, 1955). An aortic diastolic murmur is commonly found in true dissection. Various mechanisms for the murmur are described, such as aortic incompetence due to distortion of the valve ring, eddy currents in the distorted aorta, or ebb and flow into the false sac (Hirst et al., 1958). In our case the false sac entered the right atrium. The signs of apparently florid aortic incompetence, however, obscured the signs of the left-to-right shunt though there was clinical evidence of this at least seven months before death. We can find no previously reported case where the sac has ruptured into the right atrium.