The development of orthotopically positioned cardiac replacement devices requires a knowledge of the space available to guide the design of the blood pumping system. Pericardial dimensions from in vivo and cadaver studies of normal subjects have been reported, but little information is available on in vivo pericardial dimensions in patients with dilated cardiomyopathies. The critical pericardial dimensions were determined in 13 men who were cardiac transplant recipients (age, 42 ± 13 years; body mass, 72 ± 11 kg; three with ischemic and 10 with idiopathic cardiomyopathy) by comparison of corresponding pericardial axes on chest radiographs to measurements obtained during ortho-topic cardiac transplant in the context of a total artificial heart fit trial. The main pericardial dimensions measured intraoperatively were found to be the T10 midline anteroposterior (AP) axis (12.3 ± 1.4 cm), the aortic root to diaphragm length (9.7 ± 1.5 cm), the T10 total cardiac lateral axis (18.1 ± 2.3 cm), and the tricuspid annulus to left ventricular apex (12.1 ± 1.7 cm). All patients had cardiomegaly as indicated by a greater than normal cardiothoracic ratio. These data described the limited dimensions of the pericardial space available for orthotopic cardiac replacement devices. Chest film dimensions can be corrected using 0.92 and 0.88 as reduction factors for the (AP) and lateral axis dimensions, respectively. In this patient sample, there was little or no correlation between pericardial dimension and patient body mass or diagnosis. The midline AP dimension previously was identified as critical for fit; however, this study reveals that the midline distance from the root of the great vessels to the diaphragm also is critical. Although the total lateral axis of the pericardium was large, elimination of the right atrial contribution leaves only two thirds of that space (tricuspid annulus to left ventricular apex) available for device placement.
©1991 American Society of Artificial Internal Organs