The significance of the intact pericardium for cardiac performance in the dog.

Abstract

The significance of the intact pericardium for cardiac performance was examined in 18 open-chest dogs. Myocardial chord lengths (MCL) in the right and left ventricle were measured simultaneously by ultrasonic crystals implanted in the myocardium of the anterior walls. In 14 dogs, the ultrasonic elements were inserted into the myocardium through needle openings in the pericardium (intact pericardium). In four other dogs, the elements were inserted through 6-to 7-cm-long incisions in the pericardium which were sutured afterward (sutured pericardium). Stroke volume was calculated in each of seven dogs with an intact pericardium from electromagnetic measurement of flow in the superior and inferior venae cavae. After blood volume expansion to about 13 mm Hg, the pericardium was opened and the end-diastolic pressure-MCL relationships and stroke volumes before and after pericardiotomy were compared. By opening the intact pericardium, the right and left ventricular enddiastolic MCL rose by 2.7 ± 0.7% and by 3.7 ± 1.1%, respectively, and stroke volume increased by 13 ± 4%. However, by reopening the sutured pericardium, the increases in both right and left ventricular end-diastolic MCL were clearly greater (12.2 ± 5.6% and 9.9 ± 2.9%, respectively), and the restrictive effect of the pericardium was therefore overestimated when the pericardium was not left intact. Thus, after a moderate blood volume expansion, the intact pericardium exerts a certain, although moderate restrictive effect on cardiac performance.

Significance of the Right Ventricular Free Wall in Dogs with and without Pulmonary Constriction.

“…If this procedure caused a reduction in the pericardial space, the effects of pericardium on the present results would be enhanced. However, this technique was evaluated by Stokland et al (1980) and Kanazawa et al (1983), who found that it kept the pericardium intact. In the present study, an additional small incision was made in the pericardium for dissecting the right coronary artery near its origin.…”

The hemodynamic derangement associated with right ventricular diastolic collapse in cardiac tamponade: an experimental echocardiographic study.

“…Regardless of how much care is taken, any experiment in which the pericardium is incised, instruments are placed, and the defect is closed should be assumed to have made some change in pericardial compliance. 20 We made an effort during surgery to minimize such alterations and saw no further change in pericardial compliance throughout the period of data collection. Since this animal model does not permit multiple two-dimensional echocardiographic views, no attempt was made to calculate right or left ventricular volume.…”

Increased left ventricular mass after thoracotomy and pericardiotomy. A role for relief of pericardial constraint?

“…[1][2][3][4][5][6][7][8][9] In open-chest dogs at low normal cardiac volumes, this effect is most likely relatively small. At volumes approaching the high end of the physiological range, the left ventricular end-diastolic pressure-volume relation clearly shifts downward and to the right after pericardiectomy; this effect becomes marked at supranormal volumes.…”