The cardiac fossa surrounds the pericardium and may increase its restraining effects on left ventricular filling. We performed transesophageal echocardiography, during coronary or aortic valve surgery, in 38 patients (without mitral regurgitation) at baseline, sternotomy (removal of intrathoracic negative pressure), sternal divarication (lung mass withdrawn from the pericardium), and pericardiotomy. We differentiated the influence of the cardiac fossa and pericardium on left ventricular and left atrial filling according to baseline biplane left ventricular ejection fraction (<45% in Group 1 of 10 patients, ≥ 45% in Group 2 of 28 patients) with a GLM ANOVA analysis. We measured right atrial pressure (equal to pericardial pressure) and pulmonary wedge pressure; pulsed Doppler early and late left ventricular inflow (transmitral integral x annulus area), pulmonary venous systolic (left atrial reservoir) and diastolic (left atrial conduit) flow velocity-time integrals; biplane left ventricular volumes and ejection fraction in the apical views. At baseline, right atrial pressure and the left atrial inflow pattern were similar in both groups; pulmonary wedge pressure was higher in Group 1 (19 ± 6 vs 12 ± 4 mmHg, p <0.001), and left ventricular early inflow was lower in Group 1. After sternotomy, left atrial conduit decreased in both groups (7 ± 2 vs 5 ± 2 in Group 1, p <0.05; 7 ± 3 vs 6 ± 2 in Group 2, p <0.05). After sternal divarication, early left ventricular inflow decreased in both groups (75 ± 26 vs 49 ± 30 in Group 1, p <0.05; 66 ± 31 vs 109 ± 57 in Group 2, p <0.05), simultaneously with a decrease in pulmonary wedge pressure only in Group 1 (13 ± 6 vs 10 ± 4 mmHg, p <0.05); left atrial conduit was still decreased compared to baseline in both groups. After pericardiotomy, right atrial pressure decreased in both groups (9 ± 4 vs 6.7 ± 5 mmHg in Group 1, p <0.05; 7.7 ± 2 vs 6.2 ± 2 mmHg in Group 2, p <0.05), early left ventricular inflow was still lower than baseline in both groups whereas left atrial conduit had returned to baseline; left ventricular ejection fraction increased in Group 1 (38 ± 4 vs 48 ± 11%, p <0.05). In conclusion, the cardiac fossa may oppose pericardial restraint to left ventricular inflow: removal of negative intrathoracic pressure during sternotomy and sternal divarication transiently decreases total left ventricular transmural pressure before pericardiotomy, reducing early left ventricular and left atrial filling irrespective of baseline ejection fraction. Furthermore, reduced left heart filling would also result from increased resistance to flow in the extraparenchymal pulmonary veins secondary to reduced transmural venous pressure as negative intrathoracic pressure is removed.
|Number of pages||5|
|Publication status||Published - 1999|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Radiology Nuclear Medicine and imaging