Alterations in transesophageal pulsed Doppler indexes of filling of the left ventricle after pericardiotomy

Evaluation of the Pericardium with CT and MR

The pericardium plays an important role in optimizing cardiac motion and chamber pressures and serves as a barrier to pathology. In addition to pericardial anatomy and function, this review article covers a variety of pericardial conditions, with mention of potential pitfalls encountered during interpretation of diagnostic imaging. Normal and abnormal appearance of pericardium on CT and MR imaging is emphasized, including dynamic imaging correlates of pericardial pathophysiology.

Transesophageal echocardiographic area and Doppler flow velocity measurements: comparison with hemodynamic changes in coronary artery bypass surgery

OBJECTIVE

Changes in transesophageal echocardiography (TEE)-derived Doppler flow velocities through the mitral valve and pulmonary veins occur after cardiopulmonary bypass and are believed to reflect left ventricular (LV) diastolic functional impairment. The aim of this study was to determine the time-coincidence between these Doppler flow velocity parameters, LV two-dimensional (2D) short-axis area measurements, and hemodynamic parameters in patients after coronary artery bypass grafting.

DESIGN

Prospective clinical study.

SETTING

University hospital.

PARTICIPANTS

Twenty patients with normal ejection fraction undergoing elective cardiac surgery.

INTERVENTIONS

At multiple intervals during surgery and 6 hours postoperatively, mitral inflow velocity and pulmonary venous flow velocity were measured with pulsed Doppler TEE. LV short-axis area by echocardiography and cardiac output by thermodilution were simultaneously obtained.

MEASUREMENTS AND MAIN RESULTS

Time-coincidence was found in the immediate postbypass period between a decreased E/A ratio from 1.16 (95% confidence interval, 1.0 to 1.31) to 0.64 (95% confidence interval, 0.47 to 0.81, p < 0.01), a decreased E-wave deceleration time, and a significantly increased heart rate (HR) and cardiac index. End-diastolic area (EDA) and stroke volume index (SVI) decreased after sternal closure. HR, E-wave deceleration time, and SVI remained altered until 6 hours postoperatively. No change was found in pulmonary venous flow velocity parameters and systolic LV function.

CONCLUSION

In patients with normal systolic ventricular function and no inotropic support, Doppler flow velocity patterns alone did not sufficiently reflect hemodynamic changes, whereas 2D LV area, especially EDA measurements, provided useful information about hemodynamically significant LV filling impairment.

Effects of changes in atrioventricular gradient and contractility on left ventricular filling in human diastolic cardiac dysfunction

The factors responsible for abnormalities in diastolic filling indexes as assessed by noninvasive testing in human beings have been extensively studied but are not completely understood. We therefore investigated left ventricular diastolic filling indexes by radionuclide angiography during right atrial pacing simultaneously with assessment of a directly measured left atrioventricular gradient and a time constant of isovolumic relaxation in 11 patients with hypertension and diastolic dysfunction. Loading conditions were altered with nitroprusside and phenylephrine, and contractility was improved by dobutamine infusion. The maximum left atrioventricular gradient at constant heart rates was determined by loading conditions and was not significantly affected by increases in contractility or an improvement in isovolumic relaxation rate. The peak filling rate according to radionuclide angiography was highly dependent on the atrioventricular gradient and was not affected by enhancement of the isovolumic relaxation rate.

Acute effects of dynamic cardiomyoplasty on ventricular geometry and left ventricular filling detected by transesophageal doppler echocardiography

We investigated 7 patients with chronic congestive heart failure undergoing dynamic cardiomyoplasty with intraoperative transesophageal echocardiography. Biventricular wrapping acutely modified right or left ventricular geometry, but did not induce acute restriction to left ventricular filling.

Effect of acute pericardial tamponade on the relative contributions of systolic and diastolic pulmonary venous return: a transesophageal pulsed Doppler study

The effect of acute pericardial tamponade on pulmonary venous return was assessed by transesophageal pulsed Doppler echocardiography. In 14 open-chest anesthetized dogs peak pulmonary venous flow velocities in systole (VJ) and in diastole (VK) were measured during apnea and atrial pacing while acute tamponade was induced by intrapericardial instillation of 0.9% sodium chloride solution. Before intravascular volume expansion, induction of acute tamponade resulted in a significant decline in VK (43 +/- 17 to 19 +/- 8 cm/sec; p < 0.05) but no change in VJ or the ratio VJ/VK. After intravascular volume expansion, induction of acute tamponade resulted in significant reductions in VJ (43 +/- 9 to 29 +/- 10 cm/sec; p < 0.001) and VK (37 +/- 19 to 15 +/- 11 cm/sec; p < 0.001). The effect was disproportionately greater on VK, however, resulting in a significant increase in VJ/VK (1.51 +/- 0.84 to 2.58 +/- 1.41; p < 0.001). The disproportionate effect of acute tamponade on VK suggests that increased pericardial pressure directly constrains diastolic filling of the left atrium as a conduit to the left ventricle and that it does not decrease the systolic and diastolic phases of pulmonary venous return uniformly. Intravascular volume expansion increases cardiac output before acute tamponade, but during acute tamponade it amplifies the disproportionate impact of increased pericardial pressure on left ventricular diastolic filling as the left ventricle is constrained within the fluid-filled pericardial sac.

Mitral insufficiency after pericardiectomy for constrictive pericarditis

We report the case of a 24-year-old man in whom a clinical syndrome developed while he was on active military duty in Saudi Arabia that was subsequently diagnosed as constrictive pericarditis. Phrenic nerve to phrenic nerve pericardiectomy and posterior pericardial release successfully relieved the ventricular constriction with a resultant increase in the cardiac index from 1.9 to 3.8 L.min-1.m-2. Transesophageal echocardiographic monitoring during the operation disclosed trace mitral regurgitation before median sternotomy. The severity of the regurgitation noticeably increased to the moderate level immediately after pericardial resection. This echocardiographic finding had improved 1 week later, but the regurgitation still was greater than baseline. Mitral valve function had returned to baseline by 4 weeks after the operation. Possible mechanisms of this evolving pattern of perioperative mitral valve dysfunction are discussed.