Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3715_Библиотеки_им_академика_М_И_Перельмана

left ventricular lling pattern), increased tissue Doppler velocity of the medial mitral annulus and reciprocal respiratory variation of mitral and tricuspid inow Doppler velocities. About 15% of patients with chronic constrictive pericarditis have a negative, equivocal or technically conrmed echocardiogram [239].

(a) Evaluation of the pericardial morphology

The characteristic feature of pericardial thickening on echocardiogram is parallel motion of the epicardium and parietal pericardium separated by approximately 1 mm wide relatively echo-free space [85–91, 93, 94]. The best view to assess motion between the pericardial layers is the four-chamber subcostal view. Although assessment of pericardial thickness and calcication using transthoracic echocar­diography is inferior to computed tomography and cardiac magnetic resonance, assessment with transesophageal echocardiography (TEE) strongly correlates with cardiac tomography [26, 27, 79, 85–91, 93, 94, 104, 105, 190].

Several investigators have demonstrated a pericardial thickness of more than 3mm obtained using transesophageal echocardiography having 95% sensitivity and 86% specicity for detection of the thickened pericardium [79, 104, 105]. The 2003 ACC/AHA/ASE Task Force recommends transesophageal echocardiography for assessment of pericardial thickness to support the diagnosis of chronic constrictive pericarditis (class IIB) [26, 27]. Echocardiography evaluation may be inadequate in assessing pericardial thickness anterior to the right ventricle and near the right atrio­ventricular groove [26, 27, 39, 85].

Unlike echo Doppler methods and tissue Doppler imaging which rely mostly on longitudinal motion data, speckle tracking echocardiography can examine several components or planes (i.e. radial, longitudinal and circumferential) in a single data set. It can assess the torsional deformation of the myocardium in addition to strain and strain rate. Speckle tracking echocardiography can also quantify the rocking or swinging motion of the heart by measuring septal-to-lateral rotation displacement (SLRD) [47–49, 70, 71, 85–91, 93, 94, 134, 135, 138–144, 148, 187–200, 220].

“Strain reversus” is a feature characterised by diminished negative peak systolic strain in the free walls of left and right ventricles when compared with septal peak systolic strain. It is seen when diseases affecting myocardial strain values are absent. The sensitivity and specicity of left ventricular lateral wall strain to left ventricular septal wall strain ratio<0.96 are 89% and 96% respectively [7]. The left and right ventricular strain abnormalities are noted to cease following surgery [93]. A charac­teristic pattern observed following pericardiectomy is impaired early diastolic strain rate of left atrial superior and lateral walls compared with the septal wall [116].

Doppler echocardiography relies on the presence of distinct atrial and ventricular lling characteristics in relation to the respiratory cycle [10, 70, 71, 138–144]. In about 50% of patients with chronic constrictive pericarditis, mitral inow velocity decreases as much as 25% and tricuspid inow velocity increases considerably with the rst heart beat after inspiration. In contrast, respiratory variation in patients with restrictive cardiomyopathy does not differ signicantly from normal.

(c) Abnormalities of interventricular septal motion

Dissociation of intracardiac and intrathoracic pressure in chronic constrictive pericarditis means that with inspiration, the intrathoracic pressure declination is not not fully transferred to the intracardiac chambers since they are isolated by a con­stricting pericardial cover. Consequently, left ventricular diastolic lling is reduced. In chronic constrictive pericarditis, a relatively xed cardiac volume, coupled with an increased right ventricular diastolic lling during inspiration, results in a left­ward shift of the interventricular septum. The opposite change occurs during expira­tion [140, 141]. Although non-specic, another common nding in chronic constrictive pericarditis is a septal shudder or bounce, which is an abrupt displace­ment of the interventricular septum in early diastole during each cardiac cycle [40]. Septal shudder corresponds to the dip and plateau sign observed on the right ven­tricular pressure tracing.