Respiratory maneuvers in echocardiography: a review of clinical applications

Abstract

During echocardiographic examination, respiration induces cyclic physiological changes of intracardiac haemodynamics, causing normal variations of the right and left ventricle Doppler inflows and outflows and physiological variation of extracardiac flows. The respiration related hemodynamic variation in intra and extracardiac flows may be utilized in the echocardiography laboratory to aid diagnosis in different pathological states. Nevertheless, physiologic respiratory phases can cause excessive translational motion of cardiac structures, lowering 2D image quality and interfering with optimal Doppler interrogation of flows or tissue motion. This review focuses on the impact of normal respiratory cycle and provocative respiratory maneuvers in echocardiographic examination, both in physiological and pathological states, emphasizing their applications in specific clinical situations.Respiration induces cyclic physiological modification of intracardiac haemodynamics. Changes are related to variations in intrathoracic and intraabdominal pressure, systemic and pulmonary venous return, intrapericardial pressure, pericardial constraint and interdependence between the four cardiac chambers. With inspiration intrathoracic and intrapericardial pressures decrease. This results in augmented right ventricular filling and stroke volume and, as the total pericardial space is limited, a compensatory decrease in left ventricular stroke volume occurs in early inspiration. With expiration, intrathoracic and intrapericardial pressures increase, resulting in mild decrease in right ventricular diastolic filling and a subsequent increase in left ventricular filling.Because of the constraining effect of the pericardium on the combined volume of the four cardiac chambers, respiratory variation in intrapericardial pressure results in reciprocal variation in the filling of both ventricles [1]. Influence of normal respiration on echocardiographic parameters• 2D echocardiography Image quality With inspiration the anteroposterior diameter of the chest increases, and the lungs inflate and expand particularly anteriorly, partly filling the space between the heart and the thoracic cage. Inspiratory movements do not only decrease the amount of cardiac tissues that lies close to the

Doppler Echocardiographic Changes in Respiratory Diseases

“…The respiration induces marked changes in Doppler velocity curves of hepatic veins. During inspiration there is a significant increase in both normal forward systolic (S) and diastolic (D) flow velocities as well as retrograde A velocity (Ginghina et al 2009). During expiration, there is decreased diastolic flow and increased reversals.…”

“…During this phase, the preload, end-diastolic LV volume and after load decreased. So the systolic anterior motion (SAM) occurs earlier in systole, and mitral-septal contact lasts longer and LV outflow tract gradient increases (Ginghina et al 2009). Valsalva maneuver helps also to augment the diagnosis of mitral valve prolapse, as it increases the intensity of mitral regurgitation associated with MVP and it makes regurgitation to start earlier in systole due to reduction of left ventricular volume.…”

“…During inspiration the E/A ratio of transmitral flow may be reduced but of no significance in healthy subjects. However this effect may become significant in certain cardiac diseases as in coronary artery diseases and abnormal LV relaxation pattern (Ginghina et al 2009).…”

“…If the IVC is dilated without any collapse; this suggests markedly elevation of RA pressure (greater than 15 mm Hg). With intravascular volume depletion, the IVC is small (usually < 1.2 cm) with spontaneous collapse (Ginghina et al 2009).…”

“…Left lateral rotation of the patient will deflate the left lung and avoid the pulmonary interference and improve the clarity of echocardiograms. Improving the quality of image can be done by using device-driven systems, which can acquire signal averaging of echocardiographic frames over multiple cardiac cycles (Ginghina et al 2009, Lang 2005, Klingler 1989 …”