Novel marker "Ejection Times" may distinguish CCP from RCMP, finds JAMA study

While enhanced ventricular interaction is a foundational parameter to distinguish chronic constrictive pericarditis (CCP) from restrictive cardiomyopathy (RCMP), it is an enhancement of a normal phenomenon and the boundary between normal and abnormal values is not absolute.

Pseudo ventricular interaction can occur in the settings of respiratory distress or other circumstances of increased work of breathing. Atrial fibrillation, with variable diastolic intervals, will alter beat to beat ventricular stroke volumes, making respirophasic assessment more complex. Hence, even with the available ECHO and catheterization based distinguishing parameters, the distinction of these two closely mimicking but therapeutically different disease process remains challenging.

Ejection times (ETs) correlate with stroke volumes and can be easily measured from arterial pressure tracings. Jain et al aimed to assess respirophasic changes in pulmonary artery (PA) ETs and aorta (Ao) ETs as a marker for enhanced ventricular interdependence. This study evaluated patients undergoing left-side and right-side heart catheterization for assessment of CCP after noninvasive evaluation was inconclusive.

Measurements of the PA and Ao ETs were made during inspiration and expiration. Ventricular interaction was mainly assessed by evaluating the difference of ETs from expiration to inspiration as well as the difference in Ao minus the difference in PA.

A total of 10 patients with surgically proven CCP and 10 patients without CCP (restrictive cardiomyopathy or severe tricuspid regurgitation) were identified. There were no significant differences in demographic characteristics or baseline hemodynamic measurements. In patients with CCP compared with those without CCP, there was a significantly greater decrease in PA ET and a nonsignificantly greater increase in Ao during expiration vs inspiration.

Thus, the difference in Ao ET minus the difference in PA ET during expiration vs inspiration was significantly greater in those with CCP compared with those without CCP. In individuals with CP, the noncompliant pericardium impairs ventricular filling, preferentially increasing RV stroke volume with inspiration at the expense of LV stroke volume, and the inverse applying during expiration.

Evaluation of ejection times can thus simplify the invasive assessment for constriction, particularly when high-fidelity micromanometers are not available and frequent catheter-induced ventricular ectopy or mechanical aortic prostheses are present. Using PA and Ao parameters to evaluate ventricular interdependence offers several advantages. These tracings can be obtained efficiently, without the need to access both ventricles, and confront ventricular ectopy or fluid-filled catheter whip artifact.

Source: JAMA Cardiology: doi:10.1001/jamacardio.2021.3478