Trans-tricuspid L and L′ waves

Abstract

Originally described in left ventricular (LV) diastolic assessment, L wave represents an abnormal mid-diastolic component, occurring between the E and the A waves. It was detected in presence of either a significant delay in active relaxation and/or elevated atrial pressure leading to a flow during diastasis, when, in physiological conditions, an equalization of atrioventricular gradient occurs. The L wave and its corresponding L′ wave at tissue Doppler imaging (TDI) were observed, respectively, at trans-tricuspid pulse wave Doppler and tricuspid valve TDI (Figure 1A and B) in a patient undertaking mechanical ventilation due to moderate acute respiratory distress syndrome (positive end-expiratory pressure 13 cmH2O and driving pressure 13 cmH2O). Right ventricular (RV) systolic function was normal (tricuspid annular plane systolic excursion 16 mm; RV/LV ratio 0.56). Additionally, a pre-systolic pulmonary A wave, an anterograde pulmonary flow occurring during atrial contraction related to a restrictive diastolic pattern, was observed (Figure 1C). RV diastolic function is mostly neglected although it represents a key determinant of cardiac performance, patient’s clinical profile, and prognosis. Although L and L′ waves, along with pulmonary A wave, need a validation in the critically ill population, these signs may be considered as parameters of atrioventricular altered compliance related to RV overload.