Rheumatoid arthritis whatever the disease activity compared to the general population is associated with increases in both mortality and morbidity. In rheumatoid arthritis CVDs is the leading cause of death even with preserved LV systolic function[18 ].
In this study we assessed LA function by non-invasive echo-Doppler parameters (conventional, tissue Doppler and STE) in RA patients with and without disease activity. The LA deformation dynamics were impaired in RA patients compared with age and gender matched controls with more reduction of both LA-GLS and LA-PLS in disease activity versus remission. The magnitude of LA dysfunction was related to severity of left ventricular diastolic dysfunction (LVDD).
The left atrium plays at least three major physiologic roles in contraction and relaxation. During ventricular systole and isovolumic relaxation, the left atrium operates as a ‘reservoir’ that receives blood from the veins. During early ventricular diastole, the left atrium serves as a ‘conduit’ for blood transfer into the ventricle. Finally, the ‘booster pump function’ of the left atrium augments ventricular filling during the late phase of ventricular diastole. Left atrial dysfunction has been implicated in a variety of disorders, from hypertension to ischemic stroke. In this study, we excluded patients with pre-existing conditions to evaluate the impact of RA whether active or in remission on LA function.
Left ventricular diastolic dysfunction (LVDD) was reported to show high prevalence in rheumatoid arthritis, but due to its dependance on measurement of multiple diastolic dysfunction parameter[13 ]..s, it remains difficult to characterize and it had interobserver variations.
Left atrial volumes and functions are important predictors for adverse cardiac events and are considered markers for left ventricular diastolic dysfunction severity and chronicity[9 ].
The severity and chronicity of LVDD in a variety of cardiovascular conditions is an established surrogate marker for maximum left atrium volume[13 ]. In addition to size,
LA function determines the structural and functional adaptive changes of LA that characterize diastolic function of LV. In exercise, the LA contributes to one-third of the cardiac output if systolic function is preserved. So, [15 ].. LA adaptive functional changes became more evident in those patients with worsened LV systolic and diastolic function[13 ].
In this study, Lipid profile was elevated in rheumatoid arthritis patients than control and this might be partially explained by elevated inflammatory markers as CRP and ESR.
Although there were variations in cardiac dimensions and parameters of LV systolic function between all studied groups but all were still within the normal range. On the other hand, the diastolic parameters were found to be impaired in rheumatoid arthritis patients by conventional echocardiography and TDI parameters with no significant difference between disease activity state, which means that presence of rheumatoid arthritis and may be other rheumatologic diseases, can affect LV diastolic function.
In the current study, the LA volumes and indices were much elevated in rheumatoid arthritis patients compared to control with no statistical difference regarding disease activity. Also, there were reduced LA reservoir and contractile function and increased conduit function in rheumatoid arthritis patients.
This is concordant with a study in 2020 where left atrial volumes showed a significant difference between patient and controls, with no correlation to disease activity. On the other hand, this study showed an inverse relation between tissue Doppler parameters velocities (Em, Am, Sm) with the rheumatoid factor regardless disease activity or duration. They studied only LA GLS and found significant difference between patients and controls but they did not study the difference in disease activity state . To our knowledge in the literature, no previously published study compared LA GLS or LAS with different RA activity states.
Other study used another index (LA expansion index) as a predictor of AF occurrence and found LA expansion index -having a prognostic power exceeding that of LA volumes. Unfortunately, we did not include this index in the current study.
Left atrium mechanics estimated from measuring deformation of LA myocardium using strain and strain rate (SR) imaging is a new tool in cardiac imaging with the widespread use of 2D-speckle tracking echocardiography in clinical practice to pick up subclinical conditions .
In this study, there were significant reduction in LA GLS and 2D-peak LAS in rheumatoid arthritis patients and this difference is extended to be significant between active and remission cases in respect to LA GLS only. Also, the current study revealed there is significant negative correlation between LA GLS and rheumatoid arthritis disease activity score. This finding may be explained by left atrial stiffness severity. So, subclinical LA dysfunction can be anticipated from rheumatoid arthritis activity score as our study showed.
Another work, studied the effect of interleukin inhibitor on myocardial deformation and vascular function in RA patients, and they found a significant improvement in LV GLS after treatment by interleukin inhibitors especially in coronary artery disease patients [21 ]. Their data support our study findings that the disease activity is directly proportionate to worsening of myocardial function whether LV or LA function.