New insights into the potential utility of the left atrial function analysis in heart failure with preserved ejection fraction diagnosis.

AIMS: None of the conventional echocardiographic parameters alone predict increased NTproBNP level and symptoms, making diagnosis of heart failure with preserved ejection fraction (HFpEF) very difficult in some cases, in resting condition. We evaluated LA functions by 2D speckle tracking echocardiography (STE) on top of conventional parameters in HFpEF and preHF patients with diastolic dysfunction (DD), in order to establish the added value of the LA deformation parameters in the diagnosis of HFpEF. METHODS: We prospectively enrolled 125 patients, 88 with HFpEF (68±9 yrs), and 37 asymptomatic with similar risk factors with DD (preHF) (61±8 yrs). We evaluated them by NTproBNP, conventional DD parameters, and STE. Global longitudinal strain (GS) was added. LA reservoir (R), conduit (C), and pump function (CT) were assessed both by volumetric and STE. 2 reservoir strain (S) derived indices were also measured, stiffness (SI) and distensibility index (DI). RESULTS: LA R and CT functions were significantly reduced in HFpEF compared to preHF group (all p<0.001), whereas conduit was similarly in both groups. SI was increased, whereas DI was reduced in HFpEF group (p<0.001). By adding LA strain analysis, from all echocardiographic parameters, SR_CT<-1.66/s and DI<0.57 (AUC = 0.76, p<0.001) demonstrated the highest accuracy to identify HFpEF diagnosis. However, by multivariate logistic regression, the model that best identifies HFpEF included only SR_CT, GS and sPAP (R2 = 0.506, p<0.001). Moreover, SR_CT, DI, and sPAP registered significant correlation with NTproBNP level. CONCLUSIONS: By adding LA functional analysis, we might improve the HFpEF diagnosis accuracy, compared to present guidelines. LA pump function is the only one able to differentiates preHF from HFpEF patients at rest. A value of SR_CT < -1.66/s outperformed conventional parameters from the scoring system, reservoir strain, and LA overload indices in HFpEF diagnosis. We suggest that LA function by STE could be incorporated in the current protocol for HFpEF diagnosis at rest as a major functional criterion, in order to improve diagnostic algorithm, and also in the follow-up of patients with risk factors and DD, as a prognostic marker. Future studies are needed to validate our findings.

Heart Failure with Mid-Range Ejection Fraction - a New Category of Heart Failure or Still a Gray Zone.

Heart failure with midrange ejection fraction (HFmrEF) is a new category of heart failure (HF), inbetween HF with reduced ejection fraction (HFrEF) and HF with preserved ejection fraction (HFpEF). Previous studies were mainly conducted in HFrEF patients having a left ventricle ejection fraction (LVEF) lower than 35-40%. Later on, HFpEF captured the spot-light of the research field, and studies focused on patients with HF symptoms, but with a LVEF exceeding 50%. Consequently, a gap of knowledge comprising the LVEF between 40 and 49% has arisen. Current studies focusing on patients with HFmrEF are arguing the same conclusions or even having contradictory findings. HFmrEF has a prevalence of 10-20% of HF patients. HFmrEF has distinct, but intermediate clinical, structural and functional characteristics, as well as intermediate outcomes in comparison with HFrEF and HFpEF. However, there is still a large gap in evidence regarding detailed hemodynamic characteristics, long-term follow-up and optimal therapeutic options for these patients. Extensive research was recommended in order to improve knowledge about this "gray area" of patients with HF. Therefore, we aimed to provide an over-view of the existing and lacking data regarding patients with HFmrEF.