Background: Heart failure (HF) and atrial fibrillation (AF) are associated with structural and functional changes in the left atrium (LA). LA strain is an echocardiographic method to detect LA function. Whether and what similarities exist for both diseases- HFrEF and persistent AF with preserved EF still needs to be further research.
The aim of the study was 1) to measure LA strain in patients (pts) with HFrEF and AF compared to pts without structural heart disease and 2) to search for differences in LA strain values depending on sinus rhythm (SR) or atrial fibrillation (AF) at the time of the examination.
Methods: The study population includes 188 pts in three different groups. 53 pts with HF underwent CRT implantation (CRT group), 92 pts with persistent AF underwent first time a LA catheter ablation (CA group) and 43 pts without structural heart disease or AF underwent EP study (control group). In all subjects was previously measured LA strain using two-dimensional speckle tracking echocardiography.
Results: Pts characteristics: CRT group (n=53): mean age 70y, mean EF 29%, 72% male. CA group (n= 92): mean age 67y, EF 53%, 75% male. Control group (n=43): mean age 60y, mean EF 63%, 53% male. The EF was significantly lower in the CRT compared with in the two other groups (p< 0.001).
All over for LASr we found normal values in the control group (mean 39% [17 – 67%] and reduced in the CRT (mean 16 [3 – 45] %) and in the CA group (mean 19 [5 – 54] %). The LASr was significantly lower in the CRT vs the controls (p < 0.001) as well as in the CA vs control group (p < 0.001), whereas there was no disparity between CRT and CA group (p = 0.215).
At the time of the echocardiography in the CRT group 14 pts (33%) and in the CA group 35 pts (38%) had AF. Insite the CA group the LaSr was significantly lower since the pts was in AF (12 [5 – 30] %) than in SR (23 [6 – 54] %; p < 0.001). In both subgroups of the CA group the EF was not different (AF: 54 vs SR: 52 %, p= 0.63). In the CRT group the LaSr was as well significantly lower (p = 0.014) in AF (mean 11 [4 – 32] %) than in SR (17 [3 - 45) %), with the same EF in both subgroups (AF: EF 30 vs SR: EF 28%, p= 0.472). Comparing the LASr and the LAScd in pts in SR in the CRT group (LASr: mean 17 [3 - 45] %, LAScd mean: – 8 [1 – 32] %) with those in the CA group (LASr: mean 23 [6 – 54] %, LAScd: mean -13 [2 - 37] %) showed significantly differences (LaSr: p= 0.011; LaScd: p< 0.001). The LaSct didn’t show significant differences (p= 0.967, CRT: LASct -9 [2 - 26] vs CA: LASct -10 [7 - 44] %).
Discussion: In pts with persistent AF and preserved EF the LA strain was in a similar way reduced as in pts with HFrEF compared to pts without structural heart disease. The LASr is independent from the EF even worse if the measurement is done during AF. Measuring the LASr and the LAScd in SR showed significant reduced values in the pts with HF and reduced EF in comparison with the group with persistent AF and preserved EF. The LaSct due to the active atrial contraction in SR was in both groups not significantly different.
