Left atrial strain is influenced by cardiac resynchronisation therapy in advanced heart failure

Abstract Background CRT is an established treatment in patients (pts) with HFrEF. LV reverse remodeling is well studied. There is still little data about left atrial (LA) reverse remodeling. The LA strain is an echocardiographic method to detect LA function. The aim of the study was 1) to measure LA strain in HFrEF pts before CRT implantation compared to pts without structural heart disease, 2) to repeat the measurement in a FU of 6 month after CRT implantation and 3) to search for differences in LA strain values depending on SR or AF. Methods The study included 35 pts with HF who underwent CRT implantation (CRT group) and 43 pts without structural heart disease or AF who underwent EP study (control group). All subjects preserved measurement LA strain imaging using 2D speckle tracking echocardiography before CRT implantation rsp. EP study. In the CRT group the LA strain was measured again 6 month after implantation. Results Pt characteristics: CRT group (n=35), mean age 67y, 71% male, mean EF 29 %, 43% DCM, 40% ICM, 14% NICM, 1 pt myocarditis, 1 pt DCM/ICM, 1 pt DCM/myocarditis. Control group (n=43): mean age 60y, 53% male, mean EF 63 %. At the time of the echocardiography 7 pts (20%) had AF in the CRT group. For LASr we found normal values in the control group (mean 39 [17 - 67] %) and reduced in the CRT group baseline (mean 16 [3 - 45], AF: mean 10 [4 - 18]; SR: mean 17 [3 - 45] %). At the FU of 6 mo in the CRT group 3 pts (9%) still had AF. The other pts with AF had either an ablation (1 pt) or a cardioversion (3 pts). Mean EF at FU in the CRT group was 38 %. LASr was reduced as well (mean 20 [5 - 54] – SR: mean 21 [5 - 54]; AF: mean 15 [10 -19] %). We found significant higher values for LASr in the controls in comparison to the CRT group baseline and in the FU (p < 0.001). The EF was significant reduced in the CRT group baseline and in the FU compared to the controls (p < 0.001). There was no significant difference for LASr in the CRT group baseline vs FU (p = 1.110), whereas the EF showed a significant enhancement (p < 0.001). The rhythm showed no effect on the LASr (CRT: p = 0.058; 6 mo FU: p = 0.556) or the EF (CRT: p = 0.43; 6 mo FU: p = 0.934) in the CRT group or FU. Discussion Pts with HFrEF present significant lower LA strains in comparison to pts without structural heart disease. After CRT-implantation the EF increases significantly after 6 mo, whereas the LA strain is still disturbed without relevant change. We found no relevant effect of the rhythm on the EF or LA strain. A limitation of our results is the significant younger age of our control group (p = 0.004) as fibrotic remodeling increases in advanced age. Furthermore a FU of 6 mo might be too short to detect significant enhancement of the LA strain. It remains to be analyzed whether early HF treatment could prevent further fibrotic remodeling and whether LA strain measurement could provide further information for therapeutic intervention strategies.