Left ventricular size may predict a better CRT response

FUNDING ACKNOWLEDGEMENTS: Type of funding sources: None. BACKGROUND: We know that women have better responses to cardiac resynchronization therapy (CRT) (1). A possible explanation for this greater benefit has been attributed to sex difference in left ventricular (LV) size: sex-specific differences disappear when we normalize QRS duration to left ventricular end-diastolic volume (LVEDV) (2). QRS narrowing index (QI) has been showed predicting reverse left ventricular remodelling following CRT (3; 4). PURPOSE: We sought to analyse the relationship between LV dimensions pre-CRT and QRS narrowing index, as a predictor of LV remodelling, and the relationship between LV dimensions pre-CRT and echocardiographic response 1 year after CRT. METHODS: We collected data from our Cardiovascular Implantable Electronic Device (CIED) outpatients’ database, selecting patients who underwent CRT, with analysable echocardiographic images in our local PACS, and with clinical, electrocardiographic, and echocardiographic data pre-CRT and at 1-year follow-up. RESULTS: We reviewed electrocardiograms and echocardiograms of 203 patients (M=120, 59,11%) who underwent CRT from 2015 to 2020. A higher QRS/LVEDV ratio and a higher QRS/LV mass ratio were associated with higher QI (p=0.03 and p<0.001, respectively). A higher QRS/LVEDV ratio was associated with higher LVEF (p<0.001), lower LVEDV (p<0.001) and lower LVESV (p<0.001) at follow up. Similarly, a higher QRS/LV mass ratio was associated with higher LVEF (p=0.04), lower LVEDV (p=0.02) and lower LVESV (p=0.01) at follow up. CONCLUSIONS: LV size seems to have a role in prediction of a better response to CRT. Both the QRS/LVEDV ratio that the QRS/LV mass ratio may predict better electrocardiographic an echocardiographic response. [Figure: see text] [Figure: see text]