37 Correlation of cardiac magnetic resonance-derived left atrial strain and strain rate with conventional markers of diastolic dysfunction in an asymptomatic population

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Background The diagnosis of diastolic dysfunction is often challenging and, traditionally, has been assessed by cardiac imaging of structural and functional parameters such as maximum left atrial volume index (LAVi max), left ventricular mass index (LVMi) and mitral annular early diastolic velocity (e’), as well as biochemical parameters, primarily natriuretic peptide. The left atrium (LA) plays an important role in modulating left ventricular filling in diastolic dysfunction. Left atrial strain and left atrial strain rate are emerging tools in the assessment of left atrial function and can be accurately and reliably measured using cardiac magnetic resonance (CMR) feature tracking (FT). This is an updated analysis evaluating the association of CMR-derived left atrial strain (LAS) and left atrial strain rate (LASR) during reservoir, conduit and booster-pump phases of the left atrial cycle with conventional markers of diastolic dysfunction. Methods A retrospective left atrial strain analysis was performed on baseline CMR scans in 139 patients with asymptomatic diastolic dysfunction from the randomized PARABLE trial (NCT04687111). CMR scans were performed using a 1.5 Tesla scanner. CVI42 (Circle Cardiovascular Imaging Inc.) was used to perform the FT analysis. LAS and LASR were measured in the reservoir, conduit and booster-pump phases of the left atrial cycle from balanced steady-state free precession apical 2- and 4-chamber cine sequences and correlated with LAVi max, LVMi, NT-proBNP and mitral annular e’. Correlation analysis was performed using Spearman r test. Results All LAS and LASR measurements during reservoir, conduit and booster-pump phases correlated significantly with natriuretic peptide levels (table 1). Only booster-pump LAS, booster-pump LASR, total LA emptying fraction (LAEF) and booster-pump LAEF correlated significantly with LAVi max. There was also significant correlation between novel CMR-derived mitral annular e’ and several markers of LA function as shown in table 1. Only booster-pump LASR, booster-pump LAEF and total LAEF correlated significantly with echo-derived average E/e’. Conclusion Reservoir, conduit and booster-pump LAS and LASR measured by CMR-FT were significantly associated with natriuretic peptide levels and CMR-derived mitral annular e’ in asymptomatic patients with diastolic dysfunction. LA booster-pump function was additionally associated with LAVi max and echo-derived average E/e’. These novel markers, particularly booster-pump LAS and LASR, could provide incremental information when assessing for diastolic dysfunction.

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