Impact of Multi-parametric Analyses on Normal Left Atrial Strain by Cardiovascular Magnetic Resonance Feature Tracking

Left-atrial (LA) strain is the result of complex hemodynamics, increasingly assessed by feature-tracking cardiovascular magnetic resonance (CMR). We investigate the value of multi-parametric regression (MPR) analyses and the influence of the heart rate on LA-strain. As LA-strain data remains limited, CMR-quantified sex- and age-dependent normal values were derived. After following a health assessment questionnaire, 183 healthy volunteers (11-70 years, 97 females, median 32.9±28.3 years) were recruited for LA-strain assessment. LA volumetric data, left ventricular strain, transmitral and pulmonary venous blood flow parameters were utilized to create clusters for MPR analyses for all subjects and heart rate-specific subgroups (range: 60–75 beats-per-minute, N=106). In comparison to the total cohort, subgroups showed no gender differences (p>0.05) for LA reservoir, conduit and booster strains (all: 47.3±12.7%; 29.0±15.5%; 17.6±5.4%) and strain rates (all: 2.1±1.0 s−1; -2.9 ± 1.5 s−1; -2.3 ± 1.0 s−1). MPR analyses identified parameter clusters with large effect size (|R²|≥0.26) for reservoir-, conduit- and booster strain and corresponding active and passive cardiac functional parameters. Increased correlations for the subgroup were found. In contrast to previous studies, heart rate selected subgroups showed no gender differences in LA-strain. MPR analyses improve characterization of LA-strain at selected heart rates.