Cardiac dyssynchrony, particularly in patients with Left Bundle Branch Block (LBBB), poses significant challenges in clinical management. This study investigates the curvature of the interventricular septum (IVS), specifically the inverse radius of a fitted circle at 100 temporal points during the cardiac cycle, as a potential marker for detecting cardiac dyssynchrony in subjects with no diagnosed cardiac abnormalities, and with LBBB, both with and without cardiac resynchronization therapy (CRT).
Data from a previous manuscript were reanalyzed, categorizing 28 subjects into three groups with 14 subjects with no diagnosed cardiac abnormalities, and 14 LBBB patients undergoing CRT treatment, with active external pacing (pacer_on), and without active pacing (pacer_off). At all timepoints the IVS contour was fitted to a circle using the Levenberg-Marquardt algorithm, and the radius was inversed.
The inverse radius decreased depending on cardiac health with the Healthy subject group (0.43±0.16) having the lowest average inverse radius, pacer_on group (0.49±0.10), and pacer_off group (0.53±0.15) the highest inverse radius. Given a non-normal data distribution, the Kruskal-Wallis test was used for testing statistics, yielding a test statistic p-value of p-value < 0.0001, indicating significant differences among the groups. Dunn's post hoc test with Bonferroni correction revealed significant differences (p-value < 0.0001) between all groups.
These findings suggest that the inverse radius could serve as a marker for identifying cardiac dyssynchrony in LBBB patients, potentially guiding therapeutic decisions and improving patient outcomes.