Dynamic monitoring of left atrial strain: a novel paradigm for early detection of cardiotoxicity in colorectal cancer patients undergoing chemotherapy.

Background: Chemotherapy-induced cardiotoxicity significantly impacts cancer prognosis, yet conventional assessment methods lack sufficient sensitivity for early detection. This study aimed to evaluate the dynamic changes of left atrial (LA) strain parameters and their utility as diastolic function markers in colorectal cancer patients receiving chemotherapy. Methods: In this prospective cohort study, 94 patients treated with FOLFOX/XELOX regimens underwent comprehensive echocardiographic assessments at baseline (T0), after the first cycle (T1), mid-therapy (T2), and treatment completion (T3). Left atrial reservoir (LASr), conduit (LAScd), and contractile (LASct) strains, and left ventricular global longitudinal strain (LVGLS) were analyzed using speckle-tracking echocardiography. Linear mixed models characterized strain parameter trajectories, while latent class growth analysis identified heterogeneous response patterns. Correlation matrices evaluated associations between LA strain, LVGLS, and diastolic parameters, with receiver operating characteristic (ROC) curve analysis determining diagnostic performance. Results: LASr showed strong negative correlations with conventional diastolic parameters (P<0.001), demonstrating superior diagnostic accuracy [area under the curve (AUC): 0.792] versus conventional indices. The model incorporating LA strain parameters significantly outperformed the model based on traditional diastolic parameters (AUC: 0.836 vs. 0.617, P<0.001). Chemotherapy induced progressive LASr decline (40.3% at T0 vs. 35.2% at T3, P<0.001), with distinct trajectories: a gradual decline (75.5% patients) and rapid deterioration (24.5%). LVGLS correlated positively with LASr (r=0.38-0.39). Patients with >15% LVGLS reduction had higher baseline hypertension prevalence (40.7% vs. 16.4%, P=0.007) and greater LASct impairment (2.1% reduction, P=0.012). Conclusions: LA strain parameters, particularly LASr, serve as sensitive biomarkers for chemotherapy-associated diastolic dysfunction, demonstrating diagnostic superiority over conventional measures. The observed strain progression patterns enable individualized risk stratification, providing a rationale for early cardioprotective interventions.