Quantitative Assessment of Left Atrial and Ventricular Function in Hypertensive Heart Disease via Cardiac Magnetic Resonance Feature Tracking: An Experimental Study

Abstract

Objective: To investigate the value of cardiac magnetic resonance feature tracking (CMR-FT) in assessing left heart function in hypertensive heart disease (HHD) and to preliminarily explore the relationship between left atrial (LA) and left ventricular (LV) function1. Methods: Ten Bama minipigs were randomly divided into an experimental group (N=6) and a control group (N=4). The experimental group underwent laparotomy with left renal artery ligation to establish a hypertension model, while the control group underwent laparotomy without ligation. CMR-FT examinations were performed at baseline, 4 weeks, and 16 weeks post-surgery. Global LA and LV functional parameters were measured using CVI42 post-processing software. Results: Left atrial volumetric indices (LAVImin and LAVImax) did not differ between groups at baseline or 4 weeks (P>0.05), but were significantly higher in the hypertension group at 16 weeks (LAVImin 17.65±1.66 vs 11.13±1.60 mL/m², P<0.001; LAVImax 27.05±2.19 vs 20.75±3.13 mL/m², P=0.005). LA reservoir and conduit function deteriorated early: εs and εe were reduced in the hypertension group at 4 weeks (εs 36.47±3.08 vs 41.80±2.92, P=0.026; εe 20.45±1.53 vs 23.43±2.15, P=0.033) and further decreased at 16 weeks (εs 27.22±3.71 vs 39.53±2.72, P<0.001; εe 12.10±2.02 vs 23.00±1.77, P<0.001). LV volumetric parameters and LVEF remained comparable between groups at all time points (all P>0.05), whereas LV strain indices showed significant impairment in the hypertension group at 4 weeks and 16 weeks (e.g., LVRS 35.05±2.39 vs 43.45±1.80 and 29.55±1.80 vs 43.18±1.35; LVCS −18.42±1.40 vs −20.66±1.42 and −16.58±0.87 vs −19.63±0.99; LVLS −15.35±0.91 vs −18.90±0.50 and −12.63±1.73 vs −18.33±0.76; all P≤0.039). LA volumes were strongly and inversely correlated with LA strains (LAVmin with εs r=−0.845 and εe r=−0.838; LAVmax with εs r=−0.863 and εe r=−0.871; all P<0.05). Moreover, LVLS correlated positively with εs (r=0.814) and εe (r=0.875) and negatively with LA volumes (LAVmin r=−0.817; LAVmax r=−0.907), while LVRS was also associated with LA function (all P<0.05). Conclusion: CMR-FT can detect structural and functional impairments of the LA and LV in early-stage HHD earlier, more sensitively, and more accurately than conventional cardiac functional parameters. Furthermore, significant correlations exist between LA and LV functional parameters.