Association of Left Ventricular Outflow Tract Obstruction with Left Atrial Remodeling and Dysfunction in Hypertrophic Cardiomyopathy: A Three‐Dimensional Echocardiography and Left Atrial Strain Study
Weili Lin, Runming Zhong, Qianqian Que, Wenwen Lin, Rui'e Zhu, Fulai CaiABSTRACT
Purpose
To compare left atrial (LA) structure and phasic function among healthy controls and patients with nonobstructive or obstructive hypertrophic cardiomyopathy (HCM), and assess their associations with left ventricular outflow tract obstruction (LVOTO).
Methods
We studied 90 patients with HCM and 50 healthy controls. Patients were classified by the highest resting or Valsalva‐provoked LVOT gradient (LVOTG) as nonobstructive (<30 mmHg; n = 50) or obstructive (≥30 mmHg; n = 40). Threedimensional echocardiography measured LA volumes, and two‐dimensional speckle tracking measured phasic strain. Multivariable linear regression examined prespecified echocardiographic outcomes by LVOTO status. Sensitivity analyses modeled LVOTG continuously and used a 50‐mmHg threshold.
Results
Both HCM groups had greater LA enlargement and dysfunction than controls, with the largest abnormalities in obstructive HCM. In the primary adjusted model, LVOTO was associated with higher LAVImin ( B = 10.03 mL/m 2 ; 95% CI, 6.71 to 13.36; p < 0.001) and lower LASr ( B = −2.72%; 95% CI, −4.17 to −1.28; p < 0.001). The associations remained when LVOTG was analyzed per 10 mmHg and with a threshold of ≥50 mmHg. E/e′ and TRV were not significantly associated with LVOTG in these sensitivity analyses.
Conclusion
In this cross‐sectional HCM cohort, greater obstruction severity was associated with higher LAVImin and lower LASr. Prospective studies are needed to determine whether these measures are associated with clinical outcomes.