Figure 1.
T-Tubule Density Is Increased in Patients With HFpEF
T-tubules were examined in biopsies taken from nonischemic regions of the myocardium in patients undergoing coronary bypass. (A, top) Confocal images of WGA-stained cryosections, with indicated regions enlarged below. (Bottom) Distance from each cytosolic point to the nearest t-tubule or surface membrane. Scale bar = 10 μm. Overall t-tubule density was increased in heart failure with preserved ejection fraction (HFpEF), both when patients were divided by New York Heart Association (NYHA) functional class (B) or severity of diastolic dysfunction (C). T-tubule density was not significantly altered in patients comorbid for diabetes mellitus (DM) (D). Distances to nearest membrane were shorter in HFpEF (E) and negatively correlated with t-tubule density (F). ∗p < 0.05 vs. control. ncells: control = 59 (4 hearts), NYHA functional class I = 70 (4 hearts), NYHA functional class II = 74 (5 hearts), NYHA functional class III = 27 (3 hearts), E/eʹ <14 = 109 (6 hearts), E/eʹ >14 = 61 (6 hearts), nondiabetes mellitus = 86 (6 hearts), diabetes mellitus = 85 (6 hearts). Data are mean ± SD.