Whole hearts were fixed in 10% buffered formalin at the end of each experiment, and sectioned transversely at midventricle, with samples taken from the anterior to lateral free LV wall for histological assessment. These were paraffin‐embedded, sectioned at 4 μm, and stained with H&E, and immunohistochemistry for von Willebrand factor (vWF). H&E‐stained sections were quantitatively scored in a blinded fashion by a pathologist. The extent of myocardial hemorrhaging on each section was scored as 0 (none), 1 (<10%), 2 (10%–50%), or 3 (>50%), with endocardial and epicardial hemorrhage also scored as 0 (none), 1 (<5%), 2 (5%–10%), or 3 (>10%). Contraction bands and/or hypereosinophilic myocytes were also assessed as 0 (absent), 1 (present). Staining for vWF was used as a marker for endothelial cell injury. After deparaffinization and rehydration, antigen retrieval (Dako Target Retrieval Solution, pH9, Agilent) was performed for subsequent probing with an anti‐vWF antibody (GA527, 1:400, Dako). An anti‐rabbit secondary antibody (VECTASTAIN Elite ABC‐Peroxidase kit, Vector Laboratories) and 3,3′‐diaminobenzidine (SigmaFAST DAB, Sigma‐Aldrich) were used for detection and staining. Hematoxylin was used for counterstaining. vWF density was expressed as a pixel unit and calibrated by the sum of inner perimeters of vessels in each section using Adobe Photoshop 2020 (Adobe, CA). The same threshold density for vWF‐positive staining was applied to all sections. To assess apoptosis, a TUNEL (terminal deoxynucleotidyl transferase biotin‐dUTP nick end labeling) assay was performed as per manufacturer's instructions (ApopTag Plus Fluorescein In Situ Apoptosis Detection Kit, EMD Millipore Corporation, CA), and the number of TUNEL‐positive nuclei was quantified in 6 randomly picked fields/sections with an open‐source digital image analysis software (QuPath v0.2.3) at 20X and averaged. TUNEL‐positive nuclei were expressed as a percentage of total nuclei.