Natural Mechanism of Death. Macroscopic findings of the heart. (a) Concentric hypertrophy of the left ventricle is observed in the transverse section of the ventricle; many petechial hemorrhagic lesions (arrow head) are observed in both ventricle walls. (b) A sagittal section of the right atria and ventricles petechial hemorrhagic lesions (arrow head) are shown near the atrioventricular node. An autopsy case of myocardial infarction due to idiopathic thrombotic thrombocytopenic purpura. Tasaki T, Yamada S, Nabeshima A, Noguchi H, Nawata A, Hisaoka M, Sasaguri Y, Nakayama T - Diagnostic pathology (2015). Not Altered. CC.