1. Cardiomyocyte metabolic disorder
Glycosylation of contractile protein or calmodulin in diabetic patients is mediated by second messengers such as protein kinase C(PKC) and nitric oxide (NO), which leads to its abnormal function.
2. Calcium transport defect in myocardial cells
The increase of extracellular glucose level in myocardium directly causes the change of intracellular calcium concentration. It was found that the exchange of sodium and calcium in myocardial cells of type 2 diabetes mellitus was inhibited, while the calcium pump in sarcoplasmic reticulum was normal, which gradually enriched calcium in sarcoplasmic reticulum. Calcium overload of myocardial sarcoplasmic reticulum can increase spontaneous calcium release, increase myocardial diastolic tension and reduce cardiac compliance.
3. Coronary microangiopathy
There are diffuse intramural small vessel lesions in the myocardium of diabetic patients.
4. Myocardial interstitial fibrosis
It is caused by the long course of diabetes and the deposition of glycosylated collagen.
5. Cardiac autonomic neuropathy
About 83% of diabetic patients have cardiac autonomic neuropathy.