Silent myocardial ischemia and diabetes in Mexican patients with coronary heart disease.

Patients with diabetes are at increased risk for coronary heart disease (CHD) and perhaps also for silent ischemia. A cross-sectional study was conducted to assess the effect of diabetes on the occurrence of silent ischemia, and 249 patients with CHD were screened with a 24-hour Holter ECG. ANOVA, Kruskal-Wallis (KW) test and logistic regression were used for analysis. Odds ratios (OR) and 95% confidence intervals (CI95%) were calculated. There were 165 non-diabetics. Silent ischemia was more frequent in diabetics but there was no difference on the mean number of ischemic events. Total ischemic time was similar, but the median duration of ischemia was greater in diabetics (66 minutes vs. 41 min.; KW=4.8, p=0.03), as was the median ischemic time per episode (41 vs. 28; KW 5.31, p=0.02). There was a 3.5% increased risk for each year of duration of diabetes (OR 1.03, CI95% 1.0-1.08). Diabetes may increase the risk of silent ischemia through diabetic autonomic neuropathy involving the cardiac afferent sympathetic system.