Regularity of hypoxia inducible factor 1 alpha expression in acute myocardial ischaemia in rats

Acute myocardial ischaemia is a common acute .disease and a common cause of sudden death.However, it is difficult to diagnose in patients who died within 6 hours after the onset of myocardial ischaemia. The occurrence of sudden cardiac death often has pathological basis of primary heart diseases, which may lead to a series of changes in metabolism and gene expression.1 Recent research found that hypoxia inducible factor 1 alpha （HIF-1α） is a sensitive marker of hypoxia; its gene expression is upregulated within several minutes after acute myocardial ischaemia, followed by the upregulation of its protein and its expression will remain high if the inducement continues. Its expression in nonhypoxic cardiac muscle is very low. This characteristic may be used to differentiate hypoxic factors from nonhypoxic factors, and help to judge the cause of death. This study explored the expression of HIF-1α in hypoxic cardiac muscle by establishing an acute myocardial ischaemia model in mice, and observed its dynamic changes to provide reference for analysing causes of death within 48 hours after death.

Surgical outcome and clinical follow-up in patients with symptomatic myocardial bridging

Background Myocardial bridging with systolic compression of the left anterior descending coronary artery （LAD） may be associated with myocardial ischaemia. The clinical outcome in patients with surgical treatment for symptomatic myocardial bridging remains undetermined. This study assessed the middle- and long-term results of surgical treatment for symptomatic myocardial bridging. Methods From 1997 to 2006, 37 463 patients received selective coronary angiography in the Fuwai Cardiovascular Hospital, Beijing, China. Of these, 484 patients had angiographic diagnosis of myocardial bridging. Of the 484 patients, 35 underwent surgery for treatment of myocardial bridging with significant systolic arterial compression. Among the surgical treatment patients, 24 presented with other cardiac disorders, and the remaining 11 symptomatic patients with isolated myocardial bridging were included in the follow-up study. Results The angiographic prevalence of myocardial bridging was 1.3% in this study. The coronary angiographies of the 11 patients revealed myocardial bridging in the middle segment of LAD causing systolic compression 〉75% （ranging from 75% to 90%）. The mean age of patients was 48,4 years. Surgical myotomy was performed in 3 patients and coronary artery bypass grafting （CABG） in 8 patients. Eight patients were operated on with an off-pump approach and 3 with a cardiopulmonary bypass technique after median sternotomy. Conversion to on-pump CABG surgery was necessary in 1 patient because of perforation of the right ventricle. The left internal mammary artery was used in all patients with CABG. The acute clinical success rate was 100% with respect to the absence of myocardial infarction, death or other major in-hospital complications. All of the patients were followed up clinically. The median follow-up was 35.3 months （range： 6 to 120 months）. Nine patients were free from symptoms and one of them continued taking beta blockers. The remaining 2 patients with myotomy had atypical chest pain. One received coronary angiography again and no stenosis was found two years after operation; while exercise testing was performed in the other patient and revealed no evidence of myocardial ischaemia. None of the patients sustained a myocardial infarction or other major adverse cardiac events （death or vessel revascularization） during follow-up. Conclusions Myocardial bridging is a relatively common angiographic finding. Surgical myotomy or CABG should be limited to patients who are refractory to oral medication. Surgical relief of myocardial ischaemia due to systolic compression of intramyocardial coronary arteries can be accomplished with low operative risk and excellent middle- and long-term results,