Dynamic Holter Changes In Silent Myocardial Ischemia

Dynamic Holter changes in silent myocardialischemia With the insight into mechanism and advanced treatment ofacute coronary syndrome, more and more patients with the emergentdisease survive. Many of them have no angina in daily life, but theystill are the subjects with high cardiovascular risk. Studies haveshown that silent myocardial ischemia (SMI) has a high prevalencein this population. It has been demonstrated that SMI has the sameclinical significance as symptomatic myocardial ischemia ischemia.So detecting and diagnosing SMI earlier for timely treatment becomemore and more important. ACC/AHA 2002 Guidelines Update forthe Management of Patients With Chronic Stable Anginarecommended the ambulatory electrocardiogram (AECG/Holter) isan effective method in the study of SMI. Our study is to explore themechanisms and rules of silent myocardial ischemia (SMI) and toevaluate the diagnostic value of Holter in SMI. 116 patients with coronary artery diseases were investigated by12-lead ambulatory electrocardiogram for 48 hours. Observe theST-segment, the duration of every ischemia episodes, myocardialischemic threshold, the variability, etal. Analysis was conducted onthe records of Holter and the patients'life. Results indicates that 1390 ischemic episodes happened in our116 CAD patients and 85.6% of these ischemic episodes are silentmyocardial ischemia. The high prevalence of SMI in patients withknown CAD suggests us this population need to be carefullyevaluated and treated;79.6% ST-segment depressed for SMImyocardial ischemia occurred in light physical work and brain work,and the peak emerged between 6 am to 12 noon,the degree andtimes of ST-segment depressed were significant in daytime (P<0.01),with heart rate quickened in ST-segment depression (P<0.01). Wecan explain this outcome that the condition of shortage of oxygen,the activity of sympathetic nerve system at day time can increasemyocardial oxygen. Normally we suggest usingβreceptor blockerfor this condition. Highest heart rate of myocardial ischemia time(HMIT) was parallel with the degree of ST-segment depression andthe distance between HMIT and the highest heart rate of 24 hourswas very small. Ischemia threshold variability at night (IV) increased,he continuous time of ST-segment shifted became longer at night(P<0.01). This result suggesting us increased strain of coronary andabnormal sympathetic nerve system result in relative shortage ofcoronary artery, we can use calcium hydronium blocker here.We got the conclusions as followed: SMI has a relative highprevalence in patients with known CAD, which suggests that thispopulation still need to be carefully evaluated by the riskstratification;Times of ischemia, the degree of ST-segment shifted,the continuous time of ischemia, MIT, IV, could be regarded as theeffective standard for follow-up and treatment of CAD patients;There are different kinds of mechanism in silent myocardialischemia, it is necessary to use different methods in treatment andthe condition of shortage of oxygen, the activity of sympatheticnerve system and the strain of coronary artery can increasemyocardial oxygen, suggesting use of βreceptor blocker. Increasedthe strain of coronary and abnormal sympathetic nerve system leadto relative shortage of coronary artery, suggesting use of calciumhydronium blocker.