FFR could become the new criteria for non-infarct related artery(non-IRA) interventional therapy / 中国实用内科杂志

Previous studies have found that 40% of patients with acute ST-segment elevation myocardial infarction(STEMI) combine with multiple vascular lesions(MVD), which is known as one of the main risks for poor prognosis in patients with myocardial infarction.However,the management of non-IRA remains controversial, and there is no consensus on the management of non-IRA in STEMI. FFR could be a new criteria in non-IRA PCI,since it could evaluate coronary flow reserve more intuitively than coronary angiography alone.

Clinical and angiographic profiles and six months outcomes of smokers with acute ST segment elevation myocardial infarction undergoing primary percutaneous coronary angioplasty

Background Outcomes of primary percutaneous coronary intervention (PCI) for acute STEMI (ST-segment elevation myocardial infarction) in smokers are expected to be better than non-smokers as for patients of acute STEMI with or without fibrinolytic therapy. Objectives This comparative study was designed to evaluate the outcomes of primary PCI in patients with acute STEMI in smokers and non-smokers. Clinical and angiographic profile of the two groups was also compared. Methods Over duration of two year, a total of 150 consecutive patients of acute STEMI eligible for primary PCI were enrolled and constituted the two groups [Smokers (n = 90), Non-smokers (n = 60)] of the study population. There was no difference in procedure in two groups. Results In the present study of acute STEMI, current smokers were about a decade younger than non-smokers (p value = 0.0002), majority were male (98.9% vs 56.6%) were male with a higher prevalence of hypertension and diabetes mellitus (61.67% vs 32.28% and 46.67% vs 14.44%, p = 0.001) respectively. Smokers tended to have higher thrombus burden (p = 0.06) but less multi vessel disease (p = 0.028). Thirty day and six month mortality was non-significantly higher in smokers 4.66% vs 1.33% (p = 0.261) and 5.33% vs 2.66% (p = NS) respectively. Rate of quitting smoking among smokers was 80.90% at 6 months. Conclusion The study documents that smokers with acute STEMI have similar outcomes as compared to non smokers with higher thrombus burden and lesser non culprit artery involvement. Smokers present at much younger age emphasizing the role of smoking cessation for prevention of myocardial infarction.

Long-term prognosis of patients with acute myocardial infarction due to unprotected left main coronary artery disease: a single-centre experience over 14 years

<p><b>INTRODUCTION</b>Acute myocardial infarction (AMI) due to unprotected left main coronary artery (ULMCA) disease is clinically catastrophic although it has a low incidence. Studies on the long-term prognosis of these patients are rare.</p><p><b>METHODS</b>From January 1999 to September 2013, 55 patients whose infarct-related artery was the ULMCA were enrolled. Clinical, angiographic and interventional data was collected. Short-term and long-term clinical follow-up results as well as prognostic determinants during hospitalisation and follow-up were analysed.</p><p><b>RESULTS</b>Cardiogenic shock (CS) occurred in 30 (54.5%) patients. During hospitalisation, 22 (40.0%) patients died. Multivariate logistic regression analysis showed that CS (odds ratio [OR] 5.86; p = 0.03), collateral circulation of Grade 2 or 3 (OR 0.14; p = 0.02) and final flow of thrombolysis in myocardial infarction (TIMI) Grade 3 (OR 0.05; p = 0.03) correlated with death during hospitalisation. 33 patients survived to discharge; another seven patients died during the follow-up period of 44.6 ± 31.3 (median 60, range 0.67-117.00) months. The overall mortality rate was 52.7% (n = 29). Kaplan-Meier analysis showed that the total cumulative survival rate was 30.7%. Cox multivariate regression analysis showed that CS during hospitalisation was the only predictor of overall mortality (hazard ratio 4.07, 95% confidence interval 1.40-11.83; p = 0.01).</p><p><b>CONCLUSION</b>AMI caused by ULMCA lesions is complicated by high incidence of CS and mortality. CS, poor collateral blood flow and failure to restore final flow of TIMI Grade 3 correlated with death during hospitalisation. CS is the only predictor of long-term overall mortality.</p>

Prognostic Impact of Chronic Total Occlusion on Non-infarct-related Artery in Patients of Acute ST-elevation Myocardial Infarction With Emergent Primary Percutaneous Coronary Intervention / 中国循环杂志

Objective: To study the prognostic impact of chronic total occlusion (CTO) on non-infarct-related artery (non-IRA) in patients of acute ST-elevation myocardial infarction (STEMI) with emergent primary percutaneous coronary intervention (PCI). Methods: In this prospective study, a total of 185 consecutive acute STEMI patients received early stage primary PCI in our hospital from 2010-01to 2011-06 were enrolled. The patients were divided into 2 groups:non-CTO group, n=160 and CTO group, n=25. The patients were followed-up for 1 year and the primary endpoint events included the hospitalization for angina, re-MI, heart failure or revascularization and cardiac death. Results: ①There were more patients with diabetes and three vessel disease in CTO group than those in non-CTO group (40.0%vs 20.0%, P=0.049) and (68.0%vs 36.3%, P=0.003);LVEF in CTO group was lower than non-CTO group (40.0 ± 20.1%vs 51.3 ± 15.3%, P Conclusion: Non-IRA combining CTO in STEMI patients with primary PCI are usually having poor prognosis.

Correlation between procalcitonin and spontaneous recanalization of infarct related artery in patients with ST-segment elevation myocardial infarction / 中华危重病急救医学

Objective To investigate the correlation between procalcitonin (PCT) and infarct related artery (IRA) spontaneous recanalization (SR) in patients with ST-segment elevation myocardial infarction (STEMI), and to investigate the value of PCT in predicting SR. Methods A retrospective study was conducted. A total of 263 STEMI patients who received emergency coronary angiography from January 2013 to April 2016 in cardiology department of Gansu Provincial Hospital were retrospectively included. Depending on the thrombolysis in myocardial infarction trial (TIMI) grade, the patients were divided into two groups, SR group (TIMI 2-3 grade) and non-SR group (NSR group, TIMI 0-1 grade). The baseline characteristics, serum PCT, high sensitivity C-reactive protein (hs-CRP) and biochemical makers before primary percutaneous coronary intervention (PCI) were compared. According to the value of PCT, the patients were divided into four quartile groups. SR rate of every groups were compared. Multiple logistic regression analysis was used to determine the independent predictor of SR. Receiver operating characteristic (ROC) curve was plotted to assess the diagnostic value of PCT for SR. Results In 263 STEMI patients, SR occurred in 77 patients and SR rate was 29.3%. There were no statistical differences in gender, age, body mass index (BMI), past medical history and IRA between the two groups, indicating that the baseline characteristics were matched. Compared with NSR group, utilization rate of the statins were significantly higher (35.1% vs. 22.6%, P 0.110 μg/L. SR rate were 48.5% (32/66), 29.9% (20/67), 26.9% (18/67) and 11.1% (7/63), respectively. SR rate of Quartile 1 was significantly higher than the other three groups (all P < 0.05). It was shown by multiple logistic regression analysis that PCT [odds ratio (OR) = 0.432, 95% confidence interval (95%CI) = 0.108-0.863, P = 0.016], hs-CRP (OR = 0.708, 95%CI = 0.516-0.905, P = 0.037) were independent predictors for SR. The area under the ROC curve (AUC) of PCT for predicting SR was greater than that of hs-CRP [0.784 (95%CI = 0.721-0.847) vs. 0.686 (95%CI = 0.619-0.753), P < 0.05]. When the cut-off value of PCT was 0.067 μg/L, the sensitivity was 81.6%, and the specificity was 66.7%. Conclusion PCT was independent predictor of SR, which has a power value in predicting IRA recanalization in patients with STEMI.

Electrocardiographic Characteristics for the First Diagonal Branch of the Infarction Related Artery in Patients With Acute Myocardial Infarction / 中国循环杂志

Objective: To analyze the electrocardiographic (ECG) characteristics for the ifrst diagonal branch of infarction related artery (IRA) in patients with acute ST-segment elevation myocardial infarction (STEMI) in order to ifnd the rule for physician to make quick diagnosis. Methods: A total of 28 STEMI patients with coronary angiography (CAG) confirmed first diagonal branch of IRA were retrospectively analyzed. The patients were treated in our hospital from 2005-01 to 2014-06 and their ECG changes at admission were studied for ST-segment elevation/depression and q wave, Q wave changes during the period of evolution at different leads in all patients. Results: CAG presented that there were 19/28 (67.9%) patients with single vessel disease, 13 (46.4%) with isolated diagonal lesion. From onset of chest pain to AMI graph shown on ECG was about 240 (252 ± 71) min in all patients. All 28 (100%) patients were with ST-segment elevation in lead aVL, 27 (96.4%) in lead I, and 15 (55.6%) patients with ST-segment elevation by (0.5-1.0) mm. The incidence of ST-segment elevation in the chest lead was, in turn as 21 (75.0%) patients in lead V2, 16 (57.1%) in lead V3 and 12 (42.9%) in lead V1respectively; while ST-segment depression was as 28 (100%) patients in lead III, 27 (96.4%) in lead aVF and 22 (78.6%) in lead II respectively. During the period of evolution, the most q wave or Q wave formation were, in turn as 22 (88.0%) patients in lead aVL, 10 (40.0%) in lead V2, 9 (36.0%) in lead V3 and 7 (28.0%) in lead I respectively. Conclusion: The ECG changes in STEMI patients with diagonal branch of IRA have the high prevalence of ST-segment elevation in lead aVL and lead I, while there is an important feature that the ST-segment elevation < 1 mm in about half amount of relevant patients.

Multivessel Percutaneous Coronary Intervention in Patients with Acute ST-segment Elevation Myocardial Infarction in Same Sitting.

Background: Aim of the study was to evaluate the primary procedural success of Multivessel Percutaneous coronary intervention in patients with acute ST-segment elevated myocardial infarction at the same sitting. Methods: Total 23 (13.4%) patients were enrolled in this very preliminary study, among the total 171 patients who had primary PCI at our center from Jan 2010 to February 2015. Among them, Male: 20 and Female: 3. Total 52 stents were deployed in 46 territories. Mean age were for both male and female were 54 yrs. Associated coronary artery disease risk factors were Dyslipidemia, High Blood pressure, Diabetes Mellitus, positive family history for coronary artery disease and Smoking. Results: Among the study group; 17(74%) were Dyslipidemic, 11(47.8%) were hypertensive; 8(34.8%) patients were Diabetic, positive family history 4(17.4%) and 9(39%) were all male smoker. Female patients were more obese (BMI: M 26: F 27). Common diagnosis at admission based on ECG evidence was; Inferior wall myocardial infarction: 12 (52.2%), Anterior wall myocardial infarction 9(39.1%) and lateral 2(8.7%). Common stented territory was left anterior descending artery 9(39.1%), right coronary artery 7(30.4%), and left circumflex artery 7(30.4%). Stent used: Bare metal stent 3 (5.7%), DES: 49 (94.2%). Among the different drug eluting stents, Everolimus 26 (52%), Sirolimus 8(15.4%) and Zotarolimus 9(17.3%), Paclitaxel 2 (3.8%), Biolimus 2 (3.8%), Genous 2 (3.8%). Conclusion: In the current prospective non randomized study, we found that the multivessel primary PCI for ST elevation myocardial infarction with non-culprit vessel are suitable for PCI at the same sitting with better in-hospital and 1 yr survival outcome.

Significance of terminal QRS distortion on the electrocardiogram in acute inferior myocardial infarction / 中国医师进修杂志

Objective To investigate whether terminal QRS distortion on the electrocardiogram in acute inferior myocardial infarction could be as a standard for the infarct-related artery,through comparing to coronary angiography.Methods Fifty-seven patients with acute inferior myocardial infarction were enrolled,among which,the right coronary artery (RCA) occlusion (RCA occlusion group) was present in 29 cases,and left circumflex coronary artery (LCX) occlusion (LCX occlusion group) was in 28 cases.The changes of electrocardiogram was analyzed in 12 hours after the acute episode.Results The incidence of terminal QRS distortion in leads Ⅱ,Ⅲ,aVF in RCA occlusion group was 44.8％(13/29) and 39.3％(11/28)in LCX occlusion group,and there was no significant difference (P ＞ 0.05).The incidence of terminal QRS distortion in leads V4R-V5R in RCA occlusion group was 17.2％(5/29) and 7.1％(2/28) in LCX occlusion group,and there was no significant difference (P ＞ 0.05).The incidence of terminal QRS distortion in leads V7-V9 in RCA occlusion group was 6.9％(2/29),which was lower than that in LCX occlusion group[53.6％(15/28)],and there was significant difference (P ＜ 0.05).For identifying LCX as the infarct-related artery of acute inferior myocardial infarction,the sensitivity,specificity,positive and negative value in terminal QRS distortion in leads V7-V9 were 53.6％ (15/28),93.1％ (27/29),88.2％ (15/17),67.5％ (27/40).The area under curve of terminal QRS distortion in leads V7-V9 in identifying LCX as the infarct-related artery of acute inferior myocardial infarction was 0.733 (95％ CI 0.599-0.868).Conclusion Terminal QRS distortion in leads V7-V9 may be of diagnostic value in identifying the infarct-related artery in acute inferior myocardial infarction.

Clinical analysis of patients with acute myocardial infarction induced by left main artery occlusion / 中华急诊医学杂志

Objective To study clinical data of patients with acute myocardial infarction (AMI) induced by left main (LM) artery occlusion,and to find out the clinical characteristics.Method From Janurany 1995 to May 2006,there were 15 patients with AMI related with LM obstruction from 1793 AMI patients,in whom primary PCls were performed.All patients were male with a mean age of (60.6?10.4) years old (ranging from 43 to 85 years old).The clinical and interventional data were retrospectively analyzed.Results Cardiogenic shock occurred in 10 patients at admission.Primary PCls were performed with intraaortic balloon pump (IABP) in all patients.Nine patients died during short follow-up,and the mortality was 60%.Three-month follow-up was made in the all survival patients,and one patient died after 4 years.Analysis showed good collateral circulation flow from right coronary artery to left coronary artery before operation affected the short-term prognosis.Conclusions AMI related with left main artery obstruction was critically fatal with high occurrence of cardiogenic shock and high mortality.Prognosis differs at,cording to different degree of collateral circulation.Primary PCI with IABP provides a promising strategy to improve clinical outcomes.

Assessment of coronary flow velocity pattern during no-reflow phenomenon by transthoracic Doppler echocardiography combined with administration of Albunex / 中国临床药理学与治疗学

AIM: To validate the alternations of flow velocity patterns in the infarct-related artery (IRA) during no-reflow phenomenon in a canine model of acute myocardial ischemia and reperfusion by transthoracic Doppler echocardiography (TTDE) combined with myocardial contrast echocardiography (MCE) by means of administration of Albunex. METHODS: Nineteen dogs first underwent 60 min myocardial ischemia and then followed by 60 min,120 min and 180 min reperfusion ( n = 6, 6 and 7, respectively). The perfusion defect area determined by MCE at 60 min myocardial ischemia was regarded as risk area (RAMCE). The perfusion defect area defined by MCE after reperfusion was considered as no-reflow area (NRAMCE). The ratio between NRAMCE and RAMCE ≥ 25 %was regarded as the development of no-reflow phenomenon and the ratio of NRAMCE to RAMCE＜25% was considered as the myocardial reflow. The coronary flow velocity parameters in IRA were determined through TTDE. RESULTS: Two dogs died during experiment and the remaining seventeen dogs completed throughout the procedure.There were seven dogs in reflow group and ten dogs in noreflow group. No significant difference was present in reflow group between at baseline and at 60 min reperfusion in systolic peak velocity (PVs), systolic velocity time integral (VT Is), corrected systolic flow duration (cFDs),diastolic peak velocity (PVd), diastolic velocity time integral (VT Id), corrected diastolic flow duration (cFDd),diastolic deceleration rate (DDR), corrected diastolic deceleration duration (cDDD) (P＞0.05), however, a significant difference was found in no-reflow group between at baseline and at 60 min reperfusion in PVs,VTIs, cFDs, PVd, VTId and cFDd (P＜0.05). The most marked alterations during diastolic phase were the increase of DDR and reduction of cDDD. CONCLUSION: The impaired microvasculature may profoundly affect the coronary flow velocity pattern in the IRA. The increase in microvascular resistance and decrease in coronary perfused pressure can contribute to the changes.Transthoracic Doppler echocardiography combined with MCE has the capability of noninvasive assessment of coronary flow velocity pattern in the IRA during no-reflow phenomenon.

Usefulness of the Initial Electrocardiogram for Predicting the Infarct-Related Artery in Acute Inferior Myocardial Infarction

BACKGROUND AND OBJECTIVES: Eectrocardiogram (ECG) may provide valuable informations regarding the infarct-related artery (IRA), which may be of guidance in selecting the therapeutic modality. ST segment elevation in inferior leads usually indicates occlusion of right coronary artery, less often left circumflex coronary artery or rarely occlusion of left anterior descending coronary artery may be the cause. We are to determine whether the initial ECG can differentiate the right coronary artery (RCA) or left circumflex artery (LCx) occlusion in acute inferior myocardial infarction (IMI). MATERIALS AND METHOD: We compared retrospectively the ECG recorded within 12 hours from the onset of chest pain with coronary angiographic findings in 85 patients (34% of all 250 patients) having electrocardiographic criteria for IMI. RESULTS: 1) Angiographic characteristics. Of the 85 patients, IRA was RCA in 65 (76%) (38[58%] proximal, 27[42%] distal to first right ventricular branch), and LCx in 20 (24%) (nine[45%] proximal to first obtuse marginal branch or involving a high first marginal branch, eleven[55%] distal obstruction). RCA dominance was more common in RCA occlusion group (100% vs 80%, p=0.001), and LCx dominance in LCx occlusion group (15% vs 0%, p=0.001). No significant difference was noted between two groups regarding vessels diseased, involvement of left anterior descending coronary artery and contralateral artery (RCA or LCx), location of the lesion. 2) Electrocardio-graphic characteritics. Lateral limb leads (I, aVL) :ST segment depression (> or = 1 mm) was more common in RCA occlusion group (82% vs 45%, p=0.001). Isoelectric ST segment in I was more common in LCx occlusion group (100% vs 15%, p=0.001). Left precordial leads (V(5,6)) :ST segment elevation (> or = 1 mm) was more common in LCx occlusion group (60% vs 15%, p=0.001). Isoelectric ST segment was more common in RCA occlusion group (57% vs 20%, p=0.004). ST segment depression (> or = 1 mm) was not different between two groups. Right precordial leads (V(1-4)) :ST segment changes were not different between two groups. Lead I and left precordial leads (V(5,6)) :Isoelectric ST segment in lead I and ST segment elevation (> or = 1 mm) in V(5) or V(6) was more common in LCx occlusion group (60% vs 5%, p<0.05, sensitivity 60% specificity 95% positive/negative predictive value 80%/89%, test accuracy 87%). Amplitude of R wave in V(1) :Amplitude of R wave in V was greater in LCx occlusion group (3.60+/-1.42 mm vs 2.20+/-1.42 mm, p<0.05). CONCLUSION: The initial electrocardiogram was useful in differentiating LCx occlusion from RCA occlusion in patients with IMI. Absence of ST segment depression in I and aVL, and ST segment elevation in V(5,6), isoelectric ST segment in I, tall R wave in V(1) were significantly more common in LCx occlusion.

Clinical Feature of Non-Q Wave Myocardial infarction : Relationship with EKG Findings and Infarct Related Arteries

BACKGROUND: Despite extensive investigation, the clinical features and prognostic significance of the non-Q wave myocardial infarction, when compared with Q wave myocardial infarction, remain controversial. And no definite relationship between EKG findings and infarct related arteries has been reported. METHOD: A retrospective analysis was done on 205 patient with acute myocardial infarction who were undergone coronary angiography and left ventriculography. Among them, 30 patient with non-Q wave myocardial infarction and 175 patients with Q wave myocardial infarction. RESULTS: 1) There was no significant difference between the two groups in risk factors, prevalence of preinfarct angina and preinfarct heart failure. 2) The faction of patients with non-Q wave myocardial infarction who received thromobolytic therapy was significantly less, compared to patient with Q wave myocardial infarction(p<0.0001). 3) The patients with non-Q wave myocardial infarction had a smaller infarct size estimated by peak creatine phosphokinase(p<0.01). But there was no difference in Killip's classification and left ventricular ejection fraction. 4) In patients with non-Q wave myocardial infarction, 87% of the patients had one or more abnormal EKG finding other than Q wave, and the most frequent abnormal finding was primary T wave change. 5) The location of infarct-related artery was significantly different between group(p<0.0001). The most frequently involved coronary artery in non-Q wave myocardial infarction was left circumflex coronary artery, especially in patients with normal EKG findings. 6) There was no significant difference between the two groups in the prognosis. CONCLUSION: There were significant differences between non-Q wave and Q wave myocardial infarction in the infarct size and the location of infarct related arteries. but not in the risk factors, the prevalence of previous coronary artery disease and prognsis. Further prospective and collaborative studies should be performed to define conclusion.

The Effect of Thrombolysis on the Status of Infarct-Related Coronary Artery and Left Ventricular Function in Acute Myocardial Infarction

BACKGROUND: Patency of the infarct-related coronary artery may influence LV remodeling, provide a more stable electrophysiologic milieu and improves the outcome of patient with acute myocardioal infarction. The result from clinical trials have confirmed that early reperfusion in humans induced by a thrombolytic agent is associated with limitation of infarct size, preservation of ventricular function, and improved survival. The purpose of this study was evaluate the effect of thrombolytic therapy on the severity of the residual stenosis, antegrade flow of infarct-related coronary artery after acute myocardial infarction, and investigate left ventricular function and regianal wall motion abnormality depending on the thrombolytic therapy. METHODS: A retrosperctive study was performed in 166 patients with acute myocardial infarction with underwent coronary angiography within 8 days after acute attack from Oct. 1990 to Sep. 1994. Patients were grouped as thrombolysis group(n=64) who had undertaken urokinase infusion therapy within 6 hours of symptom onset and conservatively treated group(n=102) who had not received thrombolytic trerapy. At 8+/-7days, cardiac catheterization was performed. Status of the infarct related artery was assessed by resiudal % diameter stenosis, TIMI and collateral trading. Left ventricular function and wall motion were analyzed. RESULTS: 1) The was no statistical differenccs in age, sex and risk factors(diabetes, hypertension, smoking and hypercholesterolemia)between two groups. 2) The peak serum CK level was higher(2719+/-2333 vs 1951+/-2064 IU/L) and time to peak CK enzyme level was shorter(19+/-13 vs 32+/-24 hr) in thrombolysis group than conservatively treated group. 3) There was lower incidence of total occlusion(12.5% vs 30.4%), residual % diameter stenosis of infarct-related artery(67+/-34% vs 80+/-27%) and better antegrade flow(TIMI grade 0-1, 12.5% vs 32.4%) in thrombolysis group than conservatively treated group(p0.05). CONCLUSION: Thrombolytic therapy in acute myocardial infarction resulted in dquisition of early infarct-related arterial patency, effectiove antegrade flow and reduced incidence of totoal occlusion of infarct-related artery. Left ventricular ejection fraciton, regional wall motion score was not affected by thrombolytioc therapy in inhospital period.

Comparison of Clinical Findings and Coronary Angiographic Findings between Q Wave and Non-Q Wave Myocardial Infarction

BACKGROUND: Patients with non-Q wave myocardial infarction tend to have smaller infarcts and less degree of ventricular function impairment initially, however, uncomplicated non-Q wave infarctions are known to be as serious as Q wave myocardal infarction due to residual myocardal ischemia and higher reinfarction rate. METHODS: Inorder to compare the clinical and coronary angiographic findings of Q wave infarction with those of non-Q wave infarction. 58 partients with acute myocardial infarction were reviewed retrospectively. Patients were classified into Q wave(n=45) and non-Q wave infarction(n=13) according to electrocardiographic findings. RESULTS: 1) There were no significant differences between the two groups in risk factors of coronary artery disease such as hypertension, hypercholesterolemia, smoking and diabets mellitus. 2) The peak myocardial enzyme levels of CPK, CPK-MB were significantly higher in the Q wave MI group, and the percentage of wall motion abnormality on two-dimensional echocardiography was significantly higher in Q wave MI than in the non-Q wave MI group. 3) The number of involved vessel, degree of stenosis and collateral circulation were not different but high degree of stenosis of infarct-related artery was more frequent in Q wave MI group. 4) There were no significant differences between the two groups in the incidence of arrhythmia and in-hospital mortality. CONCLUSION: There were some differences in clinical and angiographic findings, but in-hospital mortality was not significant different between two groups. Futher prospective studies should be performed to clarify the long term prognosis.

Effects of Patency of the Infarct-Related Artery on the Signal-Averaged ECG in Acute Myocardial Infarction

BACKGROUND: In patients after acute myocardial infarction, signal-averaged electrocardiography is used as the one of the non-invasive methods for the prediction for ventricular arrhythmia, one of the causes ofn death in acute myocardial infarction. Signal-averaged electrocardiography has allowed the identification of low-amplitude, high-frequency signals(late potentials)in the terminal portion of the QRS complex. They are thougt to be occured in the portion of electrophysiologically unstable myocardium. The presence of late potentials identifies regions of delayed conducton in the elctrophysiologically unstable border zone of an acute infarction. These electrophysiologic change of myocardium is influenced by the patency of infarct-related artery. A patent artery is associated with electrical stability of myocardium, decreased in cidence of late potentials and improved survival. METHODS: 58 patients of acute myocardial infarction underwent signal-averaged electrocardiography, coronary angiography within 10 days after AMI, 20 of healthy persons underwent signal-averaged electrocardiography. RESULTS: In patent group, late potentials were recorded in 7 of 38 patients(18%) as compared with 13 of 20 patients(65%) of non-patent group. The statistically significant parameters of signal-averaged electrocardiography beteen patent and non-patent group were filtered total QRS duration(TQRS, 106.7+/-20.9msec), high frequency low amplitude signal (HLAS, 30.8+/-7.5 vs 41.3+/-16.5 msec)with HLAS being the most powerful varialble in the model. CONCLUSION: These results suggest that the patency of infarct-related artery is associated with electrophysiologic stability of myocardium and signal-averaged electrocardiography is one of the useful non-invasive method in risk stratification of acute myocrdial infarction.

The Change of Late Potential in Acute Myocardial Infarction and the Influence of Patency of Infarct-Related Artery on Its Development

BACKGROUND: The restoration of anterograde flow in the infarct-related artery(IRA) may improve electrophysiological consequences and survival. Patients with occluded IRA are more likely than those with patent IRA to have late potentials on signal-averaged electrocardiogram(SAEKG). The natural history of late potentials in the acute phase after AMI was reported to vary in recent studies and requires further investigation. Therefore, we investigated 1) whether parameters of SAEKG and incidence of late potentials are changed in 2 weeks after AMI, and 2) whether the status of IRA, ejection fraction, ventricular premature beats(VPB) on Holter and the use of thrombolytic agent can influence the developement of late potentials. METHOD: SAEKGs were performed in 40 patients with acute myocardial infarction(AMI, mean age : 56.6yr) and 20 normal controls(mean age : 53.0yr). SAEKGs were recorded first in 48 hours and then 2 weeks after AMI. Late potential were considered to be positive if two of the three following criteria were identified : 1) duration of filtered QRS complex>118ms, 2) duration of HFLA signal>40 ms, and 3) RMS voltage<20microV. RESULT: 1) The duration of filtered QRS complex and HFLA signal in patients with AMI in 48 hours and 2 weeks were longer than in the controls(p<0.01, p<0.05. respectively), and the RMS voltage in only 2 weeks was lower than in the controls(p<0.05). 2) There was no significant difference in the 3 parameters of SAEKG between 48 hours and 2 weeks after AMI, but the incidence of late potentials increased from 35%(14/40) to 42.5%(17/40). Of the 26 patients with a normal initial SAEKG, 3(11.5%) had late potentials in 2 weeks, whereas none of the patients with positive late potentials on initial SAEKG was normalized in 2 weeks. 3) The ejection fraction, the degree of VPB on the Holter EKG and the history of thrombolyic therapy in patients whose late potentials were positive were not different from those in patients with normal SAEKG. 4) In the 3 parameters of SAEKG, RMS voltage in patients with occluded IRA was significantly lower than in those with open IRA(p<0.05), and the incidence of late potentials were higher in the patients with occluded IRA(75%) than in those with open IRA(28.6%)(p<0.05). CONCLUSION: The incidence of late potentials on SAEKG after AMI was modestly increased in 2 weeks, but the development of late potentials was not influenced by the degree of frequently in patients with occluded IRA. These findings may indicate that the development of late potential after AMI tends to increase even in 2 weeks, and that the occlusion in IRA may unfavorably alter the electrophysiological state identified by SAEKG.