Resting Magnetocardiography Predicts 3‐Year Mortality in Patients Presenting with Acute Chest Pain without ST Segment Elevation

Objective: Magnetocardiography (MCG) as a noninvasive, noncontact and risk‐free diagnostic method predicts ischemic coronary artery disease (CAD) in patients with acute chest pain at admission with high accuracy. However, it remains unclear whether MCG findings can add prognostic information. Method: A cohort of 402 consecutive patients presenting at the intensive care unit (ICU) with acute chest pain without ST segment elevation (NSTEMI) were included in a prospective registry. In order to prove the prognostic value of MCG a head‐to‐head comparison of the admission MCG, ECG, TnI, and ECHO tests was made. Results: In 43 patients (10.7%) the MCG could not be analyzed due to insufficient signal‐to‐noise ratio. Complete follow‐up over a period of up to 3 years was obtained in 355 out of the 359 patients (98.9%). Age at admission was 67.2 ± 10.3 years, 59.7% males. In the group of patients with an abnormal MCG at admission, 43 out of 249 patients (17.3%) died in the follow‐up period, while in the group of patients with a normal MCG at admission only 4 out of 106 patients died (3.77%). The relative risk was 4.58 (95% confidence intervals: 1.68–12.42). A multivariate regression analysis revealed the highest mortality risk for patients with diabetes mellitus and an abnormal MCG at admission (RR = 18.0; 95% CI: 2.49–133.3). Conclusion: Resting MCG at hospital admission predicts 3‐year mortality in patients presenting with acute chest pain without ST segment elevation in the ECG. MCG seems to be valuable in identifying chest pain patients at highest risk.     

Prognostic Value of Continuous ST‐Segment Monitoring in Patients with Non‐ST‐Segment Elevation Acute Coronary Syndromes

Background: Patients with non‐ST‐segment elevation acute coronary syndromes constitute a heterogeneous group concerning prognosis. The 12‐lead ECG at rest is recommended for early risk stratification but is unable to reflect the dynamic nature of myocardial ischemia and coronary thrombosis. This study investigated whether continuous ST‐segment monitoring provides early prognostic information in such patients. Methods: We prospectively studied 183 patients admitted due to chest pain at rest suggestive of an acute coronary syndrome. ST‐segment monitoring was performed continuously for 24 hours from admission. Cardiac‐specific troponin I levels were determined on admission and every 6 hours for the first 24 hours. The endpoint was defined as death or nonfatal myocardial infarction, whichever occurred first by 30 days follow‐up. Results: ST episodes, defined as transient ST deviations of at least 0.1 mV, were detected in 50 patients 27.3%) and associated with worse 30‐day outcome: 22.0% endpoint rate compared to 6.8% for patients without ST episodes (P = 0.003). In a multivariate analysis, the presence of ST episodes hazard ratio, 3.07; 95% Cl, 1.26 to 7.46; P = 0.014) and peak troponin I levels > 0.2 μg/L (hazard ratio, 2.65; 95% Cl, 1.01 to 6.95; P = 0.048) were independent predictors of prognosis. The combination of ST‐segment monitoring and peak troponin I identified patients at low (2.5%, n = 79), intermediate (14.5%, n = 76), and high (25.0%, n = 28) risk for the 30‐day endpoint. Conclusions: In patients with non‐ST‐segment elevation acute coronary syndromes, continuous ST‐segment monitoring provides on‐line early prognostic information, in addition to troponin I levels. A.N.E. 2002;7(1):29–39     

Prognostic value of 2D echocardiography in patients presenting with acute chest pain and non-diagnostic ECG for ST-elevation myocardial infarction

The purpose of the present study was to test the hypothesis that early detection of regional wall motion abnormalities (WMA) by 2D echocardiography (ECHO) accurately predicts further cardiac events in patients presenting with acute chest pain. A prospective analysis was performed in subjects admitted with the first presentation of acute chest pain and a non-diagnostic ECG for acute ST-elevation myocardial infarction. Patients with known coronary artery disease were excluded. All subjects were contacted by phone for a 30days follow-up regarding cardiac events defined as PCI/CABG, AMI, and death. In 132 consecutive patients (89 male, 43 female) complete data sets consisting of case history (H; abnormal: typical angina), ECG (abnormal: ST-depression, T-inversion, atypical ST-elevation, LBBB), serum markers (TnI; abnormal: elevation of troponin I=0.5 ng/ml), ECHO (abnormal: WMA) and follow-up were available. In 45 patients, 60 cardiac events occurred (three deaths, 24 AMI, 33 PCI/CABG). Positive (PPV; %) and negative predictive values (NPV; %) of ECHO were superior to all other diagnostic tests (P<0.05 each) for adverse cardiac events, evolving AMI or death, and superior to history and ECG for later need of revascularisation (PCI/ACVB). Multivariate analysis revealed that WMA in ECHO predict cardiac events independently of age, gender, and the common combination of investigations (H/ECG/TnI). A significant independent impact of ECHO was also determined for the prediction of AMI/death or PCI/CABG. The study shows that early 2D echocardiography provides superior prognostic information concerning the risk of subsequent complications in patients with acute chest pain and a non-diagnostic ECG for ST-elevation-AMI.     

Acute myocardial infarction with significant left main coronary artery stenosis, significant 3-vessel coronary artery disease and elevated troponin-I at admission

Exercise-induced ST-segment elevation in lead aVR accompanied by ST-segment elevation in lead V1 might be a specific finding of left main coronary artery (LMCA) stenosis. Lead aVR and lead v1 ST segment elevation has been reported, during an attack of chest pain, in patients with LMCA disease with ST segment depression in leads V3, V4 and V5 (with maximal depression in V4). ST-segment elevation in lead aVR in patients with angina at rest can be related to transmural ischemia of the basal part of the interventricular septum, frequently due to LMCA or multivessel coronary disease too. 3-vessel coronary artery disease (CAD) and LMCA disease show a frequent combination of leads with abnormal ST segments during chest pain with ST-segment depression in leads I II V4-V6, and ST-segment elevation in lead aVR. When ST-segment status in lead aVR combines with troponin T, ST-segment elevation in lead aVR and positive troponin T on admission are useful predictors of LMCA or 3-vessel CAD. We present a case of acute myocardial infarction with significant left main coronary artery stenosis, significant 3-vessel coronary artery disease and elevated troponin I at admission in an 83-year-old Italian woman. Also this case focuses attention on the importance of the recognition of the patterns suspected for LMCA and/or 3-vessel coronary disease.     

Comparison of Computerized and Standard Visual Criteria of Exercise ECG for Diagnosis of Coronary Artery Disease

Objective: To review past and current studies of computerized exercise ECG criteria in order to establish which, if any, are superior to standard visual analysis for the diagnosis of coronary artery disease (CAD). Methods: Prior studies that compared multiple computerized ECG criteria were reviewed. In addition, we investigated two sets of patients that had both exercise testing and coronary arteriography at two university-affiliated Veteran's Affairs Medical Centers. Patients with previous myocardial infarction or coronary artery bypass surgery, valvular heart disease, left bundle branch block, or any diagnostic Q waves present on their resting ECGs were excluded from analysis. Sensitivity and specificity values were compiled for standard visual analysis and for the following computerized ECG criteria: ST0; ST60; ST slope; ST integral; ST index; R wave adjusted ST; ST/heart rate (HR) index; Hollenberg's Treadmill exercise score; and discriminant function analysis (DFA). Results: Despite the effects of limited challenge and work-up bias, the compiled results indicate that ST measurements recorded during the time of recovery from exercise are substantially more diagnostic than those recorded at maximal exercise. ST integral, ST60, and R wave adjusted ST60 during recovery are especially discriminating of CAD, while Hollenberg's treadmill exercise score is not. There were inconclusive results for HR adjustments to ST depression and ST index. DFA including visual analysis of the ECG consistently exhibited the greatest discriminating power of all computerized results. Conclusion: Although DFA, ST integral during recovery, or ST60 during recovery exhibited improved predictive value, further research is necessary before we can clearly offer a superior alternative to standard visual analysis.     

Non-invasive resting magnetocardiographic imaging for the rapid detection of ischemia in subjects presenting with chest pain

BACKGROUND: Early diagnosis of ischemia is complicated by the poor sensitivity of standard tests and contraindication for stress testing in unstable angina patients. Magnetocardiography (MCG) imaging can be used for the rapid, non-invasive detection of ischemia at rest. METHODS: We studied 125 patients with presumed ischemic chest pain. All were chest pain free at the time of scanning. A 6-minute resting MCG scan (CardioMag Imaging, Inc., New York, 9-channel system) was performed. Following the MCG scan, automated software data analysis was performed, and quantitative scores were automatically calculated for each subject. The presence of ischemia was determined after testing with serial troponins, stress testing, and/or coronary angiography. RESULTS: The mean age was 59.4 +/- 13.6 years. Most patients (86.4%) had non-ischemic 12-lead ECG and normal troponin (86.2%). Fifty-five patients (44.0%) were determined to be ischemic. The MCG sensitivity, specificity, positive and negative predictive value was 76.4, 74.3, 70.0 and 80.0%, respectively, for the detection of ischemia (p < 0.0001). CONCLUSIONS: MCG is a new rapid, non-invasive imaging tool able to detect repolarization abnormalities at rest consistent with ischemia in patients presenting with chest pain syndrome and normal or non-specific 12-lead ECG and normal troponin.     

Evaluation of Non-ST Segment Elevation Acute Chest Pain Syndromes with a Novel Low-Profile Continuous Imaging Ultrasound Transducer

Background: This investigation was designed to test the hypothesis that continuous cardiac imaging using an ultrasound transducer developed in our laboratory (ContiScan) is superior to electrocardiogram (ECG) monitoring in the diagnosis of coronary artery disease (CAD) in patients with acute non-ST segment elevation chest pain syndromes. Methods: Seventy patients with intermediate to high probability of CAD who presented with typical anginal chest pain and no evidence of ST segment elevation on the ECG were studied. The 2.5-MHz transducer is spherical in its distal part mounted in an external housing to permit steering in 360 degrees. The transducer was placed at the left sternal border to image the left ventricular short-axis view and recorded on video tape at baseline, during and after episodes of chest pain. Two ECG leads were continuously monitored. The presence of CAD was confirmed by coronary arteriography or nuclear or echocardiographic stress testing. Results: Twenty-four patients had regional wall motion abnormalities (RWMA) on their initial echo which were unchanged during the period of monitoring. All had evidence of CAD. Twenty-eight patients had transient RWMA. All had evidence of CAD. Eighteen patients had normal wall motion throughout the monitoring period, 14 of these had no evidence of CAD, and four had evidence of CAD. These four patients did not have chest pain during monitoring. The sensitivity, specificity, and accuracy of echocardiographic monitoring for diagnosing non-ST elevation myocardial infarction was 88%, 100%, and 91% respectively. The sensitivity, specificity, and accuracy of the ECG for diagnosis of CAD were 31%, 100%, and 52%, respectively. Echocardiography was superior to ECG (P < 0.001). Conclusions: The data indicate that continuous cardiac imaging is superior to ECG monitoring for the diagnosis of CAD in patients presenting with acute non-ST segment elevation chest pain syndromes. This technique could be a useful adjunct to ECG monitoring for myocardial ischemia in the acute care setting.     

Quality improvement in the door‐to‐balloon times for ST‐elevation myocardial infarction patients presenting without chest pain

Objective: To assess a quality improvement initiative aimed at minimizing door‐to‐balloon (DTB) times for ST‐elevation myocardial infarction (STEMI) patients presenting without chest pain. Background: Timely percutaneous coronary intervention (PCI) is the cornerstone of STEMI care. The absence of chest pain delays PCI. Improvements in DTB times may need to focus on atypical presentation patients. Methods: We compared DTB times on all STEMI patients admitted through the emergency department who underwent PCI before (Phase I; October 2004–June 2007) and after (Phase II; July 2007–October 2009) the quality improvement effort, which mandated rapid electrocardiogram (ECG) triage for an expanded list of presenting symptoms. Results: In Phase I (69 patient, 60 with chest pain), patients with chest pain had a shorter mean time to first ECG (ECG Interval) by 32.0 min (P < 0.01) and nonsignificantly faster mean DTB time by 42.0 min (P = 0.07) compared to patients who presented without chest pain. In Phase II (62 patients, 56 with chest pain) compared to Phase I, mean ECG interval decreased by 44 min (P = 0.02) and mean DTB time by 99 min (P = 0.01) in patients without chest pain, eliminating the differences in ECG intervals between typical and atypical presentations (12 min vs. 11 min, P = 0.91). Multivariable analysis controlling for on/off hours and patient characteristics confirmed these findings. Conclusions: A simple modification of emergency room ECG triage protocol, which expands indications for rapid ECG performance, was successful in improving rapid reperfusion for patients with STEMI presenting without chest pain. © 2011 Wiley‐Liss, Inc.     

The Diagnostic Value of 12‐Lead Electrocardiogram in Predicting Infarct‐Related Artery and Right Ventricular Involvement in Acute Inferior Myocardial Infarction

Background: The aim of the present study was to investigate the predictive value of presentation and 24‐hour electrocardiograms in defining the infarct‐related artery (IRA), its lesion segment, and the right ventricular involvement in acute inferior myocardial infarction (Ml). Methods: One hundred forty‐nine patients with acute inferior MI were included. Infarct‐related artery, its lesion segment, and the validity of new ECG criteria for the diagnosis of right ventricular Ml (RVMI) were investigated by means of criteria obtained from admission and 24‐hour ECGs. Results: The presence of ST‐segment elevation in lead III > lead II criterion (Criterion 1) and ST‐segment depression in lead I > lead aVL criterion (Criterion 2) from admission ECG defined the right coronary artery (RCA) as IRA with a sensitivity of 64% and a specificity of 100%. These two criteria also defined the proximal or mid lesions in RCA as culprit lesions (sensitivity of 99%, specificity of 96%). Absence of these two criteria indicated Cx as IRA with a sensitivity of 50% and a specificity of 97%. The depth of Q wave in lead III > lead II criterion (Criterion 3) had no value for discrimination of IRA, but the width of Q wave in lead III > lead II criterion (Criterion 4) supported the RCA to be IRA with a sensitivity of 60% and a specificity of 61% (Criteria 3 and 4 were obtained from 24‐hour ECGs). The finding of Criterion 1 plus Criterion 5 (ST elevation in V₁ but no ST elevation in V2) on admission ECG had a sensitivity of 63% and a specificity of 99% in the diagnosis of RVMI. Conclusion: We concluded that 12‐lead ECG is a cheap, easy, and readily obtainable diagnostic approach in discrimination of IRA and its culprit lesion segment. However, despite high specificity, due to moderate degree sensitivity, its value for the diagnosis of RVMI is questionable. A.N.E. 2001; 6(3):229–235     

Value of lead aVR in the detection of significant left main coronary artery stenosis in acute coronary syndrome

BACKGROUND: Electrocardiographic lead aVR is usually ignored in patients with chest pain. ST segment elevation in aVR may have diagnostic value in patients with acute coronary syndrome (ACS) and significant stenosis or obstruction of the left main coronary artery (LMCAS), especially when accompanied by ST segment elevation in lead V(1). AIM: To asses the value of lead aVR and V1 for the detection of LMCAS in patients with ACS. METHODS: The study group consisted of 150 patients (mean age 60.6+/-9.5 years, range 33-78 years) with ACS, including 46 with LMCAS and 104 without LMCAS. ECG recordings obtained on admission were compared between these two groups. RESULTS: In patients with LMCAS, ST segment elevation in lead aVR was two times more frequent than in remaining patients (69.6% vs 34.6% p=0.0001) whereas there were no differences in lead V(1). Sensitivity of ST elevation in aVR in detection of LMCAS was 69.6%, specificity - 65.4%, positive predictive value - 47.1%, and negative predictive value - 82.9%. In patients with LMCAS, ST segment depression was significantly more often present in ECG leads other than aVR (45.6% vs 23.1% p<0.01). Patients with LMCAS more often had hypertension (95.6% vs 77.9% p<0.05) and three-vessel disease (78.3% vs 31.8%, p<0.0001). CONCLUSIONS: The assessment of lead aVR in patients with ACS may indicate LMCAS. Additional analysis of lead V(1) does not improve diagnostic accuracy.     

Magnetocardiography in coronary artery disease with a new system in an unshielded setting

BACKGROUND: The noninvasive detection of coronary artery disease (CAD) remains a clinical challenge. Magnetocardiography is a completely noninvasive method that permits the registration of cardiac electrical activity at multiple sites in a plane above the chest cage without the need for electrodes. In contrast to the electrocardiogram (ECG) which suffers from boundary effects and a variety of potential artifacts (electrode placement, etc.) the MCG is unaffected by such impediments as the magnetic field is unaltered by surrounding tissues. HYPOTHESIS: Magnetocardiography with a newly developed single-channel system in an unshielded setting should be a better qualitative diagnostic tool than the standard ECG for the detection and assessment of CAD. METHODS: In all, 52 patients with angiographically documented CAD and unimpaired ventricular function as well as 55 controls were included in this study. A standard 12-lead ECG was obtained in all subjects. The MCG recordings were taken from 36 positions under resting conditions. From these, current density vector maps were generated during the ST-T interval. Each map was then classified using a classification system with a scale from 0 (normal) to 4 (grossly abnormal). RESULTS: While the ECG was normal in all subjects, the MCG in the controls was classified as category 0, 1, or 2. However, in patients with abnormal coronary angiograms, mainly maps in categories 3 and 4 were seen (p < 0.05). CONCLUSION: A single-channel magnetometer in an unshielded setting reveals significant differences between normals and patients with CAD with normal ECG on the basis of current density reconstruction during the ST segment when measured under resting conditions. This method might be suitable for the noninvasive detection of CAD.     

Correlation between index electrocardiographic patterns and pre‐intervention angiographic findings: Insights from the HORIZONS‐AMI trial

Objectives : To improve ECG interpretation accuracy in patients with chest pain prior to activation of the cardiac catheterization laboratory for primary percutaneous coronary intervention (PPCI). Background : Despite current guideline‐based ECG criteria, challenges remain in optimizing the rate of appropriate catheterization laboratory activation. Methods : The HORIZONS‐AMI trial enrolled 3,602 patients with chest pain consistent with myocardial infarction (MI). ECG and angiographic core laboratory databases were analyzed for correlation between the qualifying study ECG and the baseline coronary angiogram. Results : LAD occlusion manifested in >80% of cases as ST‐segment elevation in leads V2 and V3, while the culprit vessel was the RCA and LCx in 75 and 25% of cases, respectively, for inferior MI ECG patterns. The study threshold of ≥1.0 mm ST‐segment elevation in ≥2 contiguous ECG leads was not met in 189 (5.3%) patients. When stratified by culprit artery, the prevalence of reciprocal ST‐segment depression ranged from 24 to 88%, being least common for lesions in the mid‐ and distal left anterior descending artery. Despite study eligibility, no posterior MIs were enrolled. Only 36 LBBB cases were identified (25% of whom did not undergo PCI), and 5 of 11 left main coronary occlusions (45%) had ST‐segment elevation in lead aVR. Conclusions : The present study confirms prior ischemic ECG findings predicted by vectorcardiography, validates certain ECG patterns as reliable surrogate markers for acute coronary occlusion, and provides novel insights correlating index ECG ischemic changes and pre‐intervention coronary angiography. These results may enhance the rate of appropriate catheterization laboratory activation. © 2011 Wiley Periodicals, Inc.     

The Diagnostic Value of ST Segment Analysis in Ambulatory ECG Monitoring Evaluated Using Bayes' Theorem in Patients Screened for Coronary Artery Disease

Background: The diagnostic value of ambulatory ECG monitoring in screening for coronary artery disease has been studied in diverse and usually small groups of patients. There are no studies evaluating the diagnostic value of Holter recorded ST depression using the Bayes' theorem of probability, which accounts for the prevalence of the disease in prespecified populations. Purpose: Applying the Bayes' theorem, this study aimed to examine the diagnostic value of Holterrecorded 1-mm ST depression in patients screened for coronary artery disease (CAD) and to identify groups of patients who may benefit from diagnostic ST segment monitoring in ambulatory ECG recordings. Methods: The ST segment analysis was performed in 24-hour ambulatory ECG monitoring of 460 subjects (375 males; aged 35–65, mean 48.6 years), who were screened for CAD and had coronary angiography. The Bayes' formulae were used to calculate the predictive value of ST segment monitoring (posttest likelihood of CAD) in comparison to pretest likelihood of the disease based on age, gender, and symptoms. Results: The 1-mm ST depression was identified in the ambulatory ECG monitoring in 203 (44%) patients. CAD was angiographically confirmed in 279 (61%) patients. The 1-mm ST depression had 54% sensitivity, 71% specificity, 74% positive predictive value, and 50% negative predictive value for CAD. The Bayes' theorem analysis with adjustment for pretest likelihood of the disease in relation to age, gender, and symptoms showed that 1-mm ST segment depression is significant diagnostically in patients with pretest likelihood of the disease exceeding 75%, i.e., in males aged 35–45 years and females aged 56–65 years, both with typical angina. In other groups of patients regardless of the symptoms, age, and gender, detection of ST segment depression does not improve the diagnostic process. A negative result (absence of ST segment depression) can be helpful, confirming the absence of CAD in patients with 15%–25% pretest likelihood of the disease, i.e., in females aged 35–45 years with atypical angina pains and in males aged 46–55 years with nonanginal chest pains. Conclusions: Based on our observations, the 1-mm ST segment depression detected on 24-hour ambulatory ECG monitoring indicates a high likelihood of CAD in patients with < 75% pretest likelihood of the disease. ST segment analysis in other age and gender relative groups of patients, regardless of the nature of their symptoms, does not significantly improve diagnosis process.     

Prehospital identification of acute coronary syndrome/myocardial infarction in relation to ST elevation

AIM: To evaluate factors that identify patients with an acute coronary syndrome/myocardial infarction prior to hospital admission among patients with a suspected acute coronary syndrome who were transported by ambulance with and without ST elevation on the ambulance electrocardiogram (ECG). METHODS: This was a prospective observational study in the part of Stockholm that is served by South Hospital ambulance organisation and the Municipality of Goteborg. All the patients who called for an ambulance due to acute chest pain or other symptoms raising the suspicion of an acute coronary syndrome took part. Immediately after the arrival of the ambulance, a blood sample was drawn for the analysis of serum myoglobin, creatine kinase (CK) MB and troponin I. A 12-lead ECG was simultaneously recorded. Further factors that were taken into consideration were age, gender, history of cardiovascular disease, symptoms and clinical findings. RESULTS: In patients with ST elevation in prehospital ECG, the likelihood of an acute myocardial infarction increased if there were simultaneous ST depression in other leads (OR 3.94, 95% CL 1.26-12.38). For patients without an ST elevation, the likelihood of an acute myocardial infarction increased if there were: elevation of any biochemical marker OR 2.96, 95% CL 1.32-6.64; ST depression (OR 2.54, 95% CL 1.43-4.51), T-inversion (OR 2.22, 95% CL 1.10-4.48), male gender (OR 2.21, 95% CL 1.24-3.93) and increasing age (OR 1.04, 95% CL 1.01-1.06). CONCLUSION: Among patients with a suspected acute coronary syndrome, factors that increased the likelihood for an ongoing acute myocardial infarction could already be defined prior to hospital admission. For those with an ST elevation, factors were found in ECG pattern. For those without an ST elevation, such factors were found in elevation of biochemical markers, admission ECG, male gender and increasing age.     

右胸导联V4R和V5R对由右冠脉近段阻塞引起的急性ST段抬高型心肌梗死的诊断价值

目的与右冠脉阻塞关联的ST段抬高型右室心肌梗死,住院期死亡率高。本研究假设是:右胸导联(V4R和V5R导联)有助于发现ST段抬高型右室心肌梗死。1342例患者记录12导联加右胸导联心电图。结果右冠脉近段阻塞者,V4R和V5R导联常见有ST段抬高,同时伴有Ⅰ,aVL,V5和V6导联ST段压低;常规12导联心电图通常不能发现ST段抬高。结论对于急性冠脉综合征,提高对ST段抬高型心肌梗死诊断的敏感性,常规12导联附加右胸导联是一项简便的方法。     

The Value of Magnetocardiography in the Course of Coronary Intervention

Background: The noninvasive detection of restenosis after percutaneous coronary intervention (PCI) remains a clinical challenge. Previous studies have shown that magnetocardiograms reveal obvious changes in patients with coronary artery disease (CAD) and normal electrocardiogram (ECG) at rest. Hypothesis: The present study aimed to evaluate the potential of magnetocardiography (MCG) for the detection of electrophysiological changes in the course of successful PCI. Methods: Twelve‐lead ECG and unshielded four‐channel MCG (SQUID AG, Essen, Germany) were registered at nine prethoracic sites in 50 patients with CAD (62 10 years; EF = 76 11%; registration: before, 24 hours, and 1 month (n = 25) after PCI) and 57 normals (51 9 years). Current density vector (CDV) maps were reconstructed within the ST–T interval and classified from category 0 (normal) to category 4 (grossly abnormal). In both groups and at all registration times, the percentage of each category of maps was calculated and compared. Results: Most CDV maps of normals were classified as category 0, 1, or 2 compared to CAD patients before PCI with most maps of category 3 and 4 (P < 0.0005). Twenty‐four hours after PCI, more maps were classified as category 2 (P < 0.05) and less as category 4 (P < 0.005). One month after PCI the MCG results further improved: more maps were classified as category 1 (P < 0.05) and 2 (P < 0.005) and less maps as category 4 (P < 0.0001). The ECG remained unchanged in the course of PCI. Conclusion: Unshielded four‐channel MCG reveals obvious changes in the course of successful PCI on the basis of CDV map reconstruction during repolarization. The method seems to be suitable for the follow‐up of patients after PCI.     

心磁图和心电图早期诊断冠心病的真实性指标比较

目的 比较心磁图（MCG）和心电图(ECG)对急性胸痛患者早期诊断冠心病的敏感度和特异度。方法 入选287例急性胸痛患者,先后给患者做MCG和ECG,然后均接受冠状动脉造影(CAG)检查。以CAG为标准诊断方法(金标准),比较MCG和ECG诊断冠心病的灵敏度和特异度。结果 MCG诊断冠心病的灵敏度和特异度分别为88.9%和73.2%,ECG诊断冠心病的灵敏度和特异度为53.2%和55.7%。结论 在急性胸痛患者早期诊断过程中,MCG诊断的灵敏度和特异度均显著高于ECG。     

体表心电图对老年急性前壁心肌梗死左前降支闭塞部位的预测价值

目的探讨体表心电图对老年急性前壁心肌梗死左前降支（LAD）闭塞部位的预测价值。方法对62例老年急性前壁心肌梗死患者的入院心电图和冠状动脉造影资料进行回顾性分析,寻找可以预测LAD闭塞部位的心电图改变。结果62例老年急性前壁心肌梗死患者均为LAD闭塞,其中近段闭塞者45例（72.6%）,远段闭塞者17例（27.4%）。经χ2检验,STⅠ抬高、STaVL抬高、STaVF压低或至少2个下壁导联ST段压低等指标提示LAD近段闭塞（P均〈0.05）。其中,STaVF压低或至少2个下壁导联ST段压低的特异度和阳性预测值最高,为94%左右,灵敏度以STaVL抬高最高,为56%;反之,STaVL压低和STⅢ抬高则在预测LAD远段闭塞上有显著意义（P均〈0.05）,特异度和阳性预测值以STaVL压低为最高,均为100%。结论急性前壁心肌梗死时,体表心电图对预测LAD闭塞部位有重要价值。     

Takotsubo syndrome in African-American women with atypical presentations: a single-center experience

BACKGROUND: Takotsubo syndrome is comprised of the clinical presentation of an acute myocardial infarction with electrocardiographic (ECG) changes of acute ischemia, chest pain, positive biomarkers, a pathognomonic left ventricular apical wall motion abnormality, and no culprit coronary disease at cardiac catheterization. HYPOTHESIS: This study aimed at a further definition of the clinical characteristics of this syndrome in African-American (AA) patients based on our experience at a single center. METHODS: Patients who presented with this syndrome between June 2003 and June 2005 were evaluated. All patients underwent coronary angiography and noninvasive cardiac investigation, including transthoracic two-dimensional echocardiography. RESULTS: Five AA women (mean age 65 years) presented with the characteristics of the syndrome. No patient experienced chest pain, with three presenting with shortness of breath and two with nausea. Hypertension was the most common risk factor for coronary artery disease (CAD) in these patients. All but one patient had ST elevation on ECG, and troponin I elevation was present in all. Cardiac catheterization showed no obstructive CAD. The most common trigger was exacerbation of a current medical condition. All five patients developed deep, broad, diffuse T-wave inversions with a prolonged QT interval. There was no mortality during the hospital stay. CONCLUSIONS: Takotsubo syndrome is experienced by AA patients. Female AA patients may experience atypical symptoms at presentation. The development of broad, diffuse, T-wave inversions with a prolonged QT interval within 2-48 h of presentation should be considered an additional criterion when diagnosing Takotsubo syndrome.