Maximal ST Elevation Research Articles

ST Segment Resolution in Post Primary PCI Patients at Lady Reading Hospital Peshawar

Background: Primary Percutaneous coronary interventions is the standard of care for ST segment elevation. There is strong association of ST segment resolution and short and long term clinical outcomes in STEMI patients after reperfusion. This is a simple, convenient and easily available tool to evaluate reperfusion therapy and predict clinical outcomes.Objective: To find out ST Segment Resolution in ST elevation MI patients undergoing Primary PCI at Lady Reading Hospital PeshawarMaterials and Methods: A descriptive cross-sectional study was conducted at cardiology department lady reading hospital Peshawar. The study population consisted of admitted STEMI Patients with successful primary PCI.Twelve lead surface ECG obtained before and 30 minutes after successful PCI. Percentage ST Resolution (STR) was calculated for the single lead with maximal ST elevation. Patients were divided into two groups 1. Those with Complete STR (>70% STR) and 2. Patients with Incomplete STR (<70% STR).Results: Between 2nd Jan 2023 to 30th November 2023, 213 STEMI were included in the study. Mean presentation time from symptom onset was 3.97 ±1.99 SD hours, while FMC to device time was 80min. Complete ST segment resolution was noted in 73% patients. Patients with no complete ST segment resolution were elderly and had longer presentation time for PCI. Also this was more frequent in LAD territory than RCA. Conclusion: PPCI is associated with high rates of STR in STEMI patients with significantly higher rates of STR if offered earlier and in younger patients.Keywords: Primary PCI, ST resolution, ST elevation MI

Baseline predictors of final infarct size in patients with ST elevation myocardial infarction undergoing primary PCI

Abstract Background In patients with coronary artery disease, the presence and extent of myocardial scar determined from cardiac magnetic resonance (CMR) imaging have recognized associations with major adverse cardiac events. Therefore, in patients presenting with ST elevation myocardial infarction (STEMI), early prediction of final infarct size (IS) has important prognostic and therapeutic implications. Purpose We sought to determine the predictors of final IS from baseline clinical, laboratory, and CMR imaging variables in patients presenting with STEMI and undergoing successful primary PCI (pPCI). Methods After successful pPCI, 76 STEMI patients underwent baseline (within 48-hours) and 3-months follow-up CMR imaging. The baseline CMR study was used to measure left ventricular (LV) volumes, ejection fraction (EF), and global longitudinal strain (GLS), the latter calculated using feature tracking from cine images. Final IS was measured in the 3-months follow up study using signal intensity quantification by the full width at half maximum method from late gadolinium enhancement images and expressed as a percentage of the total LV mass. Serum ST2 was drawn within 48 hours of STEMI presentation. Maximum values of ECG ST elevation prior to pPCI and serum Troponin I during index hospitalization were measured. Non-collinear baseline variables deemed significantly associated with the final IS on univariable linear regression and captured in all patients were entered into a multivariable model, adjusting for age and sex. Results Mean age was 54.1±10.9 years, 64 patients (78%) being males. Mean LV EF was 43.5±9.8%. Univariable predictors of final IS included hypertension, baseline maximum troponin, ST2, maximum ST elevation, LV volumes and EF, GLS, total angiographic procedure time, the presence of multi-vessel CAD, use of thrombectomy, TIMI flow and myocardial blush grades at baseline and after wiring, and prescription of loop diuretics and potassium-sparing diuretics on discharge (Table 1). A final multivariable linear model was constructed including age, sex, maximum troponin, maximum ST elevation, ST2, LV EF and GLS. In this model, baseline LV EF, maximum troponin, and maximum ST elevation remained independently associated with the final IS. Respective beta coefficients [95% CI] were -0.63 [-1- (-0.26)], 0.22 [0.11-0.33], and 0.90 [0.22-1.58]; p=0.001, <0.001, and 0.01) (Table 2; adjusted R2=0.6, p<0.001). ST2 and GLS were no longer associated with the IS. Conclusion After successful pPCI, baseline LV EF, maximum troponin I, and maximum ST elevation were independent predictors of final IS. These simple markers can identify patients at high risk of final IS who might benefit from advanced therapeutics. Future studies are warranted to confirm the prognostic value of risk scores incorporating these markers. Advanced laboratory (ST2) and imaging (strain) markers were not independently associated with IS.

FACTORS INFLUENCING THE OUTCOME OF THROMBOLYSIS IN ACUTE MYOCARDIAL INFARCTION

Introduction: Coronary heart disease has been dened as "impairment of heart function due to inadequate blood ow to the heart compared to its needs, caused by obstructive changes in the coronary circulation to the heart." It is the cause of 25-30% of death in most of the industrialized countries. In India also, it is a major public health problem. It is aptly called by WHO as the modern epidemic. The increasing incidence of coronary heart disease may be a reection of increased longevity, adoption of high-fat diet based on meats, decreased exercise, modern lifestyle, made possible by increasing afuence. The primary goal of thrombolytic therapy is rapid, complete and sustained restoration of infarct related artery blood ow. Success rate of thrombolysis and thus the overall reduction in mortality is different among different agents used. To nd out the overall success rate of thrombolysis in intensive care unit. Find outAIMS & Objective: whether the following parameters inuence the outcome of thrombolysis and determine their role in the success/ failure of thrombolysis. Material and Methods: Patients were included who is, presence of typical chest pain suggestive of Acute myocardial infarction along with ECG evidence Criteria for thrombolysis being 2 mm or more ST elevation in two contiguous precordial leads or 1 mm or more ST elevation in two contiguous limb leads. Time window of 12 hrs. from the onset of pain to the initiation of thrombolysis. All patients received streptokinase 1.5 million units in 100ml of normal, saline over 60Drug Therapy : minutes, Aspirin was given to all patients, Use of heparin, -blockers, ACE Inhibitors was according to ICU protocols, which was in accordance with ACC/AHA recommendations. Success was dened by: Clinical-Denition of success of thrombolysis: complete subsidence of chest pain, Electrocardiographically-more than 50% ST resolution in a lead which showed maximum ST elevation initially. ST elevation is measured manually, 80ms after J point from isoelectric line. Preceding PR segment is taken as isoelectric line. Patients were analyzed for success of thrombolytic therapy at 90 minutes after initiation of thrombolytic therapy, applying the above mentioned criteria. Those who underwent successful thrombolysis were grouped into group A. Those with failed thrombolysis -Group B. The following parameters were analyzed: Age, Gender, Smoking status, Drinking status, Diabetes mellitus, Systemic Hypertension, Location of Myocardial Infarction, Time interval between the onset of pain and the initiation of thrombolytic therapy, Killip grading. Patients with inferior wall myocardial infarction had a betterResults: outcome than anterior wall myocardial infarction. Alcohol, smoking and age were factors which inuence the outcome, but were not statistically signicant. Early thrombolysis had a better out come when compared to other predictors. Success rate was 64% in those patients thrombolysed within 4 hrs. from the onset of symptoms. Time window was found to be the most powerful factor inuencing the outcome of thrombolysis in patients with acute myocardial infarction. The successConclusion: rate was signicantly higher with a lower Killip grading and the outcome worsened as the grading increased.

Frequency of ST-segment resolution after thrombolysisin acute stelevation myocardial infarction patients

Background: Acute Coronary Syndrome (ACS) is the term collectively used for referring to clinical manifestations of myocardium ischemia which include unstable angina, myocardial infarction with non-ST-segment elevation and myocardial infarction with ST-segment elevation.1 Myocardial Infarction (STEMI) is characterized by ST elevation presented on the ECG, that is the electrical presentation of the occlusion due to thrombosis in a coronary artery. After the fibrinolytic therapy in STEMI cases, the resolution of ST-segment is analyzed on ECG which serves as easy and cost-effective solution for the assessment of coronary reperfusion. In a study, it is found that 61.5% patients of STEMI showed ST-resolution after streptokinase.
 
 Aims and Objective: To determine the frequency of ST-segment resolution after streptokinase in acute STEMI patients.
 
 Materials and Methods: This cross-sectional study was carried out from 08-07- 2016 to 07-01-2017.After taking approval from ethical committee and explaining the procedure informed consent was taken. Ninety-two (92) patients were recruited from emergency Department of Tabba Heart Institute Karachi on the basis of inclusion/exclusion criteria via non-probability consecutive sampling technique. ECGs were taken at presentation. ST-elevation was recorded in millimeters in lead with maximum ST-elevation. Injection streptokinase was administered. ECG was performed after 60 minutes of infusion of injection streptokinase. ST resolution in the lead with the maximum ST elevation was noted and was labeled as positive as per operational definition.
 
 Results: The range of the age in this study was from 25 to 80 years with mean age of 54.9 ± 4.8 years. Out of 92 patients, 56(60.9%) were male and 36(39.1%) were female. Regarding ECG changes sixty patients (71.7%) were successfully resolved after streptokinase in acute STEMI patients while in twenty-six patients (28.3%) could not resolve.
 
 Conclusion: Successfully resolution of ECG changes seen in 71.7% patients after streptokinase in acute STEMI patients while could not be resolved in 28.3% patients. Thus, streptokinase could be preferred therapy for thrombolysis in STEMI.
 
 Keywords: ST-elevation myocardial infarction, streptokinase, ST- segment resolution.

Terminal T-wave inversion predicts reperfusion tachyarrhythmias in STEMI

IntroductionA reliable electrocardiographic predictor of ventricular fibrillation (VF) in patients with ST elevation myocardial infarction (STEMI) is lacking so far. Previous experimental/simulation study suggested a terminal T-wave inversion (TTWI) in ischemia-related ECG leads corresponding to anterior infarct localization as an independent predictor of reperfusion VF (rVF). This T-wave characteristic has never been tested as a rVF predictor in clinical settings. The aim of this study was to test if terminal T-wave inversion (TTWI) at admission ECG (before reperfusion) can serve as a predictor of ventricular fibrillation during reperfusion (rVF) in patients with anterior STEMI undergoing primary PCI. Methods and resultsStudy population included consecutive patients with anterior infarct localization admitted for primary PCI (n = 181, age 65 [57; 76] years, 66% male). Of those, 14 patients had rVF (rVF group, age 59 [47; 76] years, 64% male) and patients without rVF comprised the No-rVF group (n = 167, age 65 [57; 76] years, 66% male). Association of TTWI with rVF was analyzed using logistic regression analysis adjusted for relevant clinical and electrocardiographic covariates. The prevalence of TTWI in rVF group was 62% comparing to 23% in the No-rVF group, p = 0.005. TTWI was associated with increased risk of rVF (OR 5.51; 95% CI 1.70–17.89; p = 0.004) and remained a significant predictor after adjustment for age, gender, history of MI prior to index admission, VF before reperfusion, Tpeak-Tend, maximal ST elevation, and QRS duration (OR 23.49; 95% CI 3.14–175.91; p = 0.002). ConclusionsThe terminal T-wave inversion in anterior leads before PCI independently predicted rVF in patients with anterior MI thus confirming the previous experimental/simulation findings.

Electrocardiographic predictors of ventricular fibrillation in ST-segment elevation acute myocardial infarction

Abstract Introduction Ventricular fibrillation (VF) during ST-segment elevation myocardial infarction (STEMI) is a critical emergency that requires immediate action to recover sinus rhythm and prevent sudden death. The surface electrocardiogram (ECG) is an essential diagnostic tool performed during STEMI. Our objective was to identify markers on the ECG that might be useful as potential predictors of peri-infarct VF. Methods Data was obtained prospectively from consecutive patients with a STEMI diagnosis admitted to the Cardiology Acute Care Unit at a tertiary hospital from July-2019 to May-2020. In all cases, primary angioplasty was performed. Clinical and laboratory data and in-hospital complications were collected. Surface ECG parameters were evaluated at the time of diagnosis. Results Of a total of 93 patients included, 11 patients had peri-infarct VF (11.8%). No differences in age, sex or cardiovascular risk factors between groups were found. The ECG at admission showed notable differences: the degree of maximum elevation of the ST segment in mm (STmax) and the sum of such elevation (STsum) in all leads were significantly higher in the VF group (Table). A receiver operating characteristics analysis was performed in order to evaluate the diagnostic capacity of STmax for VF (Figure). A cut off of 4 mm (4mV) in STmax demonstrated the highest sensitivity and specificity for predicting VF. Patients with ST elevation >4mm in any lead had a 16 times greater probability of developing peri-infarct VF (OR 16.4, 95% CI 1.98–136.4; p=0.01). After adjusting for age, STsum also showed a significant association with peri-infarct VF. An STsum of >12mm resulted in a 4 times greater risk of VF. Conclusions The surface ECG remains an essential tool in the evaluation of patients with STEMI. The maximum ST elevation and the sum of the ST elevation demonstrates a strong association with the development of peri-infarct VF. A ST elevation >4mm in any lead is associated with a 16 times higher risk of developing VF. Funding Acknowledgement Type of funding sources: None. Table 1. Baseline demographics, electrocardiographic (ECG) and laboratory data in patients with and without ventricular fibrillation. CKD: chronic kidney disease. STmax: maximum elevation of the ST segment in the ECG measured in millivolts (mV). STsum: sum of all ST elevation on the 12 lead ECG. LVEF: left ventricular ejection fraction.Figure 1. Receiver operating characteristics (ROC) curve analysis to evaluate the diagnostic capacity of maximum ST elevation for the development of ventricular fibrillation in patients with infarction.

The Second Strategic Reperfusion Early After Myocardial Infarction (STREAM-2) study optimizing pharmacoinvasive reperfusion strategy in older ST-elevation myocardial infarction patients

The STREAM study demonstrated that a pharmaco-invasive strategy was at least as effective as primary PCI (pPCI) in patients presenting early with ST-elevation myocardial infarction (STEMI). The current trial is a response to the finding that reduced intracranial hemorrhage (ICH) in patients ≥75 years occurred after halving the dose of tenecteplase. Additionally, a subsequent analysis of full dose tenecteplase or alteplase in the Assessment of the Safety and Efficacy of a New Thrombolytic (ASSENT) trials demonstrated a steep increase in bleeding events beginning around the age of 60 years. STREAM-2 will compare the efficacy and safety of a novel pharmaco-invasive strategy as compared to routine pPCI in STEMI patients ≥60 years presenting within 3 hours from symptom onset. In the pharmaco-invasive arm patients will receive half-dose tenecteplase, as soon as possible before transport to a PCI center. In the pPCI arm, patients will be treated according to optimal standard of care defined by local practice. The key criteria for efficacy will be the number of patients achieving ≥50% ST-segment resolution before and after PCI in lead with maximal ST elevation at baseline and the clinical endpoints of death, congestive heart failure, shock or re-infarction, rescue PCI and aborted myocardial infarction, both singularly and as a composite at 30 days. Key safety criteria are total stroke, ICH and major non-intracranial bleeds. Approximately 600 patients will be randomized (400 to pharmaco-invasive treatment and 200 to pPCI). An interim analysis is planned after 300 patients are enrolled to consider adapting the trial to include a larger sample size aimed at undertaking a formal confirmatory trial. The study will provide new insights aimed at establishing an effective and safer pharmaco-invasive treatment for the growing population of older STEMI patients who cannot undergo timely pPCI.

Cardiovascular drugs attenuated myocardial resistance against ischaemia-induced and reperfusion-induced injury in a rat model of repetitive occlusion

ObjectiveWe investigated the impact of cardioprotective drugs on ST-elevation, arrhythmias and infarct size in a rat model of repetitive coronary artery occlusion.MethodsSeventy Sprague-Dawley rats were randomised to two control and...

Peri-procedural ST segment resolution during Primary Percutaneous Coronary Intervention (PPCI) for acute myocardial infarction: predictors and clinical consequences

ObjectiveECG ST segment resolution (STR) has been used to assess myocardial perfusion in STEMI patients undergoing PPCI. However, in most of the studies ECGs recorded at different time points after the actual procedure have been used, limiting the options of therapeutic interventions while the patient is still in the catheterisation laboratory. The aim of this study was to investigate the presence and clinical consequences of intra-procedural STR during PPCI. MethodsWe analysed 12 lead ECGs recorded at the onset and the end of the PPCI procedure, measuring STR in the lead with maximum ST elevation on the initial recording. STR was defined as good when > 50% compared to baseline. ResultsPre and immediately post PPCI ECGs were recorded in 467 STEMI cases whilst the patient was on the catheter lab table. Mean patient age was 63 (+/- 12) years old and 75% were men. Mean duration of symptoms to admission was 3.8 (+/- 3.4) hours and 51% of infarcts were anterior. Good ST resolution at the end of the procedure was seen in 46.5% of patients and was observed more commonly in inferior compared to anterior infarcts (60.1% vs. 32.6%, p<0.001), and in current smokers (53.2% vs. 42.4%, p=0.031). In patients presenting with symptoms for < 4 hours, good STR was more common (74% vs. 66%, p=0.019). Thrombus aspiration was used more frequently in patients who had good STR (88.5% vs 79.8% p=0.011). Patients with good ST resolution had a shorter mean hospital length of stay (3.8 vs. 4.5 days, p=0.009) and a higher left ventricular ejection fraction (49.9% vs. 44.2%, p<0.001) measured by transthoracic echocardiography prior to discharge. ConclusionGood peri-procedural ST resolution was seen in less than half of STEMI patients undergoing PPCI. There were important clinical consequences of good ST resolution. Identification of suboptimal peri-procedural ST resolution could help identify patients who may benefit from new treatments aimed at protecting the microcirculation, whilst the patients are still in the angiography laboratory.

The acetylcholine administration time plays the key role for provoked spasm in the spasm provocation test

BackgroundAcetylcholine (ACh) was administered for 3min in the ENCORE study, while the Japanese Circulation Society guidelines recommended the 20s ACh injection as an ACh test. ObjectivesWe compared the ischemic findings between ACh administration for 3min and ACh injection for 20s in the same patients and in the same ACh doses without administration of nitrates in the left coronary artery. MethodsWe investigated 30 patients with ischemic heart disease (25 men, 67±10 years, ACh 50μg: 3, ACh 100μg: 9, ACh 200μg: 18) by the above two ACh injection procedures. Temporary pacemaker was inserted and set at the rate of 40/min. Positive provoked spasm was defined as transient ≥90% narrowing and typical chest symptoms or ischemic electrocardiographic (ECG) changes. ResultsProvoked spasm was observed in 22 patients with ACh 20s injection, while 10 patients had provoked spasm by ACh 3min administration (73.3% vs. 33.3%, p<0.05). Ischemic ECG changes (50.0% vs. 23.3%, p<0.05) and chest symptoms (73.3% vs. 43.3%, p<0.05) were significantly higher with ACh 20s injection than ACh 3min administration. Pacemaker rhythm was recognized in 19 patients with ACh 20s injection, whereas 7 patients with ACh 3min administration had a pacemaker rhythm (63.3% vs. 23.3%, p<0.01). Maximal ST elevation by ACh 20s injection was significantly higher than that by ACh 3min administration (0.47±0.94 vs. 0.13±0.51, p<0.05), while maximal ST depression was not different between the two procedures. Coronary artery diameter after ACh 20s injection was significantly lower than that after ACh 3min administration in the left anterior descending artery. ConclusionsACh administration procedures (3min or 20s injection) may influence the ischemic findings in spasm provocation testing.

Abstract 11195: Differences in ST-T Changes Between Takotsubo Cardiomyopathy and Reperfused Non-Q-Wave Anterior Acute Myocardial Infarction

Introduction: In both takotsubo cardiomyopathy (TC) and reperfused non-Q-wave anterior acute myocardial infarction (AMI), giant negative T waves (Neg T) commonly appear after the resolution of ST-segment elevation (ST elevation) in precordial leads, reflecting viable but sympathetically denervated myocardium. Hypothesis: ST-T changes may differ between between TC and reperfused non-Q-wave anterior AMI, reflecting the differences in underlying electrophysiologic mechanisms between these 2 diseases. Methods: We studied 38 patients with TC and 253 with a first non-Q-wave anterior AMI who were admitted within 6 hours after symptom onset. All patients with anterior AMI underwent emergency coronary angiography, and the occlusion of the left anterior descending coronary artery was documanted and successful reperfusion (TIMI grade 3) was obtained. ECGs on admission and those with the greatest amplitude of subsequent Neg T (mean 2 days later) were studied. Results: As compared with patients with anterior AMI, those with TC were older (70 ± 11 vs 62 ± 11 years, p &lt; 0.01), more likely to be women (84% vs 20%, p&lt;0.01) and had a lower peak creatine kinase (461 ± 493 vs 1506 ± 934 mU/ml, p&lt;0.01) despite lower left ventricular ejection fraction on admission (40 ± 9 vs 51 ± 10%, p &lt; 0.01), respectively. TC was associated with a smaller maximal ST elevation on admission (4.6 ± 4.7 vs 5.9 ± 3.1 mm, p&lt;0.01), a greater maximal amplitude of Neg T (10.0 ± 4.1 vs 8.0 ± 4.8 mm, p &lt; 0.01), a greater number of leads with Neg T (9 ± 1 vs 6 ± 2, p &lt; 0.01) and a longer maximal QTc interval (643 ± 99 vs 586 ± 79 ms, p &lt; 0.01) in subacute phase, respectively. The prevalences of initial ST elevation and subsequent Neg T differed between TC and anterior AMI (Figure). Conclusions: ST-T changes in the acute and subacute phases clearly differed between TC and reperfused non-Q-wave anterior AMI. In TC, deeper NegT were more broadly distributed, suggesting that TC might be associated with more extensive viable but denervated myocardium.

Tpeak-to-Tend/QT is an independent predictor of early ventricular arrhythmias and arrhythmic death in anterior ST elevation myocardial infarction patients.

The aim of our study was to analyse the markers of transmural dispersion of ventricular repolarization, especially Tpeak-to-Tend and Tpeak-to-Tend /QT ratio, in patients with anterior ST elevation myocardial infarction on admission and to evaluate their association with in-hospital life-threatening arrhythmias and mortality. A total of 223 consecutive patients with anterior wall ST elevation myocardial infarction admitted to our Division of Cardiology between January 2010 and December 2012 were prospectively evaluated. A standard electrocardiogram was obtained on admission and then analysed. The primary end point was constituted by in-hospital ventricular arrhythmias and arrhythmic death. At univariate analysis heart rate (odds ratio = 1.03; 95% confidence intervals 1.006-1.05; p=0.001), maximal ST elevation (odds ratio =1.25; 95% confidence intervals 1.10-1.43; p=0.0001), QTc Bazett (odds ratio = 1.01; 95% confidence intervals 1.006-1.02; p=0.002), QT dispersion (odds ratio = 1.02; 95% confidence intervals 1.002-1.04; p=0.02) and both Tpeak-to-Tend and Tpeak-to-Tend/QT (odds ratio = 1.02; 95% confidence intervals 1.01-1.03; p<0.0001 and OR = 1.07; 95% confidence intervals 1.03-1.11; p<0.0001 respectively) were significantly associated with ventricular arrhythmias and arrhythmic mortality. Of note, Tpeak-to-Tend /QT remained a predictor of early ventricular arrhythmias and arrhythmic death (odds ratio = 1.04; 95% confidence intervals 1.003 - 1.10; p=0.03) independently from heart rate and maximal ST elevation. Receiver operating characteristic curve analysis showed that Tpeak-to-Tend /QT values <0.31 had a predictive negative value of 92% for the prediction of the composite outcome. Tpeak-to-Tend /QT was an independent predictor of early ventricular arrhythmias and arrhythmic mortality in patients with anterior ST elevation myocardial infarction. Especially, Tpeak-to-Tend /QT <0.31 may identify a subgroup of ST elevation myocardial infarction patients with low risk of early arrhythmias and arrhythmic death.

Predictive Implication of Initial Electrocardiogram and Creatine Kinase for Left Ventricular Ejection Fraction in Patients with Acute ST-Elevation Myocardial Infarction

Aim: Our aim was to determine the clinical, electrocardiographic (ECG) and biochemical predictors of left ventricular dysfunction in patients with acute ST elevation myocardial infarction (STEMI). Methods: Patients with STEMI admitted in Loghman Hakim hospital were studied. The ECG variables were: ECG rate, ECG rhythm, QRS duration, sum of absolute ST deviation (in all, inferior and anterior leads), number of leads with ST elevation, maximum ST elevation, presence of pathological Q waves and location of the infarct. The primary outcome measure was LVEF ≤ 40%. Results: A total of 124 patients (91 male, 33 female) were studied. Mean age of the patients was 59.1 years (SD=12.6). Of these, 52 patients (44.4%) had an LVEF ≤ 40% and angiography was recommended to 68 patients (54.8%) at the time of discharge. The multivariate analysis showed an association of LVEF ≤ 40% with prior MI, diabetes, maximum creatine kinase (CK) levels, the sum of absolute ST deviation in all and inferior leads. Conclusions: The initial ECG and CK levels in patients with STEMI may contain valuable information for risk stratification, determination of prognosis and the subsequent management plan. The results of this study warrant further studies to define patients who benefit most from invasive and sophisticated interventions.

Admission hyperglycemia is associated with failed reperfusion following fibrinolytic therapy in patients with STEMI: results of a retrospective study.

Hyperglycemia on admission is associated with increased mortality rates in patients with ST-elevation myocardial infarction (STEMI) who are treated with either fibrinolytic therapy (FT) or primary percutaneous coronary intervention (PCI). However, data regarding the relationship between hyperglycemia and the success of FT are lacking. The aim of this study was to investigate the value of admission blood glucose for the prediction of failed reperfusion following FT. This is a retrospective study of 304 STEMI patients who received FT and whose admission glucose levels were recorded. The main outcome measure was ST segment resolution≥50%. The median (interquartile range [IQR]) blood glucose level in the entire study group was 112 (95-153). In 92 (30.2%) patients, FT was unsuccessful and rescue PCI was performed. Admission glucose (126 [99-192] vs. 110 [94-144] mg/dL, p<0.001), time from symptom onset to FT (180 [120-270] vs. 150 [120-180] min, p=0.009), and maximum ST elevation amplitude (3 [2-7] vs. 3 [2-6] mm, p=0.05) were higher in the failed reperfusion group than in the reperfusion group. Admission hyperglycemia was an independent predictive factor for failed reperfusion (hazard ratio 4.79 [1.80-12.76], p=0.002), along with time from symptom onset to fibrinolysis and anterior wall myocardial infarction. In patients with STEMI who undergo FT, admission hyperglycemia is an independent predictor of the failure of fibrinolysis.

Abstract 19842: Microvascular Dysfunction in Patients with ST-Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention: No Sex Disparity

Background: Microvascular dysfunction is highly prevalent in women and presumed secondary to hormonal fluctuations, increased vascular tone, and endothelial dysfunction. Its contribution has never been examined in the acute setting. Patients with ST-elevation myocardial infarction (STEMI) with persistent ST-elevation (ST-E) post successful primary percutaneous coronary intervention (PPCI) are at risk of in-hospital cardiac events. We used ST-E recovery on ECGs pre and post PPCI to study potential sex differences in microvascular dysfunction, in conjunction with cardiac events in a STEMI population. Methods: Retrospective analysis was conducted on consecutive STEMI patients undergoing PPCI in Vancouver between May 2007 and September 2010 with evaluable ECGs pre and post PPCI. Patients with bundle branch block were excluded. Quantification of ST-E in each lead was done by electronic calipers by investigators blinded to clinical outcomes. Univariate analysis was performed by sex, for the association between ST-E recovery in the lead with maximal ST-E and the composite of in-hospital mortality, heart failure, cardiogenic shock, and reinfarction. Results: Of our 413 patients, 23% were women. In comparing baseline characteristics, age was significantly different (mean age of females = 72 vs. males = 61, p&lt;0.001). More female than male patients had incomplete (&lt;50%) ST-E recovery (20.6% vs. 12.7%, p=0.052). Women with incomplete recovery had an odds ratio of 2.3 for the primary outcome, compared with 1.4 in men, which was not statistically significant between sex. The primary outcome occurred more often in women (29.9% vs. 18.0%, p=0.012), but after adjusting for age, sex difference was no longer significant. Conclusions: Female STEMI patients are older, had more incomplete ST-E recovery after PPCI and had more in-hospital cardiac events, although significance was lost after adjusting for age. The higher prevalence of microvascular dysfunction in stable women may not be a large contributor of persistent ST-E in the acute setting. The higher incidence of incomplete ST-elevation in women may be attributable to the increasing prevalence of endothelial dysfunction with age. This novel interaction should be further examined with objective measures.

Electrocardiographic ST-segment monitoring during controlled occlusion of coronary arteries

BackgroundIschemia monitoring cannot always be performed by 12-lead ECG. Hence, the individual performance of the ECG leads is crucial. No experimental data on the ECG's specificity for transient ischemia exist. MethodsIn 45 patients a 19-lead ECG was registered during a 1-minute balloon occlusion of a coronary artery (left anterior descending artery [LAD], right coronary artery [RCA] or left circumflex artery [LCX]). ST-segment shifts and sensitivity/specificity of the leads were measured. ResultsDuring LAD occlusion, V3 showed maximal ST-segment elevation (0.26mV [IQR 0.16–0.33mV], p=0.001) and sensitivity/specificity (88% and 80%). During RCA occlusion, III showed maximal ST-elevation (0.2mV [IQR 0.09–0.26mV], p=0.004), aVF had the best sensitivity/specificity (85% and 68%). During LCX occlusion, V6 showed maximal ST-segment elevation (0.04mV [IQR 0.02–0.14mV], p=0.005), and sensitivity/specificity was (31%/92%) but could be improved (63%/72%) using an optimized cut-off for ischemia. ConclusionV3, aVF and V6 show the best performance to detect transient ischemia.

Evaluation of Gender Differences in Door-to-Balloon Time in ST-Elevation Myocardial Infarction

A delayed Door-to-Balloon (DTB) time in women with ST-elevation myocardial infarction (STEMI) has been associated with an increased mortality. The objectives of this study were to (a) quantify the components of the delayed DTB time in women and (b) assess the independent effect of gender on DTB time in patients undergoing percutaneous coronary intervention (PCI) for STEMI. Clinical parameters were prospectively collected for 735 STEMI patients undergoing primary PCI from 2006 to 2010, with particular attention to the components of DTB time, including the onset of chest pain and the 'code' notification of the STEMI team by the Emergency Department. Women were significantly older with more co-morbidity. Upon hospital arrival they also experienced delays in Door-to-Code (23 vs. 17 min, P=.012), Code-to-Balloon (63 vs. 57 min, P=.001) and thus DTB time (88 vs. 72 min, P=.001). After multivariate adjustment, independent determinants of DTB time included female gender (ratio of geometric means [RGM]=1.13; 95% CI 1.02-1.26; P=.022), hypertension (RGM=1.12, 95% CI 1.02-1.23, P=.014), maximum ST-elevation (RGM=0.97, 95% CI 0.94-0.98, P<.001), office hours (RGM=0.84, 95% CI 0.78-0.92, P<.001) and triage category (RGM=1.23, 95% CI 1.09-1.40, P=.001). Women experience delays in identification of the STEMI diagnosis and also in the PCI process. Thus a multifaceted approach addressing both the diagnosis and management of STEMI in women is required.

Endogenous serum erythropoietin and no-reflow in patients with ST-elevation myocardial infarction

In models of acute ischaemia, erythropoietin (EPO) administration has been found to attenuate vascular injury largely through reduced apoptosis, suppressed inflammation and increased nitric oxide availability. We studied the association between circulating endogenous EPO and no-reflow in patients with first ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI). Blood sampling was performed before PPCI. Consecutive patients with (n = 24) or without (n = 24) evidence of angiographic no-reflow after PPCI were enrolled. Angiographic no-reflow was defined as Thrombolysis in Myocardial Infarction (TIMI) flow ≤ 2 or as TIMI flow = 3 but with myocardial blush grade < 2. We also assessed electrocardiographic (ECG) no-reflow as ≤ 50% resolution of maximal ST elevation 60 min after PPCI. Baseline characteristics did not correlate significantly with EPO concentrations. In contrast, both angiographic and ECG no-reflow correlated with lower EPO levels at univariate analysis [median (interquartile): 4·2 (0·6-9·5) vs. 12·2 (5·2-20·3) mIU mL(-1), P = 0·001, and 4·0 (0·6-7·1) vs. 9·3 (1·0-12·6) mIU mL(-1), P = 0·01, respectively]. At multivariable analysis, decreasing EPO tertiles and left anterior descending as the infarct-related artery were the only factors that predicted both angiographic and ECG no-reflow (P = 0·017 and P = 0·02 for EPO; P < 0·005 and P > 0·05 for left anterior descending artery, respectively). We found an independent, graded, inverse relation between endogenous EPO levels and angiographic and ECG no-reflow following PPCI. In animal models of ischaemia, EPO has been found to be protective. In humans, endogenous EPO may contribute to offset the mechanisms responsible for no-reflow.

048 Unlike hyperglycemia, insulin deficiency and insuline resistance index are not associated with ST-segment resolution after primary percutaneous coronary intervention for acute myocardial infarction

Hyperglycemia is a powerful predictor of worse outcome after ST segment-elevation myocardial infarction (STEMI). Previous studies showed that hyperglycemia could be related to impaired myocardial reperfusion. This relation may be explained by absolute or relative insulin deficiency resulting in increasing toxic effect of circulating free fatty acids or in reducing glucose use in anaerobic manner in myocardium. The present study evaluates glycemic parameters, plasma insulin level, insulin resistance by index Quicki (1/log insulin + log glycemia in mg/dL) and index Homa (insulin x glycemia in μmol/L/22.5) in 105 patients with STEMI and successful percutaneous primary coronary intervention (PCI). The maximum ST elevation of single electrocardiogram (ECG) lead before and 60 minutes after PCI was measured and patients were then divided into 2 groups according to the degree of ST-segment resolution (STR): not complete (<70%) or complete (≥70%). Of the 105 patients, 62 (59.0%) had complete STR, 43 (41.0%) experienced not complete STR. Not complete STR group had a trend to a higher mean admission glucose level (1.8 ± 1.5 g/l vs 1.4 ± 0.5 g/l, p = 0.1) and a significative higher glycated haemoglobin level (6.8 ± 1.9% vs 6.1 ± 0.9%, p = 0.008). However no difference was observed for plasma insulin level (21.4 ± 23.6 mU/l vs 21.1 ± 18.4 mU/l), index Quicki (0.32 ± 0.07 vs 0.30 ± 0.04) and index Homa (142.3 ± 171.4 vs 146.7 ± 158.6) respectively in complete and not complete STR groups. In conclusion, this study confirms the association between hyperglycemia and electrocardiographic signs of complete reperfusion in patients with STEMI after PCI but this relation does not seem to be related to a absolute plasma insulin deficiency or an insulin resistance.

ST-segment dynamics during reperfusion period and the size of myocardial injury in experimental myocardial infarction

Background Exacerbation of ST elevation associated with reperfusion has been reported in patients with myocardial infarction. However, the cause of the “reperfusion peak” and relation of its magnitude to the size of myocardial damage has not been explored. The aim of our study was to assess the correlation between the ST-dynamics during reperfusion, the myocardium at risk (MaR), and the infarct size (IS). Methods Infarction was induced in 15 pigs by a 40-minute-long balloon inflation in the left anterior descending coronary artery. Tetrofosmin Tc 99m was given intravenously after 20 minutes of occlusion, and ex vivo single photon emission computed tomography was performed to assess MaR. Maximal ST elevation in a single lead and maximal sum of ST deviations in 12 leads were measured before, during, and after occlusion from continuous 12-lead electrocardiographic monitoring. A gadolinium-based contrast agent was given intravenously 30 minutes before explantation of the heart. Final IS was estimated using ex vivo cardiac magnetic resonance imaging. Results All pigs developed an anteroseptal infarct with MaR = 42% ± 9% and IS = 26% ± 7% of left ventricle. In all pigs, reperfusion was accompanied by transitory exacerbation of ST elevation that measured 1300 ± 500 μV as maximum in a single lead compared with 570 ± 220 μV at the end of occlusion ( P < .001). The transitory exacerbation of ST elevation exceeded the maximal ST elevation during occlusion (920 ± 420 μV, P < .05). The ST elevation resolved by the end of the reperfusion period (90 ± 30 μV, P < .001). Exacerbation of ST elevation after reperfusion correlated with the final IS ( r = 0.64, P = .025 for maximal ST elevation in a single lead and r = 0.80, P = .002 for sum of ST deviations) but not with MaR ( r = 0.43, P = .17 for maximal ST elevation in a single lead and r = 0.49, P = .11 for sum of ST deviations). The maximal ST elevation in a single lead and the sum of ST deviations during occlusion did not correlate with either MaR or final IS. Conclusion In the experiment, exacerbation of ST elevation is common during restoration of blood flow in the occluded coronary artery. The magnitude of the exacerbation of ST elevation after reperfusion in experimentally induced myocardial infarction in pigs is associated with infarct size but not with MaR.