The electrocardiogram in ST elevation acute myocardial infarction: correlation with coronary anatomy and prognosis

Enhanced cardioprotective activity of ferulic acid-loaded solid lipid nanoparticle in an animal model of myocardial injury

Myocardial infarction results in an increased inflammatory and oxidative stress response in the heart, and reducing inflammation and oxidative stress after MI may offer protective effects to the heart. In the present study, we examined the cardioprotective effects of ferulic acid (FA) and ferulic acid nanostructured solid lipid nanoparticles (FA-SLNs) in an isoproterenol (ISO) induced MI model. Male Sprague Dawley rats were divided into five experimental groups to compare the effects of FA and FA-SLNs. The findings revealed that ISO led to extensive cardiomyopathy, characterized by increased infarction area, edema formation, pressure load, and energy deprivation. Additionally, ISO increased the levels of inflammatory markers (COX-2, NLRP3, and NF-кB) and apoptotic mediators such as p-JNK. However, treatment with FA and FA-SLNs mitigated the severity of the ISO-induced response, and elevated the levels of antioxidant enzymes while downregulating inflammatory pathways, along with upregulation of the mitochondrial bioenergetic factor PPAR-γ. Furthermore, virtual docking analysis of FA with various protein targets supported the in vivo results, confirming drug-protein interactions. Overall, the results demonstrated that FA-SLNs offer a promising strategy for protecting the heart from further injury following MI. This is attributed to the improved drug delivery and therapeutic outcomes compared to FA alone.

Environmentally Adaptable Organo-Ionic Gel-Based Electrodes for Real-Time On-Skin Electrocardiography Monitoring

On-skin personal electrocardiography (ECG) devices, which can monitor real-time cardiac autonomic changes, have been widely applied to predict cardiac diseases and save lives. However, current interface electrodes fail to be unconditionally and universally applicable, often losing their efficiency and functionality under harsh atmospheric conditions (e.g., underwater, abnormal temperature, and humidity). Herein, an environmentally adaptable organo-ionic gel-based electrode (OIGE) is developed with a facile one-pot synthesis of highly conductive choline-based ionic liquid ([DMAEA-Q] [TFSI], I.L.) and monomers (2,2,2-trifluoroethyl acrylate (TFEA) and N-hydroxyethyl acrylamide (HEAA). In virtue of inherent conductivity, self-responsive hydrophobic barriers, dual-solvent effect, and multiple interfacial interactions, this OIGE features distinct sweat and water-resistance, anti-freezing and anti-dehydration properties with strong adhesiveness and electrical stability under all kinds of circumstances. In contrast to the dysfunction of commercial gel electrodes (CGEs), this OIGE with stronger adhesion as well as skin tolerability can realize a real-time and accurate collection of ECG signals under multiple extreme conditions, including aquatic environments (sweat and underwater), cryogenic (<-20°C) and arid (dehydration) environments. Therefore, the OIGE shows great prospects in diagnosing cardiovascular diseases and paves new horizons for multi-harsh environmental personalized healthcare.

Cardiac biomarkers and detection methods for myocardial infarction

Background

A significant heart attack known as a myocardial infarction (MI) occurs when the blood supply to the heart is suddenly interrupted, harming the heart muscles due to a lack of oxygen. The incidence of myocardial infarction is increasing worldwide. A relationship between COVID-19 and myocardial infarction due to the recent COVID-19 pandemic has also been revealed.

Objective

We propose a biomarker and a method that can be used for the diagnosis of myocardial infarction, and an aptamer-based approach.

Results

For the diagnosis of myocardial infarction, an algorithm-based diagnosis method was developed using electrocardiogram data. A diagnosis method through biomarker detection was then developed.

Conclusion

Myocardial infarction is a disease that is difficult to diagnose based on the aspect of a single factor. For this reason, it is necessary to use a combination of various methods to diagnose myocardial infarction quickly and accurately. In addition, new materials such as aptamers must be grafted and integrated into new ways.

Purpose of Review

The incidence of myocardial infarction is increasing worldwide, and some studies are being conducted on the association between COVID-19 and myocardial infarction. The key to properly treating myocardial infarction is early detection, thus we aim to do this by offering both tools and techniques as well as the most recent diagnostic techniques.

Recent Findings

Myocardial infarction is diagnosed using an electrocardiogram and echocardiogram, which utilize cardiac signals. It is required to identify biomarkers of myocardial infarction and use biomarker-based ELISA, SPR, gold nanoparticle, and aptamer technologies in order to correctly diagnose myocardial infarction.

Subepicardial burn injuries in bullfrog heart induce electrocardiogram changes mimicking inferior wall myocardial infarction

Using bullfrog hearts, we previously reproduced a ST segment elevation in electrocardiogram (ECG), mimicking human ischemic heart disease. In the present study, by inducing subepicardial burn injuries on the inferior part of the frog heart ventricle, we could reproduce typical ECG changes observed in human inferior wall myocardial infarction, such as the marked elevation of the ST segments in inferior limb leads (II, III, aVF) and their reciprocal depression in the opposite limb leads (I, aVL). Due to the decrease in Na⁺/K⁺-ATPase protein expression, the resting membrane potential of injured cardiomyocytes shifted toward depolarization. Such induced electrical difference between the injured and intact cardiomyocytes was thought to be responsible for the creation of “currents of injury” and the subsequent ST segment changes.

Early ischemic ST-segment and T-wave changes during balloon angioplasty

BACKGROUND

Acute coronary occlusion results in increased T-wave amplitude and ST-segment elevation in the ECG leads facing the ischemic region.

MATERIAL AND METHODS

We performed continuous ECG recording in 34 patients during balloon occlusion of the left anterior descending (LAD), left circumflex (LCx) and right coronary artery (RCA). Delta (Δ) ST and ΔT amplitudes were calculated by subtracting the preinflation values from the values measured during balloon inflation.

RESULTS

Occlusion of the LAD resulted in greater increase in the amplitude of the T wave than of the ST segment in lead V2 (ΔT +3.4 mm, inter-quartile range [IQR] 1-6 mm; ΔST +1.4 mm, 0.5-3 mm). During RCA occlusion, ΔST and ΔT didn't differ significantly. LCx occlusion resulted in significant differences between ΔST and ΔT in all leads, except aVF and V3-V4. In two patients (LCx), we observed a biphasic ST-T response: an initial negative change of the T-wave amplitude was followed by a positive change in leads V1-V2. In leads II, III, aVF and V4-V6, there was an initial positive change, followed by a final negative change towards the end of the occlusion.

CONCLUSION

Continuous 12‑lead ECG recording during balloon occlusion of the LCx resulted in significant differences between the ΔST and ΔT values in all leads except aVF and V3-V4. LAD and RCA occlusion resulted in less evident differences between the ST-segment and T-wave changes. A change in polarity of T-wave changes during balloon occlusion (initial negative and final positive change, or vice versa) proved to be a rare finding.

Beneficial effects of PEGylated graphene quantum dot on arrhythmias induced by myocardial infarction

Arrhythmias are one of the leading causes of early death following myocardial infarction (MI) and heart failure. Graphene derivatives have emerged as an therapeutic target that have electrical conductivity. The study aimed to evaluate the impacts of polyethylene glycol-graphene quantum dots (GQDs-PEG) on arrhythmias created by MI in the rat. Animals were randomly assigned to five groups of sham, MI, and MI + GQDs-PEG at doses of 5, 10, and 20 mg/kg. MI was induced by the closure of the left anterior descending artery. The day after MI, animals were administered vehicle (phosphate buffered saline) or GQDs-PEG at different doses every other day for 2 weeks. On day 15, electrocardiogram (ECG), mean arterial pressure (MAP), and heart contractility indices were recorded by the PowerLab data acquisition system. GQDs-PEG 20 mg/kg increased contractility and improved the reduction of MAP in the MI group. The prolonged QT and QTc intervals, inverted T wave, and deviated ST segment were modified by GQDs-PEG 10 and 20 mg/kg in rats with MI. The amplitude of the Q wave was also decreased in a dose-dependent manner in the GQDs-PEG-treated rats. The results demonstrated that 2 weeks of treatment with GQDs-PEG normalized ECG abnormalities and improved left ventricular dysfunction in rats with MI.

Diagnostic Performance of Selected Baseline Electrocardiographic Parameters for Prediction of Left Ventricular Remodeling in Patients with ST-Segment Elevation Myocardial Infarction

Objective: To evaluate the diagnostic performance of selected baseline electrocardiographic (ECG) parameters as predictors of left ventricular remodeling (LVR) in patients with a first ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI). Methods: The study was performed as a single-center cohort study, with 249 patients (74.7% males) included in the final analysis. Nine baseline ECG parameters were evaluated, with respect to occurrence of LVR 6 months after STEMI (defined as an echocardiography-assessed relative >20% increase in end-diastolic left ventricular volume compared with the value at discharge from hospital). Results: The baseline ECG predictors of LVR, identified in univariate analysis, included the number of leads with ST-segment elevation (odds ratio (OR) 1.19, 95% confidence interval (CI) 1.03–1.38, p = 0.0212), number of leads with Q-waves (OR 1.21, 95% CI 1.07–1.37, p = 0.0033), sum of ST-segment elevation (OR 1.04, 95% CI 1.00–1.08; p = 0.0253) and maximal ST-segment elevation (OR 1.14; 95% CI 1.00–1.29; p = 0.0446). When added to demographic, clinical and angiographic data, the number of leads with ST-segment elevation (OR 1.17, 95% CI 1.01–1.36; p = 0.0413), number of leads with Q-waves (OR 1.15, 95% CI 1.01–1.32; p = 0.0354) and the sum of ST-segment elevation (OR 1.04, 95% CI 1.00–1.08; p = 0.0331) successfully predicted development of LVR in multivariate logistic regression models. However, after inclusion of biochemical data in multivariate models, none of the electrocardiographic parameters, but increasing body weight, TIMI flow after PCI < 3 and higher maximal values of myocardial necrosis biomarker, was independently associated with the occurrence of LVR 6 months after STEMI. Conclusions: Our study demonstrates modest utility of pre-reperfusion ECG for the prediction of LVR occurrence after six months of STEMI.

[Detection of ECG alterations typical for myocardial ischemia : New methods 2021]

BACKGROUND

The electrocardiogram (ECG) represents an essential diagnostic tool in cardiology and beyond. Classical ECG devices enable the registration of up to 12 leads, whereas modern ECG systems enable additional leads even with a reduced number of electrodes. Additionally, "smart" devices even enable patients to record an ECG at home.

OBJECTIVE

Evaluation of a potential additional benefit of using various modern ECG systems for the detection of ECG alterations typical for myocardial ischemia.

MATERIAL AND METHODS

Presentation of various signs of ischemia in the ECG according to the latest guidelines. Demonstration of modern ECG systems and their potential advantage in the detection of signs of ischemia in the ECG based on current study results.

RESULTS

Modern ECG systems with vector-based electrocardiography can facilitate and optimize the detection of ischemic ECG alterations. Smart nonvector-based devices for patients are primarily useful for detection of arrhythmias and do not replace the 12-lead ECG for detection of ischemia, even though they can be useful for documentation of temporary ECG alterations also within the ST-segment.

CONCLUSION

The ECG systems based on vector electrocardiography can improve the detection of ECG alterations typical for ischemia compared to the conventional 12-lead ECG.

An Inkjet-Printed PEDOT:PSS-Based Stretchable Conductor for Wearable Health Monitoring Device Applications

A stretchable conductor is one of the key components in soft electronics that allows the seamless integration of electronic devices and sensors on elastic substrates. Its unique advantages of mechanical flexibility and stretchability have enabled a variety of wearable bioelectronic devices that can conformably adapt to curved skin surfaces for long-term health monitoring applications. Here, we report a poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)-based stretchable polymer blend that can be patterned using an inkjet printing process while exhibiting low sheet resistance and accommodating large mechanical deformations. We have systematically studied the effect of various types of polar solvent additives that can help induce phase separation of PEDOT and PSS grains and change the conformation of a PEDOT chain, thereby improving the electrical property of the film by facilitating charge hopping along the percolating PEDOT network. The optimal ink formulation is achieved by adding 5 wt % ethylene glycol into a pristine PEDOT:PSS aqueous solution, which results in a sheet resistance of as low as 58 Ω/□. Elasticity can also be achieved by blending the above solution with the soft polymer poly(ethylene oxide) (PEO). Thin films of PEDOT:PSS/PEO polymer blends patterned by inkjet printing exhibits a low sheet resistance of 84 Ω/□ and can resist up to 50% tensile strain with minimal changes in electrical performance. With its good conductivity and elasticity, we have further demonstrated the use of the polymer blend as stretchable interconnects and stretchable dry electrodes on a thin polydimethylsiloxane (PDMS) substrate for photoplethysmography (PPG) and electrocardiography (ECG) recording applications. This work shows the potential of using a printed stretchable conducting polymer in low-cost wearable sensor patches for smart health applications.

The relationship of the changes in lateral leads I and aVL in electrocardiogram with echocardiography and coronary angiography findings in patients with acute coronary syndrome

BACKGROUND

Electrocardiographic (ECG) study is a principle for the symptoms contributed to the acute myocardial infarction (AMI)/acute coronary syndrome (ACS). The diagnosis of involved coronary artery based on ECG changes is still a challenge. This study is aimed to evaluate the association of mere changes in I and aVL leads with the involved region found through echocardiography and involved coronary artery through angiography.

METHODS

This cross-sectional study was conducted on 100 patients referred with AMI/ACS symptoms that had mere ECG changes in I and aVL leads (ST elevation + Q wave/ST depression + inverted-T). Transthoracic echocardiography (TTE) and coronary angiography (CAG) were performed for the patients. The correlation of ECG with echocardiography and angiography was assessed.

RESULTS

Among the studied population, 39 patients (39%) were women with the mean ± standard deviation (SD) of age of 64.60 ± 9.39 years. There was no significant association between ECG changes in leads I and aVL with neither the stenosis of first diagonal (D1) coronary artery found through angiography (P = 0.580) nor the mid-anterior wall dyskinesia found through echocardiography (P = 0.380). A remarkable association between the echocardiographic findings representing mid-anterior wall ischemic dyskinesia with the stenosis of D1 coronary artery was detected (P < 0.001). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100%, 54.54%, 94.68%, and 100% were respectively found as the diagnostic values of mentioned factors.

CONCLUSION

Our findings showed significant association between D1 involvement and mid-anterior dyskinesia in echocardiography, while the changes in ECG were associated neither with echocardiographic nor angiographic outcomes.

Culprit lesion detection in patients presenting with non-ST elevation acute coronary syndrome and multivessel disease

BACKGROUND/PURPOSE

Identification of the culprit lesion in patients with non-ST elevation acute coronary syndrome (NSTE-ACS) allows appropriate coronary revascularization but may be unclear in patients with multivessel coronary disease (MVD). Therefore, we investigated the rate of culprit lesion identification during coronary angiography in NSTE-ACS and multivessel disease.

METHODS/MATERIALS

Consecutive patients presenting with NSTE-ACS and MVD, between January 2012 and December 2016 were evaluated. Coronary angiograms, intravascular imaging, and ECGs were analyzed for culprit lesion identification. Long-term clinical outcomes in terms of major adverse cardiac events (MACE) and mortality were reported in patients with or without culprit identification.

RESULTS

A total of 1107 patients with NSTE-ACS and MVD were included in the analysis, 310 (28.0%) with unstable angina and 797 (72.0%) with non-ST elevation myocardial infarction. The culprit lesion was angiographically identified in 952 (86.0%) patients, while no clear culprit lesion was found in 155 (14.0%) patients. ECG analysis allowed to predict the location of the culprit vessel with low sensitivity (range 28.4%-36.7%) and high specificity (range 90.6%-96.5%). Higher lesion complexity was associated with inability to identify the culprit. Intravascular imaging was applied in 55 patients and helped to identify the culprit lesion in 53 patients (96.4%). There was no difference in all-cause mortality (21.4% vs. 25.8%, p = 0.24) and MACE (39.2% vs. 47.6%, p = 0.07) between the cohorts with or without culprit lesion identification by angiography.

CONCLUSIONS

The culprit lesion appeared unclear by coronary angiography in >10% of patients with NSTE-ACS and MVD. Complementary invasive imaging substantially enhanced the diagnostic accuracy of culprit lesion detection.

Wrapped Left Anterior Descending Artery Presenting As Inferior Myocardial Infarction: Case Report and Review of the Literature

Acute occlusion of the left anterior descending (LAD) coronary artery generally results in ST-segment elevation in the anterior leads of the electrocardiogram and reciprocal ST-segment depression in the inferior leads. We present a case of LAD occlusion presenting as inferior wall ST-segment elevation myocardial infarction.

An Unusual Case of ST Elevation Myocardial Infarction in Angiographically Non-Obstructed Coronary Arteries

It is routinely believed that patients with electrocardiographic findings of ST elevation myocardial infarction (STEMI) will have evidence of obstructive coronary artery disease on coronary angiography. Although this is the situation in the majority of STEMI instances, in a small percentage of cases, patients presenting with STEMI are found to have minimal to no coronary artery blockage on subsequent angiography, termed MI with non-obstructive coronary arteries (MINOCA). MINOCA is a heterogenous entity with multiple causes, making a focused diagnostic workup important to select an appropriate treatment, with the goal to prevent a mortality similar to obstructive coronary disease. In this case, we describe a unique presentation of MINOCA, after a patient was diagnosed with STEMI.

Electrocardiographic identification of the culprit coronary artery in acute non-ST-elevation myocardial infarction: predictive value of N-wave and T-wave precordial instability

BACKGROUND

Recently, novel ischemic electrocardiographic changes have been described, which may be clinically significant in the identification of the culprit coronary vessel in patients with non-ST-elevation myocardial infarction (NSTEMI). We sought to determine the predictive value of N-wave, T-wave precordial instability, de-Winter ST/T-wave complex, and inferolateral myocardial infarction in the identification of the culprit artery in patients with NSTEMI referred for early invasive (<24 h) treatment.

METHODS

A total of 148 patients with NSTEMI, aged 40-91 years, were enrolled from a cohort of 510 consecutive NSTEMI subjects, hospitalized in our center in 2015-2017.

RESULTS

Of the evaluated ischemic ECG changes, the most common finding in patients with culprit left circumflex (LCx)/obtuse marginal artery or right coronary artery was T-wave precordial instability (28.3 and 13.5%, respectively), whereas in individuals with culprit left anterior descending/diagonal artery, T-wave precordial instability and N-wave in leads II, III or aVF occurred equally often (16.0%). A significant relationship was found between the occurrence of N-wave in inferolateral leads and culprit LCx/obtuse marginal. In multivariable analysis, N-wave in lead aVL [odds ratio (OR) 2.10; 95% confidence interval (CI), 1.15-3.81], and T-wave precordial instability (OR 1.56; 95% CI, 1.02-2.41) were independent predictors of culprit LCx/obtuse marginal. The accuracy of N-wave in lead aVL in predicting the culprit LCx/obtuse marginal was 73.9% and was higher than the accuracy of T-wave precordial instability, which was 69.1%.

CONCLUSIONS

In patients with NSTEMI referred for early invasive treatment, the presence of N-wave or T-wave precordial instability may be of greater clinical importance in the prediction of culprit LCx/obtuse marginal than classic ischemic changes.

[The myocardial infarction size measuring using modern methods]

An accurate quantitative assessment of myocardium necrosis area and the viable zone (stunned and hibernating) in patients with myocardial infarction is crucial for the preoperative patient selection and predicting the cardiac surgery effectiveness. Currently, researchers and clinicians are most interested in the problem of determining the viable myocardium zone. However, only the necrosis zone area directly correlates with the patients prognosis and determines the heart pathological remodeling processes. In the distant period, the data obtained can be used to predict the post-infarction period course or for analysis the relationship of the necrosis zone with arrhythmogenesis, and a number of other indicators. Thus, the necrosis zone and the viable myocardium zone are two parameters that need to be monitored in dynamics in all patients after myocardial infarction. The most accurate and reproducible method for determining the necrosis area is contrast magnetic resonance imaging of the heart, however, this technique is still inaccessible in most hospitals. In this regard, it remains relevant to estimate the necrotic myocardium area by ubiquitous non-invasive methods such as electrocardiography and echocardiography.

Validation of contemporary electrocardiographic indices of area at risk and infarct size in acute ST elevation myocardial infarction (STEMI)

BACKGROUND

Electrocardiographic (ECG) methods to assess area at risk (AAR) and infarct size (IS) in patients with ST-elevation myocardial infarction (STEMI) have been previously established but not validated against contemporary benchmark Cardiac Magnetic Resonance (CMR) measures. We compared ECG-determined and CMR-determined measures for (a) AAR, (b) IS, and (c) myocardial salvage.

METHODS

Sixty patients with ECG evidence of STEMI and CMR imaging performed within 13 days were included. The ECG-determined (a) AAR scores (Aldrich and Wilkins), (b) IS (Selvester score), and (c) myocardial salvage (i.e. [AAR-IS] / AAR × 100%), were compared with CMR-determined measures.

RESULTS

Compared with CMR-determined AAR, both the Wilkins & Aldrich scores underestimated AAR, although the Wilkins (r = 0.72, p < 0.001) showed a better correlation than the Aldrich (r = 0.54, p < 0.001). Bland-Altman analysis revealed a bias of 2.6% (95% limits of agreement: 18.5%, -13.3%) for the Wilkins and 5.9% (95% limits of agreement: 25.6%, -13.8%) for the Aldrich. Estimation of IS was similar between the Selvester score and CMR, with good correlation (r = 0.77, p < 0.001) and agreement (fixed bias 0.4%, 95% limits of agreement 20.8%, -15.5%). However, ECG-determined myocardial salvage significantly underestimated CMR-determined myocardial salvage, with an inverse correlation (r = -0.33, p = 0.01).

CONCLUSIONS

The Wilkins score is superior to Aldrich score as an ECG-AAR index, Selvester score is a reasonable ECG estimate of infarct size, though ECG derived myocardial salvage does not have enough accuracy to be used in the clinical setting; it may be an inexpensive surrogate for myocardial salvage in large research studies. Further validation and prognostic studies are required.

Coronary Artery Disease: From Mechanism to Clinical Practice

In most developed countries, coronary artery disease (CAD), mostly caused by atherosclerosis of coronary arteries, is one of the primary causes of death. From 1990s to 2000s, mortality caused by acute MI declined up to 50%. The incidence of CAD is related with age, gender, economic, etc. Atherosclerosis contains some highly correlative processes such as lipid disturbances, thrombosis, inflammation, vascular smooth cell activation, remodeling, platelet activation, endothelial dysfunction, oxidative stress, altered matrix metabolism, and genetic factors. Risk factors of CAD exist among many individuals of the general population, which includes hypertension, lipids and lipoproteins metabolism disturbances, diabetes mellitus, chronic kidney disease, age, genders, lifestyle, cigarette smoking, diet, obesity, and family history. Angina pectoris is caused by myocardial ischemia in the main expression of pain in the chest or adjoining area, which is usually a result of exertion and related to myocardial function disorder. Typical angina pectoris would last for minutes with gradual exacerbation. Rest, sit, or stop walking are the usual preference for patients with angina, and reaching the maximum intensity in seconds is uncommon. Rest or nitroglycerin usage can relieve typical angina pectoris within minutes. So far, a widely accepted angina pectoris severity grading system included CCS (Canadian Cardiovascular Society) classification, Califf score, and Goldman scale. Patients with ST-segment elevated myocardial infarction (STEMI) may have different symptoms and signs of both severe angina pectoris and various complications. The combination of rising usage of sensitive MI biomarkers and precise imaging techniques, including electrocardiograph (ECG), computed tomography, and cardiac magnetic resonance imaging, made the new MI criteria necessary. Complications of acute myocardial infarction include left ventricular dysfunction, cardiogenic shock, structural complications, arrhythmia, recurrent chest discomfort, recurrent ischemia and infarction, pericardial effusion, pericarditis, post-myocardial infarction syndrome, venous thrombosis pulmonary embolism, left ventricular aneurysm, left ventricular thrombus, and arterial embolism.

Reduced regional strain rate is the most accurate dysfunction in predicting culprit lesions in patients with acute coronary syndrome

BACKGROUND AND AIM

Predicting culprit lesions in acute coronary syndrome (ACS) could be a challenge. The aim of this study was to assess the accuracy of regional wall motion abnormalities (RWMA) using various echocardiographic techniques and ECG changes in predicting the culprit coronary lesion in a group of patients with ACS.

METHODS

In 80 consecutive patients with ACS (age 55·7 ± 9·4 years, 77% male, 15% with CCS Angina III), an echocardiographic examination of left ventricle (LV) RWMA, tissue Doppler imaging (TDI) and speckle tracking myocardial strain and strain rate (SR) were performed before intervention.

RESULTS

Of the 80 patients, one-vessel stenosis (>70%) was present in 53 (66%), two-vessel disease in 12 (15%) and multivessel disease in 15 patients (19%). About 51% of patients had hypertension, 40% diabetes and 23% dyslipidaemia. There was no relationship between individual segmental RWMA and SR. Mean regional SR, but not peak strain, correlated with culprit lesion branch: left anterior descending - LAD (r = 0·35, P = 0·005), circumflex LCx (r = 0·32, P = 0·03) and right coronary RCA (r = 0·37, P = 0·01). Only ECG changes in the LAD territory (r = 0·26, P = 0·04) correlated with the culprit lesion. SR of LAD territories ≤-0·74 was 71% sensitive and 70% specific (AUC = 0·70, CI = 0·67-0·93, P = 0·01), SR of LCx territories of ≤-0·67 was 75% sensitive and 63% specific (AUC = 0·72, CI = 0·58-0·87, P = 0·02) and SR of RCA territories ≤-0·83 was 73% sensitive and 71% specific (AUC = 0·80, CI = 0·66-0·93, P = 0·001) in predicting significant stenosis. SR was more accurate than all other techniques in predicting the culprit lesion.

CONCLUSION

In ACS, mean regional speckle tracking SR is more sensitive than peak strain, TDI, ECG changes and wall motion abnormalities in detecting significant coronary artery stenosis.

ECG analysis in patients with acute coronary syndrome undergoing invasive management: rationale and design of the electrocardiography sub-study of the MATRIX trial

BACKGROUND

The twelve‑lead electrocardiogram (ECG) has become an essential tool for the diagnosis, risk stratification, and management of patients with acute coronary syndromes (ACS). However, several areas of residual controversies or gaps in evidence exist. Among them, P-wave abnormalities identifying atrial ischemia/infarction are largely neglected in clinical practice, and their diagnostic and prognostic implications remain elusive; the value of ECG to identify the culprit lesion has been investigated, but validated criteria indicating the presence of coronary occlusion in patients without ST-elevation are lacking; finally, which criteria among the multiple proposed, better define pathological Q-waves or success of revascularisation deserve further investigations.

METHODS

The Minimizing Adverse hemorrhagic events via TRansradial access site and systemic Implementation of AngioX (MATRIX) trial was designed to test the impact of bleeding avoidance strategies on ischemic and bleeding outcomes across the whole spectrum of patients with ACS receiving invasive management. The ECG-MATRIX is a pre-specified sub-study of the MATRIX programme which aims at analyzing the clinical value of ECG metrics in 4516 ACS patients (with and without ST-segment elevation in 2212 and 2304 cases, respectively) with matched pre and post-treatment ECGs.

CONCLUSIONS

This study represents a unique opportunity to further investigate the role of ECGs in the diagnosis and risk stratification of ACS patients with or without ST-segment deviation, as well as to assess whether the radial approach and bivalirudin may affect post-treatment ECG metrics and patterns in a large contemporary ACS population.

The impact of cigarette smoking on infarct location and in-hospital outcome following acute ST-elevation myocardial infarction

Introduction: Smoking, which is a major modifiable risk factor for coronary artery diseases, affects cardiovascular system with different mechanisms. We designed this study to investigate the association of smoking with location of ST-segment elevation myocardial infarction (STEMI), and short-term outcomes during hospitalization. Methods: In 1017 consecutive patients with anterior/inferior STEMI, comprehensive demographic, biochemical data, as well as clinical complications and mortality rate, were recorded. Patients were allocated into two groups based on smoking status and compared regarding the location of myocardial infarction, the emergence of clinical complications and in-hospital mortality in univariate and multivariate logistic regression analysis. Results: Among 1017 patients, 300 patients (29.5%) were smoker and 717 patients (70.5 %) were non-smoker. Smokers were significantly younger and had lower prevalence of diabetes, hyperlipidemia and hypertension. Inferior myocardial infarction was considerably more common in smokers than in non-smokers (45.7% vs. 36%, P = 0.001). Heart failure was developed more commonly in non-smokers (33.9% vs. 20%, P = 0.001). In-hospital mortality was significantly lower in smokers (6.7% vs. 17.3%, P = 0.001). After adjustment for confounding variables, smoking was independently associated with inferior myocardial infarction and lower heart failure [odds ratio: 1.44 (1.06-1.96), P = 0.01 and odds ratio: 0.61 (0.40-0.92), P = 0.02, respectively]. However, in-hospital mortality was not associated with smoking after adjustment for other factors [odds ratio: 0.69 (0.36-1.31), P = 0.2]. Conclusion: Smoking is independently associated with inferior myocardial infarction. Although smokers had lower incidence of heart failure, in-hospital mortality was not different after adjustment for other factors.

Electrocardiogram signal generation using electrical model of cardiac cell: application in cardiac ischemia

One of the most common causes of heart failure is ischaemia. In this disease, the heart muscles die due to the lack or insufficiency of the blood in the cardiac veins. As a result of such a phenomenon, the action potential in that part of the heart would fade. In this article, using the electric model of the cardiac cell and the mechanism of producing an ECG signal in the heart, the process of producing cardiac electrical potential has been modelled. In this regard, the basic constituent signals of the ECG are generated. Afterward, by accumulating these signals, the final ECG is reproduced. In addition, by variation of the presented model parameters, the cardiac ischaemic signal is simulated in a way that the influence of ventricle ischaemia on the ventricular tissues is considered. The results of such a simulation demonstrate a sufficient match between the model output and the reported changes of the cardiac arrhythmia including ischaemic failures. Here, we report the 91% match between the simulated signal and the considered clinical data.

Effect of infarct site on the clinical endpoints of thrombolytic-treated ST-elevation myocardial infarction

INTRODUCTION

Some studies suggest better outcomes after the use of thrombolytics in inferior ST-elevation myocardial infarction (STEMI) compared to other locations. The goal of this study is to compare the clinical endpoints of thrombolytic-treated STEMI based on coronary artery distribution.

METHODS

The study population was extracted from the 2014 Nationwide Readmissions Data using the International Classification of Diseases, Ninth Revision, Clinical Modifications codes for STEMI, thrombolytic infusion, and complications of STEMI. Primary study endpoints included in-hospital all-cause mortality, length of hospital stay (LOS), cardiogenic shock, and mechanical complications of STEMI.

RESULTS

A principal diagnosis of thrombolytic-treated STEMI was identified for in 1231 patients (mean age 61.5 years; 26.5% female). Four hundred and thirty-one STEMIs occurred in the left anterior descending (LAD) artery distribution, 124 in the left circumflex (LCX) artery distribution, and 676 in the right coronary artery (RCA) distribution. In comparison to the LAD and LCX distributions, thrombolytic-treated STEMIs in the RCA distribution were associated with lower mortality (6.5% with LAD, 5.7% with LCX, and 3.6% with RCA; p = 0.02), fewer cardiogenic shock (12.3% with LAD, 12.1% with LCX, and 7.7% with RCA; p = 0.01), and shorter LOS (4.5 days with LAD, 3.9 with LCX, and 3.6 days with RCA; p < 0.01). Mechanical complications showed no significant difference based on coronary distribution (2.3% with LAD, 3.2% with LCX, and 1.2% with RCA; p = 0.17).

CONCLUSIONS

Thrombolytic-treated STEMIs in the RCA distribution were associated with lower in-hospital all-cause mortality, cardiogenic shock, and shorter LOS. Mechanical complications were not different based on coronary distribution.

Size of Anterior Wall Acute Myocardial Infarction Treated by Primary Percutaneous Coronary Intervention in United States Versus Europe/Australia Versus India (from the CRISP-AMI Randomized Controlled Trial)

International variability in infarct size following acute anterior ST-elevation myocardial infarction without shock treated with primary percutaneous coronary intervention (PCI) has been little studied. Patients enrolled in the Counterpulsation to Reduce Infarct Size pre-PCI for Acute Myocardial Infarction international randomized trial were analyzed according to their region of enrollment: United States (US) (n = 60), Europe/Australia (EU/AU) (n = 104), or India (n = 123). Cardiac magnetic resonance imaging was performed 3-5 days after PCI to assess infarct size, expressed as percentage of left ventricular mass, and analyzed by an imaging core laboratory. The relation between infarct size and region was modelled using multivariable linear regression adjusting for time from symptom onset to first hospital contact, myocardial infarction severity, and baseline characteristics. Infarct size was 36.4% of left ventricular mass in US patients (95% confidence interval [CI] 31.5 to 41.4), 36.5% (95% CI 32.6 to 40.4) in EU/AU patients, and 44.7% (95% CI 41.1 to 48.2) in patients from India (p = 0.01). In multiplicity-adjusted regression analysis, mean infarct size in patients from India was higher than in US patients (mean difference of 8.3%; 95% CI 0.7 to 15.8; p = 0.03), and EU/AU patients (mean difference of 8.2%; 95% CI 1.6 to 14.8; p = 0.01). There was no significance difference in infarct size between patients from the EU/AU and the US (mean difference of 0.1%; 95% CI -7.5 to 7.4; p = 0.99). ln conclusion, in patients with anterior ST-elevation myocardial infarction without cardiogenic shock treated with primary PCI, infarct size was larger in India compared to the United States and EU/AU, even after adjustment for performance metrics, including time to treatment, and other potential confounders. Future studies are needed to better elucidate this discrepancy.

Risk assessment model for predicting ventricular tachycardia or ventricular fibrillation in ST-segment elevation myocardial infarction patients who received primary percutaneous coronary intervention

Ventricular tachycardia/ventricular fibrillation (VT/VF) is a kind of malignant arrhythmia in ST-segment elevation myocardial infarction (STEMI) patients who received primary percutaneous coronary intervention (PPCI). However, there are no risk assessment tools to anticipate the occurrence of VT/VF.This study is to build a risk assessment model to predict the possibility of VT/VF onset in STEMI patients undergoing PPCI.A retrospective study was conducted to analyze the patients who underwent PPCI from January 2006 to May 2015. Subjects were divided into VT/VF group and no VT/VF group based on whether VT/VF had occurred or not. In addition, the VT/VF group was further separated into early-onset group (from the time that symptoms began to before the end of PPCI) and late-onset group (after the end of PPCI) based on the timing of when VT/VF happened. Multivariate regression analysis was carried out to distinguish the independent risk factors of VT/VF and an additional statistical method was executed to build the risk assessment model.A total of 607 patients were enrolled in this study. Of these patients, 67 cases (11%) experienced VT/VF. In addition, 91% (61) of patients experienced VT/VF within 48 h from the time that the symptoms emerged. Independent risk factors include: age, diabetes mellitus, heart rate, ST-segment maximum elevation, ST-segment total elevation, serum potassium, left ventricular ejection fraction (LVEF), culprit artery was right coronary artery, left main (LM) stenosis, Killip class > I class, and pre-procedure thrombolysis in myocardial infarction (TIMI) flow zero grade. Risk score model and risk rank model have been established to evaluate the possibility of VT/VF. Class I: ≤ 4 points; Class II: > 4 points, ≤ 5.5 points; Class III: > 5.5 points, < 6.5 points; and Class IV ≥ 6.5 points. The higher the class, the higher the risk.The incidence of VT/VF in STEMI patients undergoing PPCI is 11% and it occurs more frequently from the time that symptoms begin to before the end of PPCI, which, in most cases, occurs within 48 h of the event. Our risk assessment model could predict the possible occurrence of VT/VF.

ST-depression in right precordial leads with inferior STEMI and occluded right coronary artery: intertwined anatomy and ischemic areas

Right coronary artery (RCA) occlusion in inferior acute myocardial infarction is usually heralded by ST-elevation both in inferior and in right precordial leads. We report the case of a 68-year-old male, who presented marked ST-elevation in inferior leads, mirrored by ST-depression in anterior-septal and lateral leads. Right precordial lead electrocardiogram unexpectedly showed ST-depression V1R-V5R leads. Coronary angiography showed mid-left anterior descending (LAD) coronary near-complete occlusion with distal wrapping LAD. Left circumflex artery was not occluded, while RCA was occluded mid tract. The patient was treated with coronary angioplasty on RCA and LAD. Absence of ST-elevation in right precordial leads may be presumably explained by the presence of a large ischemic area distal to mid-LAD near-occlusive stenosis and of a long-wrapping LAD. Complex coronary anatomy and intertwined ischemic areas may underlie apparently discording electrocardiograms.

Correlation between electrocardiographic changes and coronary findings in patients with acute myocardial infarction and single-vessel disease

BACKGROUND

Correlation of ST-segment elevation on the 12-lead electrocardiogram (ECG) with the expected affected coronary territory is established in patients with ST-elevation myocardial infarction (STEMI). In patients with non-ST-elevation myocardial infarction (NSTEMI), correlation of ischemic ECG abnormalities with the affected coronary territory has not been well-established. We sought to investigate the correlation of electrocardiographic abnormalities with the location of 1-vessel obstructive coronary artery disease (CAD) in patients with both STEMI and NSTEMI.

METHODS

In this retrospective study, the charts of all patients referred for coronary angiography in 2012 were reviewed. Patients with a single obstructive coronary artery plus angina-equivalent symptoms and an elevated cardiac troponin I was included. Available ECGs were interpreted by an experienced cardiologist (WSA) blinded to the result of angiography. Patients with complete bundle branch block or ventricular pacing were excluded. Ischemic ECG changes were correlated to a coronary territory based on predefined criteria.

RESULTS

Of 131 included patients (mean age 64±13 years; 74% male), 29 had STEMI and 102 had NSTEMI. Eleven of 11 patients (100%) with anterior STEMI had left anterior descending artery (LAD) obstructive CAD. Of 18 patients with inferior STEMI, 14 (78%) had right coronary artery (RCA) obstructive CAD, 3 (17%) had left circumflex artery (LCX) artery obstructive CAD, and 1 (5%) had LAD obstructive CAD. Of 102 NSTEMI patients, 53 (52%) had definite ECG ischemic abnormalities. Of 31 patients with anterior definite ECG ischemic abnormalities, 30 (97%) had LAD obstructive CAD, and 1 (3%) had RCA obstructive CAD. Of 22 patients with inferior definite ECG ischemic abnormalities, 14 (64%) had RCA obstructive CAD, 5 (23%) had LCX obstructive CAD, and 3 (14%) had LAD obstructive CAD.

CONCLUSIONS

Patients with anterior STEMI had LAD obstructive CAD. Patients with inferior STEMI were highly likely to have RCA or LCX obstructive CAD. Only half of NSTEMI patients had definite ischemic ECG abnormalities. When present, anterior ischemic ECG changes in patients with single vessel CAD with NSTEMI were predictive of LAD obstructive CAD.

ECG Criteria to Differentiate Between Takotsubo (Stress) Cardiomyopathy and Myocardial Infarction

BACKGROUND

ECG criteria differentiating Takotsubo cardiomyopathy (TTC) from mainly anterior myocardial infarction (MI) have been suggested; however, this was in small patient populations.

METHODS AND RESULTS

Twelve-lead admission ECGs of consecutive 200 TTC and 200 MI patients were compared in dichotomized groups based on the presence or absence of ST-elevation MI (STEMI versus STE-TTC and non-ST elevation MI versus non ST-elevation-TTC). When comparing STEMI and STE-TTC, ST-elevation in -aVR was characteristic of STE-TTC with a sensitivity/specificity of 43% and 95%, positive predictive value (PPV) 91%, and a negative predictive value (NPV) 62% (P<0.001); when ST-elevation in -aVR is accompanied by ST-elevation in inferior leads, sensitivity/specificity were 14% and 98% (PPV was 89% and NPV 52%) (P=0.001), and 12% and 100% when associated with ST-elevation in anteroseptal leads (PPV 100%, NPV 52%) (P<0.001). On the other hand, STEMI was characterized by ST-elevation in aVR (sensitivity/specificity of 31% and 95% P<0.001, PPV 85% and NPV 59%) and ST-depression in V2-V3-V4 (sensitivity/specificity of 24% and 100% P<0.001, PPV 100% and NPV 76%). When comparing non-ST elevation MI and non ST-elevation-TTC, T-inversion in leads I-aVL-V5-V6 had a sensitivity/specificity of 17% and 97% for non ST-elevation-TTC (PPV 83% and NPV 55%) (P<0.001), and ST-elevation in -aVR with T-inversion in any lead was also specific for non ST-elevation-TTC (sensitivity/specificity of 8% and 100%, PPV 100% and NPV 53%) (P=0.006). In non-ST elevation MI patients, the presence of ST-depression in V2-V3 was specific (sensitivity/specificity of 11% and 99%, PPV 91% and NPV 51%) (P=0.01).

CONCLUSIONS

ECG on admission can differentiate between TTC and acute MI, with high specificity and positive predictive value.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov/. Unique identifier: NCT01947621.

A patient with non-ST-segment elevation acute coronary syndrome: Is it possible to predict the culprit coronary artery?

In acute coronary syndromes without ST-segment elevation (NSTE-ACS), identification of the culprit artery is, most often, not possible. In this case report, we elaborate on the likelihood of different culprit arteries in a patient with NSTE-ACS. While her symptoms were progressing, typical ECG findings of ischemia in the left coronary territories were diminishing. Instead, dynamic T-wave changes in the inferior leads were present and were most likely postischemic and "reischemic." Although the culprit artery could not be identified with certainty by means of these subtle changes, they correlated well with the findings on angiography and the ECG recorded afterward. This case report demonstrates the importance of analyzing ECG and its temporal changes in conjunction with evolving symptoms.

The relationship between grade of ischemia, success of reperfusion, and type of thrombolytic regimen

BACKGROUND

This study was aimed to determine whether the grade of ischemia can predict the success of reperfusion in patients treated with thrombolytic therapy (TT) for ST elevation myocardial infarction (STEMI).

MATERIAL AND METHODS

We enrolled 229 consecutive patients with diagnosis of STEMI and receiving TT. Patients were divided into 2 groups--grade 2 ischemia (GI2) and grade 3 ischemia (GI3)--according to initial electrocardiogram (ECG). As TT, fibrin-specific (tissue plasminogen activator (t-PA)) or non-fibrin-specific (streptokinase (SKZ)) regimens were used. Successful reperfusion was defined as >50% resolution of the maximal ST segment on 90-min ECG. We tried to evaluate whether the grade of ischemia could predict the success of reperfusion and if there were any differences in terms of successful reperfusion between different thrombolytic regimens.

RESULTS

The successful reperfusion rate was significantly higher in GI2 than GI3 (82.4% vs. 64.4% respectively, p=0.002). The success rate was lowest at anterior GI3 (55.8%). Although there was no significant difference between thrombolytic regimens in all groups (p=0.77), t-Pa was superior to SKZ in anterior GI3 (63,6% vs. 30%, p=0.061). In addition, in multivariate analysis, GI and infarct localization were found as independent predictors for successful reperfusion with TT (p=0.006 and p=0.042, respectively).

CONCLUSIONS

In the current study, we found that GI2 is an independent predictor for successful reperfusion in STEMI treated with TT. Fibrin specific regime should be preferred in anterior GI3.

Predictors of ventricular fibrillation at reperfusion in patients with acute ST-elevation myocardial infarction treated by primary percutaneous coronary intervention

Ventricular fibrillation (VF) during reperfusion (rVF) in ST-segment elevation myocardial infarction (STEMI) is an infrequent but serious event that complicates coronary interventions. The aim of this study was to analyze clinical predictors of rVF in an unselected population of patients with STEMI treated with percutaneous coronary intervention (PCI). Consecutive patients with STEMI admitted to a tertiary care hospital for primary PCI from 2007 to 2012 were retrospectively assessed for the presence of rVF. Admission electrocardiograms, stored in a digital format, were analyzed for a maximal ST-segment elevation in a single lead and the sum of ST-segment deviations in all leads. Clinical, electrocardiographic, and angiographic characteristics were tested for associations with rVF using logistic regression analysis. Among 3,724 patients with STEMI admitted from 2007 to 2012, 71 (1.9%) had rVF. In univariate analysis, history of myocardial infarction, aspirin and β-blocker use, VF before PCI, left main coronary artery disease, inferior myocardial infarction localization, symptom-to-balloon time <360 minutes, maximal ST-segment elevation in a single lead >300 μV, and sum of ST-segment deviations in all leads >1,500 μV were associated with increased risk for rVF. In a multivariate analysis, sum of ST-segment deviations in all leads >1500 μV (odds ratio 3.7, 95% confidence interval 1.45 to 9.41, p = 0.006) before PCI remained an independent predictor of rVF. In-hospital mortality was 18.3% in the rVF group and 3.3% in the group without VF (p <0.001), but rVF was not an independent predictor of in-hospital death. In conclusion, the magnitude of ST-segment elevation before PCI for STEMI independently predicts rVF and should be considered in periprocedural arrhythmic risk assessment. Despite higher in-hospital mortality in patients with rVF, rVF itself has no independent prognostic value for prognosis.

Correlation of electrocardiogram and regional cardiac magnetic resonance imaging findings in ST-elevation myocardial infarction: a literature review

BACKGROUND

Patients with acute ST-elevation myocardial infarction (STEMI) benefit substantially from emergent coronary reperfusion. The principal mechanism is to open the occluded coronary artery to minimize myocardial injury. Thus the size of the area at risk is a critical determinant of the patient outcome, although other factors, such as reperfusion injury, have major impact on the final infarct size. Acute coronary occlusion almost immediately induces metabolic changes within the myocardium, which can be assessed with both the electrocardiogram (ECG) and cardiac magnetic resonance (CMR) imaging.

METHODS

The 12-lead ECG is the principal diagnostic method to detect and risk-stratify acute STEMI. However, to achieve a correct diagnosis, it is paramount to compare different ECG parameters with golden standards in imaging, such as CMR. In this review, we discuss aspects of ECG and CMR in the assessment of acute regional ischemic changes in the myocardium using the 17 segment model of the left ventricle presented by American Heart Association (AHA), and their relation to coronary artery anatomy.

RESULTS

Using the 17 segment model of AHA, the segments 12 and 16 remain controversial. There is an important overlap in myocardial blood supply at the antero-lateral region between LAD and LCx territories concerning these two segments.

CONCLUSION

No all-encompassing correlation can be found between ECG and CMR findings in acute ischemia with respect to coronary anatomy.

Updated electrocardiographic classification of acute coronary syndromes

The electrocardiogram (ECG) findings in acute coronary syndrome should always be interpreted in the context of the clinical findings and symptoms of the patient, when these data are available. It is important to acknowledge the dynamic nature of ECG changes in acute coronary syndrome. The ECG pattern changes over time and may be different if recorded when the patient is symptomatic or after symptoms have resolved. Temporal changes are most striking in cases of ST-elevation myocardial infarction. With the emerging concept of acute reperfusion therapy, the concept ST-elevation/ non-ST elevation has replaced the traditional division into Q-wave/non-Q wave in the classification of acute coronary syndrome in the acute phase.

KEYPOINTS

In acute coronary syndrome, in addition to the traditional electrocardiographic risk markers, such as ST depression, the 12-lead ECG contains additional, important diagnostic and prognostic information. Clinical guidelines need to acknowledge certain high-risk ECG patterns to improve patient care.

Myocardial infarct size measurement using geometric angle calculation

BACKGROUND

In basic cardiovascular research focusing on animal models of myocardial infarction (MI), the measurement of infarct size is performed by planimetry of histological sections of the heart. However, in the setting of chronic MI with ongoing changes in ventricular geometry caused by wall thinning and hypertrophy, the scar area tends to become smaller.

MATERIALS AND METHODS

Here, in this study we compared infarct measurements in tissue sections (of rat and porcine hearts) based on three different calculation approaches, that is, infarct area, infarct lengths and infarct angles utilizing the centroid of the left ventricle using a newly developed calculation approach.

RESULTS

Infarct sizes from all three measurement approaches showed significant correlation with parameters of cardiac function. However, results derived from area measurements were significantly smaller than those obtained using the other two measurement approaches due to scar thinning (infarct size area: 14·81% ± 1·27 SEM, length: 23·94% ± 2·04 SEM, angle: 24·75% ± 2·13 SEM, P < 0·0001, n = 30). Moreover, results from angle measurements evidenced a much better correlation with parameters of cardiac function in a small animal model of chronic MI (e.g. ejection fraction, angle: r = -0·73; length: r = -0·64; area: r = -0·59, n = 30) as well as in a large animal model of acute MI (angle: r = -0·82; area: r = -0·67, n = 10).

CONCLUSIONS

We concluded that area-, length- and angle-based measurements can be used to determine the relative infarct size in acute MI models, although an area-based measurement might be less accurate in the setting of chronic MI. Our new method of infarct angle measurement is a reliable and simple way to calculate infarct size compared with conventional measurement approaches.

Two questions for Kounis syndrome: can we use magnetic resonance imaging in the diagnosis and does ST elevation correlates with troponin levels?

Kounis syndrome (KS) is an acute coronary vasospasm after exposure to an allergen due to mast cell degranulation and existing mediators. Various drugs, conditions, and environmental exposures can cause KS. We presented 2 cases, 1 of whom had taken an antiflu drug (containing paracetamol, pseudoephedrine, and dextromethorphan). His electrocardiogram (ECG) showed inferior ST elevations (2 mm) with normal cardiac biomarkers. His cardiac magnetic resonance imaging showed hypokinesis and myocardial hibernation on apical septum and on the left ventricle. The second patient took a pill of naproxen sodium. The ECG showed 1-mm ST elevation in leads DII, V5, and V6. His troponin was markedly elevated. These cases showed that there seems to be no correlation with ECG and troponin levels in KS. In addition, for patients in whom KS type 1 is expected without troponin elevation, noninvasive cardiac magnetic resonance imaging study seems to be appropriate for the diagnosis of KS.

Influence of small caliber coronary arteries on the diagnostic accuracy of adenosine stress cardiac magnetic resonance imaging

Background and aims

Positive predictive value (PPV) of adenosine stress cardiac magnetic resonance (CMR) for coronary artery disease (CAD) is unsatisfactory. We investigated the impact of coronary caliber variability on this limitation in CMR performance.

Methods and results

206 consecutive patients with myocardial ischemia during CMR and subsequent coronary angiography (CA) were studied. Patients were examined in a 1.5-T scanner. After adenosine infusion, myocardial first-pass sequence using gadolinium-based contrast agent was performed and compared with rest perfusion. CAD was invasively confirmed in 165 [true positive (TP); PPV, 80.1%] and ruled out in 41 patients [false positive (FP)]. TP and FP were comparable for pre-test risk and CMR findings. We found a significant association between FP CMR and the presence of a small caliber coronary vessel (proximal diameter < one standard deviation below the mean) supplying the area of ischemia (chi-square 42.6, p < 0.0001). A small caliber artery ipsilateral to the ischemic region was a predictive parameter for FP versus TP discrimination (ROC area, 0.84 ± 0.04 vs. 0.59 ± 0.05; p < 0.0001). Further increment in diagnostic accuracy was achieved by including proximal ipsilateral/contralateral coronary diameter ratios (ROC area, 0.90 ± 0.03; p < 0.03).

Conclusions

Small caliber coronary arteries found as normal variations in right-dominant or left-dominant circulation may account for hypoperfusion in the absence of coronary stenosis and thus may cause FP adenosine stress CMR results. Non-invasive assessment of proximal coronary diameters in the vessel supplying the area of ischemia could reduce FP rates, raise the diagnostic accuracy of CMR for CAD and minimize subsequent superfluous CA.

The value of the ECG for decision-making at first medical contact in the patient with acute chest pain

Background/Objectives. Rapid risk stratification of the patient with acute chest pain is essential to select the best management. We investigated the value of the ECG at first medical contact to determine size of the ischaemic myocardial area and thereby severity of risk.Methods. In 386 patients with acute chest pain, ECG findings were correlated with the coronary angiogram. Using ST-segment deviation patterns the location of the coronary culprit lesion was predicted and thereby size of the area at risk. Four groups of patients were present. Those with a narrow QRS and a total 12-lead ST-segment deviation score of >/=5 mm (group 1) or /=120 ms (group 3), and patients with previous coronary bypass grafting (CABG) or percutaneous coronary intervention (PCI) (group 4).Results. Correct coronary culprit lesion localisation was possible in 84% of the 185 patients in group 1, 40% of the total cohort. Accurate prediction was not possible in most patients in groups 2, 3 and 4, in spite of extensive coronary artery disease in group 3 and 4. Conclusions. Using the 12-lead ECG the size of the myocardial area at risk can be accurately predicted when the total ST-segment deviation score is >/=5 mm, allowing identification of those in need of a PCI. In most patients with bundle branch block, previous CABG or PCI, the ECG can not localise the culprit lesion. This approach simplifies and accelerates decision-making at first medical contact. (Neth Heart J 2010;18:301-6.).

A computationally efficient method for determining the size and location of myocardial ischemia

The purpose of this paper is to introduce a new method for solving the inverse problem of locating ischemic regions in the heart. The electrical activity in the human heart is modeled by the bidomain equations, which can be expanded to compute the potentials on the body surface. The associated inverse problem is to use ECG recordings to gain information about ischemias. We propose an algorithm for doing this, combining the level set method with a simpler minimization problem. Instead of trying to determine the shape, as in the level set method, we simply make the approximation that the ischemia is spherical. The effects of ischemia on the electrical attributes of heart tissue are examined. The new method is tested with computer simulations on synthetic body surface potential maps (BSPMs) in a realistic geometry, using realistic values for the parameters. It is shown to be, in some respects, superior to the level set approach and may be a step toward a practical algorithm useful in medical diagnostics.

Towards a computational method for imaging the extracellular potassium concentration during regional ischemia

We investigate the possibility of using body surface potential maps to image the extracellular potassium concentration during regional ischemia. The problem is formulated as an inverse problem based on a linear approximation of the bidomain model, where we minimize the difference between the results of the model and observations of body surface potentials. The minimization problem is solved by a one-shot technique, where the original PDE system, an adjoint problem, and the relation describing the minimum, are solved simultaneously. This formulation of the problem requires the solution of a 5 x 5 system of linear partial differential equations. The performance of the model is investigated by performing tests based on synthetic data. We find that the model will in many cases detect the correct position and approximate size of the ischemic regions, while some cases are more difficult to locate. It is observed that a simple post-processing of the results produces images that are qualitatively very similar to the true solution.

Predicting the culprit artery in acute ST-elevation myocardial infarction and introducing a new algorithm to predict infarct-related artery in inferior ST-elevation myocardial infarction: correlation with coronary anatomy in the HAAMU Trial

AIMS

The objective of this study is to predict the culprit artery from the electrocardiogram (ECG) by predefined criteria and to compare a new algorithm with a previous one for predicting the culprit artery in inferior ST-elevation myocardial infarction (STEMI).

METHODS AND RESULTS

In "all-comers" (n = 187) with acute STEMI, with ECG and angiography from the acute phase, the positive and negative predictive values for the prediction of the left anterior descending coronary artery, left circumflex coronary artery, or right coronary artery as the infarct-related artery were 96% and 96%, 65% and 95%, 92% and 97%, respectively. In inferior STEMI (n = 98), positive and negative predictive values to predict the right coronary artery or the left circumflex coronary artery as the culprit artery were 92% and 75% and 75% and 94%, respectively.

CONCLUSIONS

In "all-comers" with STEMI, the culprit artery could be predicted by ECG criteria with high predictive values. In inferior STEMI, a new algorithm for culprit artery prediction was successfully tested.

Evaluation of novel ECG signal processing on quantification of transient ischemia and baseline wander suppression

The performance assessment of a novel ECG signal processing technology in Fidelity 100 (test) and four modern ECG systems (controls) was conducted. A quantitative evaluation for one control and a test system was done by simultaneous recordings on 54 patients undergoing percutaneous coronary intervention (PCI) and on a biological reference signal from an ECG simulator. A qualitative performance of baseline wander suppression was done on all five systems. The results showed that the Fidelity 100 system provided excellent detection and quantification of transient ischemia and baseline wander suppression.

The value of ECG lead aVR in the differential diagnosis of acute inferior wall myocardial infarction

OBJECTIVES

To investigate whether the ST changes in the aVR lead on 12-lead ECG can be used to identify infarct-related artery (IRA) in patients with acute inferior myocardial infarction.

METHODS

The ECG features were studied in 90 patients with acute inferior myocardial infarction where IRA was confirmed by coronary angiography.

RESULTS

Right coronary artery (RCA) and the left circumflex coronary artery (LCX) were identified as IRA in 70 and 20 patients, respectively. ST depression in aVR > or = 0.1 mV was found in 14 (70%) patients who had LCX as the IRA, and in 4 (5.7%, p<0.001) patients with RCA as IRA. Using ST segment depression > or = 0.1 mV in aVR as a criterion, the sensitivity and specificity in differentiating LCX as IRA was 70.0% and 94.3%, respectively.

CONCLUSIONS

ST depression in aVR is common in patients with LCX-related acute inferior myocardial infarction. The ST changes in this lead are associated with an excellent specificity and a good sensitivity in differentiating LCX from RCA as the IRA.