The Dipolar ElectroCARdioTOpographic (DECARTO)–like method for graphic presentation of location and extent of area at risk estimated from ST-segment deviations in patients with acute myocardial infarction

Extent of Myocardium at Risk for Left Anterior Descending Artery, Right Coronary Artery, and Left Circumflex Artery Occlusion Depicted by Contrast-Enhanced Steady State Free Precession and T2-Weighted Short Tau Inversion Recovery Magnetic Resonance Imaging

Background—

Contrast-enhanced steady state free precession (CE-SSFP) and T2-weighted short tau inversion recovery (T2-STIR) have been clinically validated to estimate myocardium at risk (MaR) by cardiovascular magnetic resonance while using myocardial perfusion single-photon emission computed tomography as reference standard. Myocardial perfusion single-photon emission computed tomography has been used to describe the coronary perfusion territories during myocardial ischemia. Compared with myocardial perfusion single-photon emission computed tomography, cardiovascular magnetic resonance offers superior image quality and practical advantages. Therefore, the aim was to describe the main coronary perfusion territories using CE-SSFP and T2-STIR cardiovascular magnetic resonance data in patients after acute ST-segment–elevation myocardial infarction.

Methods and Results—

CE-SSFP and T2-STIR data from 2 recent multicenter trials, CHILL-MI and MITOCARE (n=215), were used to assess MaR. Angiography was used to determine culprit vessel. Of 215 patients, 39% had left anterior descending artery occlusion, 49% had right coronary artery occlusion, and 12% had left circumflex artery occlusion. Mean extent of MaR using CE-SSFP was 44±10% for left anterior descending artery, 31±7% for right coronary artery, and 30±9% for left circumflex artery. Using T2-STIR, MaR was 44±9% for left anterior descending artery, 30±8% for right coronary artery, and 30±12% for left circumflex artery. MaR was visualized in polar plots, and expected overlap was found between right coronary artery and left circumflex artery. Detailed regional data are presented for use in software algorithms as a priori information on the extent of MaR.

Conclusions—

For the first time, cardiovascular magnetic resonance has been used to show the main coronary perfusion territories using CE-SSFP and T2-STIR. The good agreement between CE-SSFP and T2-STIR from this study and myocardial perfusion single-photon emission computed tomography from previous studies indicates that these 3 methods depict MaR accurately in individual patients and at a group level.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifiers: NCT01379261 and NCT01374321.

Methods for presenting and visualising electrocardiographic data: From temporal signals to spatial imaging

INTRODUCTION

The electrocardiogram (ECG) is a recording of the electrical activity of the heart. It is commonly used to non-invasively assess the cardiac activity of a patient. Since 1938, ECG data has been visualised as 12 scalar traces (known as the standard 12-lead ECG). Although this is known as the standard approach, there has been a myriad of alternative methods proposed to visualise ECG data. The purpose of this paper is to provide an overview of these methods and to introduce the field of ECG visualisation to early stage researchers. A scientific purpose is to consider the future of ECG visualisation within routine clinical practice.

METHODS

This paper structures the different ECG visualisation methods using four categories, i.e. temporal, vectorial, spatial and interactive. Temporal methods present the data with respect to time, vectorial methods present data with respect to direction and magnitude, spatial methods present data in 2D or 3D space and interactive methods utilise interactive computing to facilitate efficient interrogation of ECG data at different levels of detail.

CONCLUSION

Spatial visualisation has been around since its introduction by Waller and vector based visualisation has been around since the 1920s. Given these approaches have already been given the 'test of time', they are unlikely to be replaced as the standard in the near future. Instead of being replaced, the standard is more likely to be 'supplemented'. However, the design and presentation of these ECG visualisation supplements need to be universally standardised. Subsequent to the development of 'standardised supplements', as a requirement, they could then be integrated into all ECG machines. We recognise that without intuitive software and interactivity on mobile devices (e.g. tablet PCs), it is impractical to integrate the more advanced ECG visualisation methods into routine practice (i.e. epicardial mapping using an inverse solution).

Assessment of the ST segment deviation area as a potential physiological marker of the acute myocardial infarction

The purpose of this article is to present the assessment of the ST segment deviation area as a feature estimated from electrocardiographic signals to improve the current quantitative measures, which have low correlation with standard measures, such as biomarkers. In total 20 subjects were involved in the study. They were classified into two distinct groups (anterior and inferior) related to the localization of the acute myocardial infarction (AMI). The area of the ST segment was calculated by using customized software developed in Matlab®. From the analysis of this parameter it may be possible to correlate the ST deviation area with the necrosis risk area on myocardial tissue. The correlation between the ST area estimates were compared with Aldrich score, which uses the height of the J point instead of the area. It was calculated the correlation between the ST area, the Aldrich score and biomarkers of myocardial injury in patients. A Spearman correlation coefficient of 0.58 was estimated when comparing Aldrich score and the biomarkers for inferior AMI. The coefficient was 0.99 when correlating the biomarkers to the ST area. Therefore, this feature is a potential physiological marker of inferior AMI. The possibility of estimating the necrosis extent by means of electrocardiographic analysis allows for the reduction of cost and time since there may be no requirement for additional laboratorial exams, consequently improving the treatment efficacy and the prognosis of patients affected by acute myocardial infarction.