Redefinition of the Q wave -- is there a clinical problem?

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.

Comparison of diagnostic and prognostic value of different electrocardiographic criteria to delayed-enhancement magnetic resonance imaging for healed myocardial infarction

The accuracy of various electrocardiographic (ECG) criteria for the diagnosis of healed myocardial infarction (MI) has never been validated. The objective of this study was to determine the accuracy and prognostic value of standard ECG criteria for the diagnosis of healed MI compared with cardiac magnetic resonance (CMR). Consecutive patients with known or suspected coronary artery disease who were referred for CMR were studied. Twelve-lead electrocardiography and CMR were performed the same day. A standard CMR protocol including a delayed-enhancement (DE) technique was performed. The prognostic value of using various ECG criteria and DE-CMR was assessed for the occurrence of cardiac death, nonfatal MI, or major adverse cardiac events. We studied 1,366 patients. Average follow-up was 31.4 +/- 15.8 months. Myocardial scar was detected in 507 patients (37.1%) using DE-CMR. Healed MI using various ECG criteria had sensitivity, specificity, and accuracy of 44% to 59%, 91% to 95%, and 75% to 79% compared with DE-CMR, respectively. Multivariable Cox regression analysis showed that myocardial scar using DE-CMR was the most powerful predictor for cardiac events, followed by left ventricular ejection fraction. In the absence of DE-CMR data, MI using European Society of Cardiology/American College of Cardiology (ESC/ACC) 2000 criteria was the most powerful predictor. In conclusion, various ECG criteria had limited sensitivity, but high specificity, for the diagnosis of healed MI compared with myocardial scar using DE-CMR. Myocardial scar, left ventricular ejection fraction, and MI using ESC/ACC 2000 criteria were important predictors for cardiac events.