Reperfusion therapy for ST-segment elevation myocardial infarction: has ECG information been underutilized?

Abstract

This perspective makes a contentious viewpoint that ECG information is underutilized in ST-segment elevation myocardial infarction (STEMI) and the next breakthrough rests on its full utilization. This is to better diagnose difficult cases such as ST changes during bundle branch block, posterior ST elevation and right-sided ST elevation during normal conduction, and aVR ST elevation. More importantly, this is to better characterize the STEMI for tailored reperfusion. The proposal is to develop a system capable of recording from multiple electrodes that one can apply onto oneself, and having analysis coordinated centrally via phone-internet transmission. This provides ‘longitudinal’ in addition to ‘cross-sectional’ ECG information. STEMI will be classified on a gray-scale according to its potential size and speed of Q wave evolution. The hypothesis is that large rapidly progressive STEMI is best treated by on-site fibrinolysis with prompt transferral to a percutaneous coronary intervention center; while small stuttering STEMI is best treated by primary percutaneous coronary intervention despite a long delay.

Keywords::

• ECG
• internet
• Q waves
• reperfusion
• smart phones
• STEMI

Financial & competing interests disclosure

The author has no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending or royalties.

No writing assistance was utilized in the production of this manuscript.

Key issues

• The best way to diagnose new bundle branch block at presentation is to have the recent health-check ECG tracing stored on a smart phone and to use the US FDA approved App to monitor the QRS duration since symptom onset.

• Isolated aVR ST elevation, new right or left bundle branch block (particularly when associated with suspicious ST elevation) can represent ST-segment elevation myocardial infarction (STEMI) equivalents.

• Rapidity of Q wave evolution in the infarct leads likely reflects the rate of STEMI evolution.

• Data from NRMI-2, -3, -4, registry indicated that younger patients with anterior STEMI tolerated ‘percutaneous coronary intervention (PCI)-related delay’ much worse than older patients with non-anterior STEMI.

• The proposal is on developing a simple system capable of recording from multiple electrodes that one can apply onto oneself. This centrally analyzed phone-internet-ECG service should produce both ‘cross-sectional’ and ‘longitudinal’ ECG information.

• STEMI will be classified on a gray scale according to its potential size and the speed of progression, which is reflected by speed of infarct-lead Q wave evolution.

• A hypothesis is that the large and rapidly progressive STEMI is best treated by on-site fibrinolysis with prompt preparation for rescue PCI if needed; while the small stuttering STEMI is best treated by primary PCI despite a long PCI-related delay.

• This needs to be tested by randomized trials, perhaps based on a regional registry.

• An overall objective is to have a new ECG language of STEMI that would guide tailored reperfusion therapy.

Notes

LBBB: Left bundle branch block; PCI: Percutaneous coronary intervention; RBBB: Right bundle branch block.