Extended ECG in 2016

Tobias Reichlin and co-authors: significant progress in the field of biomedical computing, signal processing, and computational power has given rise to new markers and technologies in electrocardiography. They open up new possibilities for addressing current needs in clinical cardiology. However, up to now, these ECG technologies have not been introduced into clinical practice.

The 12-lead Electrocardiogram (ECG) is the most commonly used technology in clinical cardiology. It is essential for managing patients with cardiovascular diseases, including those with:

• Acute myocardial infarction,
• Suspected chronic myocardial ischemia,
• Cardiac arrhythmias,
• Heart failure,
• Implanted cardiac devices.

Unlike many other methods in cardiology, ECG is simple, takes up little space, is mobile, widely accessible, inexpensive, and therefore particularly attractive. Standard ECG interpretation primarily relies on direct visual assessment.

Progress in biomedical computing and signal processing, as well as accessible computational power, offer exciting new opportunities for ECG analysis related to all areas of cardiology. Several digital markers of electrocardiograms and advanced technologies in this direction have shown promising prospects in preliminary research.

This article explores promising new technologies in surface ECG in three different areas. Several issues were discussed:

1. Detection of myocardial ischemia and infarction, QRS analysis of morphological features, analysis of high-frequency components of QRS (HF-QRS), and methods using vector cardiography, as well as ECG visualization.
2. Methods for in-depth analysis of P-waves to identify and treat patients with rhythm disorders. The concept of ECG visualization for non-invasive localization of rhythm disturbances is presented.
3. Several new markers for risk stratification of sudden cardiac death and patient selection for medical device therapy, including QRS score automation for quantitative scar assessment, QRS-T angle, and T-wave peak-to-end interval.

ECG mapping, for example, is a non-invasive method that combines the electrocardiogram of a vest with >250 electrodes for high-resolution recording of body surface electrical potentials with detailed geometry of the heart obtained from chest computer tomography. Local electrical signals across the entire epicardial surface of the heart can be calculated using the inverse solution method.

Despite existing preliminary data, none of the extended ECG markers and technologies have been implemented in clinical practice yet. Further refinement of these technologies and broader confirmation among a larger number of patients is a critically necessary next step to facilitate the transition of advanced electrocardiogram technologies into clinical cardiology.