First ECGs - Waller and Jimmy - 1887
Einthoven - 1912
ECG today
Digital ECGs
Digital X-ray and the Radiology workstation
ECG viewer
ECG measurements
Vectorcardiography
VCG
Electro-vectorcardiogram
Hasitha T, … Selvaraj RJ. Ease and accuracy of ECG interpretation using 12-lead ECG versus a combination of 12-lead and vector ECG (electro-vectorcardiogram) by medical students: A prospective, randomised controlled study. J Electrocardiol. 2025 Jan-Feb;88:153830. doi: 10.1016/j.jelectrocard.2024.153830.
Single dipole and derived leads
Derivation of elevated precordial leads
Kalani K, Selvaraj R et al. A mathematical model for derivation of Elevated-Electrode-Placement Electrocardiogram (EEP-ECG) leads from a standard 12-lead electrocardiogram. J Electrocardiol. 2025 Mar-Apr;89:153880. doi: 10.1016/j.jelectrocard.2025.153880.
Ventricular repolarization - T wave alternans
Chauhan VS, Selvaraj RJ. Utility of microvolt T-wave alternans to predict sudden cardiac death in patients with cardiomyopathy. Curr Opin Cardiol. 2007 Jan;22(1):25-32. doi: 10.1097/HCO.0b013e328011aa49.
Atrial Repolarization
Pulath N, … Selvaraj RJ. Atrial repolarization in patients with left ventricular dysfunction. J Electrocardiol. 2026 Jan-Feb;94:154160. doi: 10.1016/j.jelectrocard.2025.154160.
Atrial Repolarization
Pulath N, … Selvaraj RJ. Atrial repolarization in patients with left ventricular dysfunction. J Electrocardiol. 2026 Jan-Feb;94:154160. doi: 10.1016/j.jelectrocard.2025.154160.
ECG marker of synchrony - QRS duration
Parale C., … Selvaraj R. Comparison of electrocardiographic parameters between left bundle optimized cardiac resynchronization therapy (LOT‐CRT) and left bundle branch pacing—cardiac resynchronization therapy (LBBP‐CRT) Pacing Clin Electrophysiol. 2023;46(8):840–847. doi: 10.1111/pace.14793.
QRS area
Device recorded ECGs
- Smartwatches
- Hand held devices
On chest with phonocardiogram
Handheld device - ECG screening in neonates and infants
ECG leads and phonocardiogram
Faster to record
Comparable QTc
AI analysis of ECG
- Rhythm analysis, AF identification
- Age, sex, LV function
- Future risk of AF
Summary
- ECGs continue to be relevant more than 100 years later
- Very information dense investigative modality
- Potential still largely unexplored
- Provides rich opportunity for research