ECG Viewer

Load ECG File Load sample ECG

Format

Speed

Gain

Theme

Rhythm Lead

Info Display

Load an ECG file to view information

Derived Lead Set

Load an ECG file and select a derived lead set

Measurements

CL (RR)	— ms
PR interval	— ms
QRS width	— ms
QT interval	— ms

Current measurement

— ms

Amplitude

Offset

Load an ECG file to view the averaged beat

Method

Amplitude

Offset

Load an ECG file to view local frequency

Lead source

QRS: — ms

Why ECG Viewer

ECGs have not changed in the way they are presented over more than a century. Often they are still printed on paper. When presented in the digital form, this is still as an image or PDF replicating the printed ECG. In today's computer age, we should be able to better utilise the ECG recorded in a digital form.

Different formats used to store digital ECGs was a stumbling block to this approach. This has been mostly sorted out with the use of the XML format as a standard for digital ECGs. XML is a document format designed to display information in a manner that is both human readable and machine readable¹. Most ECG machines now provide the capability to store and export recorded ECGs in a standard XML format.

However, viewers for displaying and manipulating ECGs recorded in the XML format are not widely available. This app was created to see ECGs recorded in this format. Since the electrical information recorded is available as raw data, it is easy to change the way this is displayed. Simple examples are changing the ECG display speed, amplitude calibration or the lead used as the rhythm lead. But the possible customizations are really unlimited. This viewer is also used as a testing ground for different visualizations of the ECG.

Supported Formats

This viewer supports ECGs stored in the following XML-based formats:

FDA XML (HL7 aECG) — The annotated ECG format based on HL7 v3, used for regulatory submissions to the FDA. Formally known as the HL7 annotated ECG (aECG) standard.
Philips XML — The proprietary XML format used by Philips/HP ECG machines for storing and exporting 12-lead ECGs.

Privacy

No ECG data is uploaded to a server. All parsing and rendering happens entirely in your browser, and everything stays on your computer only.

About Me

I am Dr. Raja Selvaraj, a Cardiac Electrophysiologist working at the Jawaharlal Institute of Postgraduate Medical Education and Research. I created ECG Viewer in 2024, since when it has been used by thousands of people. In 2026, I have updated the site to use entirely client-side ECG parsing and rendering.

License

This software and its source code are the exclusive property of Dr. Raja Selvaraj. Unauthorized copying, modification, distribution, or hosting of this software, in whole or in part, is strictly prohibited without prior written permission.