What's new
Every change to CardioLab, newest first.
September 2026
- Improved
The axis page turns only the QRS, and shows the leads as an ECG prints them
Before
The whole beat turned with the axis, so the P and T moved with the QRS, and the six leads were laid out only in Cabrera order.
After
Only the QRS turns; the P and T stay where a normal heart puts them. The leads default to the standard printed layout with Cabrera as an option, each axis deviation lists its causes, and the quadrant method opens first, as most courses teach it.
- Improved
The 12-lead's numbers now come from the tracing you see
Before
The PR, QRS and QT beside the normal tracing came from the older model's settings rather than the beat on screen, so the PR read 26 ms short and the QRS 14 ms long, and the ST segment was dead flat.
After
The numbers are measured off the drawn beat, QTc uses Fridericia's formula and is labelled QTcF, and V2 and V3 show the small upsloping ST that most normal ECGs have.
- Improved
Tap a lead on the 12-lead to see its own measurements
Before
Tapping a lead zoomed into its wave with one number per wave, the same all-leads figure under every lead, and nothing to show where it came from.
After
The view shows the lead's own measurements: QRS shape, R and S heights, the ST at the J point with that lead's STEMI threshold, and its T and P, with calipers on the wave marking where each number comes from.
- New
Articles for the five sinus rhythms
Normal sinus rhythm, sinus bradycardia, sinus tachycardia, sinus arrhythmia and sinus arrest each have an article: how to recognise it, why it happens and what it can be mistaken for.
- New
Every rhythm article has a strip to read yourself, and the same strip annotated
Each article now carries a 30 second strip drawn by the simulator to work through first, then the same strip marked up with every interval measured.
- Improved
A new home page with a live simulator
Before
The home page showed a static screenshot and described some features that no longer existed.
After
It opens on a working lead II trace you can switch between rhythms, and shows what is new.
- Improved
The AV block family rewritten
Before
The AV block pages had short notes, and the simulator did not always draw the block its page described.
After
First degree, Mobitz I, Mobitz II, 2:1, 3:1 and complete heart block each have a full article, and the simulator draws each the way its article describes.
- Fixed
AFib and flutter baselines now match what their articles describe
The fibrillatory and flutter waves were redrawn so what you see on the trace is what the article tells you to look for.
- New
The PAC family: PACs, blocked PACs and aberrant PACs
Three articles on premature atrial contractions, with bigeminy and trigeminy, and two simulation faults they exposed fixed along the way.
- New
A cardiac axis page with three ways to read the axis
Drag the axis around the dial and watch the six limb leads follow, then work it out by the quadrant, isoelectric or three-lead method.
- Improved
The ventricular rhythms brought into line with their articles
Before
PVCs, idioventricular rhythms and VT on the simulator did not match the widths, shapes and rates their articles described.
After
They draw what their articles describe.
- Improved
Mobitz II and 2:1 block in the sidebar, with clearer page addresses
Before
Mobitz II and 2:1 block had no sidebar entries of their own, and AV block pages had addresses such as av-block-2-i.
After
Both have their own sidebar entries, and every AV block page has an address you can read, such as second-degree-av-block-mobitz-1.
- New
Articles for 17 rhythms
Each rhythm's page now explains how to recognise it, why it happens and what it can be mistaken for, beside the live trace.
- Fixed
Polymorphic VT and idioventricular rhythm drawn more faithfully
Polymorphic VT's beats now vary the way they should, and the idioventricular complex has a truer shape.
- New
Wolff-Parkinson-White pattern
A short PR and a delta wave slurring the start of a wide QRS, the triad that defines the pattern.
- New
The SVT family: AVNRT, AVRT and focal atrial tachycardia
Three narrow-complex tachycardias, each drawn with the features that tell them apart.
- New
Comment on a rhythm, or request one
Every rhythm has a way to send a comment, and a request page takes suggestions for rhythms to add.
- Improved
PACs reset the sinus node and pause the way real ones do
Before
A premature atrial beat left the sinus timing untouched, so the pause after it was the wrong length.
After
It resets the sinus node, so the pause after it is the length a real one would be.