# 12 Lead ECG Challenge vs arrhythmia

The clearest difference is price: arrhythmia at Free against 12 Lead ECG Challenge's $5.99. arrhythmia also leads on rating (4.1 vs 3.3) and update cadence (every 3 weeks vs every 10 months). 12 Lead ECG Challenge's advantage is in-app purchases (none vs 3) and review sentiment (69% vs 44%). On ads, device support and iOS requirement there is nothing between them.

arrhythmia is free to download; 12 Lead ECG Challenge costs $5.99 up front. arrhythmia sells 3 in-app purchases, starting at $2.99 per month. 12 Lead ECG Challenge asks for nothing beyond the download.

arrhythmia holds the better App Store score, 4.1 against 3.3. That said, the two scores are not equally well evidenced: arrhythmia has 113 ratings behind it against 4, so its average is the more settled of the two. Written reviews complicate that: 69% of 12 Lead ECG Challenge's written reviews are positive against 44% of arrhythmia's, so the app with the better star average is not the one people write more warmly about.

12 Lead ECG Challenge ships an update every 10 months, arrhythmia every 3 weeks. The most recent releases landed on November 2, 2026 and November 1, 2026 respectively.

## The numbers

| Metric | 12 Lead ECG Challenge | arrhythmia |
| --- | --- | --- |
| Price | $5.99 | **Free** |
| Rating | [3.3 (4 ratings)](https://appshunter.io/ios/app/12-lead-ecg-challenge/id461149429/reviews) | **[4.1 (113 ratings)](https://appshunter.io/ios/app/arrhythmia/id996560473/reviews)** |
| Number of ratings | 4 | **113** |
| Positive reviews | **68.8% of reviews** | 43.9% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 10 months | **Every 3 weeks** |
| Monetization | **Paid** | Subscription |
| Size | 51 MB | 159 MB |
| Requires iOS | 17.6 | 17.6 |
| Devices | iPhone, iPad | **iPhone, iPad, Mac** |
| Age rating | 17+ | 17+ |
| Developer | [Limmer Creative](https://appshunter.io/developer/387423724) | [Single Sail Software, LLC](https://appshunter.io/developer/359715495) |

## What reviewers say

### 12 Lead ECG Challenge

[App page](https://appshunter.io/ios/app/12-lead-ecg-challenge/id461149429)

Master 12-lead ECG interpretation with real patient cases and expert explanations. This app helps EMS providers, nurses, and physicians build accuracy and confidence in identifying critical cardiac conditions through interactive learning and customized practice.

**Highlights:** Real patient 12-lead ECG cases, Wide range of cardiac pathologies, Interactive ECG examination, Expert explanations and rationale, Customized practice sessions, Zoom and move functionality

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### arrhythmia

[App page](https://appshunter.io/ios/app/arrhythmia/id996560473)

Practice interpreting EKGs in lead II with realistic simulations. Choose rhythms to study or test your knowledge in a game mode. Ideal for healthcare professionals to hone their diagnostic skills.

**Highlights:** EKG interpretation practice, Lead II simulation, Study Mode with rhythm selection, Game Mode for random rhythm identification, Customizable rhythm sets, Realistic rhythm variations

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly | $2.99 | per month |
| Yearly | $19.99 | per year |
| Unlock All Rhythms (One-time Purchase) | $4.99 | one-time |

**What reviewers like**

- 👍 Great study tool for EKGs
- 👍 Helpful for understanding EKGs
- 👍 Good for practicing rhythm recognition
- 👍 Interactive and colorful design
- 👍 Dynamic testing

**What reviewers complain about**

- 👎 Immediately asks for paid version
- 👎 Missing common and important rhythms
- 👎 Rhythms are unrealistic
- 👎 Cannot try before signing up
- 👎 Clunky and slow horizontal scrolling

**Reported bugs**

- App no longer works after iOS update
- App does not work on Apple Watch

**Requested features**

- Add more common and important rhythms (torsades, WPW, STEMI, accelerated/tachycardic idioventricular, WAP, MAT)
- Option to read as a 12-lead instead of a single rhythm line
- Add variations to rhythms
- Add Left Bundle Branch Block
- Add a 12-lead option


## Frequently asked questions

### Is 12 Lead ECG Challenge free?

12 Lead ECG Challenge costs $5.99, with no in-app purchases.

### Is arrhythmia free?

arrhythmia is free to download, with in-app purchases available.

### Which has better reviews, 12 Lead ECG Challenge or arrhythmia?

arrhythmia is rated higher. 12 Lead ECG Challenge averages 3.3 out of 5 from 4 ratings, while arrhythmia averages 4.1 from 113 ratings.

### Do 12 Lead ECG Challenge or arrhythmia have ads?

Neither 12 Lead ECG Challenge nor arrhythmia shows ads.

### Which is updated more often, 12 Lead ECG Challenge or arrhythmia?

12 Lead ECG Challenge ships an update every 10 months, and arrhythmia every 3 weeks. Most recently, 12 Lead ECG Challenge was updated on November 2, 2026 and arrhythmia on November 1, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*