Table of Contents
General Interpretation Guidelines
These guidelines describe the criteria used to annotate ECGs in The ECG Quiz. They ensure consistency, reproducibility, and accurate scoring. You should follow these same rules when entering your diagnoses.
Important
Be sure to read how Differential Diagnoses and Multiple Interpretations are handled in The ECG Quiz.
Rate-Based Definitions
| Diagnosis | Definition |
|---|---|
| Bradycardia | A rhythm ≤ 60 bpm for ≥ 3 consecutive RR intervals |
| Tachycardia | A rhythm ≥ 100 bpm for ≥ 3 consecutive RR intervals |
| Sinus Arrest | Sinus node inactivity ≥ 3 seconds |
| Ventricular Asystole | Ventricular inactivity ≥ 3 seconds |
First-Degree AV Block Criteria
| Block Type | Definition |
|---|---|
| First-Degree AV Block | PR interval ≥ 200 ms |
Premature Complexes
Premature complexes are included only if they are not already accounted for by another rhythm diagnosis.
Include Premature Atrial Complexes (PAC), Premature Junctional Complexes (PJC), and Premature Ventricular Complexes (PVC) when:
- One or more premature beats are present
- They are not part of another diagnosis
Examples:
- Ventricular Tachycardia with no other PVCs → DO NOT include PVCs (because VT already explains them).
- Ventricular Bigeminy transitioning to Normal Sinus Rhythm with isolated PVCs → Include PVCs, because they occur outside the pattern.
Bigeminy / Trigeminy / Quadrigeminy
Include these diagnoses when there are ≥ 3 consecutive cycles of the repeating pattern.
Sinus Rhythm Categories
Sinus Rhythm is a supercategory, not synonymous with Normal Sinus Rhythm.
Only use Sinus Rhythm when one of the specific sinus subcategories cannot be determined.
| Diagnosis | Sinus Rate |
|---|---|
| Marked Sinus Bradycardia | < 40 bpm |
| Sinus Bradycardia | ≥ 40 bpm and < 60 bpm |
| Normal Sinus Rhythm | ≥ 60 bpm and < 100 bpm |
| Sinus Tachycardia | ≥ 100 bpm |
Important Notes
- Sinus Rhythm ≠ Normal Sinus Rhythm.
- Entering inus Rhythm when the correct answer is Normal Sinus Rhythm will produce:
- A False Positive for “Sinus Rhythm”
- A False Negative for missing “Normal Sinus Rhythm”
- See Hierarchical Scoring Modifications and Understanding the Results for details.
Multifocal Atrial Tachycardia (MAT) & Wandering Atrial Pacemaker (WAP)
Include these diagnoses when the ECG contains:
- ≥ 3 distinct P-wave morphologies
- No dominant P-wave shape
- Variable P–P intervals (irregular atrial pacemaking)
Rate-based differentiation:
| Diagnosis | Venticular Rate |
|---|---|
| Multifocal Atrial Tachycardia | ≥ 100 bpm |
| Wandering Atrial Pacemaker | < 100 bpm |
Junctional Rhythms
Include junctional rhythms when ≥ 3 consecutive junctional beats occur at the following rates:
| Rhythm | Rate |
|---|---|
| Junctional Bradycardia | < 40 bpm |
| Junctional Rhythm / Junctional Escape Rhythm | ≥ 40 bpm and < 60 bpm |
| Accelerated Junctional Rhythm | ≥ 60 bpm and < 100 bpm |
| Junctional Tachycardia | ≥ 100 bpm |
Permanent Junctional Reciprocating Tachycardia (PJRT)
PJRT is a rare, often incessant orthodromic AV reentrant tachycardia using a slow, concealed accessory pathway. It may occur in children or young adults and can lead to tachycardia-induced cardiomyopathy.
ECG Characteristics
- Inverted P waves in II, III, aVF, and lateral precordial leads
- Long RP interval (RP > PR) due to slow retrograde conduction
- Shorter PR interval compared to the RP interval
- Narrow-complex tachycardia, often continuous/incessant
- 1:1 AV conduction ratio
- PJRT may present with normal or mildly elevated ventricular rates (60–100 bpm)
For full PJRT educational content, see the dedicated page if available.
Additional Interpretation Guidelines
- Indications for
Important
Be sure to read how Differential Diagnoses and Multiple Interpretations are handled in The ECG Quiz.
References
References will be added soon.