Many ECG errors arise not from lack of knowledge, but from misunderstandings of electrophysiologic mechanisms. These misunderstandings are predictable — and preventable.

1. Confusing Mechanism With Morphology

Morphology is the result of a mechanism, not the mechanism itself. Clinicians often assume:

• A narrow QRS means supraventricular
• A wide QRS means ventricular
• ST elevation means ischemia

These assumptions fail frequently.

2. Misunderstanding Reentry

Reentry is not a “loop” in the abstract. It is a dynamic interaction between:

• Conduction velocity
• Refractoriness
• Pathway geometry

Misunderstanding reentry leads to misdiagnosis of:

• AVNRT
• AVRT
• Atrial flutter
• VT

3. Misinterpreting Aberrancy

Aberrancy is not a “bundle branch block during tachycardia.” It is a rate‑dependent conduction delay caused by:

• Phase 3 block
• Phase 4 block
• Functional refractoriness

This distinction matters clinically. Clinicians who want a deeper, mechanism‑based framework for distinguishing ventricular tachycardia from supraventricular rhythms with aberrancy often benefit from detailed resources on wide‑complex tachycardias.

4. Misunderstanding Ventricular Activation

Clinicians often overlook:

• Fusion complexes
• Capture beats
• Ventricular escape rhythms

These findings are central to diagnosing VT. Structured, mechanism‑based dysrhythmia instruction can help clinicians recognize fusion, capture, and ventricular escape phenomena with greater confidence.

Conclusion

Understanding mechanisms prevents misinterpretation. Misunderstanding mechanisms guarantees it.

For a curated overview of the most essential mechanism‑based ECG concepts, see: Top 10 Mechanism‑Based ECG Concepts.