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Electrocardiography of Atrioventricular Block
Bradley A Clark1, Eric N Prystowsky2
1St.Vincent Hospital, 10590 North Meridian Street, Suite 200, Indianapolis, IN 46290, USA.
Cardiology Clinics
|June 15, 2023
Summary
Delayed atrioventricular (AV) conduction, often due to AV nodal issues, can be diagnosed using electrocardiogram intervals. Specific patterns like PR prolongation or QRS width help differentiate disease location, guiding treatment for heart block.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiac Electrophysiology
Background:
- Delayed atrioventricular (AV) conduction is a common clinical finding.
- It typically originates in the AV node, manifesting as AH prolongation on intracardiac ECG and PR prolongation on surface ECG.
- Understanding the location of AV conduction delay is crucial for diagnosis and management.
Purpose of the Study:
- To elucidate the diagnostic criteria for differentiating the location of AV conduction delays.
- To correlate electrocardiographic findings with the site of block in the cardiac conduction system.
Main Methods:
- Analysis of surface electrocardiogram (ECG) parameters, including PR interval and QRS duration.
- Intracardiac electrocardiography to assess AH intervals.
- Correlation of ECG findings with the presence and type of AV block (e.g., 2:1 AV block, complete heart block).
Main Results:
- A prolonged PR interval with a narrow QRS complex suggests AV nodal disease.
- A normal PR interval with a wide QRS complex indicates infranodal disease.
- 2:1 AV block with normal PR and QRS intervals points to block within the His bundle.
- Complete heart block is characterized by independent atrial and ventricular rhythms.
Conclusions:
- Surface ECG findings, specifically PR interval and QRS duration, are valuable in localizing AV conduction delays.
- Distinguishing between AV nodal and infranodal disease impacts clinical decision-making.
- These ECG criteria aid in diagnosing various forms of heart block.
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