First degree AV block: Difference between revisions
m (Rossdonaldson1 moved page First Degree AV Block to First degree AV block) |
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==Background== | ==Background== | ||
*Also known as first-degree heart block | *Also known as first-degree heart block | ||
*Defined as prolongation of the PR interval on an electrocardiogram (ECG) to more than 200 msec (5 small squares on the | *Defined as prolongation of the PR interval on an electrocardiogram (ECG) to more than 200 msec (5 small squares on the ECG tracing) | ||
*Considered “marked” when the PR interval exceeds 300 msec (more than 7 small squares on the | *Considered “marked” when the PR interval exceeds 300 msec (more than 7 small squares on the ECG tracing) | ||
==Clinical Features== | ==Clinical Features== | ||
Revision as of 18:35, 21 November 2016
Background
- Also known as first-degree heart block
- Defined as prolongation of the PR interval on an electrocardiogram (ECG) to more than 200 msec (5 small squares on the ECG tracing)
- Considered “marked” when the PR interval exceeds 300 msec (more than 7 small squares on the ECG tracing)
Clinical Features
- Vast majority are asymptomatic and diagnosed by chance
- Exercise may reveal decreased tolerance (especially when there is markedly prolonged PR interval and with left ventricular systolic dysfunction)
Differential Diagnosis
AV blocks
- First degree AV block
- Second degree
- Third degree AV block
- AV dissociation without complete heart block
Evaluation
- ECG
- Consider rare causes:
- Lyme's disease
- Lupus
- Myocarditis
- Myocardial infarction
Management
- Asymptomatic patients do not require any specific management
- Consider a cardiology consult for patients who may have symptoms attributable to the block (rare)
Disposition
- Outpatient