First degree AV block: Difference between revisions
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==Background== | ==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== | ==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== | ==Differential Diagnosis== | ||
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==Evaluation== | ==Evaluation== | ||
[[File:FirstAVBlock.jpg|thumb|First degree AV block]] | |||
*[[ECG]] | |||
*Consider rare causes: | |||
**Lyme's disease | |||
**[[Lupus]] | |||
**[[Myocarditis]] | |||
**[[Myocardial infarction]] | |||
==Management== | ==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== | ==Disposition== | ||
*Outpatient | |||
==See Also== | ==See Also== | ||
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==External Links== | ==External Links== | ||
==References== | ==References== | ||
Latest revision as of 07:31, 6 March 2019
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