View source for First degree AV block

==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 block types}}

==Evaluation==
[[File:FirstAVBlock.jpg|thumb|First degree AV block]]
*[[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

==See Also==
*[[AV blocks]]

==External Links==

==References==
<references/>

[[Category:Cardiology]]