Differential includes ischemic events, electrolyte abnormalities, and medication overdoses in addition to rheumatologic conditions
Anterior MI
Rheumatic fever
Myocarditis
Lyme disease
Lenegre's disease
Lev's disease
SLE
Systemic sclerosis
Amyloidosis
Hemochromatosis
Sarcoidosis
Hyperkalemia
Toxicology
Beta blocker toxicity
Calcium channel blocker toxicity
Digoxin toxicity
Amiodarone
Beta blocker toxicity
Calcium channel blocker toxicity
Digoxin toxicity
Amiodarone
First degree AV block
Second degree AV block type I (Wenkebach)
Second degree AV block type II
Third degree AV block
AV dissociation without complete heart block
Trifascicular Block
Differential includes ischemic events, electrolyte abnormalities, and medication overdoses in addition to rheumatologic conditions[1][2]
Digital block
Anterior MI
Cervical spine clearance
Rheumatic fever
Nerve and regional blocks 
Myocarditis