Right atrial enlargement
Left atrial enlargement
Left ventricular hypertrophy
Right ventricular hypertrophy
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
ECG 
Cardiac enzymes
Cardiac ultrasound
D-dimer
Transcutaneous pacing
Defibrillation
Pulmonary artery catheter
IVC ultrasound