ECG
If<unk>  burden is large, consider:
TSH
BMP
Magnesium level
Ionized calcium
TSH
BMP
Magnesium level
Ionized calcium
Premature ventricular contraction
Arrhythmias:
Premature atrial contraction
Narrow-complex tachycardias
Premature junctional contraction
Wide-complex tachycardias
Wandering atrial pacemaker
AV blocks