Answer to Question 1
Rhythm Ventricular irregular; atrial regular (i.e., Ps plot through on time); grouped beating may be present.
Rate Atrial rate is greater than the ventricular rate.
P waves Normal in size and shape; some P waves are not followed by a QRS complex (i.e., more Ps than QRSs).
PR interval Inconstant; the PRI after a nonconducted P wave is shorter than the interval preceding the nonconducted beat.
QRS duration Usually 0.11 seconds or less; complexes periodically dropped.
Answer to Question 2
Sodium, potassium, calcium, and chloride