triggered by a premature beat. Automaticity is a function of phase and depolarization
ectopic activity, action potential.
Slow rates (bradycardia) can be from the atrium (sinus bradycardia) or the ventricle. In
children, some bradycardia might be a manifestation of hypoxemia. Other causes
include sinus disease (post-operative) hypercalcemia hpyermagnesemia. Treatment
includes identifying the cacuse if one is present, epinephrine, atropine, or pacemaker,
Ventricular bradycardia are functional blocks, stable patients are treated with
epinephrine, unstable patients are paced.
Fast rates (tachycardia) can stem from the atrium or the ventricle and may be
hemodynamically problematic or not. The atrial tachycardias includes:
Sinus tachycardia – Consider hyperdynamic states (fever, seizures, sepsis,
thyrotoxicosis, or hypoglycemia). Treatment is treating 1° disease atrial
tachyarrhythmias include atrial flutter, paroxysmal atrial tachycardia atrial fibrillation and
SUT. Atrial Muttler (saw tooth pattern rate 150) should get a trial of procainamide,
digoxin or ibutalide (0.1 mg/kg).
Supraventricular tachycardias can be classified as ectopic or reentrant. Ectopic SVT is
when a different pacemaker from above the AV modes sets the rate. The abnormal
rhythm is insidious in onset, SVT is variable. Adenosine does not ablate this SVT, use
esmolol, sotalol or flecainide. Reentrant tachycardias are usually sudden in onset, rate