Arrhythmia	Frequency	Recommendations and comments
Premature ventricular complexes	Common	Usually require no treatment; check for metabolic and electrolyte abnormalities.
Accelerated idioventricular rhythm	15% to 20%	Observation; no treatment usually needed
Ventricular tachycardia	Up to 60%	If nonsustained, immediate intense observation
		If sustained, give lidocaine (Xylocaine) in bolus of 1.0 to 1.5 mg per kg, followed by maintenance infusion at 1 to 4 mg per minute or direct-current cardioversion.
Ventricular fibrillation	5%	Defibrillation; if defibrillation is not initially successful, give amiodarone (Cordarone) in 300-mg bolus or lidocaine in 100-mg bolus.
Sinus tachycardia	Common	Rule out hypoxemia and hypovolemia; provide adequate analgesia; evaluate for congestive heart failure.
Atrial fibrillation	10% to 15%	Slow ventricular rate with beta blocker (e.g., propranolol [Inderal]) or calcium channel blocker (e.g., diltiazem [Cardizem]).
Paroxysmal supraventricular tachycardia	<10%	Give adenosine (Adenocard), 6 to 12 mg by IV push over 1 to 3 seconds; verapamil (Calan), diltiazem, or propranolol can be used as alternatives.
Sinus bradycardia	Up to 40% in acute inferior MI	If symptoms are present, give 0.5 to 1.0 mg of atropine IV.
First-degree atrioventricular block	15% in acute inferior MI	Observation; if symptoms are present, give atropine.
Mobitz type I block (Wenckebach block)	Up to 10%	Observation; if symptoms are present, give atropine.
Mobitz type II block	<1%	Temporary external or transvenous demand pacemaker
Complete atrioventricular block	5% to 15%	Ventricular pacemaker