ACLS Megacode 2: Bradycardia

The patient is stable and currently asymptomatic. While the heart rate/bradycardia is concerning, at this point we have no idea the etiology or type of bradycardia the patient has. Avoid “treating a number”. You have time in this scenario to gather more information while continuously assessing the patient.

The patient is currently stable and demonstrates bradycardia, specifically second degree heart block, type I (Wenkebach). It is reasonable to give atropine to attempt to increase the heart rate. Cardio version is not indicated. Transcutaneous pacing can be attempted in unstable patients unresponsive to atropine. Adenosine is not indicated for bradycardia and could actually worsen symptoms as this is an AV nodal blocking agent which could potentially precipitate complete heart block or unstable bradycardia/arrest.

The patient demonstrates unstable bradycardia. Atropine 1 mg can be given but patient has not responded to this and transcutaneous pacing should be initiated. While the patient is unstable, ACLS emphasis is on CAB (circulation, airway, breathing). The patient is currently maintaining an airway and breathing and her main issue is the bradycardia causing poor perfusion.

The answer is Atropine can be given as first line for bradycardia. Transcutaneous pacing should be attempted for unstable bradycardia. Can also give epinephrine 2-10 mcg/minute or Dopamine can be initiated at 2-20 mcg/kg/minute. Diltiazem is a calcium channel blocker and AV nodal blocking agent which would worsen the scenario. Amiodarone is an antiarrhythmic used in treatment of certain tachycardias.

The rhythm strip demonstrates asystole. This is not a shockable rhythm. Initiate CPR and give 1 mg epinephrine every 3-5 minutes, re-assessing after each round of CPR.

When an organized rhythm appears on the monitor during resuscitation, the next step is to check for a pulse. An organized rhythm does not guarantee that the heart is pumping blood: it may be pulseless electrical activity (PEA), which is managed with continued CPR and epinephrine, or a return of spontaneous circulation. Checking the pulse during the rhythm-check pause, in no more than 10 seconds, tells you which of the two you are dealing with and how to proceed. Synchronized cardioversion is reserved for unstable tachyarrhythmias with a pulse, and defibrillation is indicated only for shockable rhythms (ventricular fibrillation or pulseless ventricular tachycardia). IV fluids are not the next step until you have confirmed whether the patient has a pulse.

The “H’s and T’s” are causes of arrest that should be considered when treating cardiac arrest. H’s: Hypothermia, Hydrogen ion (acidosis), Hypoglycemia, Hypovolemia, Hypo/hyperkalemia. T’s: Thrombosis (myocardial infarction or pulmonary embolism), Tamponade, Tension pneumothorax, Trauma, Toxins.

Once a patient regains a pulse, optimize oxygenation and perfusion. If the patient remains unresponsive but has a pulse, consider targeted temperature management (TTM). If the patient regains consciousness, and if there is high suspicion of STEMI, the patient should go to catheterization. If there is not evidence of STEMI (in this case the initial rhythm was bradycardia but no ST elevation), then continued advanced critical care should be continued, maintaining oxygenation, perfusion and searching for underlying cause.