ACLS Bradycardia Algorithm

Treatment for bradycardia should be based on controlling the symptoms and identifying the cause using the Hs and Ts

1. Do not delay treatment but look for underlying causes of the bradycardia using the Hs and Ts.
2. Maintain the airway and monitor cardiac rhythm, blood pressure and oxygen saturation.
3. Insert an IV or IO for medications.
4. If the patient is stable, call for consults.
5. If the patient is symptomatic, administer atropine 1.0 mg IV or IO bolus and repeat the atropine every 3 to 5 minutes to a total dose of 3 mg:
   1. If atropine does not relieve the bradycardia, continue evaluating the patient to determine the underlying cause and consider transcutaneous pacing
   2. Consider an IV/IO dopamine infusion at 2-10 mcg/kg/minute
   3. Consider an IV/IO epinephrine infusion at 2-10 mcg/minute.
6. In the cases of Mobitz type II second-degree heart block, third-degree AV block, or third-degree AV block with new widened QRS complex, atropine is unlikely to be effective. Consider transcutaneous pacing immediately or a beta-adrenergic infusion to increase heart rate.

The Hs and Ts of Bradycardia

Potential Cause	How to Identify	Treatments
Hypovolemia	Rapid heart rate and narrow QRS on ECG; other symptoms of low volume	Infusion of normal saline or Ringer’s lactate
Hypoxia	Slow heart rate	Airway management and effective oxygenation
Hydrogen Ion Excess (Acidosis)	Low amplitude QRS on the ECG	Hyperventilation; consider sodium bicarbonate bolus
Hypoglycemia	Bedside glucose testing	IV bolus of dextrose
Hypokalemia	Flat T waves and appearance of a U wave on the ECG	IV Magnesium infusion
Hyperkalemia	Peaked T waves and wide QRS complex on the ECG	Consider calcium chloride, sodium bicarbonate, and an insulin and glucose protocol
Hypothermia	Typically preceded by exposure to a cold environment	Gradual rewarming
Tension Pneumothorax	Slow heart rate and narrow QRS complexes on the ECG; difficulty breathing	Thoracostomy or needle decompression
Tamponade – Cardiac	Rapid heart rate and narrow QRS complexes on the ECG	Pericardiocentesis
Toxins	Typically will be seen as a prolonged QT interval on the ECG; may see neurological symptoms	Based on the specific toxin
Thrombosis (pulmonary embolus)	Rapid heart rate with narrow QRS complexes on the ECG	Surgical embolectomy or administration of fibrinolytics
Thrombosis (myocardial infarction)	ECG will be abnormal based on the location of the infarction	Dependent on extent and age of MI