ACLS Algorithms Review: Adult Bradycardia Algorithm

How to treat a patient with symptomatic bradycardia.

The Bradycardia Algorithm lists the proper sequence used to treat a patient demonstrating symptomatic bradycardia with a pulse. Bradycardia is typically associated with a slow heartbeat (heart rate of fewer than 60 beats per minute). Although some people, particularly well-trained athletes, may have a resting heart rate of 40-50 beats per minute without any symptoms, it is important to understand and be able to identify the difference between symptomatic and asymptomatic bradycardia.


Symptomatic bradycardia is defined as a heart rate of fewer than 50 beats per minute and is generating symptoms caused by the low heart rate. You must be able to differentiate symptoms directly resulting from the low heart rate as opposed to those that are unrelated. Symptoms of bradycardia can include:


- Chest pressure, pain or heaviness

- Dyspnea

- Weakness

- Lightheadedness or dizziness

- Fatigue

- Syncope or near syncope


There are also several ECG rhythms you should be familiar with in order to treat bradycardia. They are:


- Sinus Bradycardia

- First-Degree AV Block

- Second-Degree AV Block

- Type I (Wenckebach Phenomenon / Mobitz I)

- Type II (Non-Wenckebach / Mobitz II)

- Third-Degree AV Block


Once symptomatic bradycardia has been identified, the first step of the Bradycardia Algorithm is to identify and treat the underlying cause – use the H’s and T’s of ACLS to help with this step. You may need to help maintain the airway and assist breathing, administer oxygen if hypoxemic, connect a cardiac and blood pressure monitor, and establish IV access. If a 12-lead ECG is readily available, it should be utilized. However, treatment should not be delayed in order to obtain one.


The next step of the Bradycardia Algorithm involves determining if the patient is showing adequate perfusion, or if there are signs or symptoms of poor perfusion caused by the bradycardia. Signs of persistent bradycardia causing poor perfusion include:


- Hypotension

- Signs of shock

- Acutely altered mental status

- Chest discomfort

- Acute heart failure


If perfusion appears adequate, simply observe and monitor. However, if the patient is showing any of the above signs that indicate poor perfusion, move forward to the next step of the algorithm, and administer atropine. If atropine is ineffective, you may consider an infusion of epinephrine or dopamine or transcutaneous pacing.


For a more detailed, step-by-step description of the Adult Bradycardia Algorithm, see below:

ACLS - Bradycardia Algorithm | eMedCert


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