Tachycardia and Its ACLS Algorithm

Causes

There are many causes of both stable and unstable tachycardia and appropriate treatment within the ACLS framework requires identification of causative factors. Before initiating invasive interventions, reversible causes should be identified and treated.

The most common causes of tachycardia that should be treated outside of the ACLS tachycardia algorithm are dehydration, hypoxia, fever, and sepsis. There may be other contributing causes and a review of the H’s and T’s of ACLS should take place as needed.

Click below to view the H and T’s table. When done click again to close the diagram.

H's and T's Table

Administration of OXYGEN and NORMAL SALINE are of primary importance for the treatment of causative factors of sinus tachycardia and should be considered prior to ACLS intervention.

Once these causative factors have been ruled out or treated, invasive treatment using the ACLS tachycardia algorithm should be implemented.

ACLS Treatment for Tachycardia

Click below to view the tachycardia algorithm diagram. When done click again to close the diagram. Tachycardia Algorithm Diagram.

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The first question that should be asked when initiating the ACLS tachycardia algorithm is: “Is the patient stable or unstable?” The answer to this question will determine which path of the tachycardia algorithm is executed.

Unstable Tachycardia

Patients with unstable tachycardia should be treated immediately with synchronized cardioversion. If a pulseless tachycardia is present patients should be treated using the cardiac arrest algorithm.

The AHA no longer provides specific shock dose recommendations for synchronized cardioversion. Instead, they instruct to refer to your specific device’s recommended energy level to maximize first shock success.

For the purposes of a basic understanding of cardioversion, the information about general shock dosages and recommendations will remain in the content on this website.

The initial recommended synchronized cardioversion voltage doses are as follows:

• narrow regular: 50-100 J; i.e., SVT and atrial flutter
• Narrow irregular: 120-200 J biphasic or 200 J monophasic; i.e., atrial fibrillation
• Wide regular: 100 J; i.e., monomorphic VT
• Wide irregular: defibrillation dose (not synchronized)

Stable Tachycardia

Patients with stable tachycardia are treated based upon whether they have a narrow or wide QRS complex. The following flow diagram shows the treatment regimen for stable tachycardia with narrow and wide QRS complex.

• Stable (narrow QRS complex) → vagal maneuvers → adenosine (if regular) → beta-blocker/calcium channel blocker → get an expert
• Stable (wide/regular/monomorphic) → adenosine → consider antiarrhythmic infusion → get an expert