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McMaster Textbook of Internal Medicine

Supraventricular Premature Beats

How to Cite This Chapter: Acosta Velez JG, Amit G, Trusz-Gluza M, Leśniak W. Supraventricular Premature Beats. McMaster Textbook of Internal Medicine. Kraków: Medycyna Praktyczna. https://empendium.com/mcmtextbook/chapter/B31.II.2.6.1. Accessed December 05, 2025.
Last Reviewed: May 3, 2025
Last Updated: February 20, 2022
Chapter Information

Definition, Etiology, PathogenesisTop

The extra beats originating outside the sinus node can be premature beats or escape beats. A premature beat comes before the next expected sinus beat, whereas the escape beat comes after the next expected sinus beat that failed to occur. Supraventricular premature beats (SPBs) and escape beats originate outside the sinus node, in the atrium, atrioventricular junction, or in the veins draining to the atria. SPBs are most frequently single but may be also multiple and have the form of nonsustained atrial tachycardia. They are common in healthy individuals.

SPBs are frequently transitory and associated with a transient triggering factor, such as emotions, stimulants (alcohol, caffeine, drugs of abuse), electrolyte disturbances, infection, or thyrotoxicosis.

Clinical Features and Natural HistoryTop

SPBs are usually asymptomatic, although sometimes patients may experience irregular heartbeats or pauses. Nonconducted SPBs can lead to bradycardia. Multiple SPBs may affect the quality of life and increase the risk of atrial fibrillation.

TreatmentTop

1. Treatment is rarely necessary. However, the triggering factors should be addressed.

2. In patients with severe symptoms, multiple SPBs, or short episodes of atrial fibrillation, consider a beta‑blocker or calcium channel blocker (verapamil or diltiazem), or rarely a class I antiarrhythmic agent (see Table 3.4-1).

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