Bradycardia and Cardiac Conduction Delay: Clinical Practice Guidelines (2018)

American College of Cardiology, American Heart Association, and the Heart Rhythm Society

Reviewed and summarized by Medscape editors

December 05, 2018

The guidelines on the evaluation and management of bradycardia and cardiac conduction delay were released in November 2018 by the ACC, AHA, and HRS.[1,2]

Sinus node dysfunction is most often related to age-dependent progressive fibrosis of the sinus nodal tissue and surrounding atrial myocardium leading to abnormalities of sinus node and atrial impulse formation and propagation and will therefore result in various bradycardic or pause-related syndromes.

Sleep disorders of breathing and nocturnal bradycardias are relatively common. Treatment of sleep apnea reduces the frequency of these arrhythmias and also may offer cardiovascular benefits. The presence of nocturnal bradycardias should prompt consideration for screening for sleep apnea, beginning with solicitation of suspicious symptoms. However, nocturnal bradycardia is not in itself an indication for permanent pacing.

The presence of left bundle branch block on electrocardiogram markedly increases the likelihood of underlying structural heart disease and of diagnosing left ventricular (LV) systolic dysfunction. Echocardiography is usually the most appropriate initial screening test for structural heart disease, including LV systolic dysfunction.

In sinus node dysfunction, there is no established minimum heart rate or pause duration where permanent pacing is recommended. It is important to establish a temporal correlation between symptoms and bradycardia when determining whether permanent pacing is needed.

In patients with acquired second-degree Mobitz type II atrioventricular (AV) block, high-grade AV block, or third-degree AV block not caused by reversible or physiologic causes, permanent pacing is recommended regardless of symptoms. For all other types of AV block, in the absence of conditions associated with progressive AV conduction abnormalities, permanent pacing should generally be considered only in the presence of symptoms that correlate with AV block.

In patients with an LV ejection fraction between 36% and 50% and AV block who have an indication for permanent pacing and are expected to require ventricular pacing over 40% of the time, techniques that provide more physiologic ventricular activation (eg, cardiac resynchronization therapy [CRT], His bundle pacing) are preferred to right ventricular pacing to prevent heart failure.

Using the principles of shared decision-making and informed consent/refusal, patients with decision-making capacity or his/her legally defined surrogate have/has the right to refuse or request withdrawal of pacemaker therapy, even if the patient is pacemaker dependent, which should be considered palliative, end-of-life care, and not physician-assisted suicide. However, any decision is complex, should involve all stakeholders, and will always be patient specific.

For more information, please go to Sinus Node Dysfunction.

For more Clinical Practice Guidelines, please go to Guidelines.

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