The American College of Cardiology, the American Heart Association, and the Heart Rhythm Society have released a guideline, published in Circulation1, on the evaluation and management of patients with bradycardia and cardiac conduction delay.

The guideline defines bradycardia as a heart rate of less than 50 beats per minute classified into 3 categories: sinus node dysfunction, atrioventricular block, and conduction disorders.

The guideline writing committee members outline the clinical presentation and approach to clinical evaluation of patients who may have bradycardia or conduction defects. They evaluated the utility of diagnostic testing tools such as monitoring devices and electrophysiological testing, assessed available treatment options including lifestyle interventions and pharmacotherapy, and commented on the use of external and implanted devices such as pacemakers (temporary and permanent).

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The guideline also includes recommendations on post-procedure surveillance and pacemaker implantation since conduction abnormalities are common after transcatheter aortic valve replacement.

Ten top clinical takeaway messages were identified and include:

  1. Sinus node dysfunction is most commonly associated with age-dependent fibrosis of the sinus node tissue.
  2. Since both nocturnal bradycardia and sleep disorders of breathing are not uncommon, treatment of sleep apnea will reduce arrhythmia frequency in along with offering additional cardiovascular benefits.
  3. Left bundle branch block found on electrocardiogram greatly increases the likelihood of underlying structural heart disease and left ventricular systolic dysfunction. Furthermore, echocardiography is usually the most suitable initial screening test to detect any underlying structural heart disease.
  4. There is no established minimum heart rate of pause duration in sinus node dysfunction where permanent pacing is always recommended.
  5. Permanent pacing is recommended regardless of symptomatology in patients with acquired second-degree Mobitz type II atrioventricular block, high-grade atrioventricular block, or third-degree atrioventricular block not caused by reversible physiologic causes.
  6. Cardiac resynchronization therapy and His bundle pacing, which potentially offer more physiologic ventricular activation, are recommended for patients with left ventricular ejection fraction between 36% and 50% and atrioventricular block who meet indication criteria for pacing.
  7. Post-procedure surveillance is recommended after transcatheter aortic valve replacement due to conduction system abnormalities.
  8. Shared decision-making and patient-centered care are emphasized for patients who have indications for pacemaker implantation.
  9. Patients with decision-making capacity or their legal surrogate have the right to refuse or request withdrawal of pacemaker therapy despite being pacemaker dependent.
  10. Further research into identifying patients who will likely benefit the most from new, emerging pacemaker technology like His bundle pacing should be conducted.

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“Treatment decisions are based not only on the best available evidence but also on the patient’s goals of care and preferences,” said Fred M. Kusumoto, MD, cardiologist at Mayo Clinic Florida in Jacksonville and chair of the writing committee, in a press release that accompanied the guidelines.2  


  1. Kusomoto FM, Schoenfeld MH, Barrett c, et al. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay [published online November 6, 2018]. Circulation. doi: 2018;0:CIR.0000000000000628
  2. Societies publish new guidance for the treatment of slow, irregular heartbeats [press release]. Dallas, Texas: American Heart Association. Published November 6, 2018. Accessed November 6, 2018.

This article originally appeared on The Cardiology Advisor