By Mark Link, M.D.
Professor of Internal
Medicine
The 2018 ACC/AHA/HRS Guideline on the Evaluation and Management
of Patients With Bradycardia and Cardiac Conduction Delay was released at
the AHA Scientific Sessions (see Kusumoto FM, et al. Circulation 6 Nov
2018. DOI: 10.1161/CIR.0000000000000628.) This comprehensive document updates
the 2012 Guideline.
The recommendations for pacing have changed little since prior
guidelines, with a few notable exceptions. Sinus node dysfunction is most often
related to age-dependent progressive fibrosis. Pacing should be limited to
those with symptoms due to bradycardia. Nocturnal bradycardia is common, and
physicians should evaluate for sleep apnea. Pacing is not usually needed.
Patients with left bundle branch block (LBBB) should be evaluated
for structural heart disease, with at least an echocardiogram. Even if
asymptomatic, those with irreversible second-degree Mobitz type II
atrioventricular block, or higher degree block, should be paced. Wenckebach
block patients should be paced only for symptoms due to bradycardia.
For patients with a left ventricular ejection fraction (LVEF) between 36 percent and 50 percent who will be paced more than 40 percent of the time, CRT or HIS bundle pacing are recommended. Post-TAVR-induced LBBB is given a IIb indication for pacing, yet the authors acknowledge that we need more information. Patients/legally defined surrogates have the right to refuse PPM and withdraw pacing, even if life-threatening.