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Table 124-1

Summary of Guidelines for Pacemaker Implantation in SA Node Dysfunction

Class I
  1. SA node dysfunction with symptomatic bradycardia or sinus pause
  2. Symptomatic SA node dysfunction as a result of essential long-term drug therapy with no acceptable alternatives
  3. Symptomatic chronotropic incompetence
  4. Atrial fibrillation with bradycardia and pauses >5 s
Class IIa
  1. SA node dysfunction with heart rates <40 beats/min without a clear and consistent relationship between bradycardia and symptoms
  2. SA node dysfunction with heart rates <40 beats/min on an essential long-term drug therapy with no acceptable alternatives, without a clear and consistent relationship between bradycardia and symptoms
  3. Syncope of unknown origin when major abnormalities of SA node dysfunction are discovered or provoked by electrophysiologic testing
Class IIb
  1. Mildly symptomatic pts with waking chronic heart rates <40 beats/min
Class III
  1. SA node dysfunction in asymptomatic pts, even those with heart rates <40 beats/min
  2. SA node dysfunction in which symptoms suggestive of bradycardia are not associated with a slow heart rate
  3. SA node dysfunction with symptomatic bradycardia due to nonessential drug therapy

Source: Data from Epstein AE et al: J Am Coll Cardiol 51:e1, 2008; Tracy CM et al: J Am Coll Cardiol 61:e6, 2013.