Sinus node dysfunction pacing mode

Sinus node dysfunction was initially described in the early 1900s, and is the primary indication for pacemaker implantation in industrialized countries. The only effective treatment for symptomatic sinus node dysfunction is cardiac pacing. However, despite the widespread use of pacing therapy for this group of patients, the optimal pacing mode, pacing system and site of ventricular stimulation for sinus node dysfunction remains controversial. The available data for the diagnosis and treatment of sinus node dysfunction are reviewed in this chapter. 

Pacing Mode Choice in Patients with Sinus Node Dysfunction... 

The DDD, AAI, and WI pacing modes are equally effective in preventing syncope owing to bradycardia in patients with sinus node dysfunction (54). However, as outhned in the following section, different pacing modes are associated with unique chnical outcomes (Table 9.4). 

DDI/R A nontracking mode which allows programming of long AV delays and protection from high-paced ventricular rates in those patients with sinus node dysfunction but intact AV conduction and normal QRS duration. This minimizes ventricular dyssynchrony due to ventricular pacing. 

Link MS, Hellkamp AS, Estes NAM, et al. High incidence of pacemaker syndrome in patients with sinus node dysfunction treated with ventricular-based pacing in the Mode Selection Trial. J Am CoU Cardiol 2004 43 2066-71. 

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