New Concepts in Pacemaker Syndrome

Abstract

After implantation of a permanent pacemaker, patients may experience severe symptoms of dyspnea, palpitations, malaise, and syncope resulting from pacemaker syndrome. Although pacemaker syndrome is most often ascribed to the loss of atrioventricular (A-V) synchrony, more recent data may also implicate left ventricular dysynchrony caused by right ventricular pacing. Previous studies have not shown reductions in mortality or stroke with rate-modulated dual-chamber (DDDR) pacing as compared to ventricular-based (VVI) pacing. The benefits in A-V sequential pacing with the DDDR mode are likely mitigated by the interventricular (V-V) dysynchrony imposed by the high percentage of ventricular pacing commonly seen in the DDDR mode. Programming DDDR pacemakers to encourage intrinsic A-V conduction and reduce right ventricular pacing will likely decrease heart failure and pacemaker syndrome. Studies are currently ongoing to address these questions.

Keywords

• VVI = ventricular-based
• VVIR = rate modulated ventricular-based
• A-V = atrioventricular
• V-V = interventricular
• V-A = ventricular-atrial
• LBBB = left bundle branch block
• LVEF = left ventricular ejection fraction
• DDDR = rate modulated dual-chamber
• SND = sinus node dysfunction
• AAI = single-chamber atrial
• AF = atrial fibrillation
• LV = left ventricular
• RV= right ventricular