CardioExchange Archive

Since the development of the first dual-chamber pacemakers in the 1980s, doctors have had the choice of using single- or dual-chamber devices in patients with traditional pacing indications. A number of pacemaker guideline consensus statements have been published over the years, but none has provided guidance on specific device types or pacing-mode selection.

The Heart Rhythm Society and American College of Cardiology Foundation recently published online the HRS/ACCF Expert Consensus Statement on Pacemaker Device and Mode Selection.  The authors intend this to be a supplement to the 2008 pacemaker guidelinesand classify indications in similar fashion, ranging from class I (general agreement regarding benefit) to class III (not useful, or harmful).  Biventricular pacing is not addressed in these documents, having been covered elsewhere .

The document is concise and clearly stated, and I would refer all those close to the field to the link above.  Below, I will add my own brief summary and comments.

Sinus node dysfunction (SND) gets a clear endorsement for dual chamber (DDD) pacing with a class I indication, even in those without manifest AV conduction abnormalities.  The authors still give a class I alternative for single-lead atrial (AAI) pacing, but only in patients with normal AV conduction. The recent DANPACE trial is cited showing reduced incidence of atrial fibrillation and need for reoperation in the patients with SND getting dual-chamber devices versus single-chamber atrial devices. Doctors have clearly embraced this indication, as single-chamber atrial pacing is rare, especially in the U.S.

Dual-chamber pacing in SND is also favored over single-chamber ventricular pacing (VVI), as it has been shown to reduce the risk for development of atrial fibrillation and the symptoms of pacemaker syndrome. Rate-responsive pacing is given a class IIa indication for patients with documented chronotropic incompetence.  This may be an academic distinction alone, as all modern pacemakers now have rate-responsive capabilities.

In AV block, dual chamber pacemakers also get a class I indication.  Single-chamber ventricular pacing is considered an acceptable alternative in sedentary patients or in patients for whom technical issues make atrial lead placement difficult or impossible. Patients with persistent or permanent atrial fibrillation are also indicated for single-chamber ventricular pacers unless efforts are being made to restore sinus rhythm.  Single-lead VDD pacing in those with intact sinus node function (e.g., a young patient with congenital AV block) gets a class IIa indication.

Fewer data were available to support consensus recommendations on some of the less common syndromes with pacing indications, and most did not rise to the level of class I.

– In carotid sinus hypersensitivity, both DDD and VVI pacing get class IIa recommendations. AAI pacing is not recommended.

– Neurocardiogenic syncope with associated bradycardia gets a class IIa recommendation for dual-chamber pacing. AAI is not recommended.  The evidence base cited is sparse for this indication, but it does not include the favorable ISSUE-3 trial reported at this year’s ACC meeting.

– Symptomatic or high-risk long-QT syndrome is a class I indication for DDD or AAI pacing.  The authors also acknowledge a role for ICD implantation in this population.

– Hypertrophic cardiomyopathy with significant LV outflow obstruction was given a class IIa indication for DDD pacing.

Although dual-chamber pacers have higher up-front costs, the authors suggest that these savings must be weighed against the difficulty of upgrading single- to dual-chamber pacing systems if the need arises later.  Studies have shown up to 45% incidence of complications with upgrade procedures. Cost-effectiveness data for dual-chamber devices, taking into account the reduction in atrial fibrillation and need for reoperation, has also been shown to be favorable.

Little controversy will likely arise from these guidelines. Device and mode selection for traditional pacemakers has been worked out in principle for years, and these guidelines generally reflect common current practice. Not covered — but very open to question — is the decision process surrounding device and mode selection in the ICD population. Recent data showing high popularity of dual-chamber ICDs despite increased complications and periprocedural mortality suggests guidance in this area would be welcome.