What determines the chamber selection for pacing in bradycardia (abnormally slow heart rate)?

From the Guidelines

The decision for which chamber to pace in bradycardias should be based on the specific type of conduction abnormality present, with atrial pacing (AAI) or dual-chamber pacing (DDD) preferred for sinus node dysfunction and ventricular pacing (VVI) necessary for atrioventricular (AV) block. The choice of pacing chamber depends on several factors, including:

• The type of conduction abnormality, such as sinus node dysfunction or atrioventricular block
• The patient's activity level, with rate-responsive pacemakers recommended for active patients
• Comorbidities, such as heart failure, which may benefit from biventricular pacing or cardiac resynchronization therapy
• Left ventricular function, as right ventricular pacing alone can worsen heart failure in some patients with reduced ejection fraction According to the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1, temporary pacing for bradycardia attributable to sinus node dysfunction (SND) can be implemented transcutaneously, via a transesophageal approach, or by insertion of a transvenous pacing electrode or pulmonary-arterial pacing catheter. The guideline also recommends that in symptomatic patients with SND, atrial-based pacing is preferred over single chamber ventricular pacing 1. Additionally, the 2013 ESC guidelines on cardiac pacing and cardiac resynchronization therapy recommend dual-chamber pacing with preservation of spontaneous AV conduction for reducing the risk of AF and stroke, avoiding PM syndrome, and improving quality of life in patients with sinus node disease 1. Overall, the decision for which chamber to pace in bradycardias requires individualized assessment of the patient's specific conduction disorder, cardiac function, activity level, and comorbidities to determine the optimal pacing strategy.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Decision-Making for Chamber Pacing in Bradycardias

The decision for which chamber to pace with in bradycardias is based on several factors, including:

• The severity of symptoms
• The underlying causes of the bradycardia
• The presence of potentially reversible causes
• The presence of adverse signs
• The risk of progression to asystole 2
• The evaluation and risk stratification of individuals presenting with asymptomatic bradycardias 3

Factors Influencing Pacing Chamber Selection

Some key factors that influence the selection of the pacing chamber include:

• The type of bradycardia (e.g. sinus node dysfunction, atrioventricular block)
• The presence of cardiac conduction defects
• The need for urgent hemodynamic support
• The potential for physiologic pacing modalities to avoid dyssynchrony from right ventricular (RV) only pacing 4

Current Guidelines and Recommendations

Current guidelines, such as the 2018 ACC/AHA/HRS Guideline on the Evaluation and Management of Patients with Bradycardia and Cardiac Conduction Delay, emphasize the importance of evaluating and managing disease states, rather than solely relying on device-based implantation recommendations 5

• The guideline highlights the need for a thorough evaluation of symptoms and underlying causes of bradycardia
• Treatment should be individualized based on the specific needs of the patient, and may include pharmacologic therapy, pacing, or other interventions 2, 6