From the Guidelines
Atrioventricular dual pace rhythm is recommended for patients with sinus node disease or AV block, as it confers a modest reduction in AF and stroke, and reduces the risk of PM syndrome, which is associated with a reduction in quality of life 1. This pacing mode, often designated as DDD, means the pacemaker senses and paces in both heart chambers. On an ECG, it appears as regular pacing spikes preceding both the P waves (atrial contraction) and QRS complexes (ventricular contraction). The key benefits of dual-chamber pacing include:
- Maintaining atrioventricular synchrony, which optimizes cardiac output by preserving the atrial contribution to ventricular filling (the "atrial kick")
- Reducing the risk of PM syndrome, which is associated with a reduction in quality of life 1
- Improving symptoms like fatigue and shortness of breath compared to single-chamber ventricular pacing alone Patients with this rhythm require regular pacemaker checks to ensure proper device function, battery status, and appropriate programming of parameters like pacing rate and AV delay to match the patient's physiologic needs. While other studies suggest dual-chamber pacing may be beneficial for patients with long QT syndrome and syncope secondary to pause-dependent VT 1, the most recent and highest quality evidence supports its use in patients with sinus node disease or AV block 1.
From the Research
Atrio Ventricular Dual Pace Rhythm
- Atrioventricular (AV) dual pace rhythm refers to the electrical conduction between the atria and ventricles in the heart, which can be affected by pacemaker settings 2, 3, 4, 5.
- In dual-chamber pacemakers, the AV delay is a critical parameter that can impact the incidence of atrial fibrillation and heart failure symptoms 3, 4.
- Studies have shown that adjusting the AV delay and pacing mode can help minimize ventricular pacing and reduce the risk of atrial fibrillation 3.
- However, the optimal AV delay and pacing mode may vary depending on the individual patient's condition, such as the presence of congestive heart failure or atrial tachycardia 2, 4.
Pacemaker Syndrome and Atrial Dissociation
- Pacemaker syndrome can occur when the pacemaker senses both atrial rhythms, leading to automatic mode switching and ventricular paced rhythm with retrograde P waves on electrocardiogram 2.
- Atrial dissociation, where two simultaneous electrically isolated atrial rhythms exist, can lead to pacemaker syndrome if the pacemaker senses both rhythms 2.
- Adjusting the atrial lead sensitivity or revising the atrial lead can help resolve pacemaker syndrome in patients with atrial dissociation 2.
Clinical Implications
- Understanding the principles of dual-chamber pacemakers and their effects on atrioventricular conduction is crucial for optimal patient management 5.
- Clinicians should be aware of the potential risks and benefits of different pacing modes and AV delays in patients with dual-chamber pacemakers 3, 4.
- Further research is needed to determine the optimal pacing strategies for patients with complex cardiac conditions, such as congestive heart failure and atrial tachycardia 2, 3, 4.