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Chronic ventricular pacing with ventriculo-atrial conduction versus atrial pacing in three patients with symptomatic
Insights
Sick sinus syndrome patients experienced symptoms with ventricular pacing. Switching to atrial pacing resolved symptoms and improved cardiac output, maintaining benefits long-term.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Devices
Background:
- Sick sinus syndrome (SSS) causes symptomatic bradycardia.
- Permanent ventricular pacing is a common treatment for SSS.
- Ventriculo-atrial (VA) conduction can complicate ventricular pacing.
Observation:
- Three SSS patients with VA conduction developed symptoms (fatigue, lightheadedness, near syncope) on ventricular pacing.
- Hemodynamic studies revealed cannon waves during ventricular pacing.
- Temporary atrial pacing eliminated cannon waves and increased cardiac output by 32-48%.
Findings:
- Permanent atrial pacing on demand resolved symptoms in all patients.
- Atrial pacing improved effort tolerance and cardiac performance.
- Hemodynamic improvements were sustained for 9-12 months post-implantation.
Implications:
- Atrial pacing is superior to ventricular pacing in SSS patients with VA conduction.
- Optimizing pacemaker mode selection is crucial for patient outcomes.
- Atrial pacing offers sustained hemodynamic benefits for bradycardia management.
Abstract:
Three patients with symptomatic sinus bradycardia due to sick sinus syndrome were treated with permanent ventricular pacing for periods ranging from 2.5 to 4 years. All three patients had ventriculo-atrial conduction on routine electrocardiography. Although ventricular pacing was effective, they complained of fatigue, lightheadedness, and near syncope. Hemodynamic studies revealed the presence of regular cannon waves in the right atrium as well as in the pulmonary artery wedge pressure curves. Temporary atrial pacing resulted in disappearance of the cannon waves and a significant rise in cardiac output (32-48%). After normal atrio-ventricular conduction was confirmed by rapid atrial stimulation and His bundle electrocardiography, the pacing mode was changed to permanent atrial pacing on demand. The effort tolerance of the patients markedly improved, and the previously mentioned symptoms disappeared. Control hemodynamic studies 9 to 12 months after implantation of the atrial demand pacemaker showed that the improvement in cardiac performance was maintained.