Publikationsserver der RWTH Aachen University
Chronische Modulation des parasympathischen Nerventonus des Atrioventrikularknotens : Entwicklung eines Neurostimulators mit transvenöser Sondenimplantation zur ventrikulären Frequenzkontrolle bei Vorhofflimmern
Abstract
dc:descriptionTOPIC: This study examines the possibility of chronic endocardial parasympathetic neural stimulation for dynamic ventricular rate control during atrial fibrillation and the development of an implantable neurostimulator with transvenuous intracardiac lead fixation and evaluation of its long-term efficacy. BACKGROUND: Efficient pharmacological ventricular rate control in patients with chronic permanent atrial fibrillation is not always easy to achieve and limited by potential side effects such as hypotension or bradycardia. Previous studys have shown, that the inferior interatrial ganglionated plexus (IAGP) selectively innervates the AV node. Temporary electrical stimulation of this plexus elicits a reduction of ventricular heart rate in patients with atrial fibrillation.METHODS: In 10 mongrel dogs, the small endocardial area in the right atrium overlying the IAGP was identified by neuromapping with probatory high-frequency stimulation (20 Hz) by using a custom-made positioning catheter with a distal pair of electrodes. After identification of the stimulation area, an active-fixation pacemaker lead was advanced through the inner lumen of the positioning catheter while leaving the catheter in the target area. After transvenuous lead fixation, the positioning catheter was slit and removed and the lead was connected with an implantable neurostimulator. An additional conventional DDD-pacemaker was implanted for initial induction of atrial fibrillation by high-frequency atrial stimulation (600 ppm) and for measurement of ventricular heart rate. In the first study group (n=5) long-term lead stability was examined by weekly-intermittent neurostimulation. In the second study group (n=4) continuous neurostimulation was performed during a period of 1 – 2 years for reduction of ventricular rate in a range of 100 – 140 bpm.RESULTS: Implantation of the neurostimulation lead was achieved in 37 ± 12 min. Neurostimulation resulted in a reversible negative dromotropic effect. The on-/offset of the negative dromotropic effect was sudden within 1 second after the initiation or termination of parasympathetic neurostimulation. The major determinants of neurostimulation efficacy were stimulation frequency, voltage and impulse duration. The required voltage for a reduction of the ventricular rate during atrial fibrillation of about 40% was less than 5 V with a chronaxie time of 0.07 ± 0,02 ms for a 50% reduction in ventricular rate. In the first study group (n = 5) weekly-intermittent neurostimulation was effective and well tolerated by the animals during a 6 month follow-up. In the second study group (n = 4) continuous neurostimulation adjusted to achieve a mean ventricular rate decrease during atrial fibrillation of about 40% was effective during a 1-2 years follow-up. CONCLUSION: Continuous parasympathetic stimulation via a cardiac neurostimulator implanted by transvenuous lead fixation and without the need of thoracotomy is possible and provides effective ventricular heart rate control during long-term follow-up. AV node selectivity and the possibility of a dynamic adjustment of the negative dromotropic effect within seconds may be an advantage over pharmacological rate control.
Degree
thesis:*- Grantor dc:publisher
- Publikationsserver der RWTH Aachen University
- Year dc:date
- 2009
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Gemein, Christopher
- Contributors dc:contributor
-
- Schauerte, Patrick
Subjects
dc:subject × 13Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger