[Treatment of tachycardic atrial fibrillation by catheter-assisted electrical stimulation of the cardiac parasympathetic nervous system].
Treatment of tachycardic atrial fibrillation (AF) is difficult in patients with congestive heart failure because many drugs which exert negative dromotropic effects (beta-blockers, calcium channel antagonists) may depress ventricular contractility and/or decrease arterial blood pressure. We have identified 2 intravascular sites in the superior (SVC) and inferior vena cava (IVC) where parasympathetic nerves, which innervate the atrioventricular node, can be stimulated electrically. In 8 dogs, a 7-F catheter with an expandable electrode basket at its tip was non-fluoroscopically positioned in the SVC and in the proximal IVC (time for positioning: 3-5 minutes). High-frequency electrical parasympathetic stimulation (PS) with 20 Hz at an impulse duration of 0.1 ms was performed during pacing induced AF.


RESULTS
With increasing stimulus strength, a graded ventricular rate slowing was observed during PS in the SVC and IVC (P < 0.01, ANOVA). The negative dromotropic effect started instantaneously after onset of PS and ceased immediately after termination of PS. During ventricular pacing at a constant rate, no decrease of the arterial blood pressure was observed during PS. PS in the IVC yielded significantly lower stimulation thresholds than in the SVC.


CONCLUSIONS
Transvenous parasympathetic stimulation for ventricular rate control during AF can easily be achieved in the SVC and IVC in dogs. This procedure may provide a foundation for investigating the usefulness of PS in humans. If the results translate to patients, PS may be very beneficial in the treatment of AF in patients with congestive heart failure.
Schauerte
P
P
Medizinische Klinik I Rheinisch Westfälische Technische Hochschule Aachen. psch@pcserver.mk1.rwth-aachen.de
Scherlag
B J
BJ
D000818:Animals; D001281:Atrial Fibrillation / Q000503:physiopathology / Q000628:therapy*; D001283:Atrioventricular Node / Q000503:physiopathology; D006328:Cardiac Catheterization / Q000295:instrumentation*; D004285:Dogs; D004599:Electric Stimulation Therapy / Q000295:instrumentation*; D004562:Electrocardiography; D004867:Equipment Design; D006321:Heart / Q000294:innervation*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D010275:Parasympathetic Nervous System / Q000503:physiopathology*; D014682:Vena Cava, Inferior / Q000294:innervation; D014683:Vena Cava, Superior / Q000294:innervation