Key result
Interatrial septum pacing with vagal stimulation prolongs A-V intervals ~9 ms more than coronary sinus pacing.
Why the study?
The effect of phasic vagal stimulation on atrioventricular conduction time may depend on the site of atrial pacing, which has not been fully characterized.
Answers are grounded in this paper and cite their sources.
Pacing site effects on vagal AV conduction in dogs should not change practice; leaves open translation to human arrhythmia management.
We tested the hypothesis that the effect of phasic vagal stimulation on atrioventricular (AV) conduction time is affected by the site of atrial pacing in anesthetized dogs. We paced the right atrium at a constant cycle length from the interatrial septum (IAS), superior coronary sinus (SCS), or inferior coronary sinus (ICS) regions, and we evaluated the time-dependent effects of vagal stimulation on AV conduction at each pacing site. When we stimulated the vagi at stimulus (St)-A phases greater than 136 +/- 40 ms and less than the phase that blocked AV conduction (182 +/- 70 ms), IAS pacing prolonged A-V intervals by 8.6 +/- 8.2 ms more than ICS pacing. A change in pacing site affected the A-V intervals by up to 30 ms when we stimulated the vagus at those times that caused the A-V intervals to prolong maximally. Furthermore, the effect of atrial pacing site on A-V intervals was modulated by AV nodal recovery times during the second or third cycles after the vagal stimulus.
No takes yet. Share an insight, caveat, or question.
Igel et al. (1997) studied this question. Interatrial septum (IAS) pacing during phasic vagal stimulation vs. Inferior coronary sinus (ICS) pacing was evaluated on Atrioventricular (AV) conduction time (A-V intervals) (Mean difference 8.6 +/- 8.2 ms). Phasic vagal stimulation combined with interatrial septum pacing prolonged A-V intervals by 8.6 +/- 8.2 ms more than inferior coronary sinus pacing in anesthetized dogs.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: