Antiarrhythmic properties of atrial pacing

Abstract

Bradycardia, atrial stretch and dilatation, autonomic nervous system disorders, and the presence of triggers such as atrial premature contractions, are factors which predispose a person to paroxysmal AF. Atrial pacing not only eliminates bradycardia but also prevents atrial premature contractions and dispersion of refractoriness, which are a substrate for atrial fibrillation. As the prolonged duration of atrial activation during pacing, especially from locations changing the physiological pattern of this activation (right atrium lateral wall, right atrium appendage), negatively influences both a mechanical and an electrical function of the atria, the atrial pacing site affects an atrial arrhythmogenesis. A conventional atrial lead location in the right atrium appendage causes non-physiological activation propagation, resulting in a prolongation of the activation time of both atria. This location is optimal according to a passive fixation of the atrial lead but the available contemporary active fixation leads could potentially be located in any area of the atrium. There is growing evidence of the benefit of pacing, imitating the physiological propagation of impulses within the atria. It seems that the Bachmann's bundle pacing is the best pacing site within the atria, not only positively influencing the atrial mechanical function but also best fulfilling the so-called atrial resynchronization function, in particular in patients with interatrial conduction delay. It can be effectively achieved using only one atrial electrode, and the slight shortening of atrioventricular conduction provides an additional benefit of this atrial pacing site.

Patient with sick sinus syndrome and implanted dual-chamber pacemaker with reduced P-wave duration following low interatrial septal pacing

“…In the presented case, the total Bachmann bundle block did not allow to place the atrial electrode physiologically. For this reason the operators had to use a different approach [14] . The low interatrial septum pacing was used in some dedicated trails which gave inconsistent results.…”

“…For this reason the operators had to use a different approach. [14] The low interatrial septum pacing was used in some dedicated trails which gave inconsistent results. In the SAFE study by Lau et al, in 385 patients with a paroxysmal AF and SSS requiring a pacemaker implantation, an alternative atrial pacing site in the right atrial septum and a continuous atrial overdrive pacing did not prevent from the development of a persistent AF (11).…”

Dlaczego warto stymulować pęczek Bachmanna? Rozważania elektrokardiograficzne i kliniczne

“…The described mechanism is less frequent than the one originating from the 1 st degree atrioventricular block haemodynamics, but the result is more or less the same. Even if atrial pacing has been considered for a long time on physiological grounds, the appropriate location of the atrial electrode can be of crucial importance [6]. The inferior and more lateral positions of the initial atrial electrical activation contribute to prolongation of the P-wave in the electrocardiogram and to inappropriate mechanical function of the atrial pump [7].…”

Review of the epidemiology, pathogenesis and prevention of atrial fibrillation after pacemaker implantation

“…77 Moreover, compared with pacing at the low atrial septum (LAS) near the coronary sinus ostium or the high atrial septum near the Bachmann's bundle, atrial appendage or high RA pacing was more likely to induce AF. 78,79 During atrial septal pacing, the P-wave is even narrower than the sinus P-wave, possibly due to the Bachmann's bundle linking to the connecting fibres in the atria and coronary sinus. 78,80 Therefore, in DDD mode, the incidence of AF is lower in the pacing near the Bachmann's bundle than in the right atrial appendage (RAA) pacing.…”

“…78,79 During atrial septal pacing, the P-wave is even narrower than the sinus P-wave, possibly due to the Bachmann's bundle linking to the connecting fibres in the atria and coronary sinus. 78,80 Therefore, in DDD mode, the incidence of AF is lower in the pacing near the Bachmann's bundle than in the right atrial appendage (RAA) pacing. Similarly, atrial overdrive pacing is more effective in preventing AF in the lower atrial septum than in the RAA.…”