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Sinus node electrogram study on sinus pacemaker shifts.
Acta Cardiologica
|January 1, 1989
Summary
Sinus pacemaker shifts, changes in the heart's natural pacemaker location, are more frequently induced by overdrive atrial pacing in patients with sick sinus syndrome (SSS). This finding aids in evaluating sinus node function.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- The human sinus node possesses dominant and subsidiary pacemaker foci.
- Sinus node dysfunction (SND) affects cardiac rhythm and requires accurate diagnostic methods.
Purpose of the Study:
- To investigate sinus pacemaker shifts and their clinical significance.
- To assess spontaneous and pacing-induced sinus pacemaker shifts in patients with and without sick sinus syndrome (SSS).
Main Methods:
- Stable sinus node electrograms (SNE) were obtained from 43 patients (8 with SSS, 35 without).
- Spontaneous and overdrive atrial pacing-induced sinus node electrograms were analyzed.
- Sinus pacemaker shifts were correlated with sinoatrial conduction time (SACTd) and sinus cycle length (SCL).
Main Results:
- Spontaneous sinus pacemaker shifts occurred similarly in normal and SSS groups (11.4% vs 12.5%).
- Overdrive atrial pacing induced sinus pacemaker shifts more frequently in the SSS group (62.5%) compared to the normal group (25.7%) (P < 0.05).
- Induced shifts were associated with loss/inversion of primary positivity, P wave changes, and prolonged SACTd and SCL.
Conclusions:
- The human sinus node exhibits multiple active pacemaker sites.
- Overdrive atrial pacing effectively unmasks sinus pacemaker shifts in patients with SSS.
- This method may serve as a valuable tool for assessing sinus node function in clinical practice.
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