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Dissociation between coronary sinus and left atrial conduction in patients with atrial fibrillation and flutter
G Ndrepepa1, B Zrenner, M A Schneider
1Deutsches Herzzentrum München and 1. Medizinische Klinik, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
Insights
Electrical signals in the coronary sinus (CS) can become dissociated from left atrial (LA) activity during atrial fibrillation and flutter. This dissociation occurs during spontaneous arrhythmias and pacing, impacting electrophysiologic study interpretations.
Area of Science:
- Electrophysiology
- Cardiac Electrophysiology
- Arrhythmia Mechanisms
Background:
- Coronary sinus (CS) recordings are standard in electrophysiologic studies, assumed to reflect left atrial (LA) activity.
- The electrical behavior of the CS during atrial arrhythmias has not been extensively studied beyond routine interpretations.
Purpose of the Study:
- To investigate the relationship between coronary sinus (CS) and left atrial (LA) electrical activity during spontaneous and induced atrial arrhythmias.
- To determine if dissociation of conduction occurs between the CS and posterior LA.
Main Methods:
- Simultaneous mapping of the LA, CS, and RA in 9 patients with atrial fibrillation (AF) and atrial flutter (AFL).
- Utilized a 64-electrode basket catheter for LA/RA mapping and a multipolar catheter for CS mapping.
- Assessed CS electrical activity during spontaneous arrhythmias and rapid atrial pacing from the proximal CS.
Main Results:
- Dissociation of conduction between the CS and posterior LA was observed in patients with spontaneous AF and AFL.
- Double potentials were noted in CS recordings during arrhythmias.
- CS activation patterns showed dissociation from posterior LA in 7 of 9 patients.
- A case of macroreentrant left atrial tachycardia involving CS muscle was identified.
- Pacing from the proximal CS induced longitudinal dissociation of CS activation.
Conclusions:
- Conduction between the CS and posterior LA can be dissociated during spontaneous atrial arrhythmias.
- Provocative proximal CS pacing can also lead to dissociation of CS and LA activation.
Introduction:
Coronary sinus (CS) recordings are routinely used during electrophysiologic studies for various supraventricular and ventricular arrhythmias with the understanding that they represent left atrial (LA) activity. However, the behavior of CS electrical activity during atrial arrhythmias has not drawn any special attention beyond standard considerations.
Methods And Results:
The study population consisted of 9 patients (3 women; mean age 59 +/- 11 years) with atrial fibrillation (AF) and atrial flutter (AFL) who developed dissociation of conduction between the CS and posterior LA during spontaneous AF and AFL. In all patients, the LA and the CS were mapped using a 64-electrode basket catheter and a multipolar electrode catheter, respectively. The right atrium (RA) was mapped simultaneously using a 24-polar electrode catheter (7 patients) or a 64-electrode basket catheter (2 patients). Eight patients showed stable double potentials in CS recordings during AF (9 episodes) and AFL (3 episodes). During ongoing arrhythmias, the first row of potentials maintained a constant relationship with the RA activity, whereas the second row of potentials was discordant with the posterior wall of the LA in 7 patients and concordant in 2 patients. In 1 patient with counterclockwise AFL, CS activation was isolated from the posterior wall of the RA until it reached the distal portion of the CS, after which it entered the lateral region of the LA. In 1 patient, a macroreentrant LA tachycardia involving CS muscle was observed. Rapid atrial pacing from the proximal CS and extrastimuli produced longitudinal dissociation of CS activation in all patients.
Conclusion:
Conduction between the CS and posterior LA can be dissociated during spontaneous atrial arrhythmias and provocative proximal CS pacing.