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Characterization of atrial fibrillation in man: studies following open heart surgery
Insights
This study classified atrial fibrillation (AF) based on atrial electrograms (AEG) in 34 patients. Findings reveal human AF is electrophysiologically heterogeneous, varying between patients and over time.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Science
Background:
- Atrial fibrillation (AF) is a complex arrhythmia.
- Understanding localized atrial activation patterns is crucial for characterizing AF.
- Previous studies have not fully elucidated the heterogeneity of atrial activation during AF.
Purpose of the Study:
- To characterize the nature of localized atrial activation during atrial fibrillation.
- To classify atrial electrograms (AEG) based on morphology and baseline characteristics.
- To investigate the electrophysiological heterogeneity of human atrial fibrillation.
Main Methods:
- Bipolar atrial electrograms (AEG) were recorded from 34 patients undergoing open-heart surgery.
- AEGs were analyzed for morphology, polarity, amplitude, and beat-to-beat intervals.
- A four-type classification system was developed based on AEG characteristics and baseline perturbations.
Main Results:
- AEGs displayed significant variability in size, shape, polarity, amplitude, and interval.
- Four distinct AEG patterns (Type I-IV) were identified, reflecting different degrees of atrial activation organization.
- In 11 patients, the type of atrial fibrillation changed between recordings, indicating dynamic changes.
- Atrial flutter-fibrillation patterns correlated with more ordered activation and slower rates.
Conclusions:
- Human atrial fibrillation is an electrophysiologically heterogeneous process.
- Atrial activation patterns can vary significantly among different patients with AF.
- Electrophysiological characteristics of AF can change over time within the same patient.
Abstract:
The nature of localized atrial activation during atrial fibrillation was characterized in 34 patients following open heart surgery. Bipolar atrial electrograms (AEG) recorded in each patient with atrial fibrillation exhibited a myriad of sizes, shapes, polarities, amplitudes, and beat-to-beat intervals. On the basis of the AEG morphology and the nature of its baseline, we have classified the recordings into four Types. Type I was characterized by discrete AEG complexes separated by an isoelectric baseline free of perturbation, Type II by discrete AEG complexes but with perturbations of the baseline between complexes, Type III by AEGs which failed to demonstrate either discrete complexes or isoelectric intervals, and Type IV in which AEGs of Type III alternated with periods characteristic of Type I and/or Type II. In 22 patients, the AEGs were recorded a second time, and in 11 of these patients the type of atrial fibrillation changed between the first and second recording period. An atrial flutter-fibrillation pattern in the ECG was associated with a relatively ordered atrial activation pattern and a relatively slow atrial rate. Human atrial fibrillation is not an electrophysiologically homogeneous process when compared among different patients or ad seriatim in the same patient.