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High-Resolution Endocardial and Epicardial Optical Mapping in a Sheep Model of Stretch-Induced Atrial Fibrillation
Published on: July 29, 2011
Differentiating atrial tachycardias with centrifugal activation: Lessons from high-resolution mapping
Masateru Takigawa1, Takamitsu Takagi1, Claire A Martin2
1Lyric Institute, CHU Bordeaux, Université de Bordeaux, Bordeaux-Pessac, France; Department of Cardiology, Tokyo Medical and Dental University, Tokyo, Japan.
Insights
Centrifugal activation in atrial tachycardia (AT) can be pseudo-focal, not always true-focal. An activation map with atrial global activation histogram (GAH) accurately differentiates these origins.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Imaging
Background:
- Centrifugal activation in focal atrial tachycardia (AT) can originate from true-focal sources or pseudo-focal sources due to passive activation.
- Distinguishing between true-focal and pseudo-focal AT is crucial for effective treatment strategies.
Purpose of the Study:
- To develop and validate a method for differentiating true-focal from pseudo-focal centrifugal activations in atrial tachycardia.
- To identify specific electrocardiographic and electrophysiological markers indicative of each activation type.
Main Methods:
- Analysis of 49 centrifugal activations in 35 patients with AT using 12-lead ECG, activation mapping, atrial global activation histogram (GAH), and local electrograms.
- GAH was used to visualize the relationship between activation area and timing relative to the cardiac cycle length.
Main Results:
- In the septal region, 80% of centrifugal activations were pseudo-focal, often originating from the opposite chamber. P-wave/flutter-wave duration < 200 ms was a key differentiator.
- Outside the septal region, pseudo-focal activations were frequently epicardial, often near the left atrial appendage. GAH scores and flutter wave characteristics effectively differentiated true-focal from pseudo-focal AT.
- Specific criteria including activation area < 5 mm², QS pattern electrograms, and GAH parameters demonstrated high accuracy in differentiating true-focal from pseudo-focal AT.
Conclusions:
- Centrifugal activation in AT is not exclusively from true-focal origins; passive pseudo-focal activation is common.
- Combining activation mapping with GAH, 12-lead ECG, and local electrograms provides an accurate method for differentiating true-focal from pseudo-focal AT.
- The study highlights the utility of GAH and specific ECG parameters in improving diagnostic accuracy for complex atrial tachycardias.
Background:
Centrifugal activation is not always the origin of a focal atrial tachycardia (AT) ("true-focal"), but passive activation from the other structures ("pseudo-focal").
Objective:
We aimed to establish a method to differentiate true-focal from pseudo-focal.
Methods:
In 49 centrifugal activations in 35 patients with AT, 12-lead electrocardiogram, activation map, atrial global activation histogram (GAH), and local electrograms were analyzed. GAH demonstrates the relation between the activation area and timing through the cycle length, displayed with a normalized value, ranging from 0 (smallest activation area) to 1.0 (largest activation area).
Results:
Of 30 centrifugal activations observed in the septal region, 6/30 (20.0%) were true-focal. The remaining 24/60 (80.0%) were pseudo-focal, of which 23 (95.8%) were from the opposite chamber. P-wave/flutter-wave duration < 200 ms discriminated true-focal from pseudo-focal (sensitivity 100%; specificity 54.5%; positive predictive value 33.3%; negative predictive value 100%). Multiple breakthrough ruled out the possibility of a true-focal AT. Other differentiating factors were an activation area within the initial 20 ms of <5 mm2 and a typical QS pattern electrogram at the origin. Of 19 centrifugal activations observed outside the septal regions, 7 were true-focal and 12 were pseudo-focal exited from an epicardial structure: 10 of 12 (83.3%) were located around the left atrial appendage and ridge. Flutter wave, GAH score ≤ 0.05, and GAH score < 0.1 for >110 ms of cycle length differentiated true-focal from pseudo-focal with a sensitivity/negative predictive value of 100%. GAH score < 0.1 for >40% of the cycle length simply discriminated true-focal from pseudo-focal with 100% accuracy.
Conclusion:
Centrifugal activation is not necessarily due to a focal AT but passive activation. The activation map with GAH in addition to the 12-lead electrocardiogram and local electrograms enables an accurate differentiation.
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