Relationship between surface electrocardiogram characteristics and endocardial activation sequence in patients with...

Area of Science:

• Cardiology
• Electrophysiology
• Medical Imaging

Background:

• The relationship between endocardial and surface electrocardiogram (ECG) activity in atrial flutter (AFl) is not fully understood.
• Accurate delineation is crucial for understanding AFl mechanisms and improving patient care.

Purpose of the Study:

• To determine the precise relationships between atrial endocardial activity and surface ECG findings in patients diagnosed with AFl.
• To correlate specific atrial activation patterns with surface ECG deflections.

Main Methods:

• Utilized a 64-electrode basket catheter in the right atrium (RA) and a decapolar catheter in the coronary sinus (CS) for left atrial recordings in 40 AFl patients.
• Employed electronic calipers to analyze the temporal relationship between endocardial and surface ECG activity.

Main Results:

• In counterclockwise AFl, RA lateral wall activation correlated with positive deflections in leads I, V1, V6, and inferior leads. Isthmus conduction time strongly correlated with plateau duration in lead III (r=0.91).
• In clockwise AFl, the F wave showed notching, with the first component from RA septum/posterior wall activation and the second from CS activity. Interatrial conduction time correlated with the interval between these deflections (r=0.84) and was prolonged compared to sinus rhythm (p=0.04).
• Activation of the RA lateral wall corresponded to negative components in leads I, inferior leads, and V6.

Conclusions:

• Surface ECG electrical activity demonstrates a strong correlation with conduction patterns in specific atrial regions.
• The polarity of the F wave on an ECG is determined by the combined electrical forces from the RA lateral wall and the left atrium.