Bipolar electrogram amplitudes in the left atrium are related to local conduction velocity in patients with atrial...

Area of Science:

• Electrophysiology
• Cardiology
• Medical Imaging

Background:

• Atrial fibrillation (AF) is a common arrhythmia.
• The relationship between bipolar electrogram amplitude and local conduction velocity (CV) in AF patients is not well understood.
• Understanding these electrophysiological properties can aid in diagnosing and treating AF.

Purpose of the Study:

• To investigate the correlation between bipolar electrogram amplitude and local CV in the left atrium (LA) of patients with AF.
• To define low-voltage zones (LVZs) and assess their electrophysiological characteristics.
• To determine if LVZs are associated with abnormal electrical potentials.

Main Methods:

• Contact bipolar voltage mapping of the LA was performed in 50 AF patients during sinus rhythm.
• Patients were categorized into three groups based on electrogram amplitude levels (<0.5 mV, 0.5-0.75 mV, 0.75-1.0 mV).
• Local CV was calculated within LVZs and non-LVZs, and the incidence of fractionated or double potentials was assessed.

Main Results:

• Low-voltage zones were consistently identified in the septal, anterior, and posterior LA across all groups.
• In the group with the lowest electrogram amplitudes (<0.5 mV), CV in the LVZ was significantly slower (0.8 m/s) compared to non-LVZ areas (1.4 m/s).
• The incidence of fractionated or double potentials was significantly higher in the lowest amplitude group (26%) compared to the other groups (6% and 5%).

Conclusions:

• A significant slowing of local conduction occurs within low-voltage zones (<0.5 mV) in AF patients.
• These low-voltage zones are frequently associated with fractionated or double potentials, suggesting localized electrical abnormalities.
• The findings highlight the electrophysiological significance of low-voltage areas in the context of atrial fibrillation.