Quantitative assessment of ventricular far field removal techniques for clinical unipolar electrograms

Abstract

The incidence of atrial tachycardia steadily increases in industrial nations. During invasive electrophysiological studies, a catheter measures electrograms within the atrium to assist detailed diagnosis and treatment planning. With unipolar and bipolar electrograms, two different acquisition modes are clinically available. Unipolar electrograms have several advantages over bipolar electrograms. However, unipolar electrograms are more affected by noise and the ventricular far field. Therefore, only bipolar electrograms are typically used in clinical settings. A recently published ventricular far field removal technique models the ventricular far field by a set of dipoles and yielded promising results in a simulation study. However, the method lacks quantitative clinical validation. Therefore, we adapted the technique to clinical needs and applied it to data sets of two patients using four different lengths of the removal window. Results were compared quantitatively by a tailored residual error measure. The used method resulted in a median reduction of the ventricular far field by approximately 89% using a removal window of optimal length for both patients. The results showed that the dipole method provides an alternative to other VFF removal techniques in clinical practice because it can reveal AA originally hidden by VFF without leading to a prolongation of the electrophysiological study.

Keywords

• electroanatomic mapping
• atrial electrograms
• unipolar electrograms
• ventricular far field removal.