What is the clinical evidence from this study?

Study design: Review. Population: Cardiac arrhythmias. Intervention: Electrogram recording and analyzing techniques.

What question did this study set out to answer?

The aim is to evaluate techniques for optimizing electrogram recording to select target sites for cardiac arrhythmia ablation.

October 14, 2019Open Access

Electrogram recording and analyzing techniques to optimize selection of target sites for ablation of cardiac arrhythmias

Key Result

A combination of unipolar and bipolar electrogram analysis techniques is helpful to optimize determination of target sites for ablation of cardiac arrhythmias.

Key Points

The aim is to evaluate techniques for optimizing electrogram recording to select target sites for cardiac arrhythmia ablation.
Review of unipolar and bipolar electrogram recording techniques and their characteristics.
Discussion of activation-repolarization mapping and decremental stimulation to evaluate arrhythmogenic areas.
Analysis of substrate mapping pitfalls and the use of omnipolar mapping.
Combination of unipolar and bipolar electrogram analysis is beneficial for identifying optimal ablation sites.
Techniques to assess high reentry vulnerability demonstrated improved identification of arrhythmogenic areas.
Factors like electrode size and catheter position significantly influence electrogram morphology.

Structured PICO

Intervention

Electrogram recording and analyzing techniques (unipolar and bipolar modes)

Outcome

Optimization of target sites for ablation

A combination of unipolar and bipolar electrogram analysis techniques provides complementary information to optimize target site selection for arrhythmia ablation.

Abstract

The extracellular electrogram is caused by transmembrane currents that flow into extracellular space during propagation of the electrical impulse. Electrograms are usually recorded in unipolar or bipolar mode that have different characteristics, but provide complementary information. Both recording modes have specific advantages, but also suffer from disadvantages. Techniques to circumvent some of the weaknesses are reviewed. The origin of remote and fractionated deflections and their relation with electrode characteristics are discussed. Epicardial and endocardial sites of origin and breakthrough sites as well as the effect of fatty tissue on extracellular electrograms are presented. Induction of tachycardia to assess the arrhythmogenic area is not always possible because of hemodynamic instability of the patient. Techniques to assess sites with high reentry vulnerability without induction of arrhythmias are outlined such as activation-repolarization mapping and decremental stimulation. Pitfalls of substrate mapping and techniques to avoid them as omnipolar mapping and characterization of complex electrograms by entropy are presented. Technical aspects that influence electrogram morphology as electrode size, filtering, contact force, and catheter position are delineated. Data from the various publications suggest that a combination of unipolar and bipolar electrogram analysis techniques is helpful to optimize determination of target sites for ablation.