The potential for inappropriate ventricular tachycardia confirmation using the Intracardiac Electrogram (EGM) Width...

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• The Intracardiac Electrogram (EGM) Width Criterion is a digital signal processing algorithm used in implantable cardioverter defibrillators (ICDs).
• It aims to enhance ventricular tachycardia (VT) detection specificity by rejecting supraventricular tachyarrhythmias.
• Optimal algorithm activation relies on EGM width testing during sinus rhythm.

Purpose of the Study:

• To evaluate the accuracy of EGM width measurements during exercise testing.
• To identify potential inaccuracies in EGM width criterion performance under exercise conditions.
• To inform optimal programming of ICDs.

Main Methods:

• Twenty-one patients with Medtronic Micro Jewel II Model 7223 ICDs participated.
• Treadmill exercise testing was performed.
• EGM width testing was repeatedly conducted during exercise and recovery phases.

Main Results:

• In 33% of patients (7/21), the EGM Width Criterion inappropriately confirmed VT detection.
• Eleven patients exhibited inappropriately wide EGM width measurements that did not meet the criterion.
• Causes included increased EGM width and misidentification of baseline irregularities as EGM onset/offset points.

Conclusions:

• The EGM Width Criterion may lead to inaccurate VT detection during exercise.
• Exercise testing is crucial for evaluating and optimizing the EGM Width Criterion.
• Recommendations are made for improved ICD programming based on exercise testing results.