EGM Width Criterion

The GEM II VR and GEM III VR devices feature the EGM Width Criterion to enhance detection specificity. The EGM Width Criterion reduces inappropriate therapies due to rapidly conducted sinus tachycardia, atrial fibrillation, or atrial flutter. The criterion uses ventricular EGM morphology to discriminate wide-complex tachycardia from narrow-complex tachycardia. In a clinical trial, the EGM Width Criterion increased VT detection specificity by 88%.

As a diagnostic tool, the EGM Width Criterion provides QRS snapshots — for visual confirmation of appropriate width classification.

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QRS Snapshot from a detected WIDE complex tachycardia.

This diagram represents the eight QRS complexes used to discriminate between a VT and an SVT. The eight complexes are available when the EGM Width detection criterion is programmed ON or PASSIVE. In this example, all eight complexes are designated WIDE, which suggests appropriate VT detection.

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QRS Snapshot from a detected NARROW complex tachycardia.

In this example, the QRS complexes are reported for a narrow-complex rhythm because the EGM Width Criterion is programmed to PASSIVE. If the EGM Width Criterion was programmed ON, this sinus tachycardia episode would not have been treated, and would have been reported as a non-sustained episode.

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