Understanding a High LEWIS Index in EKG: Causes & Implications

What Is LEWIS Index In an EKG Exam?

LEWIS index describes the ratio between heart rate in bpm during atrial pacing versus sinus rhythm. It should not exceed approximately 1 in most situations

Abnormally High

Abnormal if index <1 (i.e., if atrial conduction > ventriculoarterial [ventricular plus arterial segment] interval during pacing, indicating an intact His–Purkinje system despite underlying disease)