Gubner-Ungerleider Index (ECG LVH) Calculator

Gubner–Ungerleider Index — explanation and clinical context The Gubner–Ungerleider voltage index is an early electrocardiographic voltage criterion intended to detect left ventricular hypertrophy (LVH). It is calculated as the algebraic sum of the amplitude of the R wave in lead I plus the amplitude of the S wave in lead III (R(I) + S(III)). Classic sources and many contemporary reviews report a commonly used threshold of >25 mm (≈2.5 mV) for suggesting LVH by this index.

The index historically demonstrates high specificity but low sensitivity compared with imaging-based standards (i.e., it misses many cases of anatomic LVH while a positive result increases the likelihood of true LVH). Clinically, a Gubner–Ungerleider-positive ECG should prompt consideration of imaging (echocardiography) for confirmation, and be interpreted in the context of clinical risk factors (hypertension, age, body habitus) and other ECG criteria (for example, Sokolow–Lyon and Cornell voltage criteria). This template uses inputs in millimetres (mm) — please convert from mV when required (1 mV = 10 mm).

Reference (original and key reviews): Gubner R, Ungerleider HE. Electrocardiographic criteria of left ventricular hypertrophy: factors determining the evolution of the electrocardiographic patterns in hypertrophy and bundle branch block. Arch Intern Med.

1943;72:196–209. Additional evaluations, contemporary comparisons and performance data are reported in modern ECG-LVH accuracy studies and reviews (see references below).