[Departure map]

Abstract

Departure maps were developed for the easy recognition of abnormalities on the body surface potential maps. To construct departure maps, mean (m) and standard deviation (SD) was calculated for each lead to a value, such as potential, time-integral value, ventricular activation time, etc. For a measured value (x) of each lead, departure index was calculated as (x-m)/SD. The departure maps demonstrated body surface distribution of the departure index. Areas of departure index > 2 or < -2 were considered abnormal. Departure maps represent the location and extent of abnormal increase or decrease, and are useful for the assessment of myocardial infarction, ventricular hypertrophy, and myocardial ischemia. This technique may be applied to various parameters of body surface mapping.