An Instrument Called an Electrocardiograph Picks Up the Electrical Changes

Multiple Choice

An instrument called an electrocardiograph picks up the electrical changes in the heart muscle and amplifies them to record an electrocardiogram in the form of five or six waves. The first five waves are labeled P, Q, R, S, and T. A sixth wave, when present, is called the u wave. Which of the following statements best describes this process?

A) The myocardium is not involved.
B) Electrical changes in the heart are detectable and predictable.
C) Electrical changes in the heart are too faint to be measured.
D) Only diseased hearts give off electrical signals.
E) Electrical activity in the heart is normally steady and unchanging.