Electrocardiographic artifacts.

ANSWERS 1. e. none of the above The ECG represents a pseudo-arrhythmia due to artifacts. Two clues direct you to the correct interpretation. The first clue reveals sinus rhythm in lead II. The normal appearance of the complexes in lead II is a result of the cancellation of artifacts and not because of a transient return to normal rhythm. The second clue is that most of the leads show sharp deflections that are regular and at the same intervals as those of the R-R cycles in lead II. An example can be seen in Figure 2, where an enlargement of leads II and V3 (taken from Figure 1) reveals “X” marks above the “tips” of the QRS complexes. The native rhythm has been altered by artifacts, which are revealed as small pointed deflections on the “tips” of the QRS complexes. An artifact may be classified as a pseudo-arrhythmia or a nonarrhythmia. In this case, the artifact has the appearance of an arrhythmia. However, artifacts may not resemble an arrhythmia, but nevertheless can alter the configuration of the native underlying rhythm. This altered configuration would occur with misplaced electrodes and is considered to be a nonarrhythmic artifact. Artifacts can be found in any setting where electrocardiographic monitoring information is stored, which includes Holter monitoring, continuous bedside ECG monitoring, or use of event recorders.