EKG of the Week

A 54 y/o female with history of polyneuropathy presents with chest pain. 

Q1. What is the rhythm?

A1. Sinus Rhythm.

The rhythm is a sinus rhythm. The EKG demonstrates signal interference. This patient had an implanted bladder stimulator which was causing the interference pattern seen on the EKG. Similar patterns are seen in patients with spinal stimulators.

Loose leads, muscle contraction, shivering, tremors, and other patient movement can produce artifactual findings on a monitor, rhythm strip, or 12-lead ECG. Such pseudodysrhythmias can mimic and are often mistaken for serious dysrhythmias, including ventricular fibrillation, illustrating the need to avoid making decisions on the basis of ECG tracings without incorporating the clinical context.

(Yealy et al. Dysrhythmias. In Rosen’s Emergency Medicine, 8th ed. Ch. 79.)