Woman with chest wall mass and abnormal ECG.

PATIENT PRESENTATION

A previously healthy, 59‐year‐old female presented to the emergency department (ED) from interventional radiology (IR) because of concerns of non‐sustained ventricular tachycardia (NSVT). The patient had presented for an IR‐guided biopsy of a recently diagnosed left‐sided, anterior rib mass that was suspected to be a metastasis from an unknown malignancy. Before biopsy, her cardiac monitor displayed possible NSVT. The patient was asymptomatic and hemodynamically stable. She did note a mild muscle twitching sensation above the tumor. Patient was transported to the ED where an electrocardiogram (ECG) was performed (Figure 1).

FIGURE 1

ECG upon presentation to the emergency department. Abbreviation: ECG, electrocardiogram

DIAGNOSIS

Pseudo‐ventricular tachycardia

Upon closely examining the ECG, one can see QRS complexes buried within the artifact (blue arrows, Figure 2). The presence of concurrent normal beats in other leads can also help identify artifact (red arrows, Figure 2). The patient also had a well‐defined oxygen plethysmograph (pleth) waveform when juxtaposed to the artifact on the monitor (Figure 3). In addition, while the patient was having the above rhythm, her pulses were noted to be regular at a rate of 80–90 beats per minute. If pseudo‐ventricular tachycardia is in question, we recommend a clinician consider all of this before escalating care. Our patient was briefly initiated on amiodarone. Escalation of unnecessary care in the setting of pseudo‐ventricular tachycardia is common and has been shown to include interfacility patient transfers, prolonged courses of antiarrhythmic drugs, cardiac catherization, and even pacemaker placement.

FIGURE 2

Blue arrows demonstrate buried QRS beats within the artifact. Red arrows demonstrate normal sinus beats occurring at the same time as the artifact

FIGURE 3

Well‐developed oxygen pleth waveform (bottom blue) occurring at the same time as the artifact above it

Patient movement or tremors are a common reason for artifact. Care was taken to make sure our patient was lying completely still. Any time skeletal muscle moves beneath electrodes, random electrical activity may falsely manifest as an arrhythmia. To the best of our knowledge, pseudo‐ventricular tachycardia has never been attributed to muscle twitching from an underlying tumor.