Strikingly, 94% of internists, 58% of cardiologists, and 38% of electrophysiologists misdiagnosed the ECG as VT. 3 The investigators followed up these findings with a survey of internists, cardiologists, and electrophysiologists who were shown an ECG tracing of artifact and asked to make an interpretation. 2 They also found that misdiagnosis occurred by cardiologists, emergency medicine physicians, and house officers, highlighting the importance of recognition of artifact and true arrhythmia across all specialties. Knight et al examined patients who were misdiagnosed with VT and consequently underwent unnecessary interventions ranging from diagnostic coronary angiogram to permanent pacemaker or defibrillator implantation in addition to medical therapy.

Possible explanations for the pseudo-VT seen in this case include tremor, patient movement or disruption in lead placement, all common scenarios in the inpatient setting. The wide QRS complexes suggest VT and the twisting nature of the QRS complexes around an isoelectric line may be interpreted as polymorphic. In the absence of clinical correlation, our patient’s rhythm strip may present a challenge because of how closely it mimics VT. The application of Huang’s algorithm to our patient’s telemetry strips is one clinical tool that can be used to differentiate arrhythmia from artifact in the case of questionable electrocardiographic features. This algorithm was tested in a hospital and was able to correctly diagnose 97.3% of cases. According to the algorithm, the absence of all three signs will lead to the diagnosis of true VT.

The final sign described in the algorithm is the “spike sign” which are small spikes found within QRS complexes. The “notch” sign, also present in our patient is seen where a notch is present on a QRS complex and represents the length of the sinus cycle ( Figure 2). The explanation is that if the upper limbs are not affected by tremor, sinus rhythm will be seen in the corresponding leads. Our patient’s tracing has the characteristic “sinus sign”, wherein sinus rhythm is observed in a frontal or limb lead as demonstrated in leads III and V1 ( Figure 2). 1 According to the algorithm, the presence of any of the three characteristic signs will exclude true VT as the diagnosis. While it can sometimes be a challenge to correctly identify a patient’s rhythm, Huang et al have proposed a tested ECG algorithm to differentiate tremor induced pseudo-VT and true VT. Given that our patient had normal sinus rhythm in two leads, VT could be safely excluded from the differential diagnosis of the patient’s unusual findings. Unlike ischemic changes which are present in specific ECG leads depending on the site of an anatomic lesion, ventricular arrhythmias must be evident in all ECG leads. Notes: Note normal sinus rhythm in leads III and V1 (arrow heads), characteristic of the “sinus sign”.

This finding was most suggestive of pseudo-VT, an incidental artifact requiring no further management or investigation.įigure 2 Expanded telemetry strips to include all electrocardiogram leads. The rhythm on the telemetry monitor was re-examined and expanded to include all ECG leads and it was then noted that normal sinus rhythm was present in two of the seven leads ( Figure 2). Blood pressure at the time of the apparent arrhythmia was 90/64 mmHg, pulse was present and the patient was clinically asymptomatic.

During his hospitalization the medical team was notified by a telemetry technician after noticing sustained polymorphic VT on the monitor. Baseline ECG at the time of admission showed normal sinus rhythm and the patient denied any history of structural heart disease or dysrhythmia ( Figure 1). We present the case of a 48-year-old male whose telemetry rhythm strips appeared to be polymorphic VT but were subsequently confirmed to be artifact.Ī 48-year-old male with no known medical history was transferred to a telemetry unit from intensive care after resolution of meningitis complicated by septic shock. Artifact on electrocardiograms (ECGs) however, can be misinterpreted as VT and this possibility should be considered in an otherwise asymptomatic patient to avoid unnecessary diagnostic or therapeutic interventions. For this reason, its electrocardiographic presence in a patient should be evaluated and managed rapidly. Ventricular tachycardia (VT) has a known association with hemodynamic collapse and a risk of sudden cardiac death.

Telemetry artifact meaning