Subsequent course July 27-29, 2009: The same patient visited a third hospital with the same history. He was admitted to the CCU, where recurrent “VT with syncope” episodes were diagnosed based on telemetry recordings and the patient's report of loss of consciousness. Electrophysiologic assessment was requested. The consulting electrophysiologist diagnosed an artifact based on the following observations (Figure 1): the sharp deflection of the normal QRS complexes that are clearly seen in the second half of the tracing after the artifact stopped marching through the whole rhythm strip (Figure 1, asterisks); the polymorphic ventricular tachycardia/fibrillation–looking signals and the sharp QRS signals sometimes superimposed on each other with an extremely short (<100 milliseconds) coupling interval that physiologically cannot occur (Figure 1, arrows); and the fact that the loss of consciousness—the only piece of information supporting the diagnosis of malignant ventricular arrhythmia—was never witnessed despite multiple episodes in a telemetry-CCU setting. The lack of a cause explaining the tachyarrhythmia and the patient's drug-seeking attitude further supported the suspicion of factitious ventricular tachyarrhythmia. Figure 1 View LargeDownload Telemetry recoding on July 22, 2009, at 11:43 PM. Channel 1: electrocardiogram (ECG) (lead II, 1 mV/10 mm, 25 mm/s speed). Channel 2: ECG (lead V1, 1 mV/10 mm, 25 mm/s speed). Asterisks indicate the true QRS signals marching through the artifact. Arrows indicate nonphysiological short coupling intervals. However, the attending cardiologist was not fully reassured until radial artery pressure monitoring confirmed the presence of an artifact. During an episode of apparent VT, the arterial pressure line (Figure 2, channel 2) demonstrated the continuation of a normal pressure tracing despite the onset of electrical artifact on channel 1. Asterisks indicate the narrow QRS true ECG signals on channel 1 marching through the artifact, and channel 2 shows the pulse pressure coupled to the true QRS signals with an appropriate delay. The pulse pressure tracing does not change with the onset of the artifact, verifying that there is no hemodynamic change associated with the apparent ventricular tachyarrhythmia, and the rhythm remained normal sinus rhythm. The patient left the hospital after the attending cardiologist discussed the findings with him. Figure 2. View LargeDownload Telemetry recoding on July 29, 2009 at 4:27 AM. Channel (Ch) 1: electrocardiogram (ECG) (lead II, 1 mV/10 mm, 25 mm/s speed). Asterisks indicate the true QRS signals marching through the artifact. Channel 2: Radial arterial blood pressure (0-200 mm Hg). The pressure tracing does not change with the onset of the artifact; it continues to show normal sinus rhythm pulse pressure. July 31, 2009: The same patient, now using a different name but the same birth date, presented to yet another hospital with a history of syncope. The patient was admitted to the CCU, where telemetry showed similar VT-like episodes. An artifact was suspected by the attending cardiologist, but he still requested a consultation with an electrophysiologist, who happened to be the same specialist who was consulted before, and recognized the patient by the history and the artifact. Later, the patient was identified as a patient of the addiction program of one of the hospitals. Comment Electrocardiographic artifacts mimicking VT are not rare, especially in an intensive care unit monitoring setting. They are usually caused by poor electrode contact or patient movement. Artifacts may prompt unnecessary investigation and treatment, placing burden on the patients and the health care system.1 Electrocardiographic artifacts are typically unintentional and are not associated with hemodynamic compromise. The presented case is unusual because a patient intentionally produced an artifact that could be mistaken for VT and claimed he had syncope and chest pain to gain access to narcotic drugs. He used multiple health care facilities and even changed his alias after his actions were uncovered. Although the patient was never caught in the act (the episodes mostly occurred at nighttime, when fewer people were around), the numerous episodes of artifact and his claims of syncope with those episodes confirm that he produced them intentionally, possibly by jiggling a lead or tapping on an electrode. Lead jiggling or rhythmic tapping on the skin electrode can produce an artifact that is similar to the presented case.2 This case emphasizes the need for alertness regarding ECG artifacts, especially in telemetry units. Take-home points Electrocardiographic artifacts are not uncommon on telemetry or in other monitoring settings. Artifacts mimicking ventricular tachyarrhythmia may have certain tip-offs such as the normal QRS signals marching through the artifact, nonphysiological short coupling intervals, baseline movement and/or noise, and lack of hemodynamic compromise. Intentional artifacts are rare and can be difficult to uncover. Return to ArticleQuestions The article was corrected for an error in the department heading on February 14, 2011. References 1. Knight BPPelosi FMichaud GFStrickberger SAMorady F Clinical consequences of electrocardiographic artifact mimicking ventricular tachycardia. N Engl J Med 1999;341 (17) 1270- 1274PubMedGoogle ScholarCrossref 2. Falk RHKnowlton AA Atypical ventricular tachycardia or motion artifact? Am J Cardiol 1987;59 (8) 924PubMedGoogle ScholarCrossref
Archives of Internal Medicine – American Medical Association
Published: Feb 14, 2011
Keywords: tachycardia, ventricular,disease outbreaks,artifacts
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