Correspondence

Electrocardiographic Artifact

N Engl J Med 2000; 342:590-592February 24, 2000

Article

To the Editor:

Knight et al. (Oct. 21 issue)1 describe electrocardiographic artifacts that mimic ventricular tachycardia and the consequences of this phenomenon on patient care. At our institution as well, too many artifacts are misread as ventricular tachycardia, with unnecessary interventions and prolonged cardiac monitoring performed as a result.

In educating our house staff and other colleagues on the recognition of this type of artifact, we have found it useful to point out an electrocardiographic sign that is frequently present in pseudo–ventricular tachycardia as a result of artifact. The “notches sign,” which is visible in the illustrations in the article by Knight et al., is shown in the three recordings in Figure 1Figure 1The “Notches Sign” of Wide-Complex Artifact.. In all three patients an underlying sinus tachycardia was interrupted by what appears to be rapid, wide-complex tachycardia. During these episodes, the appearance of black notches on the electrocardiogram may reflect the superimposition of intrinsic sinus beats on artifact. To confirm the presence of artifact, one need only establish that the notch-to-notch intervals correspond to the sinus RR intervals, as can easily be done in each of these recordings. The notches sign is especially useful in cases in which the native QRS complexes are not readily recognizable within the apparent instance of rapid, wide-complex tachycardia, as in Figure 1.

Of note, in all three cases, administration of intravenous lidocaine was started for the presumed rapid polymorphic ventricular tachycardia, despite the patients' hemodynamic stability and despite a pressure tracing (Figure 1C) that clearly demonstrated the absence of true arrhythmia.

Laszlo Littmann, M.D.
Michael H. Monroe, M.D.
Carolinas Medical Center, Charlotte, NC 28232

1 References

1. 1

   Knight BP, Pelosi F, Michaud GF, Strickberger SA, Morady F. Clinical consequences of electrocardiographic artifact mimicking ventricular tachycardia. N Engl J Med 1999;341:1270-1274
   Full Text | Web of Science | Medline

To the Editor:

It is noteworthy that of the 12 patients described by Knight et al., 9 had no symptoms.

Back in the 1960s, I was training critical care nurses, and I would teach them that when they observed ventricular tachycardia on a monitor, they should go and examine the patient before initiating any pharmacologic or electrical intervention. Frequently, the nurses would discover that the apparent arrhythmia was the result of a simple bedside activity such as the patient's brushing his or her teeth.

This arrhythmia might be called “toothbrush tachycardia.” Although these electrocardiographic recordings were frequently used as teaching tools, we never fell into the trap of implanting pacemakers.

Robert M. Smith, D.O.
1004 Deep Woods Trail, Brentwood, TN 37027

To the Editor:

We would like to offer two clinical suggestions that might have prevented some of the unnecessary interventions described by Knight et al. Incorporation of these suggestions into guidelines for clinical practice might curtail unnecessary use of expensive therapies.

When possible, auscultation with a stethoscope (pioneered by Laennec) or palpation of the patient's pulse (described by Hippocrates) during electrocardiographic events can add meaningful data to the decision-making process, particularly if the events are recurrent. Perhaps intraarterial blood-pressure monitoring or transcutaneous plethysmography could be considered in place of physical examination, since these procedures are reimbursed.

Nonetheless, examination of the patient remains a useful clinical tool.

Robert W. Smith, M.D.
Ronald M. Unice, D.O.
Leanne Chrisman, M.D.
Meadville Medical Center, Meadville, PA 16335

To the Editor:

Knight et al. point out the consequences that can occur when electrocardiographic artifact is misdiagnosed as ventricular tachycardia. The authors do not emphasize, however, the obvious dire consequences of failure to recognize true ventricular tachycardia, which as a precursor of ventricular fibrillation is among the most common immediate causes of death that may be amenable to lifesaving therapy. The reader can only wonder how many avoidable deaths preceded by unrecognized ventricular tachycardia occurred among the source population during the five-year period of the study.

When life is in the balance, as is often the case in patients with ventricular tachycardia, unnecessary administration of lidocaine seems preferable to inappropriate neglect of treatment.

Anthony Squire, M.D.
Noelle Langan, M.D.
Jonathan Halperin, M.D.
Mount Sinai School of Medicine, New York, NY 10029

Author/Editor Response

The authors reply:

To the Editor: We appreciate the suggestions for techniques to improve the identification of electrocardiographic artifact and therefore avoid unnecessary procedures for patients. To establish the presence of artifact, as many clues as possible should be sought. Because it is rarely possible to examine a patient when a transient abnormality in rhythm is being recorded, accurate confirmation of artifact usually depends on a high index of suspicion and careful analysis of the electrocardiogram.

We agree with Squire and colleagues that when the available clues are insufficient to confirm the presence of artifact, an apparent wide-complex tachycardia should be considered a true arrhythmia, and in some instances treatment with lidocaine may be appropriate. However, the presence of artifact could be established with certainty in each of our cases by careful analysis of the electrocardiographic recordings. Therefore, in the patients in our series, treatment with lidocaine or other therapeutic interventions was not appropriate.

Bradley P. Knight, M.D.
Fred Morady, M.D.
University of Michigan Medical Center, Ann Arbor, MI 48109-0022

Citing Articles (4)

Citing Articles

1. 1

   R. Mahamdia, C.L. Peng, F. Héritier, K. Djédaïni, M. Roger. (2008) Pseudotorsade de pointe chez une patiente âgée de 88 ans. La Revue de Médecine Interne 29:5, 415-417
   CrossRef

2. 2

   2008. Misplacement of Leads and Electrocardiographic Artifacts. , 586-597.
   CrossRef

3. 3

   William D. Brearley, Lee Taylor, Michael W. Haley, Laszlo Littmann. (2007) Pneumomediastinum mimicking acute ST-segment elevation myocardial infarction. International Journal of Cardiology 117:2, e73-e75
   CrossRef

4. 4

   Julián Ortega-Carnicer. (2005) Tremor-related artefact mimicking ventricular tachycardia. Resuscitation 65:3, 243-244
   CrossRef