ECG Review
Arrows & Tachycardia
By Ken Grauer, MD, Professor, Dept. of Community Health and Family Medicine, University of Florida. Dr. Grauer reports no financial relationship to this field of study.
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Figure. 12-lead ECG obtained from an elderly woman with shortness of breath. |
Clinical Scenario: The ECG in the Figure was obtained from an elderly woman who was being seen in the office for shortness of breath. No chest pain. What do you make of her "arrows and tachycardia?"
Interpretation/Answer: The QRS complex is narrow and regular at a rate of about 120 beats/minute. The arrows in lead II initially suggest that the rhythm may be sinus tachycardia, however this is not the case. Instead, the small negative undulations in the baseline of the inferior leads should lead one to suspect additional atrial activity. Leads V1 and V2 show this phenomenon best. Two small, pointed upright deflections are seen within each R-R interval in these two leads. This represents regular atrial activity occurring at a rate of 240/minute. The only rhythm that manifests regular atrial activity at this rapid a rate is atrial flutter, shown here with 2:1 AV conduction.
Atrial flutter is by far the most commonly overlooked arrhythmia diagnosis. The key to not missing it is to always maintain a high index of suspicion for the diagnosis, especially when presented with a regular SVT (supraventricular tachycardia) in which the nature of atrial activity is uncertain.
The ECG image in this article was obtained from an elderly woman who was being seen in the office for shortness of breath. No chest pain. What do you make of her "arrows and tachycardia?"You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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