HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Respond to This Article Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kilbourne, M. Articles by Sorenson, C. Search for Related Content PubMed PubMed Citation Articles by Kilbourne, M. Articles by Sorenson, C.

My colleague and I use AACN’s "9 features" (those that appear in the ECG Puzzler column) in a basic ECG course we teach to nurses working in the intensive care and telehealth units in our hospital. However, we’ve been wondering about some discrepancies in the column. The first deals with heart rate. Although the ECG Puzzler states that "normal" heart rate is "60–90 beats per minute," the literature (including AACN’s literature) states that a normal rate is 60 to 100/min.

The second problem is with PR interval. According to the ECG Puzzler, a short PR interval is one that is less than 0.08 seconds. However, the literature seems to disagree on this measurement, instead suggesting that a short PR interval is less than 0.12 seconds.

The next point is about QTc and T waves. We would suggest that both of these features could include a check box that reads "cannot determine" for cases in which neither is discernible because of distortion.

Similarly, ST segments could include a check box that reads "flat," because this has been identified as an abnormality of concern in the literature.

Michele Kilbourne, RN, CCRN and Chris Sorenson, RN, MSN, CCRN
Denver, Colo

Mary G. Carey and Michele M. Pelter reply

Our thanks to these authors for their letters. First let’s deal with points the letters have in common.

Yes, it’s true that sinus rhythm historically has been defined as 60 to 100/min. However, physiologically and clinically speaking, sinus rhythm in the resting adult is specifically 44 to 84/min for men and 50 to 90/min for women.^1,2

As for the PR interval, it is normally between 0.12 and 0.20 seconds; therefore, we’ve made a correction to the column beginning with this issue. A QRS duration greater than 0.12 seconds does suggest an intraventricular conduction delay. However, given that it is often difficult to determine exactly where the QRS begins and ends, precise measurements are difficult to ensure. And so, to improve the specificity of identifying a wide QRS in the ECG Puzzler column, the criterion of "greater than 0.12 seconds" (3 small boxes) has been applied.

We concur with Ms Walden that tachycardia is greater than 100/min rather than 120/min. We also agree that there are numerous characteristics of ventricular tachycardia easily applied to a resting 12-lead ECG (eg, QRS axis). Ms Walden is not incorrect in her assessment, but the 4 signs of ventricular tachycardia she outlines are correct only with a particular ECG waveform; for the ECG waveform in our example, Ms Walden’s criteria are not helpful. Also, our overall interpretation was not incorrect; that is, we called it ventricular tachycardia. Because our column only provided a short dual-lead ECG strip typically found in clinical practice, many additional ECG criteria cannot be applied. It is for this reason that we focus on criteria that can be applied, such as QRS width and morphology.

We agree that it is important for the patient to have a cardiac evaluation—that is why we introduced the final paragraph with the word however in italics to emphasize the point. A comprehensive list of possible cardiac procedures (eg, resting ECG, serial ECG, Holter ECG, serum biomarkers, C-reactive protein level, echocardiography, stress test, angiogram, computed tomography scan, magnetic resonance images) is beyond the scope of the ECG Puzzler column. For the sake of brevity, then, we simply used "and so on."

The letter from Kilbourne and Sorenson raises 2 other points. Yes, "cannot determine" is not a fixed option for measures of QTc and T wave, but depending on the scenario presented in the ECG Puzzler we have added it as an option. Although notable, "flat" ST segments are nondiagnostic; in other words, they do not definitively identify a diagnosis. Given that the focus of our column is clinical, however, we prioritized true ST-segment deviation that meets diagnostic criteria.

REFERENCES

1. Yang XS, Beck GJ, Wilkoff BL. Redefining normal sinus heart rate [abstract 749–1]. J Am Coll Cardiol. February 1995:193A.
2. Palatini P. Need for a revision of the normal limits of resting heart rate. Hypertension. 1999;33(2):622–625.[Free Full Text]

This Article Full Text (PDF) Respond to This Article Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Kilbourne, M. Articles by Sorenson, C. Search for Related Content PubMed PubMed Citation Articles by Kilbourne, M. Articles by Sorenson, C.