Cornell Criteria
Content
Cornell Voltage Criteria
Mary G. Carey and Michele M. Pelter
Am J Crit Care 2008;17:273-274
© 2008 American Association of Critical-Care Nurses Published online http://www.ajcconline.org Personal use only. For copyright permission information: http://ajcc.aacnjournals.org/cgi/external_ref?link_type=PERMISSIONDIRECT
Subscription Information http://ajcc.aacnjournals.org/subscriptions/ Information for authors http://ajcc.aacnjournals.org/misc/ifora.shtml Submit a manuscript http://www.editorialmanager.com/ajcc Email alerts http://ajcc.aacnjournals.org/subscriptions/etoc.shtml
AJCC, the American Journal of Critical Care, is the official peer-reviewed research journal of the American Association of Critical-Care Nurses (AACN), published bimonthly by The InnoVision Group, 101 Columbia, Aliso Viejo, CA 92656. Telephone: (800) 899-1712, (949) 362-2050, ext. 532. Fax: (949) 362-2049. Copyright © 2008 by AACN. All rights reserved.
Downloaded from ajcc.aacnjournals.org by guest on October 2, 2011
ECG Puzzler
A regular feature of the American Journal of Critical Care, the ECG Puzzler addresses electrocardiogram (ECG) interpretation for clinical practice. To send an eLetter or to contribute to an online discussion about this article, visit www.ajcconline.org and click “Respond to This Article” on either the full-text or PDF view of the article. We welcome letters regarding this feature.
CORNELL VOLTAGE CRITERIA
By Mary G. Carey, RN, PhD, and Michele M. Pelter, RN, PhD
Scenario: An 83-year-old woman with ischemic cardiomyopathy comes in for a routine checkup. She is receiving appropriate medical management with pharmacological agents and has had no acute symptoms.
V3
aVL
For every ECG, we recommend that readers systematically examine the following 9 features (check all that apply): 1. Rate K Normal (60-90 beats per minute) K Bradycardia (<60 beats per minute) K Tachycardia (>90 beats per minute) 2. Rhythm K Regular K Irregular K Irregular-regular 3. P waves K One P wave for every QRS complex K Fewer P waves than QRS complexes K More P waves than QRS complexes K Cannot determine 4. PR interval K Normal (≤0.20 seconds) K Short (<0.08 seconds) K Lengthened (>0.20 seconds) K Cannot determine
5. QRS complex duration K Normal (≤0.12 seconds) K Wide (>0.12 seconds) 6. QRS complex direction lead V1 K Negative and ≤0.12 seconds (normal) K Negative and >0.12 seconds (LBBB) K Positive and >0.12 seconds (RBBB) K Cannot determine 7. ST segments K Normal K Elevated (≥2 mm) K Depressed (≥2 mm) K Elevation/depression 2 contiguous (side by side) leads (≥1 mm) 8. T wave K Normal K Inverted 9. QTc K Normal K Lengthened (>0.47 seconds)
About the Authors
Mary G. Carey is an assistant professor in the School of Nursing at the State University of New York at Buffalo. Michele M. Pelter is an assistant professor at the Orvis School of Nursing, University of Nevada, Reno.
www.ajcconline.org
AJCC AMERICAN JOURNAL OF CRITICAL CARE May 2008, Volume 17, No. 3 Downloaded from ajcc.aacnjournals.org by guest on October 2, 2011
273
V3
aVL
ANSWERS 1. Rate K Normal (60-90 beats per minute) K Bradycardia (<60 beats per minute) K Tachycardia (>90 beats per minute) 2. Rhythm K Regular K Irregular K Irregular-regular 3. P waves K One P wave for every QRS complex K Fewer P waves than QRS complexes K More P waves than QRS complexes K Cannot determine 4. PR interval KNormal (≤0.20 seconds) K Short (<0.08 seconds) K Lengthened (>0.20 seconds) K Cannot determine
5. QRS complex duration K Normal (≤0.12 seconds) K Wide (>0.12 seconds) 6. QRS complex direction lead V1 K Negative and ≤0.12 seconds (normal) K Negative and >0.12 seconds K Positive and >0.12 seconds K Cannot determine 7. ST segments K Normal K Elevated (≥2 mm) K Depressed (≥2 mm) K Elevation/depression 2 contiguous (side by side) leads (≥1 mm) 8. T wave K Normal K Inverted 9. QTc K Normal K Lengthened (>0.47 seconds)
Interpretation
Controlled atrial fibrillation at 83/min, with left ventricular hypertrophy (LVH)
Rationale
Atrial fibrillation is present with irregularly irregular ventricular activity in the absence of discrete P waves for every QRS. Although the third QRS complex has what appears to be a P wave in front of it, this pattern is not consistent throughout the strip. The ventricular rate is fewer than 100/min; therefore, the ventricular response is “controlled.” The Q wave in aVL (nearly ≥40-ms duration) suggests a prior myocardial infarction; given the patient’s cardiomyopathy, the contiguous lateral leads, I and V6, also should be evaluated. The amplitude of the S wave in V3 suggests this patient may have LVH. Although the Cornell Product is the best method for ECG diagnosis of LVH (sensitivity, 51%; specificity, 95%), the calculations are tedious and require a calculator. It is simpler for bedside clinicians to use the Cornell
Voltage Criteria (sensitivity, 42%; specificity, 95%), where LVH is present if the sum of the R wave in aVL and the S wave in V3 exceeds 20 mm (female) or 28 mm (male). In this example, lead aVL has R-wave amplitude of 4 mm and V3 has an S wave of 24 mm. The sum is 28 mm, meeting the ECG criteria for LVH.
Nursing Actions
Atrial fibrillation is the most common sustained arrhythmia, and this patient is appropriately managed because the ventricular rate is controlled. A previous ECG, and preferably an echocardiogram, would be helpful for evaluating ventricular enlargement (LVH). Patients with cardiomyopathy are vulnerable to remodeling of the left ventricle, so efforts should focus on optimizing cardiac synchrony and cardiac pump function, which is typically done with pharmacological agents and, in some cases, a pacer. Importantly, continued optimal cardiac care can improve this patient’s long-term outcome.
www.ajcconline.org
274
AJCC AMERICAN JOURNAL OF CRITICAL CARE, May 2008, Volume 17, No. 3 Downloaded from ajcc.aacnjournals.org by guest on October 2, 2011
Mary G. Carey and Michele M. Pelter
Am J Crit Care 2008;17:273-274
© 2008 American Association of Critical-Care Nurses Published online http://www.ajcconline.org Personal use only. For copyright permission information: http://ajcc.aacnjournals.org/cgi/external_ref?link_type=PERMISSIONDIRECT
Subscription Information http://ajcc.aacnjournals.org/subscriptions/ Information for authors http://ajcc.aacnjournals.org/misc/ifora.shtml Submit a manuscript http://www.editorialmanager.com/ajcc Email alerts http://ajcc.aacnjournals.org/subscriptions/etoc.shtml
AJCC, the American Journal of Critical Care, is the official peer-reviewed research journal of the American Association of Critical-Care Nurses (AACN), published bimonthly by The InnoVision Group, 101 Columbia, Aliso Viejo, CA 92656. Telephone: (800) 899-1712, (949) 362-2050, ext. 532. Fax: (949) 362-2049. Copyright © 2008 by AACN. All rights reserved.
Downloaded from ajcc.aacnjournals.org by guest on October 2, 2011
ECG Puzzler
A regular feature of the American Journal of Critical Care, the ECG Puzzler addresses electrocardiogram (ECG) interpretation for clinical practice. To send an eLetter or to contribute to an online discussion about this article, visit www.ajcconline.org and click “Respond to This Article” on either the full-text or PDF view of the article. We welcome letters regarding this feature.
CORNELL VOLTAGE CRITERIA
By Mary G. Carey, RN, PhD, and Michele M. Pelter, RN, PhD
Scenario: An 83-year-old woman with ischemic cardiomyopathy comes in for a routine checkup. She is receiving appropriate medical management with pharmacological agents and has had no acute symptoms.
V3
aVL
For every ECG, we recommend that readers systematically examine the following 9 features (check all that apply): 1. Rate K Normal (60-90 beats per minute) K Bradycardia (<60 beats per minute) K Tachycardia (>90 beats per minute) 2. Rhythm K Regular K Irregular K Irregular-regular 3. P waves K One P wave for every QRS complex K Fewer P waves than QRS complexes K More P waves than QRS complexes K Cannot determine 4. PR interval K Normal (≤0.20 seconds) K Short (<0.08 seconds) K Lengthened (>0.20 seconds) K Cannot determine
5. QRS complex duration K Normal (≤0.12 seconds) K Wide (>0.12 seconds) 6. QRS complex direction lead V1 K Negative and ≤0.12 seconds (normal) K Negative and >0.12 seconds (LBBB) K Positive and >0.12 seconds (RBBB) K Cannot determine 7. ST segments K Normal K Elevated (≥2 mm) K Depressed (≥2 mm) K Elevation/depression 2 contiguous (side by side) leads (≥1 mm) 8. T wave K Normal K Inverted 9. QTc K Normal K Lengthened (>0.47 seconds)
About the Authors
Mary G. Carey is an assistant professor in the School of Nursing at the State University of New York at Buffalo. Michele M. Pelter is an assistant professor at the Orvis School of Nursing, University of Nevada, Reno.
www.ajcconline.org
AJCC AMERICAN JOURNAL OF CRITICAL CARE May 2008, Volume 17, No. 3 Downloaded from ajcc.aacnjournals.org by guest on October 2, 2011
273
V3
aVL
ANSWERS 1. Rate K Normal (60-90 beats per minute) K Bradycardia (<60 beats per minute) K Tachycardia (>90 beats per minute) 2. Rhythm K Regular K Irregular K Irregular-regular 3. P waves K One P wave for every QRS complex K Fewer P waves than QRS complexes K More P waves than QRS complexes K Cannot determine 4. PR interval KNormal (≤0.20 seconds) K Short (<0.08 seconds) K Lengthened (>0.20 seconds) K Cannot determine
5. QRS complex duration K Normal (≤0.12 seconds) K Wide (>0.12 seconds) 6. QRS complex direction lead V1 K Negative and ≤0.12 seconds (normal) K Negative and >0.12 seconds K Positive and >0.12 seconds K Cannot determine 7. ST segments K Normal K Elevated (≥2 mm) K Depressed (≥2 mm) K Elevation/depression 2 contiguous (side by side) leads (≥1 mm) 8. T wave K Normal K Inverted 9. QTc K Normal K Lengthened (>0.47 seconds)
Interpretation
Controlled atrial fibrillation at 83/min, with left ventricular hypertrophy (LVH)
Rationale
Atrial fibrillation is present with irregularly irregular ventricular activity in the absence of discrete P waves for every QRS. Although the third QRS complex has what appears to be a P wave in front of it, this pattern is not consistent throughout the strip. The ventricular rate is fewer than 100/min; therefore, the ventricular response is “controlled.” The Q wave in aVL (nearly ≥40-ms duration) suggests a prior myocardial infarction; given the patient’s cardiomyopathy, the contiguous lateral leads, I and V6, also should be evaluated. The amplitude of the S wave in V3 suggests this patient may have LVH. Although the Cornell Product is the best method for ECG diagnosis of LVH (sensitivity, 51%; specificity, 95%), the calculations are tedious and require a calculator. It is simpler for bedside clinicians to use the Cornell
Voltage Criteria (sensitivity, 42%; specificity, 95%), where LVH is present if the sum of the R wave in aVL and the S wave in V3 exceeds 20 mm (female) or 28 mm (male). In this example, lead aVL has R-wave amplitude of 4 mm and V3 has an S wave of 24 mm. The sum is 28 mm, meeting the ECG criteria for LVH.
Nursing Actions
Atrial fibrillation is the most common sustained arrhythmia, and this patient is appropriately managed because the ventricular rate is controlled. A previous ECG, and preferably an echocardiogram, would be helpful for evaluating ventricular enlargement (LVH). Patients with cardiomyopathy are vulnerable to remodeling of the left ventricle, so efforts should focus on optimizing cardiac synchrony and cardiac pump function, which is typically done with pharmacological agents and, in some cases, a pacer. Importantly, continued optimal cardiac care can improve this patient’s long-term outcome.
www.ajcconline.org
274
AJCC AMERICAN JOURNAL OF CRITICAL CARE, May 2008, Volume 17, No. 3 Downloaded from ajcc.aacnjournals.org by guest on October 2, 2011
