The American Associatiio of Critical-Care Nurses (AACN) posted 2 practice alerts to address issues in cardiac monitoring in 2004 and updated them in April 2008.1,2 The alerts addressed 2 main reasons for use of cardiac bedside monitoring. The first reason is to detect and provide early intervention for episodes of myocardial ischemia and injury.3,4 Skilled Cardiac Monitoring at the Bedside: An Algorithm for Success Correct ECG lead selection is crucial for detection of these episodes.1,5-9 When the correct lead or leads are used, ST-segment monitoring proviide important information for patient care, provided alarms are set appropriately. Because aggressive early treatment improves outcomes in patients who have myocardial ischemia and injury, ST-segment monitoring should be used by all nurses who work in areas with cardiac monitoring.1,3-7,10,11 The second reason for cardiac bedside monitoring is to Laura Evenson, RN, MS, CNS, ACNS-BC, CCRN Monica Farnsworth, RN, MS, NES, CCRN Feature PRIME POINTS • ST-segment monitoring should be used by all nurses who work in areas with cardiac monitoring. • Ideally, treatment of acute coronary syndrome is started as soon as changes in coronary blood flow are evident. • Nurses can learn to properly monitor rhythm changes to minimize misinterprretatio of rhythms. ©2010 American Association of Critical-Care Nurses doi: 10.4037/ccn2010471 You are a nurse working in an intensive care unit (ICU), and your patient, a 62-year-old man, has just arrived from the operating room after a cholecystectomy. He is sleepy but arousable and says he has some incisioona pain. You start cardiac monitoring with lead II, as is the practice in your area. One hour later, the patient has ventricular fibrillation. After successsfu defibrillation, 12-lead electrocardiography (ECG) is done. The patient has ST-segment depression in lead III and 4 mm of ST-segment elevation in leads V3 and V4. You note that the patient’s history includes placement of a stent to the left anterior descending coronary artery 3 months before the cholecystectomy and that he had stopped taking clopidoggre 2 weeks before the current surgery. Knowing this information, would you have chosen a different way to monitor this patient? How would you decide what leads to monitor? Is it possible that the ECG changes would have been visible before the arrest, allowing intervention that might have prevented the arrest? 14 CriticalCareNurse Vol 30, No. 5, OCTOBER 2010 www.ccnonline.orgdetect serious dysrhythmias that may require treatment. If patients are not monitored by using the recommeende lead for dysrhythmia interpretation, nurses and physicians correctly diagnose a wide QRS tachycardia only 34% of the time, and erroneous interpretation can lead to inappropriate treatment.5 The AACN practice alerts1,2 identiffie expected practice for monitoriin ST-segments and dysrhythmias. During practice discussions in committtee and at the bedside, some nurses at Mayo Clinic, Rochester, Minnesota, remarked that they did not understand application of the concepts covered in the alerts. The ECG lead monitoring algorithm was developed to provide a tool to assist bedside nurses in combining the 2 concepts. Monitoring to Detect Ischemia and Injury Early detection of ischemia and/or acute myocardial injury improves both patient safety and patient outcommes3,4,8,9 ST-segment changes reflect changes in blood flow to myocardial cells. ST-segment elevation indicates an acute injury, whereas ST-segment depression signifies ischemia. The occurrence of either elevation or depression is considered an indicatiio of acute coronary syndrome (ACS). Ideally, treatment of ACS is started as soon as changes in coronaar blood flow are evident.3,5,8 As much as 70% to 80% of in-hospital ischemia is silent, and early treatment decreases in-hospital mortality due to ACS.4,6-8,10,12 Nurses who depend solely on patients’ self-reported signs and symptoms to suggest the occurreenc of ischemia or acute injury can miss important information. Unfortunaately surveys4,9,11 of nurse leaders in hospital cardiac units revealed that even in hospitals with capabilities for ST-segment monitoring, ischemia monitoring is vastly underused. The recommended practice for accurate ST-segment monitoring is lead selection based on a patient’s need.1 Patients have a unique, reproduccibl pattern of ST-segment changes known as the ST fingerpriint5-8 The ST fingerprint refers to a unique pattern of ST-segment depressiio and elevation during ischemic episodes.6 Lead selection is determiine on the basis of the patient’s ST fingerprint if known, by review of areas of ST-segment change on ECGs, or by following the practice alert1 to use lead III and the precordial lead V3.5 Traditionally, lead II was the most common lead for monitoring because of its tall R wave and accurate detectiio of heart rate. However, studies5-8 have provided evidence that lead III is more sensitive for detection of injury in the right coronary artery because the lead indicates ST-segment changes early. When nurses began using dual-lead monitoring, the precorrdia lead V1 was the other most commonly selected lead for dysrhythmmi monitoring because of its reliabillit in distinguishing wide QRS beats as supraventricular or ventricullar4,5,9,13-15 However, research has shown that lead V1 is less sensitive for detection of ischemic changes and that V3 provides more consisteen detection.5-8 At the Mayo Clinic, Rochester, lead V2 was a common lead choice; the rationale dated back to when this lead was good for detecting heart rate and minimizing the occurrence of nuisance alarms. Monitoring to Detect Dysrhythmias The other AACN practice alert2 addressed recommended leads for interpretation of dysrhythmias. Dysrhythmias occur in a variety of illnesses. Patients at marked risk for dysrhythmia should be monitoore continuously.4,9 Many nurses select leads on the basis on the nurses’ practice routine, which may not be appropriate for dysrhythmia monitoring, and lead placement is not always accurate.5,7 Some rhythms, such as atrial fibrillation or atrial flutter, can be analyzed by using a variety of leads; however, accurate interpretation of wide QRS tachycarrdi depends primarily on precorrdia lead V1.5,13-15 Wide QRS tachycardia and the need for interprettatio of this dysrhythmia are common among critically ill patients, and the treatments vary, depending on the origin of the wide QRS rhythm.5 Laura Evenson is the nurse manager of a neurosurgical unit at Saint Marys Hospital, Mayo Clinic, Rochester, Minnesota.When this project was done, Laura was the clinical nurse specialist in the medical intensive care unit at St Marys Hospital. Monica Farnsworth is a nursing education specialist in the cardiac surgery and transplant intensive care and progressive care units, Division of Education and Professional Development, and an assistant professor of nursing in the College of Medicine, Mayo Clinic, Rochester. Corresponding author: Laura Evenson, RN, MS, CNS, ACNS-BC, CCRN, Mayo Clinic, 200 First St SW, Rochester, MN 55905 (e-mail: evenson.laura@mayo.edu). To purchase electronic or print reprints, contact The InnoVision Group, 101 Columbia, Aliso Viejo, CA 92656. Phone, (800) 899-1712 or (949) 362-2050 (ext 532); fax, (949) 362-2049; e-mail, reprints@aacn.org. Authors www.ccnonline.org CriticalCareNurse Vol 30, No. 5, OCTOBER 2010 15Accurate interpretation of wide QRS tachycardia requires using leads known to meet criteria that support interpretation of the ECG findings. Nurses can learn to properrl monitor rhythm changes to minimize misinterpretation of rhythms. Drew5 supports the practiic of using precordial lead V1 for rhythm monitoring for the followiin reasons. First, visible P waves allow visualization of atrio ventriculla dissociation (a criterion used to differentiate the origin of wide QRS tachycardia). Second, V1 provides visualization of the QRS width, and QRS morphology, when analyzed, is useful in differentiating the origgi of wide QRS rhythms. An important finding in a study of lead placement by Drew5 was that QRS morphology in MCL1 is not always identical to the QRS morphology in V1 and can lead to inaccurate diagnosis of rhythm. Other investigators13-15 have also indicated differences between MCL1 and lead V1. MCL1 was a configuratiio of lead placement to provide a modified precordial lead with the 3-lead bipolar system before the availability of the 5-lead system. The 3-lead system is not as accurate as the 5-lead system for the differentiia diagnosis of aberrancy versus ectopy.5,9,15 For a 5-lead system, the recommendation is to use the precorrdia V1 lead and place the electroode accurately. If a 3-lead system is the only system available, the MCL1 lead configuration should be used. For MCL1 in a 3-lead bipolar system, the positive electrode is placed in the V1 position and the negative electrode in the left infraclaviicula fossa; the ground lead can be placed anywhere.4 AACN Practice Alerts Monitoring the routines of critical care nurses has indicated that nurses do not select leads according to diagnosis (or history of coronary disease).14 In an AACN survey5 of 769 ICU nurses publisshe in 2002, 53% of the nurses stated that routine leads (standard lead choice) were used to monitor patients regardless of the diagnosiis Despite numerous publications since the introduction of monitoriin in 1960, monitoring practices related to lead selection have not changed significantly.4,5,9 This lack of change was observed at Mayo Clinic, Rochester, and led to practiic discussions about monitoring. In order to incorporate the AACN practice alerts into evidencebaase care at the clinic, the ECG lead monitoring algorithm was developed to help nursing staff understand and apply the recommendaations Tables 1 and 2 give the expected practices (as recommennde in the AACN alerts1,2). An Algorithm for Success The ECG lead monitoring algoriith was developed in collaboratiio with the nursing clinical practice committee of the medical ICU, a clinical nurse specialist, and a nursing education specialist. Staff members’ questions and comments were incorporated into each version of the tool until nursing staff indicaate the tool was simple and easy to use and accurately reflected the content from the practice alerts.1,2 The algorithm has been endorsed by the critical and progressive care nursing practice committees at Mayo Clinic, Rochester. The algorithm (Figure 1) is a decision pathway that requires examination of a patient’s medical history for risk factors for ACS and any current signs and symptoms of myocardial infarction. If the patient is at cardiac risk, the nurse follows the pathway indicating ECG leads used to monitor specific coronary arteries or known area of ischemic involvement. If the patient Table 1 ST-segment monitoring 1. Select the best lead to identify the ST fingerprint, or choose leads III and V3 for overall visualization of primary coronary artery anatomical areas 2. Apply the ST-monitoring feature when appropriate 3. Mark lead placement with indelible ink for consistency of information 4. Prepare skin properly for electrode application Table 2 Dysrhythmia monitoring 1. Measure QTc interval for patients at risk for torsades de pointe 2. Prepare skin properly for electrode application 3. Place V lead electrode accurately 4. Mark lead placement with indelible ink for consistency 5. Select V1 for wide QRS tachycardias 16 CriticalCareNurse Vol 30, No. 5, OCTOBER 2010 www.ccnonline.orghas a history of cardiac disease with no specific known area of ischemia, leads V3 and III should be selected.1 If the patient does not have a history of risk factors for ACS or has a history of dysrhythmia, the dysrhythmia pathway is followed, which indicates that the patient should be monitored by using lead V1 and lead II or III.2 Lead III commoonl shows change in the ST segmeent earlier than lead II does.6-8 For patients with signs and symptoom of ACS and rhythm changes, the tool provides the following guide: “When patients have history of both ACS and dysrhythmias, monitor for ischemia; if wide QRS tachycardia occurs, switch to V1 to determine rhythm” (Figure 2). No V1 V2 V6 V5 V4 V3 No Yes Yes *Lead III known to show change in ST segment earlier than lead II [“Normal QRS appearance for each V lead”] History of or at risk for acute coronary artery syndrome (ie, myocardial infraction, angina, chest pain, percutaneous transluminal coronary angiography, coronary artery disease) Monitor for arrhythmias Monitor V1 and II or III* Select V3 and lead III Current or previous 12-lead ECG indicates ischemic or injury event Select lead based on possible coronary artery involved/known area of ischemia Figure 1 Algorithm for selection of electrocardiography (ECG) leads. Used with permission of Mayo Foundation for Education and Research, Rochester, Minnesota. Ischemic area ECG leads (ST elevation) Possible coronary artery involved Anterior Anteroseptal Inferior Lateral: High Low/apical Posterior V3-V4 V1-V4 II, III, AVF I, AVL V5-V6 Predominanat R in V1-V2 Left anterior descending (LAD) LAD Right coronary artery (RCA) Circumflex LAD, circumflex, RCA RCA, circumflex V1 VT SVT Figure 2 Common QRS morphology in wide QRS tachycardia: What to look for, use V1 only. When patients have a history of both acute coronary syndrome and dysrhythmias, monitor for ischemia; if wide QRS tachycardia occurs, switch to V1 to determine rhythm. Abbreviations: SVT, supraventricular tachycardia; VT, ventricular tachycardia. Used with permission of Mayo Foundation for Education and Research, Rochester, Minnesota. V1 V1 V2V3 V4 V5V6 18 CriticalCareNurse Vol 30, No. 5, OCTOBER 2010 www.ccnonline.orgwww.ccnonline.org CriticalCareNurse Vol 30, No. 5, OCTOBER 2010 19 algorithm is part of the procedural guideline on cardiac monitoring. During all education sessions, nurses are given case studies to allow discussion and practice in use of the tool. Laminated copies of the algoriith were created and hung next to each ECG monitor as a visual tool to assist staff with appropriate ECG lead placement. Table 3 is a summary of the educational activities. During simulation exercises, nurses now readily identify appropriiat lead selection and correct anatomical placement of ECG patches. They bring case studies to the progressive care and critical care clinical nurse specialists and nursing education specialists for questions or case study use that support application of the informatiio at the bedside. Ongoing practiic discussions have revealed that many staff can articulate the need to individualize lead selection and which leads to choose. Lead placemeen by nurse orientees is verified by preceptors in one of the orienteees skill demonstrations. Use of the Algorithm The front page of the ECG lead selection algorithm (Figure 1) is the main focus of the document and incorporates both AACN practice alerts.1,2 Nurses are taught to consider the main reason a patient is having cardiac monitoring: are the nurses most concerned with potential cardiia blood flow problems, which correspond to a history of ACS, or are they concerned about rhythm changes? The main decision point on the algorithm asks this question and directs the nurses to lead selectiio according to the answer. If the answer is yes to blood flow problems, a table is included that provides lead selection based on coronary artery and corresponding cardiac anatomy. If current ECG findings (bedside monitor and 12-lead ECG) and a patient’s history do not indicate specific coronary artery or cardiac anatomy to monitoor leads V3 and III should be used.1 On the front page (Figure 1) is a drawing of a chest that shows correec placement of the precordial (V) lead. Each precordial lead also has a corresponding diagram of the normma QRS configuration for the lead. The purpose of the diagrams is to guide the decision on where to place the precordial (V) lead on the chest and provides a quick reference for how the placement normally should look. For instances in which rhythm monitoring is a priority, illustrations are provided for quick reference on appropriate QRS configuration for Implementation of the Algorithm Education was provided to staff nurses to improve their understandiin of rationale for appropriate ECG lead placement. A variety of venues and teaching methods were used to present the algorithm and provide opportunities for case study practice and questions. In the progressive care and intensive care orientation programs, formal educational conteen on how to monitor patients has been included. ECG lead selection is also incorporated into simulation training for orientees during critical care orientation. Basic and advanced ECG classes are offered continually throughout the year, and the algoriith is included in these classes. For advanced training, an advanced arrhythmia class is offered twice a year, and the ECG lead selection algorithm and electrode placement are incorporated into this class. The Table 3 Education on algorithm for selection of electrocardiography (ECG) leads Class or teaching venue Basic ECG class Essentials of Progressive and Intensive Care (EPIC), ST/QT class EPIC, bundle branch blocks EPIC, cardiovascular complications EPIC, simulation center laboratories Advanced ECG class Team day in multiple individual intensive care units and progressive care units New Wings, cardiovascular progressive care class Cardiovascular surgery 6-week review sessions Hearts All-a-Flutter Class (an advanced dysrhythmia class) Concepts taught with lead monitoring algorithm Coronary anatomy and lead placement Lead selection Lead selection Lead selection Lead placement and lead selection Lead selection, lead placement, normal QRS configuration, interpretation of wide QRS tachycardia Lead placement, lead selection, interpretation of wide QRS tachycardia Lead placement, lead selection, interpretation of wide QRS rhythms, hands-on lead inspectiio of patients Lead selection, interpretation of wide QRS tachycardia Lead selectionrhythm interpretation. Common QRS configurations in wide QRS tachycardia in ventricular tachycarddi and in supraventricular tachycarrdi are presented in columns on the back of the algorithm as the configurration would appear in lead V1. The rationale for recommendation of V1 for monitoring of dysrhythmiia is based on criteria that apply to V1 specifically to aid in distinguisshin between ventricular and supraventricular rhythms. Although criteria also exist for differentiation of wide QRS tachycarrdi that apply to the precordial lead V6, nurses stated that includiin these criteria in the tool was confusing. A survey of staff nurses indicated that information on lead V6 was not helpful and made the tool harder to use; thus, pictures of lead V6 are not included. During teaching sessions on arrhythmia detection, right bundle branch block and left bundle branch block are reviewed to improve nurses’ understanding and recognition of QRS morphology. Nurses are taught that when a patient has ECG evidence of dysrhytthmi along with ischemia or injury, they should monitor for ischemia and injury changes, switching to the precordial lead V1 for recording of strips when a wide QRS tachycardia is present. The nurses are instructed to place 2 electrodes on the chest, 1 in the V1 position and 1 in the V3 position, to simplify changing from one lead to another when the clinical events change. (Treatment for ongoing ischemia and/or injury requires continual assessment of response to interventions. When a rhythm change occurs, a nurse can switch leads to interpret the ECG findinng and treat the patient.) A statemeen on the back page of the tool reminds nurses to change the leads monitored when a change is clinicaall indicated. The algorithm is printed front to back in a bright color and is placed on or near the monitors in monitored units. The tool is laminated to facilitate cleaniin with disinfectant in between patient admissions. Practice Alert Revisions 2008 The updated ST-segment monitorrin practice alert1 from April 2008 includes an expected practice for patients who do not have definitive ACS but may have ACS or are haviin the syndrome ruled out. For these patients, leads III and V5 should be monitored.1 The practice alert does not include a statement of supportiin evidence for this recommendatiion The practice alert also includes an expected practice for noncardiac patients undergoing surgical proceduur or admitted to the ICU. Lead V5 is valuable for identifying demandrellate ischemia, which appears to be more common in this noncardiac group of patients. The evidence for this practice is level IV: limited clinicca studies to support recommendatioons Therefore, these changes were not included in the ECG lead monitorrin algorithm. One source publicatiion1 for using precordial lead V5 did not provide data for use of the lead, and the case study actually described changes in lead V3. Recommendations for Practice Use of the ECG lead monitoring algorithm or a similar tool at the bedside can help nurses select leads and individualize monitoring accordiin to a patient’s needs. Strategic placement of the algorithm at the bedside will facilitate its use. Nurses will continue to need ongoing educattio and mentoring in correct application of ECG leads and principlle of monitoring. Audits of nursiin practice should include physical placement of electrodes and lead selection. The results from audits will highlight improvement in practiic and/or ongoing educational needs. Involvement of staff nurses in the audit process is an excellent method of highlighting evidencebaase practice at the bedside. CCN Financial Disclosures None reported. References 1. Johnson K. AACN practice alert: ST-segment monitoring. American Association of Critical-Care Nurses Web site. http://www.aacn.org /WD/Practice/Docs/ST_Segment_ Monitoring_04-2008.pdf. Issued April 2008. Accessed January 21, 2010. 2. Bourgault A. AACN practice alert: dysrhytthmi monitoring. American Associatiio of Critical-Care Nurses Web site. http://www.aacn.org/WD/Practice/Docs /Dysrhythmia_Monitoring_04-2008.pdf. Issued April 2008. Accessed January 21, 2010. 3. Gibler WB, Cannon CP, Blomkalns AL, et al; American Heart Association Council on Clinical Cardiology; American Heart Associaatio Council on Cardiovascular Nursing; Quality of Care and Outcomes Research Interdisciplinary Working Group; Society of Chest Pain Centers. Practical implementattio of the guidelines for unstable angina/non-ST-segment elevation myocardial infarction in the emergency department. Ann Emerg Med. 2005;46(2):185-197. 4. Drew BJ, Califf RM, Funk M, et al; American Heart Association. AHA scientific statement: practice standards for electro cardio graphic monitoring in hospital settings: an American Now that you’ve read the article, create or contribute to an online discussion about this topic using eLetters. Just visit www.ccnonline.org and click “Respond to This Article” in either the full-text or PDF view of the article. To learn more about cardiac monitoring, read “Bedside Cardiac Monitoring” by Carol Jacobson in Critical Care Nurse, 2003;23(6):71-73. Available at www.ccnonline.org. 20 CriticalCareNurse Vol 30, No. 5, OCTOBER 2010 www.ccnonline.orgHeart Association scientific statement from the Councils on Cardiovascuula Nursing, Clinical Cardiology, and Cardiovascular Disease in the Young: endorsed by the International Society of Computerized Electrocardiiolog and the American Association of Critical-Care Nurses. J Cardiovasc Nurs. 2005;20(2):76-106. 5. Drew BJ. Celebrating the 100th birthday of the electrocardiogram: lessons learned from research in cardiac monitoring [published corrections appear in Am J Crit Care. 2002;11(5):411 and 2002;11(6):503]. Am J Crit Care. 2002;11(4):378-386. 6. Flanders SA. ST-segment monitoring: putting standards into practice [published correction appears in AACN Adv Crit Care. 2008;19(2):120]. AACN Adv Crit Care. 2007;18(3):275-284. 7. Drew BJ, Funk M. Practice Standards for ECG monitoring in hospital settings: executive summary and guide for implementation. Crit Care Clin North Am. 2006;18(2):157-168. 8. Flanders SA. Continuous ST-segment monitoring: raising the bar. Crit Care Nurs Clin North Am. 2006;18(2):169-177. 9. Drew BJ, Califf RM, Funk M, et al; American Heart Association; Counciil on Cardiovascular Nursing, Clinical Cardiology, and Cardiovascular Disease in the Young. Practice standards for electrocardiographic monitorrin in hospital settings: an American Heart Association scientific statement from the Councils on Cardiovascular Nursing, Clinical Cardioloogy and Cardiovascular Disease in the Young: endorsed by the Internatiiona Society of Computerized Electrocardiology and the American Association of Critical-Care Nurses. Circulation.2004;110(17):2721-2746. 10. Pelter MM, Adams MG, Drew BJ. Transient myocardial ischemia is an independent predictor of adverse in-hospital outcomes in patients with acute coronary syndromes treated in the telemetry unit. Heart Lung. 2003;32(2):71-78. 11. Tisdale LA, Drew BJ. ST segment monitoring for myocardial ischemia. AACN Clin Issues. 1993;4(1):34-43. 12 Drew BJ, Pelter MM, Adams MG, Wung SF, Chou TM, Wolfe CL. Is 12-lead ST-segment monitoring necessary to detect ongoing ischemia in patients with unstable coronary syndromes [abstract]? Circulation. 1997;96(8 suppl):I-14. 13. Jacobson C. Narrow QRS complex tachycardias. AACN Adv Critical Care. 2007;18(3):264-274. 14. Drew BJ. Bedside electrocardiographic monitoring: state of the art for the 1990s. Heart Lung. 1991;20(6):610-623. 15. Rauen CA, Chulay M, Bridges E, Vollman KM, Arbour R. Seven evidencebaase practice habits: putting some sacred cows out to pasture. Crit Care Nurse. 2008;28(2):98-124. 16. Landesberg G, Luria M, Cotev S, et al. Importance of long-duration postoperative ST-segment depression in cardiac morbidity after vascular surgery. Lancet. 1993;341(8847):715-719. www.ccnonline.orgCCN Fast Facts CriticalCareNurse The journal for high acuity, progressive, and critical care Facts According to 2 practice alerts from the American Association of Critical-Care Nurses (AACN), there are 2 main reasons for use of cardiac bedside monitoring: (1) to detect and provide early intervention for episodes of myocardial ischemia and injury and (2) to detect serious dysrhythmias that may require treatment. At Mayo Clinic, Rochester, Minnesota, we developed the ECG lead monitoring algorithm to provide a tool to assist bedside nurses in combining the 2 concepts of ST-segment monitoring and dysrhythmias (Figure). Skilled Cardiac Monitoring at the Bedside: An Algorithm for Success Evenson L, Farnsworth M. Skilled cardiac monitoring at the bedside: an algorithm for success. Crit Care Nurse. 2010;30(5):14-22. The algorithm is a decision pathway that requires examination of a patient’s medical history for risk factors of acute coronary syndrome and any current signs and symptoms of myocardial infarction. Use of this algorithm or a similar tool at the bedside can help nurses select leads and individualize monitoring according to a patient’s needs. Strategic placement of the algorithm at the bedside will facilitate its use. Nurses will continue to need ongoing education and mentoring in correct application of ECG leads and principles of monitoring. No V1 V2 V6 V5 V4 V3 No Yes Yes *Lead III known to show change in ST segment earlier than lead II [“Normal QRS appearance for each V lead”] History of or at risk for acute coronary artery syndrome (ie, myocardial infraction, angina, chest pain, percutaneous transluminal coronary angiography, coronary artery disease) Monitor for arrhythmias Monitor V1 and II or III* Select V3 and lead III Current or previous 12-lead ECG indicates ischemic or injury event Select lead based on possible coronary artery involved/known area of ischemia Figure Algorithm for selection of electrocardiography (ECG) leads. Used with permission of Mayo Foundation for Education and Research, Rochester, Minnesota. Ischemic area ECG leads (ST elevation) Possible coronary artery involved Anterior Anteroseptal Inferior Lateral: High Low/apical Posterior V3-V4 V1-V4 II, III, AVF I, AVL V5-V6 Predominanat R in V1-V2 Left anterior descending (LAD) LAD Right coronary artery (RCA) Circumflex LAD, circumflex, RCA RCA, circumflex V1 V2V3 V4 V5V6 22 CriticalCareNurse Vol 30, No. 5, OCTOBER 2010 www.ccnonline.orgCopyright of Critical Care Nurse is the property of American Association of Critical-Care Nurses and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.