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  1. Identifying Acute STEMI in the Presence of Paced Rhythm - Journal of Emergency Medical Services

    Subscribe | Newsletters | Advertise | Contact Us             Journal Supplements Subscribe Jobs Featured Jobs Search Jobs Post A Job Products Buyer's Guide Product Reviews Hot Products Hot Products Submissions Product Announcements Product Videos Webcasts White Papers Videos Ask the Expert Education & Training EMS 10 Interviews EMS Today Fitness JEMS Games Product Spotlight Home About Us Advertise Contact Us Our Team Authors Community Submit A Press Release News Patient Care Airway & Respiratory Cardiac & Resuscitation Trauma Administration & Leadership Communications & Dispatch Documentation & Patient Care Reporting Training Operations Ambulance & Vehicle Ops Equipment & Gear Rescue & Vehicle Extrication Major Incidents Mass Casualty Incidents Terrorism & Active Shooter Mobile Integrated Healthcare   Home About Us Advertise Contact Us Our Team Authors Community Submit A Press Release News Patient Care Airway & Respiratory Cardiac & Resuscitation Trauma Administration & Leadership Communications & Dispatch Documentation & Patient Care Reporting Training Operations Ambulance & Vehicle Ops Equipment & Gear Rescue & Vehicle Extrication Major Incidents Mass Casualty Incidents Terrorism & Active Shooter Mobile Integrated Healthcare Home Identifying Acute STEMI in the Presence of Paced Rhythm Identifying Acute STEMI in the Presence of Paced Rhythm Mon, Jan 18, 2016 By Tom Bouthillet, NREMT-P EMS responds to a local coffee shop for a 77-year-old male who has reportedly fainted. While en route the call is upgraded to an unconscious patient and an engine company is dispatched for backup. On arrival the patient is conscious but lethargic. He appears acutely ill. The skin is pale and diaphoretic. His past medical history includes hypertension, dyslipidemia, myocardial infarction, a coronary artery bypass graft and heart failure. His current medications are aspirin, metoprolol, atorvastatin, lisinopril and furosemide. Upon further questioning he admits to chest discomfort. His OPQRST assessment is as follows: ≫ Onset:  15 minutes prior to EMS arrival; ≫ Provoke:  Nothing makes the pain feel better or worse; ≫ Quality:  Dull; ≫ Radiate:  The pain does not radiate; ≫ Severity:  7/10; and ≫ Time:  No previous episodes. His vital signs are a heart rate of 74, respiratory rate of 22, blood pressure of 116/67, oxygen saturation of 88% on room air and a temperature of 98.4 degrees F. The patient is relocated to the ambulance and undressed from the waist up. A well-healed surgical scar is noted from previous open-heart surgery as well as an implantable medical device in the upper-left chest. Other notable findings include jugular venous distention and breath sounds that reveal crackles in the lung bases. [Native Advertisement] Figure 1: Initial rhythm Figure 2: Ventricular paced rhythm   The patient is placed on oxygen via nasal cannula at 4 Lpm. The cardiac monitor is attached—the 12-lead ECG shows ventricular paced rhythm. (See Figures 1 and 2, above.) DISCUSSION There are those who say it’s impossible to identify acute ST elevation myocardial infarction (STEMI) in the presence of paced rhythm. Some paramedics will even argue that performing a 12-lead ECG on a patient with a ventricular paced rhythm is a waste of time. In paced rhythm, much like left bundle branch block, the ST segments and T wave should be deflected opposite the majority of the QRS complex. Leads with a mostly positive QRS complex (see Figure 3A, below) are expected to show ST-segment depression and leads with a mostly negative QRS complex (see Figure 3B, below) are expected to show STsegment elevation. Figure 3: Appropriate ST-segment and T-wave discordance A group of investigators came up with a scoring system to identify acute myocardial infarction in the presence of left bundle branch block, known as Sgarbossa’s criteria. 1  (See Figure 4, below.) The criteria included: Concordant ST-segment elevation (ST-segment elevation in a lead with a positive QRS) ≥ 1 mm. ST-segment depression in leads V1, V2, or V3. Discordant ST-segment elevation (STsegment elevation in a lead with a negative QRS) ≥ 5 mm. Of these, the first criterion has stood the test of time and is considered to be the most reliable. Other researchers proposed a modification to Sgarbossa’s third criterion that takes into account the depth of the S wave. 2  Specifically, they’ve shown that ST-segment elevation ≥ ¼ the depth of the S wave is both sensitive and specific for identifying acute STEMI in the presence of left bundle branch block. Figure 4: Sgarbossa's criteria Figure 5: Concordance (ST-segment elevation ≥ 1 mm)   In this case we see concordant ST-segment elevation in leads I, aVL, V2, V5 and V6. (See Figure 5, above.) We also see excessively discordant ST-segment elevation (ST-segment elevation ≥ ¼ the depth of the S wave) in leads V3 and V4. (See Figure 6, below.) Figure 6: Excessive discordance (ST-segment elevation ≥ ¼ depth of S wave) When we mark these leads we can see a familiar pattern that is consistent with left anterior descending (LAD) occlusion. (See Figure 7, below.) Figure 7: LAD occlusion pattern Figure 8: Reciprocal change in lead III   When ST-segment elevation from LAD occlusion “crosses over” to the high lateral leads, we should look for reciprocal changes in the inferior leads. (See Figure 8, above.) The QRS is negative in lead III so we would normally expect ST-segment elevation. Instead, we see ST-segment depression. Therefore, we can assume this represents a reciprocal change. CASE CONCLUSION The 12-lead ECG was transmitted to the hospital and the cardiac cath lab was activated. The patient went into cardiac arrest upon arrival at the ED and was not successfully resuscitated. REFERENCES 1. Sgarbossa E, Pinski S, Barbagelata A, et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block.  N Engl J Med . 1996;334(8):481–487. 2. Smith S, Dodd K, Henry T, et al. Diagnosis of ST-elevation myocardial infarction in the presence of left bundle branch block with the ST-elevation to S-wave ratio in a modified Sgarbossa rule.  Ann Emerg Med . 2012;60(6):766–776. To read more cardiac cases, visit Tom Bouthillet’s blog  ems12lead.com , or visit the other blogs within the JEMS blog network:  fireemsblogs.com. By Tom Bouthillet, NREMT-P Tom Bouthillet, NREMT-P ( @tbouthillet ) is editor-in-chief of ems12lead.com ( @EMS12Lead ), aclsmedicaltraining.com ( @ACLSMedTraining ), and ecgmedicaltraining.com ( @ECGTraining ). Sponsored Content is made possible by our sponsor; it does not necessarily reflect the views of our editorial staff. Journal Archives Prev 2016 2015 2014 2013 2012 2011 Next Feb 2016 Volume 41 Issue 2 Jan 2016 Volume 41 Issue 1 Prev 2016 2015 2014 2013 2012 2011 Next Copyright © 2016: PennWell Corporation, Tulsa, OK. All Rights Reserved. UTILITY Home About Us Contact Us Terms of Use Subscribe Advertise Submit a Press Release RSS Feeds Privacy Policy Topics News Patient Care Leadership Training Major Incidents Mobile Integrated Healthcare Operations Sections Authors Columns Community Jobs Journal Products Supplements Webcasts

    Magazine Articles

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    Mon, 18 Jan 2016

  2. 10 Things Every EMS System Should Be Doing - Journal of Emergency Medical Services

    Allina Health EMS is a great example of how one agency turned things right-side up again by focusing on direct caregivers and those who support direct caregivers. 

    Magazine Articles

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    Fri, 15 Jan 2016

  3. ZOLL Launches Major RescueNet ePCR Software Upgrade for Compliance with National Standards - Journal of Emergency Medical Services

    ZOLL Medical Corporation announced a major software upgrade for RescueNet ePCR, making it compliant with NEMSIS 3, the latest version of the national data collection and reporting standards.  

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    Wed, 16 Dec 2015

  4. ECCU 2015 Conference Wednesday Report - Journal of Emergency Medical Services

    Cardiac guidelines at ECCU 2015 focus on high-quality and compression-only CPR.

    Online Articles

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    Wed, 9 Dec 2015

  1. Study Assesses Nitroglycerin's Effect on Hypotension in STEMI Patients - Journal of Emergency Medical Services

    Magazine Articles

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    Mon, 23 Nov 2015

  2. Firefighter Medics Treat Their Own in Boston Fire - Journal of Emergency Medical Services

    Four people, including at least three firefighters, were taken to hospitals.

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    Mon, 23 Nov 2015

  3. Cardiac Emergencies Require Efficient and Rapid Care for Survival - Journal of Emergency Medical Services

    There's a wide range of cardiac emergencies that can develop into rapidly evolving life-threatening situations.

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    Mon, 23 Nov 2015

  4. An EMS Guide to Wake-Up Ischemic Strokes - Journal of Emergency Medical Services

    Learn about the complexity of assessing and managing ischemic strokes with unknown "last known normal."

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    Fri, 20 Nov 2015

  5. How Centre LifeLink EMS Found Success in Increasing Cardiac Arrest Survival Rates - Journal of Emergency Medical Services

    The cardiac arrest survival rate in State College, Pa., increased from 4% to 20% by focusing on training, community involvement and forging strong links in the chain of survival.

    Magazine Articles

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    Fri, 20 Nov 2015

  6. Spotlight on EMS Compass at NASEMSO Fall Meeting

    State officials hear lessons learned, next steps for performance measure initiative.

    Online Articles

    Online Articles

    Fri, 16 Oct 2015

  7. Spotlight on EMS Compass at NASEMSO Fall Meeting - Journal of Emergency Medical Services

    State officials hear lessons learned, next steps for performance measure initiative.

    Online Articles

    Online Articles

    Fri, 16 Oct 2015

  8. ZOLL to Focus on Delivering One-of-a-Kind Rescuer Experience at EMS World Expo - Journal of Emergency Medical Services

    ZOLL Medical Corporation will offer attendees the opportunity to experience the company’s expanded portfolio of advanced CPR and acute critical care technologies, along with its integrated data solutions.

    Online Articles

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    Wed, 16 Sep 2015

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