12 Lead Acquisition and Interpretation APRIL 23 11:00 AM

Transcription

1 12 Lead Acquisition and Interpretation APRIL 23 11:00 AM Presented by : Jennifer Robson, Prehospital Care Specialist Dr. Don Eby, Local Medical Director

2 Objectives Upon completion of this webinar, you should be able to: Describe 12-lead ECG use in the prehospital setting Discuss conditions that may alter the acquisition/ interpretation of a 12-lead ECG Relate 12-lead ECG acquisition/interpretation to simulated prehospital case studies 2

3 The Why: Identify an acute myocardial infarction, and door to reperfusion time Identify transient ischemic changes in angina or acute coronary syndromes 3

4 The Who and Why: 2010 AHA Guidelines Diagnosis time Reperfusion time EMS should routinely acquire an ECG as soon as possible for all pts exhibiting signs and symptoms of ACS Recommend implementing 12-lead ECG diagnostic programs 4

5 The When: Suspected cardiac ischemia * Arrhythmia Rhythm interpretation 5

6 The How: Lead placement is critical Limb leads : LA, RA, LL, RL 6

7 The How: Precordial (Chest) Leads Lead placement is critical 7

8 Important to consider Privacy Scene time Critical patients 8

9 The Challenges Clear Accurate Prompt 9

10 The Challenges: Lead contact (hair, skin condition) Movement (patient, vehicle, cables) 10

11 The Challenges: Electro-magnetic interference 11

12 What does an ECG represent? ECG represents electrical activity measured as voltage and how it changes over time Voltage- Vertical lines (mm): 1 milli-volt = 10 mm (2 large boxes) Time- Horizontal lines: 0.04 sec = 1 mm square (small box) 0.20 sec = dark box/ 5x 1 mm square (large box) 1.0 sec = 5 large boxes/ 25 small boxes 12

13 Back to the Basics ECG Interpretation 5 Step Method: Rate Rhythm P wave PR interval QRS 13

14 ECG changes with ischemia and infarction 14

15 Interpreting a STEMI What to look for: ST Elevation (0.04 sec after J point) > 1mm (one small box) in limb leads > 2mm in chest leads Present in two anatomically contiguous leads 15

16 Interpreting a STEMI Septal Anterior Lateral Inferior V1 V2 V3 V4 V5 V6 I avl II III avf LII LI ASS (backwards) ALL L S A I L S L I I A L 16

17 Interpreting a STEMI Reciprocal changes: ST depression Infarction on the opposite side Ischemia II, III, avf I, avl,v leads 17

18 18 Interpreting a STEMI STEMI Mimickers Left Ventricular Hypertrophy Left Bundle Branch Block Ventricular Rhythms Benign Early Repolarization Pericarditis Hemorrhagic Stroke Pulmonary Embolism Aortic Dissection Brugada Syndrome Hypothermia Hyperkalemia Coronary Vasospasm Ventricular Aneurysm Paced rhythm

19 Interpreting a STEMI Remember: ST elevation is presumptive of an AMI 12-Lead ECG can be a useful tool in the prehospital setting if done promptly and accurately A normal 12-Lead ECG does NOT rule out an AMI 19

20 AskMAC #1 Question: When treating a patient with suspected cardiac ischemia, should I acquire a 12-Lead ECG before giving nitro or ASA? 20

21 AskMAC #2 Question: What position should patients be in when we are doing a 12-Lead ECG? 21

22 AskMAC #3 Question: I was under the impression that 12 leads were to be done on patient's with chest pain or symptoms consistent with ischemia. Should we be doing 12 leads on other patients to rule out any underlying cardiac conditions? 22

23 Case Study 1 Code 4 at 0845hrs to a residence for a 88 y/o male c/o back pain, chest pain diaphoretic, agitated, obvious distress, c/o 7/10 heavy-like chest discomfort unchanged with palpation, movement or respiration, seems to move down both arms, mildly SOB and slightly nauseous since 0700hrs. 23

24 Case Study 1 PmHx: smoker, HTN, hyperlipidemia The patients wife tells you that recently her husband has been under increased stress at work. HR: 50 R/S RR: 24 R/S BP: 105/66 Sp02: 97% Skin: pale, cool, diaphoretic Pupils: ERL 3mm Lead II: NSR BGL: 6.2mmol/L 24

25 Case Study 1 12-Lead ECG #1 25

26 Case Study 1 12-Lead ECG #2 (5 minutes later) 26

27 Question from the crowd What exactly does avr represent? a refers to augmented (magnified) V refers to voltage R refers to right arm 27

28 Case Study 2 Code 1130hrs for an 80 y/o F pt. - syncope elderly female sitting in a chair with an unaltered LOA. Tells you she was in church when she had a sudden onset of feeling ++ tired and hot and woke up lying on the floor with surrounding bystanders who had called 911 Bystanders state episode lasted approx. 30 seconds, they assisted the pt. to the floor. 28

29 Case Study 2 PmHx: HTN, Osteoporosis, episodes of weakness over the past month HR: 70 R S RR: 20 R S BP: 150/74 Sp02: 98% Skin: pale, warm, dry Pupils: ERL 4mm Cap: 2 seconds GCS: 15 Lead II: NSR BGL:7.6mmol/L 29

30 Case Study 2 12-Lead ECG ***Meets STEMI Criteria*** 30

31 Bottom Line 12-Lead ECG s are used by emergency physicians to diagnose and manage patients with suspected cardiac conditions As Case 2 illustrates, prehospital 12-Lead ECG s can also be used by paramedics to change their treatment of patients 31

32 References Aehlert, B. (2013). ECG s Made Easy (Fifth Ed.) St. Louis, Missouri: Elsevier. Davis M, Lewell M, McLeod S, Dukelow A. A prospective evaluation of the utility of the prehospital 12-lead electrocardiogram to change patient management in the emergency department. Prehosp. Emerg. Care 2013;18(June 2012):9-14. Ontario Base Hospital Group Education Subcommittee. (2008). Medical Advisory Committee 12-Lead Medical Directive Training. Hamilton, Ontario: Ontario Base Hospital Group. O Connor, R., Brady, W., Brooks, S., Diercks, D., Ghaemmaghami, C., Menon, V., O Neil, B., Travers, A., & Yannopoulos, D Phalen, T., & Aehlert, B. (2012). The 12-Lead ECG in Acute Coronary Syndromes (Third Ed.). Maryland Heights, Missouri: Elsevier. SWORBHP. (2015). askmac. Retrieved April 3, 2015 online at: 32