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Is He Having The Big One?

Is He Having The Big One?. Sirous Partovi, M.D. Department of Emergency Medicine TTUHSC, El Paso. ECG #1- 68 year old with chest pain for 3 days. ECG #2- 66 year old man with 1 hour history of chest pressure . ECG #3- 39 year old AAM with chest pain, PMH HTN.

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Is He Having The Big One?

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  1. Is He Having The Big One? Sirous Partovi, M.D. Department of Emergency Medicine TTUHSC, El Paso

  2. ECG #1- 68 year old with chest pain for 3 days

  3. ECG #2- 66 year old man with 1 hour history of chest pressure

  4. ECG #3- 39 year old AAM with chest pain, PMH HTN

  5. ECG #4 - 62 year old with profuse diaphoresis and vomiting

  6. ECG #5-72 year old male- PMH: CRF,a-fib presents with generalized weakness for 1 hour.

  7. ECG #6- 45 year old female with onset of chest discomfort 2 hours ago – PMH ?Cancer

  8. ECG #7 – 50 year old man with crushing substernal chest pain for 30 minutes

  9. ECG #8- 72 year old female with history of HTN found unconscious

  10. ECG #9- 67 year old man with PMH of MI in respiratory failure due to acute CHF

  11. ECG #10- Chest pain radiating to the jaw in a 41 year old woman

  12. Objectives • Understand the etiology of chest pain • Distinguish between Acute Coronary events requiring thrombolysis and those that do not. • Recognize the more common conditions that may cause a pseudo-infarction pattern on ECG.

  13. Chest Pain • 2% of all ED visits • 10-20% are diagnosed with AMI • 1.7 million admissions to hospitals annually • $5 Billion spent on admitted patients which AMI was subsequently ruled out in

  14. Chest Pain- AMI • 1.1 million cases of AMI annually • 50% present to EDs • 2%-8% rate of misdiagnosis • 11,000 missed diagnosis of MI per year • 20% of money awarded in malpractice cases

  15. Differential Diagnosis of Chest Pain Cardiac • Ischemic • Angina • Unstable angina • AMI • Non-ischemic • Pericarditis • Aortic dissection • Valvular • Myositis

  16. Differential Diagnosis of Chest Pain Non-cardiac • Gastroesophageal Causes • GERD • Esophageal spasm • PUD • Boerhaave’s Syndrome • Cholecystitis

  17. Differential Diagnosis of Chest Pain Non-cardiac • Non-gastroesophageal • Pneumothorax • Pulmonary embolism • Musculoskeletal • Somatoform disorders

  18. Chest Pain-Diagnosis • History and Physical • ECG • Cardiac serum markers

  19. AMI- World Health Organization (WHO) Definition • A combination of two of three characteristics: • Typical symptoms (i.e., ischemic-type chest discomfort) • A rise and fall in serum cardiac markers • Typical ECG pattern involving the development of Q waves

  20. Acute MI - History • 70%-80% present with ischemic type CP • Less than 25% of patients admitted to hospital with ischemic-type CP are diagnosed with AMI • Unusual symptoms for AMI • Elderly • Women • Diabetics

  21. Features of H&P That Increase the Probability of AMI Panju et al, JAMA. 1998;280:1256-1263 History and Physical LR • Chest pain radiating to both arms 7.1 • Third heart sound 3.2 • Hypotension 3.1 • Chest pain radiating to right shoulder 2.9

  22. Likelihood Ratio Positive LR • Odds that a patient with a positive test result has the target disorder Pos LR= Sensitivity/(1-Specificity) Negative LR • Odds that a patient with a negative test result has the target disorder Neg LR= (1-Sensitivity)/Specificity

  23. Historical Features That Decrease the Probability of AMI Panju et al, JAMA. 1998;280:1256-1263 Quality of Chest Pain LR • Pleuritic 0.2 • Sharp or stabbing 0.3 • Positional 0.3 • Reproduced by palpation 0.2-0.4

  24. ECG evolution in Q-wave Myocardial Infarction • Tall peaked T-waves • ST-segment elevation • Appearance ofabnormalQ wave • Decrease of ST-segment elevation with the beginning of T-wave inversion • Isoelectric ST-segment with symmetrical T-wave inversion

  25. Tall T- Waves • The earliest sign of AMI • Due to subendocardial ischemia • Within minutes or hours after the onset of chest pain • Transient • Most ECGs fail to show this pattern

  26. ECG evolution in Q-wave Myocardial Infarction • Tall peaked T-waves • ST-segment elevation • Appearance ofabnormalQ wave • Decrease of ST-segment elevation with the beginning of T-wave inversion • Isoelectric ST-segment with symmetrical T-wave inversion

  27. ST-Segment Elevation • The most common early ECG sign • STE - specificity 91% , sensitivity 46% • Mortality increases with the number of ECG leads showing ST elevation • STE decreases in the first 7-12 hours • STE resolves within 2 weeks in 90% of IWMI, but only in 40% of anterior MI

  28. Reciprocal ST-Segment Depression • Seen in up to 82% • Marked early, 50% resolve within 24 hours • Due to reciprocal electrical alteration • Increases specificity of AMI to 99% • Seen in 72% of IWMI • Indicative of: • Larger AMI • Lower ventricular ejection fraction • Higher mortality

  29. ECG evolution in Q-wave Myocardial Infarction • Tall peaked T-waves • ST-segment elevationrepresents a stage beyond ischemia -i.e. injury • Appearance ofabnormal Q-wave • Decrease of ST-segment elevation with the beginning of T-wave inversion • Isoelectric ST-segment with symmetrical T-wave inversion

  30. Abnormal Q-Waves • Most commonly presents while ST-segment still elevated • 12-20% of Q-waves do not persist • CHF is more common with persistent Q-waves

  31. ECG evolution in Q-wave Myocardial Infarction • Tall peaked T-waves • ST-segment elevation • Appearance ofabnormalQ wave • Decrease of ST-segment elevation with the beginning of T-wave inversion • Isoelectric ST-segment with symmetrical T-wave inversion

  32. ECG evolution in Q-wave Myocardial Infarction • Tall peaked T-waves • ST-segment elevationrepresents a stage beyond ischemia -i.e. injury • Appearance ofabnormal Q wave • Decrease of ST-segment elevation with the beginning of T-wave inversion • Isoelectric ST-segment with symmetrical T-wave inversion

  33. Criteria for Thrombolysis • ST elevation (greater than 1 mm in two or more contiguous leads), time to therapy 12 hours or less, age less than 75 years. • Bundle branch block (obscuring ST-segment analysis) and history suggesting acute MI.

  34. AMI Diagnosis- ECG Factors Influencing ECG Interpretation • Clinical observation of the patient • Knowledge of clinical data • Training and experience of interpreter

  35. AMI Diagnosis- ECG Gjorup et al, J Intern Med. 1992; 231: 407-412 • 16 IM residents read 107 ECGs • Looking for signs indicative of AMI • Disagreement in 70% of the cases

  36. AMI Diagnosis- ECG Willems et al, NEJM. 1991; 325:1767-1773 • 8 cardiologists interpreted 1220 ECGS • High interobserver agreement -  of 0.67 • 125 ECGs read twice • Different diagnosis for 10%-23% of ECGs

  37. AMI Diagnosis- ECG Massel et al. Am Heart J. 2000;140:221-6 • 3 cardiologists - 75 ECGs • 2 occasions (within 7 days) • First reading: Presence or absence of thrombolysis eligibility criteria • Second reading: criterion 1 plus the subjective opinion that the changes represented acute transmural injury

  38. Interobserver variability in thrombolytic therapy eligibility Is there 1 mm ST elevation? Does this represent an AMI? Agreement kappa Agreement kappa Rater 1 vs 2 93.3 86.2 94.7 88.2 Rater 2 vs 3 88.0 75.8 94.7 88.0 Rater 1 vs 3 86.7 72.9 94.7 88.2 Overall 78.2 88.5 AMI Diagnosis- ECG

  39. Errors in AMI • ECG of a patient who is otherwise eligible may be incorrectly interpreted as being nondiagnostic • ST-segment elevation may be erroneously interpreted as suggesting an AMI, resulting in the inappropriate overuse of thrombolysis

  40. Errors in AMI – Missed Diagnosis • ECG of a patient who is otherwise eligible may be incorrectly interpreted as being nondiagnostic • ST-segment elevation may be erroneously interpreted as suggesting an AMI, resulting in the inappropriate overuse of thrombolysis

  41. Errors in AMI - Missed Diagnosis McCarthy et al, Ann Emerg Med.1993;22:5795-82 • Rate of missed AMI among 6 NE hospitals • 1050 patients with AMI • 1.9% misdiagnosed • 25% of the patients with missed AMI had STE of at least 1 mm • Death or severe complications in 25% of pts

  42. Errors in AMI - Missed Diagnosis Pope et al, NEJM 2000;342:1163-70 • 10,689 patients, 10 hospitals (ACI-TIPI trial) • 17% had acute cardiac ischemia (ACI) • 8% AMI • 9% UA • 6% stable angina • 21% other cardiac diagnosis • 55% noncardiac diagnosis

  43. Errors in AMI – Missed Diagnosis Pope et al • Of 894 AMI patients, 19 (2.1%) was missed • 8 (47%) had one of the following ECG readings: LVH, LBBB, BER, pericarditis • 7 (41%) minor ST segment abnormality with <1mm of ST segment deviation • 14 of 19 had NQWMI

  44. Errors in AMI – Missed Diagnosis Brady et al, AEM, April 2001 • 11 ECGs with STE • 45 yo male with HTN, DM and chest pain • 458 EPs

  45. Errors in AMI – Missed Diagnosis Brady et al, AEM, April 2001 • Overall rate of correct

  46. Errors in AMI • ECG of a patient who is otherwise eligible may be incorrectly interpreted as being nondiagnostic • ST-segment elevation may be erroneously interpreted as suggesting an AMI, resulting in the inappropriate overuse of thrombolysis

  47. Errors in AMI - Over Diagnosis Lee et al, Ann Int Med 1989;110:957-62.   • No AMI in 25% of patients with acute chest pain and ST-segment elevation • For every 8 patients appropriately treated with a thrombolytic agent 1 or 2 will be treated unnecessarily

  48. Errors in AMI-Over Diagnosis Sharkey et al, Am J Cardiol 1994;73:550-3 • 93 patients with chest pain receiving thrombolytic therapy, AMI did not occur in 10 (11%) • LVH- 30% • BER- 30% • IVCD- 30%

  49. Impact of Errors • Bleeding consequences • Life-threatening bleed- 0.4% • Moderate bleed- 5% • Not treating an eligible thrombolysis candidate • Financial consequences • Missed AMI is the leading cause of malpractice loss in the ED setting

  50. Causes of ST Segment Elevation Cardiac • Acute myocardial infarction •   Variant (Prinzmetal's) angina •   Acute pericarditis •   Left ventricular aneurysm •   Left ventricular hypertrophy •   Bundle branch blocks •   Benign Early repolarization

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