Myocardial Infarction
Dr. Mohmmed AL jaberi
6/05/2014
Introductions
 When myocardial blood supply is abruptly reduced or cut off to
a region of the heart, a sequence of injuri...
Myocardial Blood Supply
Myocardial Blood Supply
 The left anterior descending coronary artery ( LAD ) :
– it's branches usually supply the anteri...
Inferior
II, III, aVF
Lateral
I, AVL,
V5-V6
Anterior /
Septal
V1-V4
Localising The Arterial Territory
Acute Anterior STEMI
• ST elevation and Q wave formation in V2-5, I and aVL.
• Reciprocal ST depression in lead III
Hyperacute anteroseptal STEMI
• ST elevation is maximal in the anteroseptal leads (V1-4).
• Q waves are present in the sep...
Extensive Anterolateral STEMI
• ST elevation in V2-6, I and aVL .
• Reciprocal ST depression in III and AVF
Anterior-inferior STEMI
• ST elevation in the precordial and inferior leads.
• Hyperacute T waves, most prominent in V1-3
...
High lateral STEMI
• ST elevation primarily localised to leads I and aVL
• It is usually associated with reciprocal ST dep...
Anterolateral STEMI
• ST elevation in the anterior (V2-4) and lateral leads (I, aVL, V5-6).
• Q waves waves are present in...
Inferior STEMI
Inferior STEMI
• Inferior MIs account for 40-50% of all myocardial infarctions
• Generally have a more favourable prognosi...
Inferior STEMI
 RCA occlusion is suggested by :
* ST elevation in lead III > lead II
* Presence of reciprocal ST depressi...
Inferior STEMI / LCX occlusion
• ST elevation in the inferior (II, III, aVF)
• ST depression & T wave inversion in aVL
• Q...
Inferior STEMI / RCA occlusion
• ST elevation in the inferior II, III and aVF with
• Early Q-wave formation in II, III and...
Inferolateral STEMI
• ST elevation in the inferior (II, III, aVF) & lateral leads (I, V5-6).
• ST depression in V1-3 is su...
Inferoposterolateral STEMI
• ST elevation in the inferior (II, III, aVF) & lateral leads (I, V5-6)
• ST depression in V1-3...
Posterior MI
• ST depression in V2-3
• Tall, broad R waves (> 30ms) in V2-3
• Dominant R wave (R/S ratio > 1) in V2
• Upri...
Myocardial Ischemia
Introductions
 Non-ST-elevation acute coronary syndrome (NSTEACS) encompasses two
main entities :
– Non-ST-elevation myoc...
Morphology Of ST Depression
• ST depression can be either upsloping, downsloping, or
horizontal .
• Horizontal or downslop...
Morphology Of ST Depression
ST depression: upsloping (A), downsloping (B), horizontal (C)
Distribution of ST segment depression
• ST depression due to Subendocardial Ischaemia is usually
widespread — typically pr...
T wave inversion
• T wave inversion may be considered to be evidence of
myocardial ischemia if:
– At least 1 mm deep
– Pre...
Wellens’ Syndrome
• Wellens’ syndrome is a pattern of inverted or biphasic T waves
in V2-4 (in patients presenting with is...
Type 1 Wellens’
– Type 1 Wellens’ T-waves are deeply and symmetrically inverted
Type 2 Wellens’
– Type 2 Wellens’ T-waves are biphasic, with the initial deflection
positive and the terminal deflection n...
Non-specific ST segment and T wave changes
• The following changes may occur with myocardial
ischaemia but are relatively ...
Widespread Subendocardial Ischaemi
• Widespread ST depression, seen in leads I, II and V5-6
• There is also some subtle ST...
High lateral STEMI !/ Reciprocal change
• Horizontal ST depression in III and aVF
• Regional ST depression should prompt y...
Type 2 Wellens’ syndrom
• T waves in V1-4 — biphasic in V1-3 and inverted in V4.
• It’s highly specific for a critical ste...
Inverted U waves
• There are inverted U waves, most prominent in leads V5-6.
• This is an infrequently recognised but very...
Dynamic ST depression in a patient with chest pain A
• Widespread ST depression(I, II, V5-6) indicates subendocardial
isch...
Dynamic ST depression in a patient with chest pain B
• The ST changes have now resolved.
• Inferior ST segments and Q wave...
References
Thank You
Myocardial Ischemia and Infarction
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Myocardial Ischemia and Infarction

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Myocardial Ischemia and Infarction

  1. 1. Myocardial Infarction Dr. Mohmmed AL jaberi 6/05/2014
  2. 2. Introductions  When myocardial blood supply is abruptly reduced or cut off to a region of the heart, a sequence of injurious events … ischemia >>> necrosis >>>> fibrosis (scarring) .  Rupture of an Atherosclerotic Plaque followed by Acute Coronary Thrombosis is the usual mechanism .  MI's resulting from total coronary occlusion ( Q-wave MI ) .  MI's resulting from subtotal occlusion ( non Q-wave MI ) .  2/3 of MI's presenting to ER evolve to non-Q wave MI's .
  3. 3. Myocardial Blood Supply
  4. 4. Myocardial Blood Supply  The left anterior descending coronary artery ( LAD ) : – it's branches usually supply the anterior and anterolateral walls of the left ventricle and the anterior 2/3 of the septum  The left circumflex coronary artery ( LCX ) : – its branches usually supply the posterolateral wall of the left ventricle  The right coronary artery ( RCA ) : – its branches supplies the right ventricle, the inferior and true posterior walls of the left ventricle, and the posterior 1/3 of the septum. The RCA also gives off the AV nodal coronary artery in 85-90% of individuals; in the remaining 10-15%, this artery is a branch of the LCX
  5. 5. Inferior II, III, aVF Lateral I, AVL, V5-V6 Anterior / Septal V1-V4 Localising The Arterial Territory
  6. 6. Acute Anterior STEMI • ST elevation and Q wave formation in V2-5, I and aVL. • Reciprocal ST depression in lead III
  7. 7. Hyperacute anteroseptal STEMI • ST elevation is maximal in the anteroseptal leads (V1-4). • Q waves are present in the septal leads (V1-2). • There is also some subtle STE in I, aVL and V5, with reciprocal ST depression in lead III. • There are hyperacute (peaked ) T waves in V2-4
  8. 8. Extensive Anterolateral STEMI • ST elevation in V2-6, I and aVL . • Reciprocal ST depression in III and AVF
  9. 9. Anterior-inferior STEMI • ST elevation in the precordial and inferior leads. • Hyperacute T waves, most prominent in V1-3 • Q waves in V1-3, as well as leads III and aVF
  10. 10. High lateral STEMI • ST elevation primarily localised to leads I and aVL • It is usually associated with reciprocal ST depression and T wave inversion in the inferior leads .
  11. 11. Anterolateral STEMI • ST elevation in the anterior (V2-4) and lateral leads (I, aVL, V5-6). • Q waves waves are present in both the anterior and lateral leads, most prominently in V2-4 • Reciprocal ST depression in inferior leads III and AVF
  12. 12. Inferior STEMI
  13. 13. Inferior STEMI • Inferior MIs account for 40-50% of all myocardial infarctions • Generally have a more favourable prognosis than ant. MI (in- hospital mortality only 2-9%) . • Up to 40% of patients with an inferior STEMI will have a concomitant right ventricular infarction . • Up to 20% of patients with inferior STEMI will develop significant bradycardia due to second or third-degree AV block. • Inferior STEMI may also be associated with posterior infarction , which confers a worse prognosis . • Both RCA and circumflex occlusion may cause infarction of the inferior wall
  14. 14. Inferior STEMI  RCA occlusion is suggested by : * ST elevation in lead III > lead II * Presence of reciprocal ST depression in lead I * Signs of ventricular infarction : STE in V1 & V4R  Circumflex occlusion is suggested by : * ST elevation in lead II = lead III * Absence of reciprocal ST depression in lead I * Signs of lateral infarction: ST elevation in the lateral leads I and aVL or V5-6
  15. 15. Inferior STEMI / LCX occlusion • ST elevation in the inferior (II, III, aVF) • ST depression & T wave inversion in aVL • Q-wave formation in III and aVF • ST elevation in lead II = lead III and absent reciprocal change in lead I suggest a circumflex artery occlusion
  16. 16. Inferior STEMI / RCA occlusion • ST elevation in the inferior II, III and aVF with • Early Q-wave formation in II, III and aVF • ST depression & T wave inversion in aVL • ST elevation in lead III > II with reciprocal change present in lead I and ST elevation in V1-2 suggests RCA occlusion with associated RV infarction .
  17. 17. Inferolateral STEMI • ST elevation in the inferior (II, III, aVF) & lateral leads (I, V5-6). • ST depression in V1-3 is suggestive of associated posterior infarction (the R/S ratio > 1 in V2 is consistent with this)
  18. 18. Inferoposterolateral STEMI • ST elevation in the inferior (II, III, aVF) & lateral leads (I, V5-6) • ST depression in V1-3 with tall, broad R waves and upright T waves and a R/S ratio > 1 in V2 indicate concomitant posterior infarction (this patient also had ST elevation in the posterior leads V7-9).
  19. 19. Posterior MI • ST depression in V2-3 • Tall, broad R waves (> 30ms) in V2-3 • Dominant R wave (R/S ratio > 1) in V2 • Upright T waves in V2-3
  20. 20. Myocardial Ischemia
  21. 21. Introductions  Non-ST-elevation acute coronary syndrome (NSTEACS) encompasses two main entities : – Non-ST-elevation myocardial infarction (NSTEMI). – Unstable angina (UA)  The differentiation between these two conditions based on the presence/absence of raised cardiac enzymes at 8-12 hours after the onset of chest pain. Both produce the same spectrum of ECG changes and symptoms and are managed identically in the ER  There are two main ECG abnormalities seen with NSTEACS: – ST segment depresion – T wave flattening or inversion  Other ECG patterns of ischaemia : – Hyperacute T waves or pseudonormalisation of previously inverted T waves (i.e. becoming upright) suggest hyperacute STEMI . – U-waves inversion
  22. 22. Morphology Of ST Depression • ST depression can be either upsloping, downsloping, or horizontal . • Horizontal or downsloping ST depression ≥ 0.5 mm at the J- point in ≥ 2 contiguous leads indicates myocardial ischaemia (according to the 2007 Task Force Criteria ). • ST depression ≥ 1 mm is more specific and conveys a worse prognosis. • ST depression ≥ 2 mm in ≥ 3 leads is associated with a high probability of NSTEMI and predicts significant mortality (35% mortality at 30 days). • Upsloping ST depression is non-specific for myocardial ischaemia.
  23. 23. Morphology Of ST Depression ST depression: upsloping (A), downsloping (B), horizontal (C)
  24. 24. Distribution of ST segment depression • ST depression due to Subendocardial Ischaemia is usually widespread — typically present in leads I, II, V4-6 and a variable number of additional leads. • A pattern of widespread ST depression plus ST elevation in aVR > 1 mm is suggestive of left main coronary artery occlusion .
  25. 25. T wave inversion • T wave inversion may be considered to be evidence of myocardial ischemia if: – At least 1 mm deep – Present in ≥ 2 continuous leads that have dominant R waves (R/S ratio > 1) – Dynamic — not present on old ECG or changing over time
  26. 26. Wellens’ Syndrome • Wellens’ syndrome is a pattern of inverted or biphasic T waves in V2-4 (in patients presenting with ischaemic chest pain) that is highly specific for Critical Stenosis Of The LAD Artery. • Patients may be pain free by the time the ECG is taken and have normally or minimally elevated cardiac enzymes; however, they are at extremely high risk for extensive anterior wall MI within the next 2-3 weeks.  There are two patterns of T-wave abnormality in Wellens’ syndrome: – Type 1 Wellens’ T-waves are deeply and symmetrically inverted – Type 2 Wellens’ T-waves are biphasic, with the initial deflection positive and the terminal deflection negative
  27. 27. Type 1 Wellens’ – Type 1 Wellens’ T-waves are deeply and symmetrically inverted
  28. 28. Type 2 Wellens’ – Type 2 Wellens’ T-waves are biphasic, with the initial deflection positive and the terminal deflection negative
  29. 29. Non-specific ST segment and T wave changes • The following changes may occur with myocardial ischaemia but are relatively non-specific: – ST depression < 0.5 mm – T wave inversion < 1 mm – T wave flattening – Upsloping ST depression
  30. 30. Widespread Subendocardial Ischaemi • Widespread ST depression, seen in leads I, II and V5-6 • There is also some subtle ST elevation in V1-2 and aVR with small Q waves in V1-2, suggesting that the cause of the widespread ischaemia is a proximal LAD occlusion
  31. 31. High lateral STEMI !/ Reciprocal change • Horizontal ST depression in III and aVF • Regional ST depression should prompt you to scrutinise the ECG for signs of reciprocal ST elevation… In this case there is subtle ST elevation in aVL , there is a high lateral STEMI
  32. 32. Type 2 Wellens’ syndrom • T waves in V1-4 — biphasic in V1-3 and inverted in V4. • It’s highly specific for a critical stenosis of the proximal LAD
  33. 33. Inverted U waves • There are inverted U waves, most prominent in leads V5-6. • This is an infrequently recognised but very specific sign of ischaemia this patient had a 12-hour troponin of 4.0 ng/mL.
  34. 34. Dynamic ST depression in a patient with chest pain A • Widespread ST depression(I, II, V5-6) indicates subendocardial ischaemia. • Q wave in lead III with slightly elevated ST segment suggests the possibility of early inferior STEMI
  35. 35. Dynamic ST depression in a patient with chest pain B • The ST changes have now resolved. • Inferior ST segments and Q waves are stable — this patient had a history of prior inferior MI • Troponin was raised, confirming that the initial ST depression was due to NSTEM
  36. 36. References
  37. 37. Thank You

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