9 - The Heart: Ischemic Heart Disease Flashcards by G V

Ischemic Heart Disease (IHD): Defined

Imbalance between the myocardial supply (perfusion) and cardiac demand for oxygenated blood

Starts with Angina –> ends with MI

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IHD: IHD Syndromes (4)

MI
Angina Pectoris (chest pain)
Chronic IHD with heart failure
Sudden cardiac death (consequence of MI)

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IHD: Angina Pectoris - Defined

Characterized by chest pain – interpreted differently as ‘constricting’, ‘squeezing’ and so on

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IHD: Angina Pectoris - Types

Stable (typical) – relieved by rest but precipitated by physical activity; pain relieved by sublingual nitroglycerine and rest tested by treadmill

Prinzmetal – due to spasm of coronary artery, good response to nitroglycerine

Unstable – increasing in frequency, impending MI, dangerous type within 30 minutes

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IHD: Angina Pectoris - Types

Stable (typical) – relieved by rest but precipitated by physical activity; pain relieved by sublingual nitroglycerine and rest tested by treadmill

Prinzmetal – due to spasm of coronary artery, good response to nitroglycerine

Unstable – increasing in frequency, impending MI, dangerous type within 30 minutes

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IHD: MI - Incidental and Risk Factors A

A. Coronary Arterial Occlusion
- Atheromatous plaque leads to intra plaque hemorrhage or rupture

Mnemonics: HAS LIPIDS

H- Hereditary 
A- Age 
S- Sex
L- Lipid ( hyperchelestrol)
I- Inactivity ( Sedentary life style)
P- Pressure ( Hypertension)
I –increased weight ( Obesity)
D- Diabetes
S- Smoking

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IHD: MI - Incidental and Risk Factors A

A. Coronary Arterial Occlusion
- Atheromatous plaque leads to intra plaque hemorrhage or rupture

Mnemonics: HAS LIPIDS

H- Hereditary 
A- Age 
S- Sex
L- Lipid ( hyperchelestrol)
I- Inactivity ( Sedentary life style)
P- Pressure ( Hypertension)
I –increased weight ( Obesity)
D- Diabetes
S- Smoking

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IHD: MI - Non-Atheromatous Conditions (6)

Vasospasm (cocaine)
Emboli
Ischemia without evident atherosclerosis
Sickle cell disease
Shock
Vasculitis

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IHD: MI - Patterns: Transmural (3)

Caused by occlusion of epicardial vessels

*FULL THICKNESS

Atherosclerosis, plaque changes and superimposed thrombus

**ECG: ST Segment ELEVATION/Q wave

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IHD: MI - Patterns: Transmural (3)

Caused by occlusion of epicardial vessels

*FULL THICKNESS

Atherosclerosis, plaque changes and superimposed thrombus

**ECG: ST Segment ELEVATION/Q wave

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IHD: MI - Patterns: Subendocardial (3)

Necrosis limited to *inner 1/3 to one half of the ventricular wall

Follows plaque disruption secondary to thrombolysis

*Non-ST elevation infarcts” –> No Q waves (no myocyte death)

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IHD: MI - Patterns: Subendocardial (3)

Necrosis limited to *inner 1/3 to one half of the ventricular wall

Follows plaque disruption secondary to thrombolysis

*Non-ST elevation infarcts” –> No Q waves (no myocyte death)

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IHD: MI - Supply, Frequency, Region

LAD - 40-50%
RCA - 30-40%
Left circumflex - 15-20%

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IHD: MI - Morphology

Difficult to identify if TTC stains VIABLE tissue leaving necrotic tissue unstained

Older infarcts easy to ID and represent ischemic coagulative necrosis

Inflammatory cells seen in infarct

Myocytolysis

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IHD: MI - Morphology

Difficult to identify if TTC stains VIABLE tissue leaving necrotic tissue unstained

Older infarcts easy to ID and represent ischemic coagulative necrosis

Inflammatory cells seen in infarct

Myocytolysis within 6 hours

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IHD: MI - Enzymes

1st check Troponin I –> after 2-3 hrs, sustained for 2 weeks; highly specific but not sensitive

CKMB: released immediately (2-3 hours), peaks at 2nd day, and is normal by 3rd day

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IHD: MI - Enzymes

1st check Troponin I –> after 2-3 hrs, sustained for 2 weeks; highly specific but not sensitive

CKMB: released immediately (2-3 hours), peaks at 2nd day, and is normal by 3rd day

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IHD: MI - Microscopy 1st day

Vascular congestion within 3 hours

Swelling and Redness - Acidophilia within 6 hours

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IHD: MI - Microscopy 24 hrs

Red and swollen - full coagulative necrosis

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IHD: MI - Microscopy 48 hrs

Yellowing of infarct due to macrophages

IHD: MI - Microscopy 3 days

Yellow infarct surrounded by red border due to fibroblast proliferation

IHD: MI - Microscopy 1-3 weeks

Yellow infarct due to collagen

IHD: MI - Microscopy 3 months

Grey, white scar due to fibrosis

IHD: MI - Microscopy 3 months

Grey, white scar due to fibrosis

What occurs in the first hour of MI?

Cell death because of arrhythmia (monitor ever 50 minutes) Palpate pulse (Vtach, AFIb)

What can occur on the 7th day of MI and also what's a good enzyme to confirm this?

Re-infarction/Ventricular rupture due to weak scar that isn't fully formed by all of the collagen So, ventricle isn't strong enough to withhold the hemodynamic force CKMB great to confirm this

IHD: MI - Reperfusion infarcts

Usually hemorrhagic (red infarcts) Irreversibly injured myocytes exhibit contraction bands Intensely eosinophilic stripes ( closed sarcomeres)

IHD: MI - C/F (4)

1. Severe chest pain radiating to left shoulder 2. 'Silent' MI refers to no pain by elderly and diabetics 3. Diaphoresis 4. Atypical presentations include **Abdominal epigastric pain mimicking severe colic and back pain

IHD: MI - C/F (4)

IHD: MI - Diagnosis with Enzymes (4)

CKMB, cTnT, and cTnI is first 3-12 hrs. CKMB and cTnI peak at 12 hr. CKMB returns to normal 48-72hrs cTnI in 5-10 days cTnT in 5-14 days

IHD: MI - Consequences and complications (1 of 3) - Contractile Dysfunction

Left ventricular failure leads to congestion and edema of lung: massive infarct leads to cardiogenic shock and has high mortality

IHD: MI - Consequences and complications (2 of 3) - Arrhythmias within 1 hour of MI can cause death

Sinus bradycardia Tachycardia Heart block Ventricular fibrillation

IHD: MI - Consequences and complications (3 of 3) - Myocardial rupture after 7 days

Necrotic ventricle is vulnerable and ruptures and causes hemopericardium and cardiac tamponade and immediate death Rupture of ventricular septum causes acute VSD and left to right shunts

IHD: MI - Consequences and complications - 1. Contractile Dysfunction

Left ventricular failure leads to congestion and edema of lung: massive infarct leads to cardiogenic shock and has high mortality

IHD: MI - Consequences and complications - 2. Arrhythmias within 1 hour of MI can cause death

Sinus bradycardia Tachycardia Heart block Ventricular fibrillation

IHD: MI - Consequences and complications - 3. Myocardial rupture after 7 days

Necrotic ventricle is vulnerable and ruptures and causes hemopericardium and cardiac tamponade and immediate death Rupture of ventricular septum causes acute VSD and left to right shunts

IHD: MI - Consequences and complications - 4. Pericarditis

Fibrinous deposition due to inflammation Known as Dressler's Syndrome - Post MI pericarditis (etiology thought to be immune mediated)

IHD: MI - Consequences and complications - 5. Right Ventricular Infarction

Ventricular septal infarcts and infarction of the posterior part of left ventricles Causes acute right sided heart failure

IHD: MI - Consequences and complications - 6. Extension of Infarct

New infarcts develop around existing infarcts

IHD: MI - Consequences and complications - 7. Expansion of infarct

Depends on severity of obstruction Associated with anteroseptal infarcts. Due to necrosis, myocardium shows thinning, dilation and stretching

IHD: MI - Consequences and complications - 8. Mural Thrombus

Formation leads to thromboembolic complications MI Apex of LV 6 months later ventricular bulge not contracting during systole, suffers massive STROKE and expires

IHD: MI - Consequences and complications - 9. Ventricular aneurysms

After 3 months Scarred myocardium gives rise to true aneurysms Once scar is formed. Terminal portion of infarction will dilate. Not in harmony with cardiac muscle  dilation of ventricle (ventricular aneurysms

IHD: MI - Consequences and complications - 9. Ventricular aneurysms

IHD: MI - Consequences and complications - 10. Papillary muscle dysfunction and ruptures causes?

Mitral regurge secondary and functional

IHD: MI - Consequences and complications - 11. Progressive Heart Failure

AKA Chronic IHD

Mnemonic to remember complications of MI is?

“APPEAR” ``` A- Arrhythmias P- Pump failure P- Pericarditis E- Embolisation A-Aneurysm of the ventricle R- Rupture ( cardiac wall or papillary muscle ) ```

High Yield Fact: Common cause of death in MI is?

Arrhythmias ( Ventricular tachycardia and ventricular fibrillation ) - within 2 hrs.

High Yield Fact: Delayed complication dramatic and sudden rupture of myocardium can occur when?

4-8 days post MI