Ischemia sdr Flashcards
HYPOXIA
= metabolic impairment of cell function due to a
decreased oxygen supply
ISCHEMIA
= Hypoxia + Decreased cleansing of metabolic waste
→ For the myocite
• Lactate ↔ Piruvate
• H+
ISCHEMIC HEART DISEASE
= a syndrome
→ characterized by ischemia of the myocyte cells & interstitium as a consequence of an impaired coronary flow (macro and/or microvascular)
→ inadequate supply of blood and oxygen to an area of the myocardium due to the occurrence of an imbalance between myocardial oxygen supply and demand.
Myocardial ischemia syndromes
CAUSES
- Nonatherosclerotic
2. Atherosclerosis
Nonatherosclerotic Causes of IHD
slide 3
ATHEROSCLEROSIS
“The most common cause of myocardial ischemia is atherosclerotic disease of an epicardial coronary artery (or arteries) sufficient to cause a regional reduction in myocardial blood flow and inadequate perfusion of the myocardium supplied by the involved coronary artery.”
Coronary artery disease- (CAD)
Definition
Pattern
Definition ( European Society of Cardiology 2019)
CAD “is a pathological process characterized by
atherosclerotic plaque accumulation in the epicardial arteries, whether obstructive or non-obstructive ”
Pattern:
progressive
various clinical presentations
ATHEROSCLEROTIC PLAQUES
Plaques stability, activity and vulnerability
Stable atherosclerotic plaques
Composition
- Fibrous cap between intima and media
- Lipid core
- Hypocellularity
Stable when
Fibrous tissue exceed the lipids
Noninflammatory cells»_space; inflammatory cells
ATHEROSCLEROTIC PLAQUES
Plaques stability, activity and vulnerability
Unstable plaque
= culprit lesion for an acute vascular event
─ Fibrous cap: Thikness ↓→ cap Inflammation & Rupture &Thrombus formation
[Macrophages↑(~1/4of cap), Smooth muscle cells ↓, apoptosis ↑]
─ Necrotic Core↑ → Lipids»_space; Fibers
─ Plaque size ↑
─ Neovascularization ↑ + Intraplaque hemorrhage ↑
─ Perivascular inflammation
─ ↑ Paradoxical remodeling (stenosis ↓)
Pathogenesis of Atherosclerotic Plaques
- Endothelial damage
- Protective response results in production of
cellular adhesion molecules
3.Monocytes and T lymphocytes attached to
‘sticky’ surface of endothelial cells
4.Migrate through arterial wall to subendothelial space
5.Macrophages take up oxidised LDL cholesterol - Lipid-rich foam cells
- Fatty streak and plaque
Results of myocardial ischemia
Conclusions:
take a look at slides 5,6,7 ─ Acidosis → Pain ─ Mechanical inhomogeneity→ mechanical remodeling ↓ • diastolic dysfunction • systolic dysfunction • dilatation • HF • myocardial ruptures ─ Electrical inhomogeneity → electrical remodeling
↓
• rhythm disorders
• conduction disorders
• SCD
Ischemic heart disease (IHD)
Classification
Chronic coronary syndromes
- Chronic stable angina
- Asymptomatic and symptomatic pts with stabilized symptoms < 1 year after an ACS Or
patients with recent revascularization - Asymptomatic and symptomatic pts >1 year after initial diagnosis or revascularization
Ischemic heart disease (IHD)
Classification
Acute coronary syndromes (ACS)
- Unstable angina
- ST elevation myocardial infarction
- Non ST elevation myocardial infarction
Other IHD Forms in which pain is not a dominant symptom
- Asymptomatic subjects in whom CAD is detected at screening
- Ischemic dilated cardiopathy with progressive heart failure
- Ischemic mitral regurgitation
- Rhythm and conduction disturbances
- Sudden cardiac death
- Vasospastic (Prinzmetal) and microvascular angina
Ischemic syndromes
Clinical Pattern
CAD
- Chronic coronary sdr. (Former stable CAD) =>
1.Chronic stable angina
2.Asymptomatic (Silent)
Ecg ischemia
- Acute, unstable(due to aterotrombosis)ACS :
>Without necrosis -> Unstable anginaTn (–)
>With necrosis =>
1. ST elevation MI= STEMI
2. Non-ST elevation MI= NTEMI
- Sudden cardiac death
Ischemic syndromes
Symptoms
Chest pain
Diaphoresis
Anginal equivalents (dyspnea, faintness, fatigue, and frequent belching)
Non–chest locations of discomfort (either exertional or at rest)
- Neck or mandibular discomfort or pain
- Throat tightness
- Shoulder discomfort
- Interscapular or infrascapular discomfort
- Upper arm or forearm discomfort (more often left-sided)
- Mid-epigastric burning
Nausea or vomiting (due to increased vagal tone secondary to inferior
myocardial ischemia or infarction)
Symptoms Determined by complication
> heart failure symptoms
− Dyspnea on exertion, Dyspnea at rest, Paroxysmal nocturnal dyspnea
− Gradual↑of exertional dyspnea with ↓effort tolerance)
> Dizziness and syncope
Ischemic syndromes
Signs /Physical examination
- normal physical findings OR
* findings related to the the consequences of myocardial ischemia or evidence of risk factors
Ischemic syndromes
Cardiovascular characteristic signs when present
Auscultation
- S3 may be present
- transient apical Mitral systolic murmur (holosystolic or mid- late) due to reversible papillary muscle dysfunction that results in mitral regurgitation