IHD Flashcards
Mention each type and cause of ischemia
⬆️demand:⬆️hypertension
⬇️supply: hypotension / shock
⬇️oxygenation : pneumonia or CHF
⬇️oxygen carrying capacity:anemia
Define angina
Ischemic induced pain that doesn’t cause myocytes death
When cell death occurs in heart due ischemia the clinical manifestation is present as
MI
Sudden cardiac death is caused by
After MI or due to lethal arrhythmia
What is the acute clinical presentation of IHD
Acute coronary syndrome : catastrophic manifestations
of unstable angina, acute MI, and SCD
Ratios of obstruction in stable and unstable angina
70-75% stable
90% unstable which results in MI or sudden death
Ischemia induce which molecules to induce autonomic afferent
Adenosine and bradykinin
Types of angina
Typical/ stable
Crescendo/unstable
Prinzmetal/variant
Which type of angina Responds to vasodilators such as nitroglycerin and calcium channel
blockers.
Variant
Variant angina occurs at
- Occurs at rest
- Caused by coronary artery spasm.
- Completely normal vessel can be affected.
Episodic chest pain associated with particular levels of exertion
- Crushing or squeezing substernal sensation, that can radiate down the
left arm or to the left jaw (referred pain)
All indicate which type of angina and can be solved
Typical
By rest (reducing demand) or by drugs such as
nitroglycerin (vasodilator
Which type of angina is Associated with plaque disruption and superimposed thrombosis,and/or vasospasm.
Unstable
Unstable occurs at
Increasingly frequent pain, precipitated by progressively less exertion or
even occurring at rest.
Calcium channel blockers can be used in which type of angina
Variant
Risk factors of MI
Atherosclerosis and increased age( occurs at any age) and DM
Myocardial chemical response to ischemia
Within seconds of vascular obstruction: aerobic
glycolysis ceases drop in ATP➡️
accumulation of potentially noxious metabolites
(e.g., lactic acid) in the cardiac myocytes.
Due to drop in atp myocardial cells will lose the ability to
Contract
Within few minutes of ischemia which Ultrastructural changes occur
myofibrillar relaxation, glycogen depletion, cell
and mitochondrial swelling
These early changes are potentially reversible.
Severe ischemia lasting
20-40min
irreversible damage and coagulative necrosis of myocardium indicates
Severe ischemia
Irreversible injury of ischemic myocytes first
occurs in
subendocardial zone:
- The last area to receive blood delivered by the
epicardial vessels
infarct usually achieving its full extent within 3 to 6 hours
3 to 6 hours
Describe the difference between myocardial , infraction types in terms of thickness
Transmural Involve the full thickness of the ventricle while Subendocardial limited to the inner third of the myocardium
Non-ST elevation infarcts is characteristic of
Subendocardial infarction
features of an acute MI depend on:
The size and distribution of the involved vessel
- The rate of development and the duration of
the occlusion
- Metabolic demands of the myocardium
- Extent of collateral supply
Vessels involved in 40% to 50% of all MI
proximal left anterior descending (LAD)
artery occlusion
Vessel that result, in infraction in most of right ventricle
30% to 40%: Proximal right
coronary artery (RCA)
Infraction of the left lateral ventricle is caused by
15% to 20% : proximal left
circumflex (LCX) artery
Silent infarcts percentages
10% to 15%of MIs
- Common in diabetes mellitus
- Elderly.
Describe MI pain
Pain typically lasts several
minutes to hours, and is not
relieved by nitroglycerin or
rest.
Clinical futures of MI
Severe, crushing substernal
chest pain (or pressure) that
can radiate to the neck, jaw,
epigastrium, or left arm.
The pulse generally is rapid and weak, and
patients are often diaphoretic and nauseous .
• With massive MIs (involving more than 40% of
the left ventricle): cardiogenic shock
develops. And severe hypotension
Q waves, ST segment changes, and T wave
inversions
• Arrhythmias
And cardiac enzymes
All indications of??????
MI
death rate for MI
7%
A 1/3 of persons with (??????) will die, usually
of an arrhythmia within an hour of symptom
onset.
STEMI.
ST segment elevation MI
