Myocardial Infarction

Question 1

Right coronary artery supplies blood to:

Left coronary artery supplies blood to:

Answer 1

Right atrium, both ventricles, conducting system (sinoatrial node, atrioventricular node)
Left atrium, left ventricle, interventricular septum

Question 2

What is angina?

Answer 2

It feels like a pressing, squeezing pain that is usually in the chest under the breastbone, but sometimes in the shoulders, arms, neck and jaws.
Angina is usually precipitated by exertion and it is usually relieved within a few mins or by taking medication like nitrates (nitroglycerin) which dilates coronary arteries, allowing more blood to flow.

Question 3

What is angina? Myocardial ischemia

Answer 3

It is a recurring pain or discomfort in the chest that happens when there is not enough blood supply to the heart

Question 4

What is myocardial ischemia?

Answer 4

It is when the lumen is partially blocked which the oxygen supply to the heart muscle will reduce.

Question 5

What is ischemia?

Answer 5

It is the inadequate blood supply to a local area due to the blockage of the blood vessel of that area.

Question 6

What is myocardial infarction?

Answer 6

When there is a complete blockage of blood supply to a portion of a heart.

Question 7

Myocardial infarction/ischemia will result from:

Answer 7

Partial obstruction of a coronary artery.
- Atherosclerotic plaques will cause partial or complete blockage of the lumen of the coronary arteries which reduce the oxygen supply.
Cardiac vasospasm
- uncontrolled vasoconstriction
Thrombus
- these atherosclerotic plaques can rupture. When these ruptures, it will induce platelet activity and coagulation cascade and form a thrombus.
Embolus
- when the thrombus detach from the vessel wall, it will be carried in the bloodstream as a embolus.

Question 8

Types of angina:

Answer 8

Stable angina:
- Experiencing symptoms during physical exertion but relieved when resting and by taking medication
Unstable angina:
- includes one or more of the following: more severe, prolonged, more frequent symptoms, experience angina even with minimal exertion
Vasospatic/Prinzmetal’s angina:
- result from vasospasm of coronary artery
- occur during at rest
- smoking will increase the risk

Question 9

Common consequences of myocardial infarction

Answer 9

Sudden cardiac arrest
Cardiac arrhythmia 
Ventricular remodelling
Deep vein thrombosis
Recurrent myocardial infarction

Question 10

Treatment

Answer 10

Controlling risk factors
- non-modifiable = age, gender, genetic factors
- modifiable = diabetes, hypertension, sedentary lifestyle, smoking
Pharmacological treatment
- calcium channel blocker = effective in reducing the frequency and severity of angina, dilates blood vessel for blood to flow
- aspirin = antiplatelet agent , prevent thrombus formation
(as atherosclerotic plaques rupture, the damage of the artery wall which will activate the coagulation activity form clot which leads to MI)
Surgical treatment
- PTCA
- CABG