Easy-to-Understand Myocardial Infarction Pathophysiology

SimpleNursing Editorial Team May 14, 2018
Heart Attack: Easy-to-Understand Myocardial Infarction Pathophysiology

Today, we’ll be talking about the pathophysiology of myocardial infarction (MI) and the different therapeutic modalities concerning the condition.

MI as Traffic Accidents

Think of your myocardial infarction as one huge traffic jam inside the heart that’s causing blockage to the highway, impeding the circulation of blood and oxygen. Since there’s blockage, no cars (red blood cells) are getting through to oxygenate the heart.

Keep this concept in mind while we move on with our discussion to have a clearer and better understanding of what really happens with a client who has a myocardial infarction.

Basic Knowledge

We will have a quick stop with anatomy and physiology before getting into the details of what it means to have a myocardial infarction and how it can be treated.

The heart is composed of coronary arteries that are mainly responsible for feeding the heart with sufficient amount of oxygen. Therefore, the coronary arteries are the freeways or highways of the heart.

To sustain life, oxygen must circulate adequately to and from the heart. For this reason, people who are unable to receive enough oxygen due to life-threatening circumstances like drowning manifests cyanosis and dies in six minutes due to the inability of tissues to receive oxygen. This is what pretty much happens with myocardial infarction.

When the coronary arteries (highways of the heart) are occluded for some specific reason, backup and congestion are expected which may lead to a series of heart ailments.

Stable Angina

Stable angina is basically a pain in the heart occurring activities like exercise. When the sympathetic nervous system kicks in, it causes vasoconstriction which is basically the narrowing of blood vessels leading to inefficient oxygen distribution. The pain felt with stable angina is relieved by the rest because oxygen is now properly going to the apex of the heart.  

Unstable Angina

Unlike stable angina which is caused by vasoconstriction, unstable angina is caused by a blockage.

When dealing with unstable angina, what are the things that you need to provide?

  1. Nitroglycerin is given to promote vasodilation. This means that nitro is given to basically add more lanes to the freeway so that there is sufficient perfusion of blood and oxygen going to the apex of the heart.
  2. Aspirin 325 mg is given due to its anti-platelet property. Aspirin helps the blood to go around smoothly around the clot or whatever is obstructing oxygen flow.
  3. Morphine is another treatment modality that one should consider when taking care of a client with MI. Morphine is mainly given to relieve the pain stressing the heart.

If the pain is not relieved, unstable angina can lead to myocardial infarction or tissue death.

Why is there tissue death inside the heart? Due to lack of oxygen received by the tissues. It’s like tightly putting a tourniquet around your finger for about six minutes or so, causing the distal portion to become cyanotic and the chances of losing that finger are high. The tissues of your finger die because of the absence of oxygen. This is similar to MI.

  1. Give a beta-blocker or heparin drip. While heparin is not necessarily the medication responsible for cleaning up the heart from clots, it prevents further accidents or blockages from happening. A heparin drip is an anti-coagulant which contributes to lesser clamping inside the blood vessel.

So, that’s basically what a nurse should do in cases of myocardial infarction.

On our next topic, we’ll show what MI looks like on an EKG strip and provide you with further information about the condition.

See you there!

Want to ace Nursing School Exams & the NCLEX?

Make topics click with easy-to-understand videos & more. We've helped over 1,000,000 students & we can help you too.


Nursing students trust SimpleNursing

Simplenursing student
I cannot express enough gratitude for Nurse Mike and this wonderful platform he has created. I had a subscription to SimpleNursing the entire 2 years of my nursing school career and it was the best resource I had available to me. The visuals, the explanations, the memory tricks, the songs, the study guides, and the test questions are brilliant.
read more
Simplenursing student
Before starting nursing school, I was a C-average student. I didn't think I'd be competent enough and make it through my second semester. I was told about SimpleNursing and purchased it immediately. Long story short, I graduated nursing school with honors and passed all of my classes with As and Bs only. I would have never been able to do that without the help of SimpleNursing. Nurse Mike teaches in the only way that I am able to learn and I cannot thank him enough.
read more