Angina and Coronary Heart Disease/Ischaemic Heart Disease

Angina and Coronary Heart Disease

Angina and Coronary Heart Disease/Ischaemic Heart Disease

What is Angina?

Angina is a common symptom of Coronary Heart Disease and therefore  often a precursor to a heart attack (Myocardial Infarction). Patients suffering angina usually describe a pressure, heaviness, tightness or squeezing sensation in the chest neck or left arm. Angina most commonly presents itself during exertion and when the heart is under ‘stress’. I will explain why this is shortly.

What Causes Angina?

What Causes Angina? Angina and Coronary Heart Disease
Image Credit http://www.cvtsa.com/
As mentioned in my post on the differences between Cardiac Arrest and a Heart attack, the Heart, like all organs, has its own blood supply. The larger of these vessels are called the Coronary Arteries. Over time (depending on diet, lifestyle and genetics) plaque called atheroma can build up in these arteries.

This build up of fatty deposits in the Coronary Arteries is what we know as Coronary Heart Disease.
The narrowing of the arteries caused by these atheroma is called a Stenosis.



Now a large percentage of people will have plaque build up in their arteries but it never becomes flow limiting so they will go through their life without ever knowing. Atheroma become an issue when they cause a flow limiting stenosis (narrowing) or block off the artery completely.

If an artery totally occludes (blocks) then the muscle it supplies blood to will start to die and this is what we know as a heart attack but what do we mean by flow limiting?

Flow Limiting Coronary Heart Disease (CHD) Ischaemic Heart Disease


What Causes Angina? Angina and Coronary Heart Disease
Ischaemic Heart Disease occurs when a stenosis has become so significant  that the blood vessel is no longer able to supply SUFFICIENT blood to the heart muscle for it to perform properly. When insufficient blood reaches the muscle then there is a variance between the amount of Oxygen required by the muscle and the amount of Oxygen received. This reduces the functionality of the heart but is also the main cause of Angina (the most common symptom of Ischaemic Heart Disease).
Time for an analogy… 
Imagine a 4 lane motorway (freeway) its a Sunday lunchtime when the motorway develops a 25% Stenosis when a car breaks down blocking just one lane. This blockage is not flow limiting because the flow of traffic is maintained using the other three lanes.
On another very similar motorway there is a car crash and three of the four lanes are blocked (a 75% Stenosis), this time the rest of the traffic slows and can only pass the blockage one car at a time and a traffic jam forms. This stenosis is flow limiting not enough traffic is reaching its destination if this was an artery then the patient could develop angina, shortness of breath or sometimes palpitations.

Exercise Induced Chest Pain – Exertional Angina

Sometimes even arteries with severe blockages can cope with the demands of a resting heart. When a heart exercises the demand for blood increases and then the blocked blood vessel can no longer cope with the demands of the heart. This is why most cases of Angina are exertional (induced by exercise or effort).
Continuing the analogy from earlier… Picture a motorway with 3 Lanes blocked at 4am on a Sunday morning – hardly any traffic has to pass and the blockages is not flow limiting. This is like a resting heart. Now the exercising heart is like this same motorway but at 5pm on a Friday evening (rush hour) the remaining lane cannot cope with the demands of rush hour traffic and is severely flow limiting.
This is why Angina normally presents itself during effort because it is when the heart is ‘stressed’ that the blockage becomes problematic.
When Angina has a clear trigger (such as exercise) it is said to be Stable Angina. Unstable Angina can occur during any time of day, even at rest. It can also have a crescendo pattern (it gets more frequent and more painful or longer lasting) Unstable Angina is said to be more severe than stable angina and a stronger indicator of a pending heart attack.
When Angina is suspected then a persons Doctor should refer them on for further testing, the 3 most common tests for Coronary Heart Disease are Exercise Tolerance Tests, Cardiac CT Scans and Angiograms.
I will focus on these tests in future posts 🙂
Time for a quick Latin/Greek Lesson before you go? 

The term ANGINA derives from the Latin angina (“infection of the throat”) from the Greek ἀγχόνη ankhonē (“strangling”), and the Latin pectus (“chest”), and can therefore be translated as “a strangling feeling in the chest”. Thank you Wikipedia.

Thanks for Reading if you know someone with Angina or having chest pain then why not share this with them? 🙂
Time to fight this cold!
Cardiac Technician

Image courtesy of dream designs / FreeDigitalPhotos.net

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