Can ECG Spot Angina?

We can often experience chest pain and there can be many causes for this. One cause may be angina, which is a serious health problem related to the heart. An electrocardiogram (ECG) is a common test which assesses the heart’s rhythm and electrical activity and it can indicate various cardiac conditions including angina. 

Angina Pectoris (Often shortened to just angina) is a health problem that presents as chest pains, caused by reduced blood flow to the heart muscles. While can suffer from angina there is greater prevalence among People assigned female at birth (PAFAB) than in people assigned male at birth (PAMAB).¹ Angina itself presents no life-threatening concern apart from uncomfortable chest pain. However, it greatly increases the chances of heart attack and stroke. These conditions can significantly affect a person’s quality of life or be fatal. Therefore, this condition must be recognised and treated.

An ECG is a diagnostic test that is often used by paramedics and doctors. It consists of electrodes that are placed on the skin and record the electrical activity of the heart. This will produce a graph which shows the change in voltage over time. For normal heart activity, this will present a graph that has distinct waves. During an angina attack , the graph will have several irregularities which allows a diagnosis to take place.

This article will now explore angina in depth by assessing its: causes and risk factors, symptoms, diagnosis and treatment. This article will also explore how an ECG can be vital in diagnosing angina and how a doctor can tell a patient has angina from the graph.

About angina 

There are two types of angina: Stable and unstable angina. Stable angina is predictable and has known triggers for an attack. These triggers can include stress or exercise which trigger an attack. This type of angina is also predictable in that a few minutes rest after exercise can resolve an attack. 

On the other hand, unstable angina is a lot more unpredictable. There can be no identifiable triggers for unstable angina and it may not be able to resolve with rest. This type of angina is uncommon compared to stable angina but some people can develop unstable angina from stable angina.

Causes and risk factors 

The direct cause of angina is atherosclerosis. This is a technical term to refer to the narrowing of blood vessels due to the build-up of fatty deposits. Due to this narrowing, there is a decreased blood flow through the coronary arteries. The knock-on consequence of this is that there is less oxygen for the heart to use and this affects its ability to pump blood. Ultimately this leads to angina. If the fatty deposit was allowed to completely build-up to block the artery then this is a heart attack. Now we will move to assess the risk factors for atherosclerosis.

However, there are a myriad of causes and risk factors that can increase your chances of developing angina such as: 

• Sex (There is a greater prevalence of angina in PAFAB than in PAMAB)¹
• Age (in those aged 70 and over there is a 7.1% prevalence of angina)²
• Genetics (If there is a family history of atherosclerosis or angina then there is an increased chance that you might also develop the disease)³
• Lifestyle (unhealthy diet, lack of exercise, smoking and alcohol)^4,5

In general, an individual should live a healthy life if they wish to minimise their risk of angina.  

Symptoms

The main symptom of angina is chest pains. These chest pains are often described as a feeling of tightness or heaviness. Chest pains can spread to other areas of the body such as the jaw and heart and can be caused by triggers as discussed before with stable angina.

Once the trigger is removed and an individual rests for some time, the chest pains should subside. However, there can be no triggers for angina as was discussed with unstable angina. Chest pains also may not subside with this type.

While chest pains are the main symptom of angina there are others as well. These include:

• Dizziness
• Breathlessness
• Fatigue
• Nausea
• Sweating

Diagnosis

Once symptoms appear, is it important to see a doctor to obtain a diagnosis or rule out the possibility of angina. There are many tools by which a doctor can diagnose angina in an individual.

Coronary angiography

A coronary angiography might sound quite complicated but it is a relatively simple procedure. The term can be broken down into “coronary” referring to the heart, “angio-” referring to angina and “-graphy” more or less meaning a test like an x-ray. 

This procedure involves inserting a catheter into a blood vessel which supplies a dye. Afterwards, an x-ray is taken of the chest. The dye will allow the arteries of the heart to show clearly on the x-ray.  Therefore, the structure and function of the heart, including any atherosclerosis, can be assessed

An exercise ECG

An ECG can be used when a patient is resting or during exercise. An ECG taken during exercise is preferred due to its sensitivity and its specificity to angina and coronary disease. There are several distinct patterns to these ECGs that would indicate that angina is the cause of chest pains. 

One pattern is horizontal or downward-sloping ST-segment depression or elevation. This occurs in the early stages of exercise and will persist for ~3 minutes after exercise. An “ST-segment depression” sounds very technical and needs to be understood in relation to a normal ECG. The exact details of what this means are not needed but what should be understood is that your doctor can identify this to confirm a diagnosis of angina.⁶

How efficient is ECG in spotting angina? 

An ECG is extremely efficient in spotting angina. If there are changes to the electrical patterns in the heart, an ECG will pick these up. While we have mentioned ST depression, there are a variety of nuanced changes that can occur to an ECG in angina. These are identifiable and distinct allowing an ECG to be efficient. Several repeat recordings of ECGs can be taken as well. Therefore even if a pattern is missed in one recording, it will be in another.

There are also several benefits to using an ECG that make it efficient. An ECG is a non-invasive technique unlike coronary angiography. An ECG consists of electrodes placed on the skin so it can be performed easily and at little risk to a patient. In addition, there are a variety of conditions related to the heart that can be picked up as well. The multi-modality of this test therefore makes it preferable.

Treatment

Several treatment options are available for people with angina. While undergoing treatment carries a certain amount of discomfort, this is preferable to the heart attacks and strokes that it could cause if untreated.

Medicines

Medicines with angina are prescribed with three main goals. The first group of medicines are aimed at treating attacks when they occur, such as glycerin trinitrate.

Another group of medicines is aimed at preventing attacks. This includes beta-blockers and calcium channel blockers. 

Finally, another group is aimed to prevent heart attacks and strokes. This includes aspirin, statins and ACE inhibitors. However, these medicines may not work effectively enough and surgery may be needed. 

It should be noted that the above medicines listed are for stable angina. In unstable angina, a slightly different set of medicines will be prescribed. These would be aimed at reducing blood clots and reducing the risk of heart attack or stroke. These medicines include aspirin and clopidogrel.

Surgery

There are two main surgeries that an individual can undergo for angina: Coronary artery bypass graft, and coronary angioplasty and stent insertion. Coronary artery bypass graft reroutes blood around the blocked or narrowed artery to the heart. This is accomplished by taking a section of blood vessels from another part of the body and grafting it onto the problematic artery. Coronary angioplasty and stent insertion modify the problematic artery. The artery is forcibly widened by the use of a stent to keep blood flow at optimum levels.

Change in lifestyle and diet

Another treatment avenue is changing lifestyle so that the condition is not worsened. If you are a smoker, it is paramount to stop as soon as you can. Smoking is a risk factor in angina and continuing to smoke is not ideal. Smoking also has implications for your lung health such as increasing the risk of cancer. 

Losing weight is another change to a person’s lifestyle that is needed. Often atherosclerosis is caused by the build-up in fatty deposits in the arteries. It makes sense to minimise the ability of the body to create these fatty deposits by losing weight. An increased weight also affects blood pressure so it is preferable to lose weight for this reason as well. One way of losing weight is by increased exercise. This has other knock-on effects on health than just losing weight. 

In addition, changes to your diet can help you lose weight. Being in a calorie deficit is the main way to lose weight regardless of what the foods are that make up those calories. However, you should be aware to avoid foods that increase the low-density lipoprotein cholesterol in the food as this type of cholesterol contributes to the narrowing of arteries.

Summary

In summary, angina is a serious condition that affects a person’s quality of life. It has a variety of risk factors, some in our control and some out of our control. If you develop angina, the chief symptom you will feel is chest pains. However, other symptoms like breathlessness can occur. If you get these symptoms, you should visit a doctor who might administer an exercise ECG or coronary angiography. An exercise ECG is preferable as it is non-invasive and highly efficient. If you are diagnosed with angina, there are a variety of treatments available to you including surgery. However, changes in your lifestyle are also important.