How Does Heart Enlargement Affect The Risk Of Myocardial Infarction (Heart Attack)?

Introduction

Are you worried about how an enlarged heart could affect your health? - We all aim to have a healthy heart, and we attempt to do whatever we can to keep it this way. However, this can be difficult to achieve for those with an enlarged heart, which is why you are right to be cautious. An enlarged heart, also known as cardiomegaly, is a condition where it becomes abnormally dilated (stretched) or thick, making it larger than normal and affecting its ability to pump blood. Whilst it can be a condition, an enlarged heart is usually a sign of another condition, such as valvular heart disease or high blood pressure.¹ 

Heart enlargement can significantly increase your risk of a myocardial infarction, more commonly known as a heart attack. However, how exactly does this occur? In this article, the relationship between heart enlargement and the heightened risk of myocardial infarction will be broken down, allowing you to gain a better understanding of these conditions and helping you to understand the warning signs. Additionally, it will cover how to prevent and manage this condition. Therefore, let’s not wait for another beat and dive deep into the details and tools to take control of your heart.

Heart enlargement (cardiomegaly)

Cardiomegaly, meaning enlargement of the heart, is an umbrella term incorporating the various conditions that cause it.¹ An enlarged heart is defined as an increase in size, normally occurring as a symptom of another health condition. These conditions cause the muscles around the heart to thicken or stretch out its chambers, making it bigger. 

In recent years, it has become increasingly prevalent and associated with high mortality.² This enlargement can occur to the heart's atria or the left and right ventricles. Many varieties of cardiomegaly are distinguished by left ventricular dilation and systolic dysfunction, despite right ventricular impairment and diastolic dysfunction taking place in some cases.³ Due to it mainly being caused by other conditions, it usually remains undiagnosed until the first symptoms of the underlying condition appear. 

Types 

There are two main types of heart enlargement, including:

• Dilated cardiomyopathy: This is the most common type of heart enlargement, where the heart walls (ventricles) are stretched out, becoming thin, often resulting in heart failure, as the heart struggles to pump blood around the body³
• Hypertrophic cardiomyopathy: During this type of heart enlargement, the heart walls thicken, normally due to increased workload. This thickening can occur in the septum, the muscular wall located between the left and right sides of the heart. This mainly occurs due to an inherited heart condition, which can be passed on through families⁴

Causes

As mentioned previously, heart enlargement is not considered a condition itself but a consequence of another underlying health condition, which include:¹

• High blood pressure
• Congenital heart disease
• Coronary heart disease
• Heart valve disease
• Obesity
• Drug abuse
• Thyroid disease
• Pregnancy
• Infections, such as endocarditis

Symptoms

Heart enlargement is often not diagnosed until the symptoms of the primary condition arise, with some patients not presenting any symptoms (asymptomatic). However, those that do present symptoms show signs including:

• Shortness of breath
• Tiredness
• Chest pain
• Palpitations, including an irregular heartbeat
• Fainting
• Swelling of feet, ankles and legs
• Lightheadedness

Myocardial infarction (heart attack)

Heart attacks, also known as Myocardial infarctions, occur when a section of the heart muscle is not receiving sufficient blood flow or becomes blocked, contributing to heart disease. When a small mound of plaque in the coronary artery builds up and cracks open, blood clots are developed. The body responds to the crack by trying to fix it, making the mound bigger. The size of the mound then causes the tissue downstream from the clot to become starved of blood flow. As a result, the heart muscle cells begin to die due to the low flow of red blood cells reaching them, which are full of oxygen, requiring a constant blood supply to survive.⁵ These are considered life-threatening medical emergencies. According to the British Heart Foundation, every year, around 100,000 people are hospitalised as a result of a heart attack, with coronary heart disease causing around 68,000 deaths.

Types

Two main types of heart attacks are considered to take place, which occur due to several different reasons. According to the NHS, myocardial infarctions are classified by a measurement taken from electrocardiograms (ECGs) known as the ST segment and the level of troponin (heart protein) in the blood. The two types are:

• Type 1: these are spontaneous heart attacks caused by ischemia as a result of a primary coronary event, i.e., plaque rupture⁶ 
• Type 2: These are considered to have occurred when ischemia occurs due to an increased demand for oxygen (i.e., hypertension) or decreased supply (i.e., embolism or hypotension)⁶

A sudden severe spasm can also stop blood flow, causing the coronary artery to contract. 

Causes

There are a few factors that can lead to the cause of a heart attack⁷:

• Coronary artery disease (CAD), which is the most common cause
• Plaque build-up and rupture
• Blood clots
• Damage to the heart muscles
• Harmful drugs
• Hypoxia - which is described as a sudden drop in oxygen levels

Symptoms

The associated symptoms of a heart attack include:⁸

• Chest and upper body pain
• Lightheadedness 
• Shortness of breath
• Cough
• Anxiety
• Wheezing
• Irregular heartbeat
• Choking sensation

If you suspect you are having a heart attack or suspect someone is having one, you should call 999 (emergency services) and request an ambulance. 

Key risk factors

Whilst anyone can suffer a heart attack, certain risk factors increase your chances. These include:

• High blood pressure
• Diabetes
• Smoking
• Age
• High levels of cholesterol

How heart enlargement increases the risk of heart attacks

As mentioned previously, there are two main ways in which the heart can become enlarged, with the different types increasing the risk of heart attacks (myocardial infarction) in different ways.

• Dilated cardiomyopathy: During this type of enlargement, the heart's chambers are stretched, and as a result, they become thinner. This can make it harder for the heart to pump blood, leading to heart failure as sufficient blood is not being pumped.^3,9 Additionally, this weakened heart function makes it harder to supply the heart with nutrients and oxygen, increasing the risk of a heart attack. Studies have shown that among the deaths caused by heart enlargement, over 70% of these are attributed to pump failure⁹
• Hypertrophic cardiomyopathy: During this condition, the heart becomes enlarged due to the muscles in the heart becoming thicker, making it harder for the heart to pump blood. Hearts can become stiff, increasing the strain on the arteries. Studies have shown that left ventricular hypertrophy, where the left ventricle of the heart becomes thicker, significantly increases the risk of heart attacks (myocardial infarctions)¹⁰

There are other reasons as to how heart enlargement increases the risk of heart attacks, which include:

• Higher risk of blood clots: The decreased speed of blood flow due to enlarged heart chambers increases the risk of blood clot formation, which can block the coronary arteries, leading to a heart attack
• Impaired blood flow: Poor blood flow and circulation often associated with enlarged hearts increase the risk of ischemia, which is caused by a lack of oxygen to the heart muscle
• Increased workload: Whether the heart muscles have become thicker or have stretched and become thin, the heart has to work harder to pump blood, increasing oxygen demand. In many cases, if the coronary arteries cannot meet the increased demand, a heart attack can occur

In addition, there are also certain health conditions which can increase the risk of a heart attack in those with an enlarged heart. These include conditions such as:

• Hypertension
• Coronary artery disease 
• Arrhythmias (irregular heartbeats)

Prevention and Management

There are various ways in which the risk of experiencing a heart attack can be prevented in patients with enlarged hearts. In most cases, these include methods to prevent heart enlargement and manage the condition if you have already been diagnosed. These include:

• Controlling your blood pressure and reducing the strain on your heart can help prevent and manage heart enlargement, subsequently reducing the risk of experiencing a heart attack
• Lifestyle changes - making changes to your diet and incorporating more exercise, together with reducing bad habits such as smoking and drinking alcohol, can reduce risk factors for both heart attacks and heart enlargement

There are also medications that can be prescribed, such as beta-blockers, to help decrease the effects of an enlarged heart, decreasing the risk of myocardial infarction. 

Summary

In order to protect your health, it is extremely important to understand the relationship between heart enlargement and the risk of myocardial infarctions. Heart enlargement, also known as cardiomegaly, can occur due to dilated or hypertrophic cardiomyopathy. This increase can significantly increase the likelihood of heart attacks due to a higher risk of blood clots, impaired blood flow, and an increased strain on the heart. However, identifying the risk and carrying out preventive measures, such as managing blood pressure and adopting a healthier lifestyle, can reduce this risk. Therefore, even though an enlarged heart can provide substantial obstacles, heart health can be maintained, and potentially fatal consequences can be avoided with quick action and informed decision-making. So stay vigilant, take control, and prioritise your heart’s well-being.