Coronary Heart Disease

Coronary heart disease (CHD), also known as coronary artery disease, is a condition where the heart’s blood supply is blocked or interrupted by a buildup of fatty substances in the coronary arteries. These fatty substances form a substance called plaque, which narrows the arteries and reduces blood flow to the heart.

This disease is considered the leading cause of death globally. According to the World Health Organization (WHO), around 17.9 million people died from coronary heart disease in 2019, accounting for 31% of all global deaths.

Causes of Coronary Heart Disease

The primary cause of coronary heart disease (CHD) is atherosclerosis, a gradual build-up of plaque in the walls of the coronary arteries. Plaque is a sticky substance made up of cholesterol, fat, calcium, and other substances found in the blood.

As plaque builds up, it narrows the arteries and reduces blood flow to the heart. This can cause chest pain (angina), shortness of breath, and other symptoms. In some cases, a complete blockage of a coronary artery can lead to a heart attack.

Risk Factors for Coronary Heart Disease

Coronary heart disease (CHD) is a major health concern, and there are several risk factors that can contribute to its development. These factors can be broadly categorized into modifiable and non-modifiable factors.

Modifiable Risk Factors:

• Unhealthy Diet: A diet high in saturated and trans fats, cholesterol, and sodium can increase your risk of CHD. These substances can contribute to plaque buildup in the arteries.
• Physical Inactivity: Lack of regular exercise weakens the heart and blood vessels, making them more susceptible to damage. Aim for at least 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous-intensity aerobic activity per week.
• Smoking: Smoking damages the blood vessels and increases the risk of blood clots. It also lowers HDL (good) cholesterol levels and raises LDL (bad) cholesterol levels.
• Obesity and Overweight: Excess weight puts a strain on the heart and can increase blood pressure and cholesterol levels.
• Diabetes: Diabetes can damage blood vessels and nerves throughout the body, including those that supply the heart.
• High Blood Pressure (Hypertension): Uncontrolled high blood pressure puts a strain on the heart and can damage blood vessels.
• High Cholesterol: High levels of LDL (bad) cholesterol and low levels of HDL (good) cholesterol can contribute to plaque buildup in the arteries.
• Stress: Chronic stress can increase blood pressure and inflammation, both of which are risk factors for CHD.
• Sleep Apnea: Sleep apnea is a condition in which breathing repeatedly stops and starts during sleep. This can lead to oxygen deprivation, which can damage the heart.

Non-Modifiable Risk Factors:

• Age: The risk of CHD increases with age.
• Sex: Men are generally at higher risk of CHD than women, although women’s risk increases after menopause.
• Family History: Having a close relative with CHD, such as a parent, sibling, or child, increases your risk.

Complications of Coronary Heart Disease

Coronary heart disease (CHD) is a serious condition that can lead to a number of complications, some of which can be life-threatening. 

• Heart attack: A heart attack occurs when a blood clot completely blocks a coronary artery, cutting off blood flow to a part of the heart. This can cause heart muscle damage or death.
• Angina (chest pain): Angina is a type of chest pain that occurs when the heart muscle doesn’t get enough blood. It can feel like a squeezing or pressure in the chest, and it may also radiate to the shoulders, arms, jaw, back, or stomach.
• Heart failure: Heart failure is a condition in which the heart can’t pump blood effectively enough to meet the body’s needs. This can lead to fatigue, shortness of breath, and swelling in the legs and ankles.
• Arrhythmia: Arrhythmia is an irregular heartbeat. Some arrhythmias are harmless, but others can be serious and even life-threatening.
• Stroke: A stroke occurs when a blood clot blocks a blood vessel in the brain or when a blood vessel in the brain bursts. Strokes can cause permanent brain damage and can lead to death.
• Peripheral artery disease (PAD): PAD is a condition in which the arteries in the legs are narrowed. This can cause pain, cramping, and numbness in the legs. In severe cases, PAD can lead to amputation.
• Aortic aneurysm: An aortic aneurysm is a bulge in the aorta, the largest artery in the body. If the aneurysm bursts, it can cause life-threatening bleeding.

Common Symptoms of Coronary Heart Disease

Coronary heart disease (CHD) can manifest in various ways, and sometimes there might not be any noticeable symptoms at all. However, there are some common signs to watch out for.

Chest pain (angina) is the most frequent symptom of CHD. It’s a discomfort or pain in the chest that feels like pressure, tightness, or squeezing. The pain can radiate to shoulders, arms, jaw, back, or stomach. Stable angina is triggered by exertion or stress and subsides with rest, while unstable angina can occur at rest and is a more serious indicator. Angina is typically a warning sign that the heart isn’t getting enough oxygen-rich blood to meet its demands. Unlike a heart attack, angina typically isn’t a complete blockage of blood flow, but rather a significant narrowing of the coronary arteries.

You might experience difficulty catching your breath (dyspnea), especially during physical activity or even while resting in severe cases. Pain in the upper body is another common symptom. Discomfort or pain can extend to your shoulders, arms, neck, jaw, or back along with chest pain.

Weakness, fatigue, or dizziness can occur due to reduced blood flow to the heart and the rest of the body. Nausea or feeling sick can be a surprising symptom of CHD, but it can sometimes accompany chest pain. Breaking into a cold sweat can be another indicator of reduced blood flow and potential discomfort.

Heart Attacks and the Link to Coronary Heart Disease

A heart attack, also known as a myocardial infarction (MI), occurs when blood flow to a part of the heart muscle is severely blocked or cut off completely. This blockage is typically caused by a build-up of plaque in the coronary arteries, the vessels supplying blood to the heart.

Over time, fatty deposits, cholesterol, and other substances can accumulate in the walls of the coronary arteries, forming plaque. This process is called atherosclerosis. Plaque buildup narrows the arteries, reducing blood flow to the heart muscle. 

Sometimes, a piece of plaque can rupture or break open. This triggers the blood to clot in an attempt to repair the damaged area. In a heart attack, the blood clot can completely block the narrowed artery, preventing oxygen-rich blood from reaching the heart muscle.

Without sufficient oxygen, the heart muscle cells begin to die within minutes. The longer blood flow is blocked, the more extensive the damage becomes. This cell death can disrupt the heart’s electrical signals, leading to irregular heartbeats (arrhythmias). In severe cases, a large area of heart muscle death can significantly weaken the heart’s pumping ability, potentially leading to heart failure.

Silent Ischemia and Coronary Artery Disease

Coronary heart disease (CHD) can silently wreak havoc on the heart muscle through a condition called silent ischemia. This means there’s insufficient blood flow to the heart, but unlike angina, there are no noticeable symptoms like chest pain or discomfort.

This silent characteristic makes it particularly dangerous because individuals remain unaware of the reduced blood flow depriving their heart muscle of vital oxygen. This threat can significantly elevate the risk of a sudden heart attack. 

1. Progressive Heart Muscle Damage: Even without symptoms, the lack of oxygen due to reduced blood flow can damage the heart muscle cells over time. This weakens the heart and makes it less efficient at pumping blood. Damaged heart tissue is also more prone to developing irregular heartbeats (arrhythmias), which can further disrupt blood flow and increase the risk of a heart attack.
2. Unpreparedness for Symptoms: Because there’s no warning sign like angina, a person experiencing silent ischemia might not recognize the initial stages of a heart attack. This can lead to a delay in seeking medical attention, which is crucial during a heart attack to minimize damage. Early intervention can significantly improve the chances of a full recovery.

How is Coronary Heart Disease Diagnosed?

Coronary heart disease (CHD) diagnosis typically involves a two-pronged approach: gathering information through a medical history and physical exam, followed by specific tests to confirm the presence and severity of the disease. 

Your doctor will discuss your symptoms in detail, including chest pain characteristics, shortness of breath, and any other relevant experiences. They’ll inquire about your family history of heart disease, risk factors like high blood pressure, cholesterol levels, diabetes, and lifestyle habits such as smoking and physical activity.

A physical exam will involve checking your blood pressure, listening to your heart for any abnormal sounds (murmurs) that might indicate narrowed arteries, and potentially examining your pulse for irregularities.

Based on the initial assessment, your doctor might recommend further tests to get a clearer picture:

• Electrocardiogram (ECG): This painless test measures the electrical activity of your heart and can detect abnormal heart rhythms that might suggest CHD.
• Echocardiogram (Echo): This ultrasound technique creates images of your heart, revealing any structural abnormalities or reduced pumping efficiency caused by CHD.
• Exercise stress test: This test monitors your heart’s electrical activity and response to physical exertion (usually walking on a treadmill or riding a stationary bike). Abnormal changes in heart rhythm or blood pressure during exercise can indicate narrowed arteries.
• Chest X-ray: While not a direct diagnostic tool for CHD, a chest X-ray can provide a broader picture of your heart and lungs, potentially revealing abnormalities related to CHD.
• Blood tests: These can assess cholesterol levels, blood sugar levels (for diabetes), and other markers that might contribute to CHD risk.
• Coronary artery angiography: This specialized X-ray technique involves injecting a contrast dye into the coronary arteries to visualize any blockages. While highly accurate, it’s an invasive procedure typically used for diagnosis before treatment decisions.
• Coronary artery calcium scan: This non-invasive test uses CT scans to detect calcium buildup in the coronary arteries, which can indicate the presence and severity of plaque buildup.

How is Coronary Heart Disease Treated?

Coronary heart disease (CHD) treatment focuses on two main goals: managing symptoms and preventing future complications like heart attack or stroke. The approach typically involves a combination of lifestyle changes, medications, and sometimes procedures or surgery.

Lifestyle Modifications:

• Diet: A healthy diet low in saturated and trans fats, cholesterol, and sodium is crucial. Fruits, vegetables, whole grains, and lean protein sources are encouraged.
• Exercise: Regular physical activity, like at least 150 minutes of moderate-intensity exercise or 75 minutes of vigorous-intensity exercise per week, strengthens the heart and improves blood flow.
• Weight management: Losing excess weight reduces strain on the heart.
• Smoking cessation: Smoking is a major risk factor for CHD. Quitting smoking significantly improves heart health.
• Stress management: Chronic stress can worsen CHD. Techniques like relaxation therapy or meditation can be beneficial.

Medications:

• Cholesterol-lowering medications: Statins are the mainstay for lowering LDL (bad) cholesterol and reducing plaque buildup.
• Blood pressure medications: Medications can help control high blood pressure, reducing strain on the heart.
• Antiplatelet medications: These medications help prevent blood clots that can trigger heart attacks.
• Angina medications: Beta-blockers and nitrates can help manage angina symptoms by improving blood flow and reducing heart workload.

Procedures and Surgery:

In some cases, depending on the severity of CHD, procedures or surgeries might be necessary to improve blood flow to the heart:

• Angioplasty and stenting: A minimally invasive procedure where a balloon is used to open a narrowed artery, followed by inserting a stent to keep it open.
• Coronary artery bypass graft (CABG): A surgical procedure where a healthy blood vessel is grafted from another part of the body to bypass a blocked coronary artery.

What Medications are Most Commonly Prescribed for Coronary Heart Disease?

Cholesterol-lowering medications are often the first line of defense to prevent plaque buildup in arteries. A common type are statins, which lower LDL (bad) cholesterol levels. Examples include atorvastatin (Lipitor), rosuvastatin (Crestor), simvastatin (Zocor), and others.

Antiplatelet medications help prevent blood clots from forming in the arteries, which can lead to heart attacks or strokes. Common examples include aspirin, clopidogrel (Plavix), and ticagrelor (Brilinta).

Uncontrolled high blood pressure puts a strain on the heart. Several medication classes can help manage blood pressure, depending on the individual’s needs. Blood pressure medications in the form of Beta-blockers, ACE inhibitors, ARBs (angiotensin receptor blockers), and diuretics are some possibilities.

Angina medications help manage chest pain (angina) symptoms associated with CHD. Beta-blockers and nitrates are common types. Beta-blockers like metoprolol (Lopressor) slow the heart rate and reduce its workload. Nitrates, like nitroglycerin, relax blood vessels to improve blood flow and ease chest pain.