What Is Heart Disease? Causes, Types, Symptoms, and Prevention

What Is Heart Disease?

Heart disease — more precisely called cardiovascular disease (CVD) — is an umbrella term for a range of conditions that affect the heart's structure and function. It is the world's number one cause of death, responsible for approximately 18 million deaths annually — about one-third of all global deaths.

Despite its prevalence, heart disease is largely preventable through lifestyle choices and medical management of risk factors.

Types of Heart Disease

Coronary Artery Disease (CAD)

The most common form. CAD occurs when the coronary arteries — which supply blood to the heart muscle — become narrowed or blocked by atherosclerosis: the buildup of fatty plaques inside the artery walls. Reduced blood flow can cause angina (chest pain or pressure), and complete blockage triggers a heart attack (myocardial infarction).

Heart Failure

Heart failure (also called congestive heart failure) occurs when the heart muscle is too weak or too stiff to pump blood effectively. It does not mean the heart stops — it means the heart is not pumping efficiently enough to meet the body's needs. Symptoms include breathlessness, fatigue, and fluid accumulation in the legs and lungs.

Arrhythmias

Abnormal heart rhythms. The heart may beat too fast (tachycardia), too slow (bradycardia), or irregularly. Atrial fibrillation (AFib) is the most common arrhythmia — an irregular and often rapid heartbeat that increases stroke risk. Ventricular fibrillation is immediately life-threatening.

Heart Valve Disease

The heart's four valves regulate blood flow between chambers and out to the body. Valve disease occurs when valves do not open or close properly — due to calcification, infection (endocarditis), or congenital defects. Severe cases may require valve repair or replacement surgery.

Congenital Heart Defects

Structural heart abnormalities present from birth. About 1% of babies are born with a heart defect. Many are minor; others require surgery in infancy or childhood.

Cardiomyopathy

Disease of the heart muscle itself, making it harder for the heart to pump blood. Can be genetic, caused by viral infections, alcohol abuse, or other conditions.

How Atherosclerosis Leads to Heart Attacks

The development of CAD unfolds over decades:

1. Repeated injury to the artery's inner lining (endothelium) from high blood pressure, smoking, high cholesterol, or high blood sugar triggers inflammation.
2. LDL cholesterol particles ("bad" cholesterol) become trapped in the damaged artery wall and oxidize, triggering an immune response.
3. White blood cells (macrophages) infiltrate the area and engulf oxidized LDL, forming foam cells that accumulate into a fatty streak.
4. Over time, a fibrous cap covers the fatty deposit, forming a plaque. The plaque narrows the artery and reduces blood flow.
5. A vulnerable plaque can rupture. Blood platelets rush to the rupture site and form a clot, which can suddenly block the artery — causing a heart attack.

Risk Factors

Modifiable

• High blood pressure — directly damages artery walls
• High LDL cholesterol — fuels plaque formation
• Smoking — accelerates atherosclerosis and promotes clot formation
• Type 2 diabetes — damages blood vessels throughout the body
• Obesity — particularly abdominal fat
• Physical inactivity
• Poor diet — high in saturated fat, trans fat, sodium, and processed foods
• Excessive alcohol consumption
• Chronic stress — contributes through hormonal effects on blood pressure and inflammation

Non-Modifiable

• Age (risk increases significantly after 65 for women, 45 for men)
• Family history of early heart disease
• Sex (men at higher risk before menopause; women's risk increases post-menopause)

Warning Signs of a Heart Attack

Classic symptoms include:

• Chest pain, pressure, tightness, or squeezing — often described as an elephant sitting on the chest
• Pain radiating to the left arm, shoulder, jaw, neck, or back
• Shortness of breath
• Cold sweat, nausea, or lightheadedness

Women more often experience atypical symptoms: unusual fatigue, indigestion, back pain, or jaw pain — sometimes without chest pain. This contributes to women's heart attacks being underdiagnosed.

Call emergency services immediately if you suspect a heart attack. Every minute of delay costs heart muscle.

Prevention and Treatment

Lifestyle

• Mediterranean or heart-healthy diet (rich in vegetables, fruits, whole grains, healthy fats, lean protein)
• Regular aerobic exercise (150+ minutes/week of moderate intensity)
• Quit smoking
• Maintain healthy weight
• Manage stress

Medical Treatment

• Statins to lower LDL cholesterol
• ACE inhibitors or ARBs for blood pressure and heart failure
• Beta-blockers for arrhythmias and heart failure
• Antiplatelet agents (aspirin, clopidogrel) to prevent clotting
• Angioplasty and stenting to open blocked arteries
• Coronary artery bypass graft (CABG) surgery for severe multi-vessel disease