What is heart disease?
Heart disease — also called cardiovascular disease — is an umbrella term covering a range of conditions that affect the structure and function of the heart. The heart beats about 100,000 times a day, pumping five litres of blood per minute through a network of vessels that, laid end-to-end, would circle the Earth more than twice.
The most common form is coronary artery disease (CAD), in which the arteries feeding the heart muscle become narrowed by plaque (atherosclerosis). Think of it like a slow-building blockage in a pipe: years of plaque accumulation gradually restrict blood flow, and eventually a clot can completely block an artery — causing a heart attack.
"Heart disease," "cardiovascular disease," and "coronary heart disease" are used interchangeably in the media. Technically, cardiovascular disease is the broadest term. This guide uses both terms to reflect standard clinical usage.
Types of heart disease
Coronary artery disease (CAD)
The most prevalent form, affecting approximately 18 million American adults. CAD develops when atherosclerotic plaque builds up inside the coronary arteries, reducing blood flow to the heart muscle. When plaque ruptures, a blood clot forms rapidly, potentially causing a myocardial infarction (heart attack). Most people with CAD have no symptoms until the arteries are significantly narrowed — the first manifestation in some patients, tragically, is sudden cardiac death.
Heart failure
Heart failure means the heart cannot pump enough blood to meet the body's needs. It affects about 6.7 million Americans and is the leading cause of hospitalisation in people over 65. Two main types:
- HFrEF (reduced ejection fraction): The heart muscle is weakened and cannot squeeze forcefully enough — often caused by a prior heart attack.
- HFpEF (preserved ejection fraction): The heart squeezes normally but the muscle is stiff and cannot fill properly — more common in women, older adults, and those with hypertension or diabetes.
Arrhythmias
Abnormal heart rhythms ranging from harmless palpitations to life-threatening ventricular fibrillation. Atrial fibrillation (AFib) — affecting 6 million Americans — is the most common serious arrhythmia. The upper chambers quiver chaotically, which can allow blood clots to form and dramatically increases stroke risk.
Valvular heart disease
The heart has four valves that keep blood flowing in the right direction. Valvular disease occurs when one or more valves don't open or close properly — either narrowing (stenosis) or leaking (regurgitation). Severe cases require surgical or catheter-based repair or replacement.
Cardiomyopathy
Disease of the heart muscle itself. Types include dilated (enlarged, weakened heart), hypertrophic (abnormally thickened muscle — a leading cause of sudden cardiac death in young athletes), and restrictive (stiffened muscle, often from infiltrative diseases like amyloidosis).
Symptoms and warning signs
Heart disease often develops silently over decades. By the time symptoms appear, significant damage may already have occurred. Recognising the warning signs — and knowing which ones demand emergency care — can be life-saving.
Chest pain, pressure, squeezing, or tightness · Pain spreading to jaw, left arm, back, or stomach · Sudden severe shortness of breath · Fainting or near-fainting · Sudden cold sweat · Signs of stroke (face drooping, arm weakness, speech difficulty)
| Symptom | Classic (often men) | Atypical (often women) | Urgency |
|---|---|---|---|
| Chest discomfort | Pressure, squeezing — "elephant on chest" | Burning, aching, or vague discomfort | Emergency |
| Radiating pain | Left arm, shoulder, neck | Jaw, back, both arms, upper abdomen | Emergency |
| Breathlessness | With exertion or at rest | May be the only symptom | Emergency |
| Nausea / vomiting | Less common in men | More common, may dominate | Urgent |
| Cold sweat | Sudden diaphoresis | Similar | Emergency |
| Unusual fatigue | Often precedes event | Can appear days/weeks before MI | See doctor |
Women are significantly more likely to present with atypical symptoms — nausea, jaw pain, extreme fatigue — rather than classic chest pressure. This has historically led to underdiagnosis and delayed treatment. Never dismiss cardiac symptoms in women because they don't fit the "classic" description.
Causes and risk factors
Modifiable risk factors
🩺 Hypertension
- Affects 1 in 3 adults
- Damages arterial walls
- Silent — no symptoms
- Target: below 130/80 mmHg
🩸 High Cholesterol
- LDL drives plaque formation
- Statins reduce risk 25–35%
- PCSK9 inhibitors for high-risk
- Diet and exercise also help
🚬 Smoking
- Doubles heart disease risk
- Damages endothelium directly
- Risk drops rapidly after quitting
- 10 years post-quit: near normal
⚖️ Obesity / Diabetes
- Metabolic syndrome cluster
- GLP-1 drugs show CV benefit
- 5–10% weight loss is protective
- Insulin resistance worsens risk
🛋️ Physical Inactivity
- 150 min/week moderate exercise
- Reduces risk by 35%
- Improves all risk factors
- Any amount helps
😰 Chronic Stress
- Elevates cortisol chronically
- Promotes inflammation
- Drives unhealthy behaviours
- Mindfulness shows modest benefit
Non-modifiable risk factors
- Age: Risk rises sharply after 45 in men, 55 in women.
- Sex: Men have higher risk earlier; women's risk equalises post-menopause.
- Family history: First-degree relative with MI before 55 (men) or 65 (women) roughly doubles your risk.
- Genetics: Familial hypercholesterolaemia affects 1 in 250 and can cause MI in young adults.
How heart disease is diagnosed
| Test | What it measures | Clinical use |
|---|---|---|
| Lipid panel | Total cholesterol, LDL, HDL, triglycerides | Risk assessment, statin decisions |
| Troponin (hs-cTnI/T) | Heart muscle protein released during damage | Diagnosing heart attack — gold standard |
| BNP / NT-proBNP | Cardiac stress hormone | Diagnosing and monitoring heart failure |
| hsCRP | High-sensitivity C-reactive protein | Inflammation marker; refines CV risk |
| ECG (12-lead) | Heart's electrical activity | Detects MI, arrhythmias, conduction defects — first-line test |
| Echocardiogram | Cardiac ultrasound — structure & function | Ejection fraction, valves, wall motion — most informative non-invasive test |
| CT calcium score (CAC) | Calcified coronary plaque | Risk stratification — score of 0 is very reassuring |
| CT coronary angiography | Coronary artery anatomy | Non-invasive alternative to catheterisation |
| Stress test | ECG / echo during exercise or pharmacological stress | Unmasks CAD not apparent at rest |
| Coronary angiography (cath) | Gold standard — direct coronary visualisation | Defines severity; enables immediate stenting |
Treatment options
| Drug class | Examples | Primary use | Key benefit |
|---|---|---|---|
| Statins | Atorvastatin, Rosuvastatin | High cholesterol, CAD prevention | Reduce LDL 40–60%, stabilise plaque |
| PCSK9 inhibitors | Evolocumab, Alirocumab | Very high CV risk, statin intolerance | Reduce LDL up to 70% on top of statin |
| ACE inhibitors / ARBs | Lisinopril, Losartan | Heart failure, hypertension, post-MI | Reduce mortality in HFrEF by 20–25% |
| Beta-blockers | Carvedilol, Metoprolol | Heart failure, angina, post-MI | Reduce sudden cardiac death |
| SGLT2 inhibitors | Empagliflozin, Dapagliflozin | Heart failure, diabetes | Reduce HF hospitalisation ~30% |
| Antiplatelet agents | Aspirin, Clopidogrel | Post-MI, post-stent | Prevent clot formation |
| Anticoagulants | Apixaban, Rivaroxaban | AFib — stroke prevention | Reduce AFib stroke risk by 60–70% |
| Diuretics | Furosemide, Spironolactone | Heart failure fluid relief | Relieve congestion, improve symptoms |
The INTERHEART study found that nine modifiable risk factors account for over 90% of the risk for a first heart attack. Lifestyle medicine is the foundation of prevention.
- Diet: Mediterranean and DASH diets have the strongest evidence. Key: olive oil, fish, whole grains, legumes, nuts, abundant vegetables. Limit red meat, refined carbohydrates, and ultra-processed foods.
- Physical activity: 150 minutes per week of moderate aerobic exercise reduces cardiac risk by 35%. Two sessions of resistance training per week add further benefit.
- Smoking cessation: The single most cost-effective intervention. Within one year of quitting, heart disease risk drops by 50%.
- Weight management: Every 1 kg of weight loss reduces systolic blood pressure by ~1 mmHg.
- Sleep: Target 7–9 hours. Both <6 and >9 hours are associated with increased cardiovascular risk.
- Alcohol: Current evidence suggests minimising or avoiding alcohol for cardiovascular health.
- Pacemaker: Implanted device that delivers electrical impulses when the heart beats too slowly. Essential for sick sinus syndrome and heart block.
- ICD (Implantable Cardioverter-Defibrillator): Like a pacemaker but delivers a life-saving shock for ventricular fibrillation. Recommended for EF <35% or prior cardiac arrest.
- CRT (Cardiac Resynchronisation Therapy): Biventricular pacemaker coordinating both ventricles. Improves symptoms and survival in HFrEF with LBBB.
- LVAD (Left Ventricular Assist Device): Mechanical pump to support a failing heart — as a bridge to transplant or permanent therapy.
Cardiac rehabilitation is one of the most underutilised yet evidence-backed interventions in cardiology.
- Typically 36 supervised sessions over 12 weeks
- Reduces mortality after heart attack by up to 26%
- Reduces hospital readmission by 31%
- Includes education on diet, medications, and stress management
- Indicated after: MI, stenting, bypass surgery, heart failure, valve repair
- Only ~20–25% of eligible patients complete a programme — access and awareness remain barriers
Surgical and interventional procedures
PCI (Angioplasty and Stenting)
The most common cardiac procedure — over 600,000 performed annually in the U.S. A balloon catheter is threaded to the blocked artery (usually via the wrist — radial approach) and inflated to compress the plaque, then a drug-eluting stent is deployed to keep the artery open. Most patients go home the next day. Dual antiplatelet therapy (aspirin + a P2Y12 inhibitor) is required for 6–12 months after drug-eluting stent implantation.
CABG (Coronary Artery Bypass Grafting)
Open-heart surgery in which vessels harvested from the chest (internal mammary artery — the preferred conduit) or leg (saphenous vein) are grafted around blocked coronary arteries. Preferred over PCI in patients with complex multi-vessel disease, diabetes, or left main stenosis — offering better long-term outcomes in these scenarios.
TAVR (Transcatheter Aortic Valve Replacement)
Revolutionary catheter-based replacement for severe aortic stenosis — delivered via femoral artery without open-heart surgery. Now approved for patients across all surgical risk categories. Most patients leave hospital within 2–3 days.
Prevention: Life's Essential 8
The AHA's "Life's Essential 8" framework identifies the key metrics for optimal cardiovascular health:
- Blood pressure: Below 120/80 mmHg. Check annually if normal.
- Blood glucose: Fasting below 100 mg/dL, HbA1c below 5.7%.
- Cholesterol: LDL below 100 mg/dL (below 70 with established heart disease).
- Healthy weight: BMI 18.5–24.9.
- Physical activity: 150+ min/week moderate or 75+ min vigorous aerobic exercise.
- Healthy diet: Mediterranean or DASH pattern — vegetables, fruits, whole grains, fish, nuts.
- Avoid tobacco: Never smoke; quit immediately if you do.
- Sleep: 7–9 hours nightly. Screen for sleep apnoea if you snore heavily.
Living with heart disease
A diagnosis of heart disease can be frightening — but it is not the end. Millions of people live full, active lives with heart disease when it is properly managed.
Medication adherence
Cardiovascular medications only work when taken consistently. Stopping statins, beta-blockers, or antiplatelet therapy abruptly can trigger a rebound effect and significantly increases cardiac risk. If cost, side effects, or regimen complexity is making adherence difficult, talk to your cardiologist — there are almost always solutions.
Home blood pressure monitoring
Invest in a validated upper-arm blood pressure monitor. A week of twice-daily home readings provides far more diagnostic information than a single office measurement. Bring your log to every appointment.
Emotional wellbeing
Depression and anxiety are two to three times more common in people with heart disease — and they independently worsen cardiovascular outcomes. If you are struggling emotionally after a cardiac event, ask for a referral to cardiac psychology. Cardiac rehabilitation also has significant mental health benefits.
Frequently asked questions
Coronary artery disease (CAD) is the most common type, affecting approximately 18 million American adults. It is caused by atherosclerosis — the buildup of fatty plaque inside the coronary arteries. CAD is responsible for most heart attacks and the majority of heart disease deaths worldwide.
Research by Dr. Dean Ornish demonstrated that significant lifestyle changes — a very low-fat diet, regular aerobic exercise, stress management, and smoking cessation — can partially reverse coronary artery disease. Aggressive statin and PCSK9-inhibitor therapy can also stabilise and modestly regress atherosclerotic plaque. Complete reversal is generally not achievable, but meaningful arrest of progression is a proven clinical goal.
Early warning signs include chest discomfort with exertion, unexplained shortness of breath, palpitations, and unusual fatigue — especially in women, who may experience these symptoms days or weeks before a cardiac event. Crucially, many people with significant CAD have no symptoms until a heart attack occurs, which is why proactive risk assessment — blood pressure, cholesterol, glucose — matters enormously after age 40.
Atherosclerosis begins far earlier than most people realise — fatty streaks have been found in children as young as 3 years old in autopsy studies. Clinically significant disease typically manifests from age 45 in men and 55 in women. Familial hypercholesterolaemia can cause heart attacks in people in their 20s and 30s, independent of lifestyle.
Yes, genetics play a significant role. A first-degree relative who had a heart attack before age 55 (men) or 65 (women) roughly doubles your personal risk. Familial hypercholesterolaemia — affecting 1 in 250 people — causes severely elevated LDL from birth and dramatically increases risk even independent of diet or lifestyle. If you have a strong family history, discuss it with your doctor — you may benefit from earlier screening and preventive treatment.
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