Heart Glossary
Empowering Your Knowledge
Explore our Heart Glossary, a reliable reference designed to explain common and complex heart terms in plain language. We aim to make cardiology more understandable so you feel informed and supported in conversations about heart health.
Heart Glossary
A complete guide from A to Z, explaining common heart terms in clear, simple language to help you understand your heart health.
A Terms
ACE Inhibitors
Definition: ACE inhibitors help lower blood pressure by blocking a hormone that tightens blood vessels.
Why it matters: They are used for high blood pressure, heart failure, and after heart attacks.
Related terms: ARBs, Heart Failure, Hypertension.
Adrenaline
Definition: Also called epinephrine, this hormone increases heart rate, blood pressure, and opens airways.
Why it matters: Used in emergencies like cardiac arrest and anaphylaxis.
Related terms: Cardiac Arrest, Epinephrine, Resuscitation.
Amiodarone
Definition: A medication used to treat abnormal heart rhythms like atrial fibrillation or ventricular tachycardia.
Why it matters: It helps maintain rhythm but requires careful monitoring.
Related terms: Arrhythmia, Atrial Fibrillation, QT Interval.
Anemia
Definition: A condition where the body lacks enough healthy red blood cells to carry oxygen efficiently.
Why it matters: In people with heart disease, anemia can worsen symptoms and increase complications.
Related terms: Heart Failure, Fatigue, Oxygen.
Aneurysm
Definition: A bulge in a weakened artery wall that may rupture.
Why it matters: Can cause severe bleeding or stroke if it bursts.
Related terms: Aorta, Stroke, Surgery.
Angina
Definition: Chest discomfort caused by reduced blood flow to the heart muscle.
Why it matters: Often a warning sign of coronary artery disease.
Related terms: Heart Attack, ECG, Coronary Arteries.
Angiogram
Definition: An imaging test using contrast dye and X-rays to view the coronary arteries.
Why it matters: Helps detect blockages and guide treatments like stenting.
Related terms: Cardiac Catheterization, Stent, Coronary Artery Disease.
Angioplasty
Definition: A procedure using a balloon to widen narrowed or blocked coronary arteries.
Why it matters: Restores blood flow and can prevent heart damage.
Related terms: Stent, Revascularisation, Coronary Artery Disease.
Aorta
Definition: The body'92s largest artery, carrying oxygen-rich blood from the heart.
Why it matters: Aortic diseases like aneurysms can be life-threatening.
Related terms: Aortic Valve, Aneurysm, Surgery.
Aortic Valve
Definition: A valve that regulates blood flow from the heart into the aorta.
Why it matters: Malfunction can lead to breathlessness and heart failure.
Related terms: Aorta, Echocardiogram, Heart Valve.
Arrhythmia
Definition: Any abnormal heart rhythm '97 too fast, too slow, or irregular.
Why it matters: Some are harmless; others require treatment to prevent complications.
Related terms: Atrial Fibrillation, Palpitations, ECG.
Atherosclerosis
Definition: Buildup of fatty plaques inside arteries, leading to narrowed vessels.
Why it matters: Major cause of heart attacks and strokes.
Related terms: Cholesterol, Statins, Coronary Artery Disease.
Aspirin
Definition: A medication that reduces blood clotting and inflammation.
Why it matters: Used to prevent heart attacks and strokes but may increase bleeding risk.
Related terms: Stent, Heart Attack, Antiplatelet.
Atrial Fibrillation
Definition: A common irregular heartbeat where the atria beat chaotically.
Why it matters: Increases risk of stroke and heart failure.
Related terms: Arrhythmia, Anticoagulant, Stroke.
Atrial Flutter
Definition: A type of arrhythmia with rapid but regular atrial contractions.
Why it matters: Can cause palpitations and increase stroke risk.
Related terms: Atrial Fibrillation, ECG, Ablation.
Atropine
Definition: A drug that speeds up the heart by blocking vagal nerve effects.
Why it matters: Used in emergencies to treat dangerously slow heart rates.
Related terms: Bradycardia, Heart Block, Resuscitation.
B Terms
Bacterial Endocarditis
Definition: Infection of the inner lining of the heart and its valves, typically caused by bacteria entering the bloodstream.
Why it matters: Can damage heart valves, lead to heart failure, and cause septic emboli if not treated promptly.
Related terms: Heart Valve, Antibiotics, Surgery.
Baroreceptors
Definition: Specialized nerve endings in the walls of certain arteries that sense changes in blood pressure.
Why it matters: They trigger reflex adjustments in heart rate and vessel tone to keep blood pressure stable.
Related terms: Blood Pressure, Autonomic Nervous System, Reflex Bradycardia.
Beta Blockers
Definition: Medications that block adrenaline receptors, reducing heart rate and blood pressure.
Why it matters: Used to treat angina, arrhythmias, heart failure, and after heart attacks to improve outcomes.
Related terms: Bisoprolol, Metoprolol, Bradycardia.
Bicuspid Aortic Valve
Definition: A congenital condition where the aortic valve has only two leaflets (cusps) instead of three.
Why it matters: Can lead to early valve wear, stenosis, or regurgitation, sometimes requiring repair or replacement.
Related terms: Aortic Valve, Echocardiogram, Valve Replacement.
Bioprosthetic Valve
Definition: A heart valve replacement made from animal tissue (e.g., pig or cow) rather than metal or plastic.
Why it matters: These valves don'92t usually require long-term blood thinners but may wear out over 10'9620 years.
Related terms: Valve Replacement, Mechanical Valve, Anticoagulation.
Bisoprolol
Definition: A selective beta-1 blocker that slows the heart and lowers blood pressure.
Why it matters: Commonly prescribed for heart failure and high blood pressure; well-tolerated with fewer side effects.
Related terms: Beta Blockers, Heart Failure, Hypertension.
Blood Pressure
Definition: The force of blood against the walls of the arteries as the heart pumps.
Why it matters: High blood pressure is a leading risk factor for heart disease and stroke; low blood pressure can cause dizziness or shock.
Related terms: Hypertension, Hypotension, ACE Inhibitors.
Bypass Surgery
Definition: Coronary artery bypass grafting (CABG) uses vessels from elsewhere in the body to reroute blood around blocked coronary arteries.
Why it matters: Restores blood flow to the heart muscle, relieving angina and preventing heart attacks.
Related terms: Stent, Angioplasty, Coronary Artery Disease.
Bradycardia
Definition: A slow heart rate, usually below 60 beats per minute.
Why it matters: Can cause fatigue, dizziness, or fainting; may require treatment like a pacemaker.
Related terms: Pacemaker, Atropine, Arrhythmia.
Brugada Syndrome
Definition: A genetic disorder that causes a specific abnormal ECG pattern and increases the risk of sudden cardiac arrest.
Why it matters: Often undiagnosed until a serious arrhythmia occurs; may require an implantable defibrillator for prevention.
Related terms: ECG, Sudden Cardiac Death, Genetic Testing.
Bundle Branch Block
Definition: Delay or blockage of electrical impulses in the right or left bundle branches of the heart'92s conduction system.
Why it matters: Can affect heart function and is often a sign of underlying heart disease; visible on an ECG.
Related terms: ECG, Pacemaker, Conduction System.
B-Type Natriuretic Peptide (BNP)
Definition: A hormone produced by the heart in response to stretching of the ventricles.
Why it matters: Blood levels help diagnose and gauge severity of heart failure.
Related terms: Heart Failure, Echocardiogram, Biomarker.
C Terms
CABG (Coronary Artery Bypass Grafting)
Definition: Uses vessels from elsewhere in the body to reroute blood around blocked coronary arteries.
Why it matters: Restores blood flow, relieves angina, and improves survival in severe coronary disease.
Related terms: Bypass Surgery, Stent, Angioplasty.
Calcium Channel Blockers
Definition: Medications that block calcium entry into heart and vessel walls, lowering blood pressure and controlling arrhythmias.
Why it matters: Used for hypertension, angina, and certain arrhythmias. Examples: diltiazem, amlodipine.
Related terms: Cardizem, Amlodipine, Beta Blockers.
Calcium Score
Definition: A CT measure of calcium deposits in the coronary arteries.
Why it matters: Indicates the burden of atherosclerosis and helps predict heart disease risk.
Related terms: CTCA, Statins, Coronary Artery Disease.
Cardiac Arrest
Definition: Sudden loss of heart function due to an abnormal rhythm (often VF or VT).
Why it matters: Immediate CPR and defibrillation are critical for survival.
Related terms: Defibrillation, CPR, Ventricular Fibrillation.
Cardiac Catheterization
Definition: Invasive procedure inserting a thin tube into the heart'92s vessels to diagnose or treat blockages.
Why it matters: Allows angiogram imaging and interventions like stenting in one session.
Related terms: Coronary Angiogram, PCI, Stent.
Cardiac CT Angiography (CTCA)
Definition: A non-invasive CT scan with contrast to visualise coronary arteries.
Why it matters: Alternative to invasive angiogram for detecting blockages.
Related terms: Calcium Score, Coronary Angiogram, CTA.
Cardizem (Diltiazem)
Definition: A calcium channel blocker that slows heart rate and relaxes vessels.
Why it matters: Used for hypertension, angina, and certain arrhythmias.
Related terms: Calcium Channel Blockers, Digoxin, Beta Blockers.
Cardioversion
Definition: A procedure (electrical or pharmacologic) to restore normal heart rhythm.
Why it matters: Treats arrhythmias like atrial fibrillation to reduce stroke risk and symptoms.
Related terms: Atrial Fibrillation, Defibrillation, Antiarrhythmic.
Carotid Artery
Definition: Major neck vessels supplying the brain.
Why it matters: Plaque here can cause stroke; may need ultrasound or surgery.
Related terms: Carotid Endarterectomy, Stroke, Ultrasound.
CK (Creatine Kinase)
Definition: An enzyme released when heart or muscle is damaged.
Why it matters: CK-MB isoenzyme helps diagnose myocardial infarction.
Related terms: Troponin, Myocardial Infarction, Biomarker.
Cholesterol
Definition: A fatty substance in the blood necessary for cell function but harmful in excess.
Why it matters: High LDL levels lead to plaque buildup and coronary artery disease.
Related terms: LDL, HDL, Statins.
Coronary Angiogram
Definition: Invasive X-ray procedure using dye to view coronary arteries.
Why it matters: Gold standard for detecting blockages and guiding treatment.
Related terms: Angioplasty, Stent, PCI.
Coronary Artery Disease
Definition: Narrowing of coronary arteries due to atherosclerotic plaque.
Why it matters: Leading cause of angina, heart attacks, and heart failure.
Related terms: Statins, CABG, Angioplasty.
D Terms
Defibrillation
Definition: Delivering an electric shock to the heart to restore a normal rhythm.
Why it matters: It'92s the cornerstone of treating life-threatening arrhythmias like ventricular fibrillation.
Related terms: AED, CPR, Ventricular Fibrillation.
Deep Vein Thrombosis (DVT)
Definition: A blood clot forming in a deep vein, usually in the legs.
Why it matters: Can travel to the lungs (pulmonary embolism), which is potentially fatal.
Related terms: Pulmonary Embolism, Anticoagulant, Compression Stockings.
Diabetes Mellitus
Definition: A metabolic disorder marked by high blood sugar due to insulin problems.
Why it matters: Greatly increases risk of coronary artery disease, stroke, and heart failure.
Related terms: Atherosclerosis, HbA1c, Insulin.
Dilated Cardiomyopathy
Definition: A condition where the heart'92s chambers enlarge and weaken, reducing pump function.
Why it matters: Can lead to heart failure and arrhythmias; may require device therapy or transplant.
Related terms: Heart Failure, Echocardiogram, ICD.
Digoxin
Definition: A medication that increases heart contraction strength and slows heart rate.
Why it matters: Used in heart failure and atrial fibrillation to improve symptoms and control rate.
Related terms: Heart Failure, Atrial Fibrillation, Beta Blockers.
Diuretics
Definition: Medications that increase urine output to reduce fluid overload.
Why it matters: Essential in treating hypertension and heart failure by lowering blood volume.
Related terms: Loop Diuretics, Spironolactone, Hypertension.
Dobutamine
Definition: A drug that strengthens heart contractions and improves cardiac output.
Why it matters: Used in acute heart failure or cardiogenic shock to support circulation.
Related terms: Inotrope, Heart Failure, ICU Care.
Doppler Ultrasound
Definition: A test using high frequency sound waves to measure blood flow.
Why it matters: Non invasively assesses vessel patency, valve function, and detects clots.
Related terms: Echocardiogram, DVT, Vascular Study.
Dyslipidemia
Definition: Abnormal levels of lipids (cholesterol, triglycerides) in the blood.
Why it matters: A key risk factor for atherosclerosis, heart attacks, and strokes.
Related terms: Statins, HDL, LDL.
E Terms
Echocardiogram (Echo)
Definition: An ultrasound test that creates moving pictures of the heart'92s valves and chambers.
Why it matters: Non-invasively assesses heart function, valve disease, and structural abnormalities.
Related terms: Doppler Ultrasound, Ejection Fraction, Valve Replacement.
ECG (Electrocardiogram)
Definition: A recording of the electrical activity of the heart, usually via surface electrodes.
Why it matters: Detects arrhythmias, ischemia, and conduction abnormalities instantly at bedside.
Related terms: Arrhythmia, Cardiac Arrest, Bundle Branch Block.
Ejection Fraction
Definition: The percentage of blood the left ventricle pumps out with each beat.
Why it matters: Key measure of heart function; low values indicate systolic heart failure.
Related terms: Heart Failure, Echocardiogram, BNP.
Embolism
Definition: Obstruction of a blood vessel by a clot or other material carried in the bloodstream.
Why it matters: Can cause stroke, pulmonary embolism, or myocardial infarction depending on location.
Related terms: Deep Vein Thrombosis, Pulmonary Embolism, Anticoagulant.
Endarterectomy
Definition: Surgical removal of plaque from the inner lining of an artery.
Why it matters: Commonly performed on carotid arteries to prevent stroke in patients with significant stenosis.
Related terms: Carotid Artery, Stroke, Surgery.
Endocarditis
Definition: Inflammation or infection of the inner lining of the heart chambers and valves.
Why it matters: Can destroy valves and produce life-threatening complications if not treated with prolonged antibiotics or surgery.
Related terms: Bacterial Endocarditis, Heart Valve, Blood Cultures.
Endothelium
Definition: The thin layer of cells lining the interior surface of blood vessels.
Why it matters: Plays a critical role in vascular tone, blood clotting, and inflammation; dysfunction contributes to atherosclerosis.
Related terms: Atherosclerosis, Vasodilation, Nitric Oxide.
Entresto (Sacubitril/Valsartan)
Definition: A combination medication for heart failure that inhibits neprilysin and blocks angiotensin receptors.
Why it matters: Reduces mortality and hospitalization in patients with reduced ejection fraction heart failure.
Related terms: Heart Failure, ARBs, Neprilysin.
F Terms
Familial Hypercholesterolemia
Definition: A genetic disorder causing very high LDL ('93bad'94) cholesterol from birth.
Why it matters: Greatly increases risk of early atherosclerosis and heart disease.
Related terms: Cholesterol, Atherosclerosis, Statins.
Fibrate
Definition: A class of lipid-lowering drugs that reduce triglycerides and raise HDL ('93good'94) cholesterol.
Why it matters: Used in dyslipidemia when triglycerides are high; examples include gemfibrozil and fenofibrate.
Related terms: Dyslipidemia, Statins, Cholesterol.
Fractional Flow Reserve (FFR)
Definition: An invasive measure of pressure differences across a coronary artery narrowing during angiography.
Why it matters: Guides decision on whether to stent borderline lesions.
Related terms: Coronary Angiogram, PCI, Pressure Wire.
Framingham Risk Score
Definition: A tool estimating 10-year cardiovascular risk based on age, cholesterol, blood pressure, and smoking status.
Why it matters: Helps guide preventive strategies for heart disease.
Related terms: Risk Factors, Primary Prevention, Statins.
Furosemide
Definition: A potent loop diuretic that increases urine output to reduce fluid overload.
Why it matters: Essential in treating acute and chronic heart failure to relieve congestion.
Related terms: Diuretics, Heart Failure, Edema.
G Terms
Gallop (Heart Sound)
Definition: An extra heart sound (S3 or S4) heard during auscultation that indicates abnormal cardiac function.
Why it matters: An S3 gallop may suggest heart failure; an S4 gallop often indicates a stiff ventricle or hypertrophy.
Related terms: Heart Failure, Echocardiogram, S3, S4.
Genetic Testing
Definition: Laboratory analysis of DNA to identify inherited cardiac conditions.
Why it matters: Detects familial cardiomyopathies or channelopathies, guiding family screening and prevention.
Related terms: Hypertrophic Cardiomyopathy, Brugada Syndrome, Family Screening.
Glyceryl Trinitrate (GTN)
Definition: A nitrate medication that dilates blood vessels to relieve angina.
Why it matters: Rapid onset of action makes GTN the first-line emergency treatment for chest pain.
Related terms: Angina, Nitroglycerin, Vasodilation.
Graft (CABG)
Definition: A blood vessel segment (arterial or venous) used to bypass blocked coronary arteries during surgery.
Why it matters: The type and patency of grafts affect long-term outcomes after bypass surgery.
Related terms: CABG, Saphenous Vein, Internal Mammary Artery.
GP IIb/IIIa Inhibitors
Definition: Intravenous drugs that block platelet aggregation to prevent clot formation during PCI.
Why it matters: Used in high-risk angioplasty to reduce thrombotic complications.
Related terms: PCI, Stent, Abciximab.
H Terms
Haemodynamics
Definition: The study of blood flow and pressures within the cardiovascular system.
Why it matters: Guides management of heart failure, shock, and valvular disease by analysing flow, pressure, and resistance.
Related terms: Cardiac Output, Blood Pressure, Stroke Volume.
Heart
Definition: The heart is a muscular organ about the size of your clenched fist, located in the centre of the chest. In adults, it weighs roughly 250-350 g and contracts about 100,000 times per day to pump blood throughout the body.
Why it matters: As the central pump of the circulatory system, the heart delivers oxygen and nutrients to tissues and removes waste products.
Related terms: Cardiac Output, Myocardium, Fist.
Heart Block
Definition: A delay or interruption in the electrical signals that control heart rhythm, occurring at the AV node or His'96Purkinje system.
Why it matters: Can cause bradycardia, dizziness, or syncope; severe cases may require a pacemaker.
Related terms: AV Node, Pacemaker, Bradycardia.
Heartburn
Definition: A burning sensation behind the breastbone caused by stomach acid refluxing into the oesophagus.
Why it matters: Commonly mistaken for angina; persistent symptoms may indicate gastroesophageal reflux disease (GERD).
Related terms: GERD, Acid Reflux, Antacids.
Heparin
Definition: An anticoagulant drug that enhances antithrombin activity to prevent blood clot formation.
Why it matters: Used in acute coronary syndromes, during dialysis, and to prevent or treat deep vein thrombosis.
Related terms: Anticoagulant, DVT, Protamine.
Holter Monitor
Definition: A portable device worn 24'9648 hours to continuously record the heart'92s electrical activity.
Why it matters: Detects intermittent arrhythmias not captured on a standard ECG.
Related terms: ECG, Arrhythmia, Event Monitor.
Hypercholesterolemia
Definition: Elevated levels of cholesterol in the blood, particularly LDL ('93bad'94) cholesterol.
Why it matters: Major risk factor for atherosclerosis, coronary artery disease, and stroke.
Related terms: Statins, LDL, HDL.
Hypertrophic Cardiomyopathy
Definition: A genetic condition where the heart muscle (often the septum) thickens abnormally.
Why it matters: Can obstruct blood flow, cause arrhythmias, and increase risk of sudden cardiac death.
Related terms: Echocardiogram, Sudden Cardiac Death, Genetic Testing.
hs-CRP (High-Sensitivity C-Reactive Protein)
Definition: A blood test measuring low levels of CRP, a marker of systemic inflammation.
Why it matters: Elevated hs-CRP predicts increased risk of heart attack and stroke in otherwise healthy individuals.
Related terms: CRP, Inflammation, Cardiovascular Risk.
Hypotension
Definition: Abnormally low blood pressure (<90/60 mm Hg).
Why it matters: Can cause dizziness, fainting, and shock if severe; may signal underlying disease or dehydration.
Related terms: Orthostatic Hypotension, Dehydration, Vasopressors.
Hypertension
Definition: Persistently elevated blood pressure ( 140/90 mm Hg) in adults.
Why it matters: Leading modifiable risk factor for heart disease, stroke, and kidney disease.
Related terms: ACE Inhibitors, Beta Blockers, Lifestyle Modification.
I Terms
IABP (Intra-aortic Balloon Pump)
Definition: A mechanical device inserted into the aorta that inflates and deflates in sync with the heartbeat to improve coronary perfusion and reduce cardiac workload.
Why it matters: Used in cardiogenic shock or severe heart failure to stabilise patients and boost cardiac output.
Related terms: Cardiogenic Shock, Mechanical Circulatory Support, ICU.
ICD (Implantable Cardioverter Defibrillator)
Definition: A small device placed under the skin that continuously monitors the heart rhythm and delivers a shock if a life-threatening arrhythmia is detected.
Why it matters: Prevents sudden cardiac death in patients at high risk of ventricular tachycardia or fibrillation.
Related terms: Defibrillation, Arrhythmia, Pacemaker.
ICU (Intensive Care Unit)
Definition: A specialised hospital unit providing continuous monitoring and advanced support for critically ill patients.
Why it matters: Delivers life-saving interventions such as mechanical ventilation, inotropes, and invasive haemodynamic monitoring.
Related terms: Haemodynamics, Inotropes, Mechanical Ventilation.
Infarction
Definition: Tissue death due to prolonged lack of blood supply'97most commonly myocardial infarction (heart attack).
Why it matters: Leads to permanent damage of the heart muscle; timely reperfusion is critical to limit injury.
Related terms: STEMI, Troponin, Reperfusion.
Inflammation
Definition: The body'92s immune response to injury or infection, which can contribute to atherosclerosis.
Why it matters: Chronic vascular inflammation accelerates plaque formation and instability, raising heart attack risk.
Related terms: Atherosclerosis, hs-CRP, Endothelium.
INR (International Normalized Ratio)
Definition: A standardised measure of how long it takes blood to clot, used to monitor warfarin therapy.
Why it matters: Maintains the balance between preventing clots and avoiding bleeding complications.
Related terms: Anticoagulant, Warfarin, Bleeding Risk.
Interventional Cardiology
Definition: A subspecialty using catheter-based techniques (like angioplasty and TAVI) to treat structural and coronary heart disease.
Why it matters: Offers minimally invasive alternatives to surgery, reducing recovery time and risk.
Related terms: PCI, TAVI, Coronary Angiogram.
Ischemia
Definition: Reduced blood flow to tissues, causing oxygen deprivation; in the heart, manifests as angina.
Why it matters: Prolonged ischemia leads to infarction; detecting and alleviating it prevents heart damage.
Related terms: Angina, Stress Test, Coronary Artery Disease.
Ischemic Heart Disease
Definition: A condition characterised by reduced blood supply to the heart muscle, usually due to atherosclerosis.
Why it matters: Leading cause of angina, myocardial infarction, and heart failure worldwide.
Related terms: Atherosclerosis, MI, Angioplasty.
J Terms
JVP (Jugular Venous Pressure)
Definition: The pressure within the jugular vein, reflecting right atrial pressure and central venous pressure.
Why it matters: Elevated JVP can indicate heart failure, fluid overload, or right-sided heart dysfunction.
Related terms: Right Heart Failure, Central Venous Pressure, Kussmaul Sign.
Junctional Rhythm
Definition: A heart rhythm originating from the AV node rather than the sinoatrial node, typically 40'9660 bpm.
Why it matters: May occur in sick sinus syndrome or with AV node enhancement; can cause bradycardia symptoms.
Related terms: AV Node, Bradycardia, Pacemaker.
K Terms
Kawasaki Disease
Definition: An acute vasculitis in children affecting medium-sized arteries, including coronary arteries.
Why it matters: Can lead to coronary aneurysms and long-term cardiac complications if not treated early.
Related terms: Coronary Aneurysm, IVIG Therapy, Pediatric Cardiology.
Korotkoff Sounds
Definition: The sounds heard through a stethoscope when measuring blood pressure with a cuff and sphygmomanometer.
Why it matters: The first sound (Phase I) marks systolic pressure; disappearance (Phase V) marks diastolic pressure.
Related terms: Blood Pressure, Sphygmomanometer, Hypertension.
Kussmaul Sign
Definition: A paradoxical rise or lack of fall in jugular venous pressure on inspiration.
Why it matters: Suggests right ventricular failure, constrictive pericarditis, or restrictive cardiomyopathy.
Related terms: JVP, Constrictive Pericarditis, Right Heart Failure.
L Terms
LDL (Low-Density Lipoprotein)
Definition: LDL is a type of cholesterol that transports fats to cells but can deposit in artery walls.
Why it matters: Elevated LDL levels are a major risk factor for atherosclerosis and coronary artery disease.
Related terms: Atherosclerosis, Statins, HDL.
Left Bundle Branch Block
Definition: A conduction delay or block in the left bundle branch of the heart'92s conduction system visible on ECG.
Why it matters: Can indicate underlying heart disease and affect interpretation of ECG signs of myocardial infarction.
Related terms: ECG, Conduction System, Pacemaker.
Left Ventricular Hypertrophy (LVH)
Definition: Thickening of the myocardium of the left ventricle, often due to chronic pressure overload.
Why it matters: Increases risk of heart failure, arrhythmias, and ischemic heart disease.
Related terms: Hypertension, Echocardiogram, Sudden Cardiac Death.
Lignocaine (Lidocaine)
Definition: A class 1B antiarrhythmic and local anaesthetic that blocks sodium channels.
Why it matters: Used to treat ventricular arrhythmias and as a local anaesthetic.
Related terms: Antiarrhythmic, Ventricular Tachycardia, Local Anaesthetic.
Lipids
Definition: Fats in the blood including cholesterol and triglycerides essential for cell function but harmful in excess.
Why it matters: Dysregulated lipid levels lead to plaque formation and cardiovascular disease.
Related terms: Cholesterol, Fibrate, Statins.
Long QT Syndrome
Definition: A condition characterized by prolonged QT interval on ECG, predisposing to torsades de pointes.
Why it matters: Can lead to syncope and sudden cardiac death; may be congenital or drug-induced.
Related terms: ECG, Torsades de Pointes, Arrhythmia.
M Terms
Metoprolol
Definition: A selective beta-1 blocker used to slow the heart rate and lower blood pressure.
Why it matters: Reduces mortality after myocardial infarction, controls angina, and manages certain arrhythmias.
Related terms: Beta Blockers, Heart Failure, Hypertension.
Mitral Regurgitation
Definition: Backflow of blood from the left ventricle into the left atrium due to an incompetent mitral valve.
Why it matters: Causes volume overload of the left atrium and ventricle, may lead to heart failure; surgical repair or replacement may be needed.
Related terms: Mitral Stenosis, Echocardiogram, Heart Failure.
Mitral Stenosis
Definition: Narrowing of the mitral valve opening, restricting blood flow from the left atrium to the left ventricle.
Why it matters: Leads to left atrial enlargement, atrial fibrillation, and pulmonary hypertension; often requires valve intervention.
Related terms: Rheumatic Fever, Atrial Fibrillation, Valve Replacement.
Mitral Valve Prolapse
Definition: A condition in which one or both mitral valve leaflets bulge (prolapse) into the left atrium during systole.
Why it matters: Often benign but can cause mitral regurgitation and palpitations; detected via echocardiogram.
Related terms: Murmur, Echocardiogram, Mitral Regurgitation.
Morphine
Definition: An opioid analgesic used to relieve severe pain, including chest pain from myocardial infarction.
Why it matters: Provides pain relief and reduces sympathetic drive, decreasing heart workload in acute coronary syndromes.
Related terms: Myocardial Infarction, Analgesic, ACS.
Murmur
Definition: An abnormal sound heard during heart auscultation, caused by turbulent blood flow.
Why it matters: May indicate valvular disease, septal defects, or high flow states; requires further evaluation.
Related terms: Echocardiogram, Valvular Disease, Cardiac Auscultation.
Myocardial Infarction
Definition: Death of heart muscle tissue due to prolonged ischemia'97commonly known as a heart attack.
Why it matters: One of the leading causes of death worldwide; rapid reperfusion therapy is critical to limit damage.
Related terms: STEMI, NSTEMI, Troponin.
Myocarditis
Definition: Inflammation of the heart muscle, often due to viral infection.
Why it matters: Can cause heart failure, arrhythmias, or sudden death; diagnosis often involves MRI or biopsy.
Related terms: Cardiac MRI, Viral Infection, Heart Failure.
N Terms
Neprilysin Inhibitors
Definition: Drugs that block the enzyme neprilysin, preventing breakdown of beneficial peptides like natriuretic peptides.
Why it matters: When combined with ARBs (as in Entresto), they reduce mortality and hospitalisations in heart failure.
Related terms: Entresto, Natriuretic Peptides, ARBs.
Nicorandil
Definition: A vasodilator that combines nitrate-like effects with ATP-sensitive potassium channel opening.
Why it matters: Used for angina relief and has cardioprotective properties.
Related terms: Nitrates, Angina, Vasodilation.
Nitrates
Definition: A class of medications (e.g., nitroglycerin) that dilate blood vessels by releasing nitric oxide.
Why it matters: First-line therapy for acute angina and chest pain relief.
Related terms: GTN, Angina, Vasodilation.
NSTEMI (Non-ST Elevation Myocardial Infarction)
Definition: A type of heart attack where blood flow is reduced but the ECG does not show ST-segment elevation.
Why it matters: Still requires urgent treatment (antithrombotics, possible PCI) to limit heart muscle damage.
Related terms: STEMI, Troponin, PCI.
NT-proBNP (N-terminal pro-B-type Natriuretic Peptide)
Definition: A blood biomarker released by the heart in response to stretch, indicating ventricular stress.
Why it matters: Helps diagnose and assess severity of heart failure; guides therapy intensity.
Related terms: BNP, Heart Failure, Biomarker.
Nuclear Stress Test
Definition: A stress test using a small amount of radioactive tracer to image blood flow in the heart during exercise or drug-induced stress.
Why it matters: Detects areas of ischaemia or infarction not always seen on ECG or echo.
Related terms: MPI, Stress Test, Ischaemia.
NYHA Classification
Definition: The New York Heart Association system categorises heart failure by symptom severity'97from I (no symptoms) to IV (symptoms at rest).
Why it matters: Guides prognosis and treatment decisions (e.g., when to add advanced therapies or devices).
Related terms: Heart Failure, Ejection Fraction, ACC/AHA Stages.
O Terms
Occlusion
Definition: Complete blockage of a blood vessel, stopping blood flow beyond the obstruction.
Why it matters: In coronary arteries, occlusion causes myocardial infarction if not rapidly opened.
Related terms: PCI, Thrombosis, Reperfusion.
OCT (Optical Coherence Tomography)
Definition: An intravascular imaging technique using near-infrared light to visualise vessel walls at high resolution.
Why it matters: Helps assess plaque characteristics and guide stent sizing during PCI.
Related terms: IVUS, Coronary Angiogram, Stent.
Oral Anticoagulants
Definition: Medications taken by mouth (e.g., warfarin, dabigatran, apixaban) that reduce blood clotting.
Why it matters: Prevent stroke in atrial fibrillation and treat or prevent venous thromboembolism.
Related terms: INR, NOACs, DVT.
Oxygen Saturation (SpO )
Definition: The percentage of hemoglobin binding sites in the bloodstream occupied by oxygen.
Why it matters: A key vital sign; low values signal respiratory or cardiac dysfunction requiring intervention.
Related terms: Pulse Oximetry, Hypoxemia, Oxygen Therapy.
Oxygen Therapy
Definition: Administration of supplemental oxygen via mask, nasal cannula, or ventilator.
Why it matters: Improves oxygen delivery to tissues in conditions like heart failure, COPD, or during acute coronary syndromes.
Related terms: Oxygen Saturation, Venturi Mask, CPAP.
P Terms
Pacemaker
Definition: A small device implanted under the skin that sends electrical impulses to regulate the heart rate.
Why it matters: Used in bradycardia, heart block, and some heart failure cases to maintain adequate cardiac output.
Related terms: Bradycardia, Heart Block, AV Node.
Palpitations
Definition: A sensation of feeling your own heart beating, often described as fluttering or pounding.
Why it matters: Can be benign or indicate arrhythmias; warrants evaluation if recurrent or associated with dizziness.
Related terms: Arrhythmia, ECG, Anxiety.
Patent Foramen Ovale (PFO)
Definition: An opening between the left and right atria that fails to close after birth.
Why it matters: May allow paradoxical emboli, increasing stroke risk; closure can be considered in select patients.
Related terms: Stroke, Echocardiogram, Embolism.
PCI (Percutaneous Coronary Intervention)
Definition: A nonsurgical procedure using catheters to place stents and open blocked coronary arteries.
Why it matters: Standard treatment for many heart attacks and unstable angina to restore blood flow.
Related terms: Angioplasty, Stent, Thrombosis.
Pericarditis
Definition: Inflammation of the pericardium, the sac surrounding the heart.
Why it matters: Causes chest pain and can lead to pericardial effusion or tamponade if severe.
Related terms: Pericardiocentesis, Tamponade, NSAIDs.
Pericardiocentesis
Definition: A procedure to remove fluid from the pericardial sac with a needle.
Why it matters: Emergency treatment for cardiac tamponade to relieve pressure on the heart.
Related terms: Tamponade, Pericarditis, Echocardiogram.
Perhexilene
Definition: A metabolic modulator medication (tablet) that improves myocardial efficiency under ischaemic conditions.
Why it matters: Used in refractory angina to reduce symptoms by optimizing energy use.
Related terms: Angina, Metabolic Therapy, Ischemia.
Plaque
Definition: A fatty deposit of cholesterol and other substances on artery walls.
Why it matters: Can narrow arteries and rupture, causing heart attacks or strokes.
Related terms: Atherosclerosis, Cholesterol, Statins.
Preload
Definition: The ventricular end-diastolic volume that stretches the heart muscle before contraction.
Why it matters: Influences stroke volume; increased preload can worsen heart failure symptoms.
Related terms: Frank'96Starling Law, Afterload, Cardiac Output.
Pulmonary Hypertension
Definition: Elevated blood pressure in the pulmonary arteries.
Why it matters: Leads to right heart strain and can progress to right heart failure.
Related terms: Right Heart Failure, Vasodilators, Echocardiogram.
Q Terms
Questran (Cholestyramine)
Definition: A bile acid sequestrant medication used to lower cholesterol by binding bile acids in the gut.
Why it matters: Reduces LDL cholesterol levels and helps prevent atherosclerosis when statins are insufficient or contraindicated.
Related terms: Statins, Dyslipidemia, Atherosclerosis.
QRS Complex
Definition: Part of the ECG waveform representing ventricular depolarization.
Why it matters: Duration and morphology help diagnose bundle branch blocks, ventricular hypertrophy, and conduction delays.
Related terms: ECG, Bundle Branch Block, Ventricular Depolarization.
Q Waves
Definition: Initial negative deflection on an ECG lead, representing septal depolarization.
Why it matters: Pathological Q waves can indicate prior myocardial infarction.
Related terms: Myocardial Infarction, ECG, Infarction.
QT Interval
Definition: The time from the start of the Q wave to the end of the T wave on an ECG, reflecting total ventricular depolarization and repolarization.
Why it matters: Prolonged QT can predispose to torsades de pointes and sudden cardiac death; monitored when using certain medications.
Related terms: Long QT Syndrome, Torsades de Pointes, ECG.
R Terms
Rheumatic Fever
Definition: An inflammatory disease following group A streptococcal infection, affecting the heart, joints, skin, and brain.
Why it matters: Can lead to rheumatic heart disease, causing chronic valve damage.
Related terms: Mitral Stenosis, Antibiotics, Valve Replacement.
Right Atrium
Definition: The right upper chamber of the heart that receives deoxygenated blood from the body via the venae cavae.
Why it matters: Plays a key role in filling the right ventricle; its dysfunction can lead to systemic venous congestion.
Related terms: Superior Vena Cava, Tricuspid Valve, Atrial Fibrillation.
Right Ventricle
Definition: The right lower chamber that pumps deoxygenated blood into the pulmonary artery towards the lungs.
Why it matters: Right ventricular failure leads to systemic congestion and can be caused by pulmonary hypertension.
Related terms: Pulmonary Artery, Echocardiogram, Heart Failure.
Right Coronary Artery
Definition: One of the two main coronary arteries supplying blood to the heart muscle, primarily the right side of the heart.
Why it matters: Blockages here can cause inferior myocardial infarctions and affect the heart'92s conduction system.
Related terms: Left Anterior Descending (LAD), Stent, Myocardial Infarction.
Restenosis
Definition: The re-narrowing of an artery after it has been treated with angioplasty and stenting.
Why it matters: Can cause recurrent angina and may require repeat intervention.
Related terms: Angioplasty, Stent, PCI.
Risk Factors
Definition: Characteristics or exposures (e.g., smoking, hypertension, diabetes) that increase the likelihood of developing heart disease.
Why it matters: Identifying and modifying risk factors reduces the incidence of cardiovascular events.
Related terms: Framingham Risk Score, Hypertension, Dyslipidemia.
Rosuvastatin
Definition: A statin medication that lowers LDL cholesterol and raises HDL cholesterol.
Why it matters: Reduces the risk of cardiovascular events by slowing the progression of atherosclerosis.
Related terms: Statins, Cholesterol, Atherosclerosis.
S Terms
SA Node (Sinoatrial Node)
Definition: The heart'92s natural pacemaker located in the right atrium that initiates each heartbeat.
Why it matters: Dysfunction can cause bradycardia or arrhythmias requiring pacemaker therapy.
Related terms: AV Node, Pacemaker, Rhythm.
Spironolactone
Definition: A potassium sparing diuretic that blocks aldosterone receptors.
Why it matters: Reduces fluid overload and improves survival in heart failure patients.
Related terms: Diuretics, Heart Failure, Potassium.
STEMI (ST-Elevation Myocardial Infarction)
Definition: A full-thickness heart attack marked by ST-segment elevation on ECG.
Why it matters: Requires immediate reperfusion therapy (PCI or thrombolysis) to minimise damage.
Related terms: PCI, Thrombolysis, Troponin.
Statin
Definition: A class of drugs that inhibit HMG-CoA reductase to lower LDL cholesterol.
Why it matters: Proven to reduce heart attacks, stroke, and cardiovascular mortality.
Related terms: Cholesterol, Atherosclerosis, Rosuvastatin.
Stroke
Definition: Sudden loss of brain function due to interruption of blood supply (ischaemic) or bleeding (hemorrhagic).
Why it matters: Rapid identification and treatment (thrombolysis for ischaemic) can reduce permanent damage.
Related terms: TIA, Carotid Artery, Anticoagulant.
SVT (Supraventricular Tachycardia)
Definition: A rapid heart rhythm originating above the ventricles, often abrupt in onset and termination.
Why it matters: Causes palpitations and dizziness; may require vagal maneuvers or medication to terminate.
Related terms: AV Node, Vagal Maneuver, Tachycardia.
Syncope
Definition: A temporary loss of consciousness due to reduced cerebral blood flow.
Why it matters: Can signal arrhythmias, structural heart disease, or vasovagal episodes.
Related terms: Tachycardia, Blood Pressure, ECG.
T Terms
Tachycardia
Definition: A heart rate exceeding 100 beats per minute in adults.
Why it matters: May indicate arrhythmias, fever, hypovolemia, or ischemia; persistent forms require evaluation.
Related terms: SVT, Atrial Fibrillation, ECG.
TAVI (Transcatheter Aortic Valve Implantation)
Definition: A minimally invasive procedure to replace a diseased aortic valve via catheter.
Why it matters: Alternative to open surgery for high-risk patients with aortic stenosis.
Related terms: Aortic Valve, Echocardiogram, SAVR.
Thrombolysis
Definition: Administration of drugs (e.g., alteplase) to dissolve blood clots in vessels.
Why it matters: Key therapy in early STEMI and some strokes to restore blood flow.
Related terms: STEMI, Stroke, PCI.
Torsades de Pointes
Definition: A polymorphic ventricular tachycardia associated with prolonged QT interval.
Why it matters: Can degenerate into ventricular fibrillation; treated with magnesium and pacing.
Related terms: QT Interval, Long QT Syndrome, Arrhythmia.
Tricuspid Valve
Definition: The valve between the right atrium and right ventricle that prevents backflow during systole.
Why it matters: Disease (stenosis or regurgitation) leads to right-sided heart failure and systemic congestion.
Related terms: Right Ventricle, Echocardiogram, Valve Repair.
Troponin: Troponin is a type of protein found in heart muscle cells. It plays a key role in helping your heart muscle contract. When heart cells are damaged, such as during a heart attack, troponin is released into the bloodstream.
Why it matters: Troponin levels are measured with a blood test and are one of the most important tools doctors use to detect heart damage. A high troponin level usually suggests injury to the heart, most commonly from a heart attack, but it can also be seen in conditions like heart failure, myocarditis, or after strenuous exercise.
Related terms: Myocardial infarction, ECG, Cardiac enzymes, Chest pain
U Terms
Ultrasound
Definition: Imaging technique using high-frequency sound waves to visualise heart structures and blood flow.
Why it matters: Forms the basis of echocardiography and vascular studies, guiding diagnosis and treatment.
Related terms: Echocardiogram, Doppler, CTCA.
U Wave
Definition: A small ECG deflection following the T wave, thought to represent late repolarization of Purkinje fibers.
Why it matters: Prominent U waves can indicate electrolyte disturbances like hypokalaemia.
Related terms: ECG, QT Interval, Hypokalaemia.
Uremic Pericarditis
Definition: Inflammation of the pericardium in patients with advanced kidney failure.
Why it matters: Treat with dialysis and may require pericardiocentesis if tamponade occurs.
Related terms: Pericarditis, Dialysis, Tamponade.
V Terms
Valve
Definition: A flap of tissue in the heart or vessels that ensures one-way blood flow.
Why it matters: Valve disease (stenosis or regurgitation) can impair cardiac output and often requires repair or replacement.
Related terms: Aortic Valve, Mitral Regurgitation, TAVI.
Ventricle
Definition: One of two lower heart chambers that pump blood'97right to the lungs, left to the body.
Why it matters: Ventricular function is critical; dysfunction leads to heart failure and low output.
Related terms: Left Ventricle, Right Ventricle, Ejection Fraction.
Ventricular Septal Defect (VSD)
Definition: A hole in the wall (septum) between the heart'92s two ventricles.
Why it matters: Allows mixing of oxygenated and deoxygenated blood, which can lead to heart failure and pulmonary hypertension if large.
Related terms: Atrial Septal Defect, Congenital Heart Disease, Eisenmenger Syndrome.
Ventricular Fibrillation (VF)
Definition: A life-threatening arrhythmia where ventricles quiver instead of pumping.
Why it matters: Immediate defibrillation is required to prevent sudden cardiac death.
Related terms: Defibrillation, Ventricular Tachycardia, CPR.
Ventricular Tachycardia (VT)
Definition: A fast, potentially dangerous heart rhythm originating in the ventricles.
Why it matters: Can deteriorate into VF; treated with antiarrhythmics, cardioversion, or ICD.
Related terms: VF, ICD, Amiodarone.
W Terms
WPW (Wolff-Parkinson-White) Syndrome
Definition: A pre-excitation syndrome where an extra conduction pathway causes tachyarrhythmias.
Why it matters: Can cause paroxysmal supraventricular tachycardia; may require ablation.
Related terms: SVT, ECG, Ablation.
X Terms
X-Ray (Chest X-Ray)
Definition: A radiographic image of the chest used to assess heart size, lung fields, and vasculature.
Why it matters: Quick, non-invasive tool to detect cardiomegaly, pulmonary edema, and other pathologies.
Related terms: Echocardiogram, CTCA, Cardiomegaly.
Y Terms
Y Descent
Definition: The downward deflection in jugular venous tracing reflecting rapid ventricular filling.
Why it matters: Prominent in constrictive pericarditis and restrictive cardiomyopathy.
Related terms: JVP, Kussmaul Sign, Pericarditis.
Z Terms
Zoll ICD
Definition: An implantable cardioverter defibrillator brand/device that treats life-threatening arrhythmias.
Why it matters: Provides continuous rhythm monitoring and automated defibrillation shocks.
Related terms: ICD, VF, VT.
