Glossary

Here you will find selected key terms with their accompanying definitions.

A

ACE inhibitor: Angiotensin Converting Enzyme inhibitor- medication for treating hypertension and heart failure.

Acute Mitral Regurgitation: Blood re-enters the left atrium during ventricular systole.

Annulus: Fibrous tissue which maintains the shape of valve leaflets.

Anticoagulant: Medication used to prevent blood coagulation.

Aorta: Largest artery in the body which arises from the left ventricle.

Aortic Aneurysm: Dilation of the aorta to more than 1.5 times its original size, rupture is life-threatening.

Aortic Valve: Located between the left ventricle and the aorta, has 3 leaflets.

Arrhythmia: Irregular heartbeat.

Atria: The 2 upper chambers of the heart.

Atrioventricular bundle branch: Branches of the bundle of His that play a role in the conduction of electrical activity of the heart.

Atrioventricular Node: Located in the inferior portion of the right atrium and propagates electrical impulses to the Bundle of His.

B

Bachmann's bundle: A pathway responsible for conducting the electrical activity from the right atrium to the left atrium.

Beck's triad: Three medical signs of cardiac tamponade. These signs are low blood pressure, distended neck veins and muffled heart sounds.

Bicuspid Valve: Located between the left atrium and ventricle, is also known as the mitral valve and has 2 leaflets.

Bundle of His: Fibres split into left and right bundle branches which supply their corresponding ventricle.

C

Cardiac Tamponade: Condition where blood or fluids fill the pericardium, prevents efficient heart contraction.

Chordae Tendineae: Tendons composed mainly of collagen that attach the papillary muscles to the AV valves.

Coronary Heart Disease: Reduced blood flow to the myocardium due to narrowing of the coronary blood vessels.

Coronary Vessels: Arise from aortic sinuses and supply the heart myocardium with oxygenated blood.

Costal cartilage: Cartilage that prolongs the ribs forward.

D

Ductus Arteriosus: Hollow tube between aorta and left pulmonary artery in fetal heart.

E

Electrocardiogram (ECG): Records the electrical activity of the heart over a period of time using electrodes placed on the skin, ECG trace can be used to diagnose some heart conditions.

F

Foramen Ovale: Hole in the inter-atrial septum that allowed shunting of oxygenated blood between the right and left atria in the fetal heart.

Fossa Ovalis: Oval shaped depression in the adult right atrium just above the coronary sinus.

I

Inferior Vena Cava: Formed by 2 iliac veins and drains deoxygenated blood into the inferior right atrium.

Intercostal space: Anatomical space between ribs.

L

Left Atrium: Receives oxygenated blood from the lungs through the pulmonary vein and forms heart base.

Left Ventricle: Pumps oxygenated blood through the aorta and forms the apex of the heart.

Lethargy: A situation of fatigue.

Ligamentum Arteriosum: Fibrous band that runs between the aortic arch and left pulmonary artery.

M

Manubrium: Top part of the sternum that joins with the body of the sternum.

Mediastinum: The central compartment of the thorax.

Moderator Band: Muscular band of heart tissue found in the right ventricle of the heart which supplies the papillary muscles.

O

Oedema: Excess fluid in body tissues.

P

P Wave: Represents atrial contraction and is small due to the small muscle mass of the atria.

Papillary Muscles: Muscles located on the ventricle interior surface, contract during systole to prevent valve prolapse.

Patent Ductus Arteriosus: Failure of ductus to close, occurs in 2 in every 1000 individuals.

Patent Foramen Ovale: Incomplete closure of foramen ovale, occurs in 25% of population.

Pericarditis: Inflammation of the pericardium.

Pericardiocentesis: Procedure of removing excess fluid from the pericardium.

Pericardium: Fluid-filled sac that surrounds the heart.

PR Interval: Represents the time taken for the spread of electrical activity to the ventricles. It is the distance between the start of the P wave and the start of the QRS complex.

PR Segment: Represents the time taken for the spread of electrical activity from the AV node, to the bundle of His, the bundle branches then the ventricular muscles. It is the distance between the end of the P wave and the start of the QRS complex.

Pulmonary Arteries: Carry deoxygenated blood from the right ventricle to the lungs.

Pulmonary Trunk: Thick short vessel separated from the right ventricle by the pulmonary valve, splits into the pulmonary arteries at T5 level.

Pulmonary Valve: Located between the right ventricle and pulmonary artery, has 3 leaflets.

Purkinje Fibres: Travel from the apex of the heart towards the atrioventricular septum and the base of the heart propagate the electrical impulse to the muscles of the ventricles.

Q

QRS Complex: Represents ventricular contraction and has a large amplitude due to the large muscle mass of the ventricles.

QT Interval: Represents the time between ventricular depolarisation and repolarisation. It is the distance between the start of the QRS complex and the end of the T wave.

R

Right Atrium: Receives de-oxygenated blood y through the superior and inferior vena cava and pumps it into the right ventricle.

Right Ventricle: Pumps deoxygenated blood through the pulmonary artery to the lungs.

S

Sinoatrial Node: Stuated in the superoposterior right atrium wall and initiates the normal electrical pattern of the heart.

ST Segment: Is the distance between the end of the S wave and the start of the T wave. It is also isoelectric.

Stenosis: Narrowing of a valve which leads to the obstruction of blood flow between chambers of the heart.

Sternum: The bone in the centre of the chest that connects to the ribs.

Superior Vena Cava: Formed by 2 brachiocephalic veins and drains deoxygenated blood into the right atrium at the level of the 3^rd rib.

T

T wave: Represents ventricular repolarisation.

Trabeculae Carneae: Rounded irregular muscles projecting from the inner surface of ventricles.

Tracheal bifucation: Division of the trachea into the right and left bronchi.

Tricuspid Valve: Located between the right atrium and ventricle, has 3 leaflets.

V

Ventricles: The 2 lower chambers of the heart.

X

X-ray: A scan used to visualise the internal part of the body.

Image Credits: National Institutes of Health (USA) 2017 - All Image Usage Complies with CC BY-SA 3.0.