| Aneurysm | Abnormal bulging of a blood vessel in the heart due to weakness in the vessel wall, posing a risk of rupture and internal bleeding. |
| Aorta | The main artery of the body that distributes oxygenated blood to all parts of the body from the left ventricle. |
| Aortic Valve | A valve between the left ventricle and the aorta that prevents backflow of blood into the left ventricle. |
| Atrial Depolarization | The electrical activation that leads to atrial contraction, represented by the P wave on an electrocardiogram (ECG). |
| Atrial Fibrillation | A heart arrhythmia characterized by an irregular and often rapid heart rate, reflected in a distinct ECG pattern. |
| Atrium | Upper chambers of the heart; the right atrium receives deoxygenated blood from the body, and the left atrium receives oxygenated blood from the lungs. |
| Bicuspid Valve | Also known as the mitral valve; it allows blood flow from the left atrium to the left ventricle and prevents backflow. |
| Coronary Artery | Arteries that supply blood to the heart muscle itself. |
| Diastole | Phase of the cardiac cycle when the heart muscles relax and the chambers fill with blood; the tricuspid and bicuspid (mitral) valves are open, while the pulmonary and aortic valves are closed. |
| ECG | Electrocardiogram, a tracing representing the electrical events during a heartbeat. |
| Inferior Vena Cava | A large vein carrying deoxygenated blood from the lower body back to the right atrium of the heart. |
| Left Ventricle | A chamber of the heart that pumps oxygenated blood into the aorta for systemic circulation. |
| Mitral Valve | A valve that allows blood flow from the left atrium to the left ventricle and prevents backflow, also known as the bicuspid valve. |
| Myocardial Infarction | Often referred to as a heart attack; occurs when a blockage in a coronary artery prevents blood from reaching a section of the heart muscle, causing tissue damage or death. |
| Pulmonary Artery | The artery carrying deoxygenated blood from the right ventricle to the lungs for oxygenation. |
| Pulmonary Valve | A valve located between the right ventricle and the pulmonary artery that prevents backflow of blood into the right ventricle. |
| Pulmonary Veins | Veins that carry oxygenated blood from the lungs back to the left atrium of the heart. |
| Right Ventricle | A chamber of the heart that pumps deoxygenated blood to the lungs through the pulmonary artery. |
| Superior Vena Cava | A large vein carrying deoxygenated blood from the head, neck, and upper limbs back to the right atrium of the heart. |
| Systole | Phase of the cardiac cycle when the heart muscles contract, propelling blood out of the heart; the tricuspid and bicuspid valves are closed to prevent backflow into the atria, while the pulmonary and aortic valves are open. |
| Tricuspid Valve | A valve that allows blood flow from the right atrium to the right ventricle and prevents backflow. |
| Ventricular Depolarization | The electrical event that triggers ventricular contraction, represented by the QRS complex on an ECG. |
| Ventricular Repolarization | The process allowing the ventricles to relax, represented by the T wave on an ECG. |
