Definition: Blockage of coronary arteries by atherosclerotic plaque, leading to death of heart muscle tissue due to interrupted blood supply.
Ischemia of the Heart
Definition: Lack of oxygen supply to the heart muscle due to narrowing or blockage of coronary arteries.
Cardiac Electrophysiology
Definition: Branch of cardiology dealing with the diagnosis of heart rhythm disorders and conduction system issues, and finding treatments for these disorders.
Diagnosis: Uses electrocardiography (ECG) and electrophysiological testing via cardiac catheterization.
Electrocardiogram (ECG)
Definition: A graph showing the electrical activity of the heart over time; it measures voltage as a function of time.
Measurement: Achieved by attaching electrodes to the body.
Output: The electrical signal is printed on millimeter paper as an electrocardiogram.
Normal ECG Features:
Typical shapes: P wave, QRS complex, ST segment, and T wave.
ECG Waveforms
P Wave
Represents: Electrical activity of the atria (atrial depolarization), indicating the passage of the electrical signal from the sinoatrial (SA) node to the atria.
Normal Indication: "Sinus rhythm," the normal heart rhythm.
Abnormalities: Changes or absence can indicate problems originating in the SA node or atria (e.g., atrial fibrillation, where P waves may be absent).
QRS Complex
Represents: Electrical impulse passing from the atria to the ventricles through the conduction system, causing ventricular contraction.
ST Segment
Significance: Changes indicate the severity of myocardial infarction; ST segment elevation indicates a severe infarction.
T Wave
Represents: Repolarization, the return of the atria and ventricles to their resting electrical state after contraction.
Significance: Changes can indicate damage to the heart muscle, electrolyte imbalances (especially potassium levels), ischemia, or pathological enlargement of the ventricles.
Cerebrovascular Accident (CVA) – Stroke
Definition: Damage to part of the brain due to interrupted blood supply, depriving brain tissue of oxygen and nutrients.
Ischemic Stroke: Blockage of blood vessels in the brain due to a blood clot, leading to oxygen deprivation.
Hemorrhagic Stroke: Rupture of a blood vessel in the brain.
Transient Ischemic Attack (TIA) – Mini-Stroke
Definition: Temporary disruption of blood supply to part of the brain.
Symptoms: Similar to a stroke but last for a shorter duration (minutes to hours), resolving without permanent damage.
Significance: May indicate an increased risk of future stroke.
Heart Failure
Definition: Failure of the heart to pump oxygenated blood efficiently to all parts of the body.
Types: Can be right-sided or left-sided heart failure.
Aphasia
Definition: Impairment of the ability to communicate through language, speech, or writing due to damage in the language-related areas of the left hemisphere of the brain, often resulting from a stroke.
Echocardiograph
Definition: A device that uses ultrasound to create anatomical images of the heart and blood flow.
Use: Allows assessment of heart chamber size, heart muscle thickness, valve function, blood flow direction and velocity, and detection of abnormal blood flow patterns.
Advantages: Non-invasive, does not expose the patient to radiation, and provides extensive information about the heart's structure and function.
Combination with Stress Test: Sometimes combined with an exercise stress test to assess coronary artery condition.
Defibrillator
Definition: A device that delivers an electrical shock to the heart to stop rapid, life-threatening arrhythmias, especially ventricular fibrillation.
Mechanism: The electrical shock stops the pathological electrical activity, allowing the SA node to resume its normal pacing function.
Types: External defibrillators and implantable cardioverter-defibrillators (ICDs) for individuals at risk of recurrent arrhythmias.
Holter Monitor
Definition: A device for continuous monitoring of the cardiovascular system by recording system parameters over an extended period, usually 24 hours.
Process: Patient records activities and symptoms to correlate with recorded data, identifying links between symptoms and cardiovascular activity.
Types:
Holter ECG: Detects heart rhythm abnormalities.
Holter Blood Pressure Monitor: Measures blood pressure repeatedly throughout the day to identify hypertension.
Hyperlipidemia
Definition: High levels of lipids (fats) in the blood, including cholesterol, which is a significant risk factor for atherosclerosis.
Cardiogenic Shock
Definition: Shock resulting from severe impairment of heart function due to arrhythmia, impaired contractility, or impaired relaxation.
Mechanism: Leads to decreased tissue perfusion due to reduced blood pressure.
Causes: Severe heart attack (MI), cardiac tamponade, trauma to the heart.
Other Causes of Shock: Hypovolemic (fluid loss), anaphylactic (severe allergic reaction), septic (severe infection), and neurogenic (damage to the central nervous system) shock.
Symptoms: Pallor, sweating, cold skin, rapid and weak pulse, irregular breathing, reduced urine output, changes in consciousness.
Hemiplegia
Definition: Paralysis of one side of the body, resulting from a stroke in the opposite hemisphere of the brain.
Arteriosclerosis
Definition: Deposition of calcium in the arteries due to aging or thickening of small arteries due to aging or hypertension; distinct from atherosclerosis.
Hemiparesis
Definition: Weakness on one side of the body due to a stroke in the opposite hemisphere of the brain.
Pulmonary Edema
Definition: Fluid accumulation in the lung alveoli, causing impaired gas exchange, often due to left-sided heart failure.
Cardiac Tamponade
Definition: Compression of the heart due to fluid accumulation in the pericardial space (between the pericardium and myocardium), impairing heart relaxation and reducing cardiac output.
Treatment: Fluid administration, medications to improve heart function, pericardiocentesis (fluid drainage), or surgical removal of part of the pericardium.
Troponin
Definition: An enzyme found in heart muscle cells involved in muscle contraction; used as a marker of heart damage.
Significance: Elevated levels in the blood indicate damage to heart muscle cells, such as in ischemia; remains elevated for about two weeks after damage.
Atherosclerosis
Definition: Development of fatty plaques on the inner walls of arteries, gradually blocking blood flow.
Causes: Diet high in animal fat and refined sugar, smoking, obesity, lack of physical activity, and genetic predisposition.
Treatment: Prevention, medications, or interventional procedures such as bypass surgery.
Hypertension
Definition: High blood pressure, typically defined as values above 140/90 mmHg.
Cyanosis
Definition: Bluish discoloration of the skin and mucous membranes due to low oxygen levels in the blood; associated with heart failure, lung diseases, and congenital heart defects.
Cholesterol
Definition: A type of lipid used to build cell walls and important for various bodily functions.
Source: Produced in the liver and obtained from animal-based foods.
Types:
HDL (High-Density Lipoprotein): Transports cholesterol from the body to the liver for removal, protecting against heart disease.
LDL (Low-Density Lipoprotein): Transports cholesterol from the liver to tissues; excess LDL can lead to cholesterol deposition in blood vessel walls, causing atherosclerosis.
Hypercholesterolemia
Definition: High levels of cholesterol in the blood, increasing the risk of ischemic heart disease.
Triglycerides
Definition: Fats used to store energy in the body; high levels are associated with obesity, heart disease, stroke, pancreatitis, and fat accumulation.
Stress Test
Definition: A test to identify or rule out ischemic heart disease.
Procedure: Patient walks on a treadmill with increasing speed and incline while ECG changes are monitored.
Ischemic Heart Diseases (IHD)
Definition: Conditions characterized by reduced blood supply to the heart muscle due to blockages in the coronary arteries.
Types: Stable and unstable angina, myocardial infarction.
Renin-Angiotensin-Aldosterone System (RAAS)
Definition: A system activated when blood pressure decreases.
Process:
Kidneys release renin.
Renin converts angiotensinogen to angiotensin I.
ACE converts angiotensin I to angiotensin II.
Angiotensin II stimulates aldosterone release, increasing sodium and water reabsorption in the kidneys and raising blood pressure; it also causes the pituitary gland to release ADH.
Aneurysm
Definition: Localized widening of an artery due to weakening of the arterial wall, which can rupture and cause life-threatening bleeding.
Bypass Surgery
Definition: Surgical procedure to improve blood supply to areas of the heart with blocked coronary arteries.
Procedure: Damaged arteries are replaced with blood vessels taken from elsewhere in the patient's body (e.g., chest arteries or leg veins).
Steroids
Definition: A type of lipid with a carbon skeleton, mainly produced in the adrenal glands, liver, testes, and ovaries.
Coronary Arteries
Definition: Arteries that supply blood to the heart muscle; originate from the aorta and form branches around the heart.
Plaque
Definition: Accumulation of LDL cholesterol beneath the endothelium of coronary arteries, leading to atherosclerosis and narrowing.
Process:
LDL undergoes oxidation, triggering an inflammatory response.
Macrophages accumulate and ingest oxidized LDL, becoming foam cells.
Foam cells die and accumulate.
Connective tissue forms, creating a fibrous cap around the lipid core, forming a plaque that protrudes into the artery.
Ventricular Fibrillation
Definition: A life-threatening arrhythmia in which the ventricles quiver instead of contracting effectively.
Cause: Primarily ischemia of the heart muscle.
Treatment: Immediate CPR and defibrillation.
Atrial Fibrillation
Definition: An arrhythmia characterized by rapid and irregular contraction of the atria.
Complications: Reduced cardiac output, heart failure, and increased risk of blood clot formation.
Causes: Hypertension, atherosclerosis, heart disease, and hyperthyroidism.
Treatment: Medications or electrical cardioversion.
Cardiac Catheterization
Definition: An invasive procedure in which a catheter is inserted into the coronary arteries to visualize blockages or narrowings.
Process: Dye is injected, and X-ray imaging is used to identify blockages, which can be opened with balloons or stents.
Stent
Definition: A mesh tube used to widen narrowed arteries and provide structural support.
Types: Newer stents release drugs to prevent re-narrowing.
Angina Pectoris
Definition: Chest pain due to narrowing of the coronary arteries; can be stable or unstable.
Pulmonary Embolism
Definition: Blockage of a blood vessel in the lung by a blood clot, usually originating in the deep veins of the legs or pelvis.
Medications:
Statins: Lower cholesterol levels by inhibiting cholesterol production in the liver.
Nitrites: Dilate coronary arteries.
Beta-blockers: Decrease heart muscle oxygen consumption by slowing heart rate.
Aspirin: Prevents blood clot formation, reduces pain and inflammation.
ACE Inhibitors: Dilate blood vessels and reduce blood pressure by inhibiting the renin-angiotensin-aldosterone system.
Diuretics: Increase urine excretion to reduce fluid volume and prevent edema.