# Cardiovascular Diseases (CVDs) A group of diseases affecting the heart and blood vessels. The text specifically discusses: - Angina pectoris - Heart attack (Myocardial Infarction) - Heart failure (Congestive Heart Failure) - Congenital heart problems ## 2.16.1 Angina Pectoris **Cause:** Primarily due to atherosclerosis, which narrows coronary arteries, reducing blood flow to the heart muscle. This is often linked to the formation of fatty streaks and atheromas. **Symptoms:** Occasional chest pain, especially when the heart is working hard due to physical or emotional stress. **Significance:** It is a signal that a part of the heart is not receiving sufficient oxygen, indicating a risk of future heart attack. ## 2.16.2 Heart Attack (Myocardial Infarction) **Causes:** - A blood clot completely blocking a coronary artery. - Atherosclerosis reaching a critical level, leading to massive damage to the heart muscle. - **Plaque Rupture:** When the fibrous cap of an atheroma breaks, triggering rapid clot formation. **Symptoms:** - Sudden, heavy squeezing ache or discomfort in the center of the chest. - Pain may radiate to the shoulder, arm, neck, or jaw. - Other symptoms include sweating, nausea, shortness of breath, dizziness, or fainting. **Process:** The entire process is called myocardial (heart muscle) infarction (death due to lack of oxygen). **Consequences:** - Dead heart muscle cells are not replaced because cardiac muscles do not divide. - Scar tissue (connective tissue) grows into the damaged areas. - Scar tissue cannot contract like cardiac muscle, permanently weakening the heart. ## 2.16.3 Heart Failure (Congestive Heart Failure) **Definition:** The inability of the heart to pump all the blood coming to it. **Mechanism:** The cardiac output (blood pumped out) is unable to keep pace with the venous return (blood returning to the heart). For more on heart cycles, see . **Consequence:** Leads to a backlog of blood in the venous system and inadequate blood supply to the body. This is often a progression from chronic . ## 2.16.4 Congenital Heart Problem **Cause:** Result from abnormalities in embryonic development of the heart. **Example:** Malfunctioning of cardiac valves, such as valvular stenosis (narrowing of a heart valve).

2.16 Stages Of Cardiovascular Disease Development | Blood Circulatory System Of Man | Biology 12