TOPIC 4 - CARDIOVASCULAR CONDITIONS (DISEASE OF CARDIAC VALVES)-edited

Definition: Aortic stenosis is characterized by the narrowing or incomplete opening of the aortic valve which reduces or blocks blood flow from the left ventricle to the aorta.
- This condition leads to insufficient blood supply to the rest of the body.
Classification: It is classified as a type of valvular heart disease.
Normal Aortic Valve Area: The normal area of the aortic valve ranges from 3-4 cm².
Symptoms:
- Symptoms typically manifest when the valve area decreases to one-fourth of the normal size.

Aortic stenosis can arise from several causes:
- Congenital: A condition present at birth.
- Rheumatic: Caused by rheumatic fever.
- Degenerative/Calcific: Age-related degeneration or calcification of the valve.

When the aortic valve opening becomes incomplete, it creates a pressure gradient between the left ventricle and the aorta.
- This condition is described as increased afterload.
- Initially, left ventricle function is maintained by compensatory pressure hypertrophy.
- However, once compensatory mechanisms are exhausted, left ventricle function begins to decline.

Syncope: Exertional syncope occurs due to inadequate blood flow.
Angina: Pain arises from increased myocardial oxygen demand leading to a mismatch between demand and supply.
Dyspnea: Patients experience dyspnea on exertion due to heart failure affecting both systolic and diastolic function.
Sudden Death: Occurs due to severe aortic stenosis complications.

General: Patients with a prosthetic aortic valve or a history of endocarditis should receive endocarditis prophylaxis before dental procedures.
Medical Management:
- Medical interventions have a limited role since aortic stenosis is primarily a mechanical issue.
- Vasodilators are relatively contraindicated in severe aortic stenosis due to risks of hypotension.
Aortic Balloon Valvotomy: This procedure shows minimal benefit in treatment.
Surgical Replacement: Considered the definitive treatment approach.

Definition: Characterized by the narrowing of the mitral valve, resulting in an obstruction to inflow into the left ventricle, causing a slower filling rate.
- This condition ultimately leads to reduced left ventricle filling.
Predominant Cause: The most common cause is rheumatic carditis.
Trends: The prevalence and incidence of mitral stenosis have decreased due to declines in rheumatic heart disease.
Normal Mitral Valve Area: The normal area for the mitral valve is around 4-6 cm².

Key causes include:
- Rheumatic Heart Disease: Accounts for 77-99% of cases.
- Infective Endocarditis: Represents 3.3% of cases.
- Mitral Annular Calcification: Contributes to about 2.7% of cases.

Serial Echocardiography: To monitor the condition based on severity:
- Mild: every 3-5 years.
- Moderate: every 1-2 years.
- Severe: annually.
Medications:
- Medical therapy is limited for mitral stenosis as it is also a mechanical problem.
- Medications such as beta-blockers, calcium channel blockers (CCBs), and Digoxin are used to control heart rate, improving diastolic filling.
- Diuretics are used to manage fluid overload.
Procedures:
- Identify patients early who may benefit from percutaneous mitral balloon valvotomy.
Infective Endocarditis Prophylaxis: Recommended for patients with prosthetic valves or a history of infective endocarditis during dental procedures.

Definition: Aortic regurgitation is characterized by the leakage of blood from the aorta back into the left ventricle during diastole due to incompetence of the aortic valve (the valve fails to close completely).
- The left ventricle must work harder to pump blood out to prevent this backflow, leading to long-term weakening of the left ventricle muscle, potentially resulting in heart failure.

Common Causes:
- Endocarditis: Inflammation of the inner layer of the heart.
- Aortic Dissection: A serious condition involving a tear in the aorta.

Common observational findings include:
- Wide Pulse Pressure: A significant difference between systolic and diastolic blood pressure readings.
- Diastolic Murmur: An abnormal sound heard during the diastolic phase of the heart cycle.
- Florid Pulmonary Edema: Severe fluid accumulation in the lungs.

Description: Classified as a true surgical emergency.
Management Approaches:
- Positive Inotropes: Medications like dopamine or dobutamine can be administered.
- Vasodilators: Agents such as nitroprusside may also be used.

General Considerations: Endocarditis prophylaxis in dental procedures for patients with a prosthetic aortic valve or history of endocarditis is crucial.
Medical Management:
- Medications including vasodilators (ACE inhibitors) and Nifedipine may improve stroke volume and reduce regurgitation, but they are typically indicated only if the patient is symptomatic or has hypertension.
Serial Echocardiograms: To monitor the disease progression in patients.
Surgical Treatment: Determined as the definitive treatment option.

Definition: Mitral regurgitation is defined as the backflow of blood from the left ventricle (LV) to the left atrium (LA) during systole resulting from incomplete closure of the mitral valve.
Prevalence: Mild (physiological) mitral regurgitation can be seen in up to 80% of normal individuals.
Causes of Acute Mitral Regurgitation:
- Endocarditis: Infection leading to valve dysfunction.
- Acute Myocardial Infarction (MI): Can lead to structural valve changes.
- **Malfunction or