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Overview of Viral Diseases

• Emphasis on understanding growth, structure, and function of the heart.

• Knowledge of the right and left side of the heart is essential, especially regarding the four cardiac valves.

Cardiac Valve Dysfunction

• Conditions can lead to two main types of valve dysfunction:

  • Stenosis:

    • Definition: A valve cannot open properly.

    • Effects: Limits blood flow; can lead to increased pressure in the heart chambers and associated organ dysfunction.

  • Regurgitation:

    • Definition: A valve cannot close properly.

    • Effects: Abnormal backflow of blood; can lead to volume overload in the heart chambers and decreased efficiency of the heart.

Focus on Rheumatic Heart Disease

• Rheumatic heart disease serves as a representative condition for studying stenosis and regurgitation.

• Triggered by:

  • Group A Streptococcal Infection:

    • Typically presented as a common bacterial throat infection.

• Importance of early treatment to prevent complications.

Pathophysiological Processes

• Acute Rheumatic Fever (ARF):

  • Initiated by an autoimmune response to the initial streptococcal infection.

  • Can lead to:

    • Carditis: Inflammation of the heart, which can damage heart valves.

• Damage to valves can progress to:

  • Stenosis: Impaired blood flow due to narrowed valve.

  • Regurgitation: Backward flow of blood due to incomplete valve closure.

Understanding Valve Dysfunction

• Understanding the terms:

  • Stenosis: Effects on the body include increased workload on the heart.

  • Regurgitation: Can result in heart failure over time if untreated.

  • Incompetent Valve: Refers to valves that fail to close properly, leading to similar consequences as regurgitation.

Determinants of Rheumatic Fever in New Zealand

• Specific risk factors and prevalence related to rheumatic fever in the New Zealand context should be addressed.