I. CVS – Function

To begin learning about cardiovascular diseases, we must first understand what the Cardiovascular system does, i.e. Function.

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Heart's function is to pump blood through the body

–> supply tissues with vital nutrients

–> facilitates excretion of waste products  

Functional components necessary for cardiac function:

  1. Myocardium – Engine (pump)
  2. Valves (part of endocardium) – Maintain unidirectional blood flow (channels blood in correct direction)
  3. Conduction system – Maintain coordinated pumping rhythm. 
  4. Blood supply – Provides sufficient nutrients to heart – Coronary arteries (3 main: Left anterior descending artery, left circumflex arteries, right coronary artery)

Once we understand the main functions of the heart, we can appreciate what happens when there is heart failure. Heart failure is a multifactorial disease that may have a single or multiple causes, and it is the common end point of many cardiovascular diseases.

Definition of heart failure: Clinical condition where - 

  • the heart is unable to meet the body’s demands (despite compensatory mechanisms)
  • although the venous filling pressure is normal or raised

Congestive heart failure:

Heart failure involving both right and left ventricles

- Fluid accumulates in the lungs, legs, abdominal cavity

- Reduced flow of arterial blood from the heart à can lead to peripheral circulatory failure (cardiogenic shock)

 

 

The main features of Heart Failure are described in a mindmap in section IV: Main Cardiovascular Diseasee