Cardiovascular system

• Cardiovascular system


  The system responsible for circulating blood, oxygen, nutrients, and other substances throughout the body
• The cardiovascular system is highly relevant to all healthcare professionals
• Genetic disorders frequently associated with heart defects


  • Down syndrome - septal defects common, "a hole in the heart"
  • Duchenne Muscular Dystrophy patients - heart failure
  • Premature babies - ongoing health issues (cardiac/respiratory)
  • Mechanical hearts - a growth area due to reduced availability of donor hearts, patients at risk of blood clots -> stroke
• Remember to consider indirect effects of cardiovascular system disorders on speech and language therapy issues
• Indirect effects of cardiovascular system disorders on speech and language therapy


  • Respiratory co-morbidity, aspiration
  • Inability to undertake particular physical activities
  • Engagement with assessments if fatigued/unwell
  • Appointment load
  • SLT awareness of cardiovascular system issues - ability to raise concerns
• Diffusion


  The process by which molecules spread from an area of high concentration to an area of low concentration
• Convective transport


  The transport of substances by bulk flow or fluid stream
• Convective transport requires energy and is driven by a pressure gradient
• How a pressure gradient is created


  1. Heart - pump

  2. Two parallel circulations - systemic (body) and pulmonary (lungs)
• Types of blood vessels


  • Arteries - elastic and muscular
  • Arterioles - resistance vessels with smooth muscle, controlled by nerves
  • Capillaries - exchange vessels with very small diameter and thin walls
  • Veins - capacitance vessels with thin, tough walls that are easy to distend and collapse
• Blood pressure


  The pressure of blood in the blood vessels
• Systolic pressure


  The pressure generated by a cardiac contraction (systole)
• Diastolic pressure


  The pressure remaining in the vessels during cardiac relaxation (diastole)
• Hypertension


  Clinic blood pressure (BP) is 140/90 mmHg or higher
• Hypertension is common in the UK population, and its prevalence is influenced by age and lifestyle factors. With an ageing population, the prevalence of hypertension and requirement for treatment will continue to increase.
• Autorhythmic


  The heart can continue to beat outside the body, as it is provided with oxygen and kept moist
• Heart muscle cells


  • Work cells - responsible for contraction
  • Conduction system - responsible for initiating and propagating the heartbeat
• Electrical conduction system of the heart


  1. Sinoatrial node - initiates the heartbeat

  2. Atrioventricular node - allows conduction from atria to ventricles

  3. Bundle of His and Purkinje fibres - fast conduction system
• Sinus rhythm


  The 'normal' cardiac rhythm
• Cerebral circulation


  • Essential to maintain blood supply to the brain, which is highly sensitive to oxygen deprivation and requires a continuous supply of glucose
  • Only 2% of body mass but consumes 20% of oxygen at rest and receives 14% of cardiac output
  • Loss of consciousness after just a few seconds of cerebral ischemia
  • Structural adaptations like the Circle of Willis to maintain perfusion when one carotid artery is obstructed
• Stroke (Cerebrovascular accident, CVA)


  Cerebral ischemia - obstruction of blood supply to the brain. Two types: ischemic (80%) and hemorrhagic (20%)
• Causes of intracranial hemorrhage include high blood pressure, aneurysms, and vascular malformations.
• Ischemic strokes are commonly caused by atherosclerosis of arteries and emboli (travelling blood clots, e.g. from the heart in atrial fibrillation).
• Transient ischemic attack (TIA) is when stroke symptoms recover within 24 hours.

  
• Fit and healthy people normally have a sinus rhythm.
• An electrocardiogram (ECG) is a recording of the heart's electrical activity by attaching electrodes to the arms, legs, and chest.
• An echocardiogram is an ultrasound scan of the heart that provides very useful information about its structure and function.
• It is important for healthcare professionals to "know your pulse" and "know your patient's pulse".