Cardiovascular Dysfunction Flashcards
What is the scope of physio in CV dysfunction?
- Management of acute surgical/medical patients
- Cardiac rehab & community care
- Cardiac transplantation
- Research
What are some of the investigations used for CV dysfunction?
- History taking
- Physical examination
- ECGs
- Echocardiography
- Exercise testing
- Myocardial perfusion imaging
- MRI
- PET
- Cardiac catheterisation
What two factors determine blood pressure?
- Total peripheral resistance (TPR)
- Cardiac output (CO)
Mean arterial pressure (MAP) = CO x TPR
How is pulmonary vascular resistance different to systemic?
TPR is much lower than vascular
What causes the difference in blood pressure between systemic and pulmonary circulation?
Differences in vascular resistance mediated by SNS in smooth muscle in the arterioles - increases vasoconstriction & BP
How is blood pressure regulated acutely?
Baroreceptor reflex
Where are baroreceptors located in the heart?
- Carotid sinus
- Aortic arch
What effect does the vagus nerve have on the heart?
- Efferent nerve for the heart
- Slows contractility, heart rate etc
How is a decrease in arterial blood pressure regulated by baroreceptors?
- Central control (medulla/hypothalamus)
- Decreased PNS outflow
- Increased SNS outflow
- Increased HR
- Vasoconstriction
- Increased forced cardiac contraction
How can bed rest affect blood pressure?
24 hours bed rest reduces SNS activity in response to orthostatic (upright) stimulus
What are the symptoms of orthostatic intolerance (low BP)?
- Light headedness
- Dizziness
- Yawning
- Nausea
- Feeling warm
- Abdominal discomfort
What are the reasons for orthostatic intolerance after bed rest (low BP)?
- SNS dysfunction
- Reduced plasma volume
- Cardiac atrophy
- Arrhythmia (bradycardia, tachycardia etc)
- Drugs
- Vaso-vagal syncope (pain, emotion, medical procedure)
What are the consequences of hypertension?
Major risk factor for
- Heart failure
- Myocardial ischaemia & infarction
- Stroke
- Retinopathy
- Nephrosclerosis & renal failure
What are the two main things hypertension effects?
- Mediates arterial damage
- Increases afterload (direct pressure load on left ventricle)
What does increased after load cause?
- Systolic dysfunction
- Diastolic dysfunction
- Increased myocardial O2 demand
What does arterial damage cause?
- Accelerated atherosclerosis
- Weakened vessel wall
What are some of the other CHD risk factors hypertension interacts with?
- Cholesterol
- HDL
- Smoking
- Diabetes
- LVH
What is the main cause of hypertension?
Essential (no definitive cause, 95% of cases)
What are the characteristics of essential hypertension (EH)?
- 80% have stage 1
- Genetics important
What are the non-pharmacological treatments of hypertension?
- Weight reduction
- Adopt DASH eating plan
- Dietary sodium reduction
- Physical activity
- Moderation of alcohol consumption
What are some of the pharmacological treatments of hypertension?
- Diuretics
- Anti-adrenergic agents
- Ca channel blockers
- ACE inhibitors
- Angiotensin-II receptor blockers
- Vasodilators
What is heart failure?
When the heart cannot pump enough blood to meet the requirements of the tissues
What are the types of heart failure?
- Systolic vs diastolic
- Right vs left
What happens in left sided congestive heart failure?
- LV weakens, cannot empty
- Decreased CO
- Decreased renal blood flow (body starts retaining fluid)
- Backup of blood into pulmonary vein
- High pressure in pulmonary capillaries
- Can cause pulmonary oedema
