Week 5: hypertension, heart failure, PVD, cardiomyopathy, conduction defects Flashcards
What hormones/ substances are responsible for vasoconstriction
- Endothelin 1
- Angiotensin 2
- Oxidants
What hormones/ substances are responsible for vasodilation
- Nitric Oxide
- Prostaglandin I2
- Endothelium-derived hyperpolarising factor
Systolic/diastolic pressure tends to increase/decrease with age
SYSTOLIC: increases with age
DIASTOLIC: decreases after 60yo
What BP level is considered stage 1 hypertension
Stage 1: >140/90
What BP level is considered stage 2 hypertension
Stage 2: >160/100
What BP level is considered severe hypertension
Systolic >180 or Diastolic >110
From which stage of hypertension should medication be given
Treat stage 2 if BP remains high after 24h monitor
Treat severe hypertension immediately
Effects of Angiotensin 2
- Increases sympathetic activity
- Na+ reabsorption & K+ secretion in renal tubules
- Water retention in kidney tubules
- Aldosterone secretion from adrenal cortex (which reinforces Na+ reabsorption and water retention)
- Vasoconstriction of arteries
- ADH secretion from posterior pituitary
What drugs might cause hypertension
- Nasal decongestants (sympathomimetic amines)
- Oestrogen eg OCP
- Amphetamines, cocaine
- Corticosteroids, mineralocorticoids
- Erythropoitin
- Ciclosporin
Adrenal causes of hypertension
- Phaeochromocytoma (excess epinephrine)
- Cushing’s (excess cortisol)
- Conn’s (excess aldosterone)
Parathyroid causes of hypertension
Hyperparathyroidism
Growth hormone causes of hypertension
Acromegaly
Thyroid hormone causes of hypertension
- Hypothyroidism (increased vascular resistance)
* Hyperthyroidism (increased metabolic rate)
How long can a leg remain ischaemic for before it becomes un-salvage-able
3-6h
After this, irreversible nerve/ muscle damage
2 main causes of acute limb ischaemia
- Atrial fibrillation
2. Thrombosis on top of pre-existing atherosclerosis
When should a carotid endarterectomy be done
if >70% occlusion found on carotid duplex
What features are typical in a cardiac syncope
- Sudden collapse, no prodrome
* Often rapid recovery
How do channelopathies cause cardiac arrest
- Disordered ion movement in and out of myocytes
2. Eventually leads to polymorphic VT/VF (torsades de pointes)
What kind of arrhythmia does Long QT syndrome result in
Polymorphic Ventricular Tachycardia (torsades de pointes
What kind of arrhythmia does Long QT syndrome result in
Polymorphic Ventricular Tachycardia (torsades de pointes
Pathophysiology of long QT syndrome
Channelopathy (usually potassium, but may be sodim) causing prolonged ventricular repolarisation
What might provoke arrhythmia in long QT syndrome
- Exercise
- Startle reflex
What kind of arrhythmia does Brugada syndrome result in
Ventricular fibrillation
Pathophysiology of Brugada syndrome
Sodium channelopathy