Cardiovascular Physiology Flashcards
What are the four stages of the valsalva maneouvre?
- Increase in intrathoracic pressure
- Reduced venous return, with stimulation of baroreceptor reflex to produce tachycardia and vasoconstriction
- Rapid reduction in intrathoracic pressure causes pooling of blood in pulmonary vasculature
- Overshoot in blood pressure before levels normalise
How can you manage cyanotic episodes in patients with tetralogy of fallot prior to corrective surgery?
- Oxygen to reduce pulmonary vascular resistance
- Increase systemic vascular resistance using knee-to chest position or squatting
- Opioids and anxiolytics can reduce tachypnoea but may also reduce systemic vascular resistance
- Treat the cause
What are the physiology changes seen during a cyanotic episode in a tetralogy of fallot patient?
- Acute increase in pulmonary vascular resistance
- Leads to increased right to left shunt
- This can also be triggered by an acute decrease in systemic vascular resistance
- Leads to hypoxia, hypercapnoea and acidosis
- This leads to tachypnoea and more negative intrathoracic pressure
- This causes more venous return, which flows via the right to left shunt- This establishes a vicious cycle
What are the triggers of a ‘tet spell’ or cyanotic episode in tetralogy of fallot?
- Tachycardia
- Hypotension
- Crying
- Defaecation
What conditions are associated with tetralogy of Fallot?
- DiGeorge Syndrome
- Down syndrome
- Cleft lip or palate
- Hypospadias
- 22q11 chromosome deletion syndrome
What are the cardinal features of Tetralogy of Fallot?
- Right ventricular outflow obstruction or pulmonary stenosis
- Overriding aorta
- Ventricular septal defect
- Right ventricular hypertrophy
What are the signs on examination of congenital heart disease?
- Cyanosis on exertion e.g. crying
- Tachypnoea and sweating while feeding
- Unexplained persistent tachycardia
- Hepatomegaly
- Peripheral oedema
- Radio-femoral pulse delay
- Murmur (not innocent)
What are the causes of collapse in the neonatal period?
- Congenital heart disease
- Sepsis
- Hypoglycaemia
- Trauma
- Metabolic disorder
- Endocrine disorder
What are the NICE recommendations for chronic heart failure?
First line:
ACE inhibitor
Beta blocker
Second line:
Aldosterone inhibitor
Third line:
Cardiac resynchronisation therapy or digoxin
What are the causes of a fourth heart sound?
Increased atrial activity during diastole, before the first heart sound
It can occur in any left ventricular disease
What is the difference between a thrusting and a tapping apex beat, in terms of cause?
Hypertension causes a thrusting apex beat, while mitral stenosis causes a tapping apex beat
What are the causes of a pathalogical third heart sound?
Mitral regurgitation
Tricuspid regurgitation
Constrictive pericarditis
Dilated left ventricle
Myocardial infarction
How is hypertensive retinopathy graded?
1 - arterial narrowing
2 - arteriovenous nipping
3 - haemorrhages and exudates
4 - all of the above with papilloedema
What are the causes of a prolonged QT interval?
Hypocalcaemia
Myocarditis
Ischaemic heart disease
Hypothermia
Antiarrhythmic drugs
What are the causes of a shortened QT interval?
Hypercalcaemia
Digoxin
Inotropes
Catecholamines
