Cardiovascular

Question 1

Atrial fibrillation

Answer 1

Irregular and extremely rapid (300-600bpm) atrial contractions
AVN only intermittently activated –> irregular ventricular function
Caused by MCI, heart failure, hypertension, bronchitis, hypothroidism
Risk of thromboembolism –> warfarin
Slow contractions: digoxin, b-blockers, verapamil, amiodarone

Question 2

Heart valve disease

Answer 2

Loss of effective pumping –> reduced CO

Fatigue; breathlessness; angina; oedema

Question 3

Stenosis of heart valve

Answer 3

Excessive calcification
Congenital malformation
Rheumatic fever
Atherosclerotic degeneration

Question 4

Regurgitation of heart valve

Answer 4

Bacterial infection/inflammation
Prolapse (poorly supported/weak valve leaflets)
Ventricular or aortic dilation

Question 5

Atherosclerosis

Answer 5

Chronic inflammatory response of walls of large arteries initiated by injury to endothelium
Can lead to hypertension

Question 6

Myocardial ischaemia

Answer 6

Caused when oxygen demand in cardiac muscle exceeds its supply
Inhibition of Na/K pump causing partial depolarisation, which can reduced the size of subsequent AP and slow their conduction in the myocardium

Question 7

Endothelium

Answer 7

Acetylcholine and prostacyclin caused relaxation in artery wall
When endothelium rubbed away, acetylcholine caused contraction but prostacyclin still caused relaxation

Question 8

Bradycardia

Answer 8

Unusually slow heart rate
Sinus dysfunction/hypothyroidism/exacerbated by b-blockers or cardiac glycosides
Cardiac arrest, atrial fibrillation, thromboembolism
Treated with muscarinic ACh antagonist –> prevent parasympathetic