QuestionSBA
QuestionChoice
This is an angiotensin receptor blocker, which like ACE inhibitors is associated with hyperkalaemia, not hypokalaemia.
10023618
d
Candesartan
QuestionChoice
This is an ACE inhibitor which causes hyperkalaemia, not hypokalaemia.
10023616
b
Ramipril
QuestionChoice
Digoxin causes delayed after-depolarisations (DADs), not early after-depolarisations. It causes DADs by inhibiting Na+/K+ ATPase which leads to an increased intracellular Na+ conc (usually pumps Na+ out and K+ in) as well as reduced Ca2+ efflux via NCX. This results in high concentrations of Ca2+ inside the myocyte. When the Ca2+ content in the sarcoplasmic reticulum is too high, RyR receptors spontaneously open during diastole which releases Ca2+ without an action potential stimulus. This increases Ca2+ efflux via NCX (increasing the intracellular Na+ concentration) and causes depolarisation leading to a delayed after depolarisation. If this depolarisation reaches the threshold to open voltage-gated Na+ channels, it causes an action potential to be formed.
10023619
e
Digoxin
QuestionChoice
This is a loop diuretic which can cause hypokalaemia. Hypokalaemia reduces the activity of K+ channels and the Na/K pump. This prolongs the plateau phase of the cardiac action potential, leading to increased Ca2+ influx via L-type Ca2+ channels. This results in an increase in the cytosolic Ca2+ concentration, so more Ca2+ leaves the cell via NCX (sodium-calcium-exchangers) and more Na+ is brought into the cell. This can cause depolarisation and action potentials before a cell has a chance to repolarise, leading to EADs.
10023615
a
Furosemide
QuestionChoice
This is a potassium-sparing diuretic which can cause hyperkalemia, not hypokalaemia.
10023617
c
Spironolactone
Concept
Chapter
2693
5690
Conduction pathways through the heart
Topic
159
Cardiovascular physiology
17121
A 74-year-old male is experiencing palpitations and comes to the ED. An ECG is performed which shows prolonged early after-depolarisations (EADs). The patient is on a variety of medications which the doctor thinks could be contributing to his EADs.

Which of the following medications can cause EADs?
a