-
Question 1
Incorrect
-
Regarding loop diuretics, which of the following statements is INCORRECT:
Your Answer: Intravenous furosemide has a peak effect within 30 minutes.
Correct Answer: The risk of hypokalaemia is greater with loop diuretics than with an equipotent dose of a thiazide diuretic.
Explanation:Hypokalaemia can occur with both thiazide and loop diuretics. The risk of hypokalaemia depends on the duration of action as well as the potency and is thus greater with thiazides than with an equipotent dose of a loop diuretic. Hypokalaemia is dangerous in severe cardiovascular disease and in patients also being treated with cardiac glycosides. Often the use of potassium-sparing diuretics avoids the need to take potassium supplements. In hepatic failure, hypokalaemia caused by diuretics can precipitate encephalopathy, particularly in alcoholic cirrhosis.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 2
Incorrect
-
Regarding the cardiac cycle, which of the following statements is INCORRECT:
Your Answer: Diastole is usually twice the length of systole.
Correct Answer: The second heart sound occurs in late diastole caused by closure of the atrioventricular valves.
Explanation:Diastole is usually twice the length of systole at rest, but decreases with increased heart rate. During systole, contraction of the ventricles compresses the coronary arteries and suppresses blood flow. This is particularly evident in the left ventricle, where during systole the ventricular pressure is the same as or greater than that in the arteries and as a result more than 85% of left ventricular perfusion occurs during diastole. This becomes a problem if the heart rate is increased as the diastolic interval is shorter and can result in ischaemia. The second heart sound, caused by closure of the semilunar valves, marks the end of systole.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 3
Correct
-
Which of the following best describes digoxin:
Your Answer: A positive inotrope and negative chronotrope
Explanation:Digoxin is a cardiac glycoside used in the treatment of atrial fibrillation and flutter, and congestive cardiac failure. It acts by inhibiting the membrane Na/K ATPase in cardiac myocytes. This raises intracellular sodium concentration and increases intracellular calcium availability indirectly via Na/Ca exchange. The increase in intracellular calcium levels causes an increases the force of myocardial contraction (positive inotrope), and slows the heart rate (negative chronotrope).
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 4
Incorrect
-
Which of the following describes the pulse pressure:
Your Answer: Systolic/diastolic pressure
Correct Answer: Systolic - diastolic pressure
Explanation:During systole, the pressure in the left ventricle increases and blood is ejected into the aorta. The rise in pressure stretches the elastic walls of the aorta and large arteries and drives blood flow. Systolic pressure is the maximum arterial pressure during systole. During diastole, arterial blood flow is partly maintained by elastic recoil of the walls of large arteries. The minimum pressure reached before the next systole is the diastolic pressure. The difference between the systolic and diastolic pressure is the pulse pressure.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 5
Incorrect
-
An elderly patient presents to ED following a fall after feeling light headed when standing up. You are reviewing his medication and note that he is taking a high dose of furosemide. Loop diuretics act primarily at which of the following sites in the nephron:
Your Answer: Collecting ducts
Correct Answer: Thick ascending limb
Explanation:Loop diuretics inhibit the Na+/K+/2Cl- symporter on the luminal membrane in the thick ascending limb of the loop of Henle, thus preventing reabsorption of NaCl and water. These agents reduce reabsorption of Cl- and Na+ and increase Ca2+ excretion and loss of K+ and Mg2+.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 6
Incorrect
-
Which of the following is NOT a benefit of low molecular weight heparin (LMWH) over unfractionated heparin therapy:
Your Answer: It has a greater ability to inhibit factor Xa directly rather than inhibit antithrombin III.
Correct Answer: Its effects can be rapidly and completely reversed with protamine sulfate.
Explanation:Advantages of LMWHGreater ability to inhibit factor Xa directly, interacting less with platelets and so may have a lesser tendency to cause bleedingGreater bioavailability and longer half-life in plasma making once daily subcutaneous administration possibleMore predictable dose response avoiding the need for routine anticoagulant monitoringLower associated risk of heparin-induced thrombocytopenia or of osteoporosis
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 7
Incorrect
-
What is the effect of a positive inotrope on the Starling curve:
Your Answer: Causes a leftward shift along the curve
Correct Answer: Shifts the curve upwards
Explanation:Contractility (inotropy) is the intrinsic ability of cardiac muscle to develop force at a given muscle length. It is determined by the intracellular [Ca2+] and can be estimated by the ejection fraction. Increases in contractility cause an increase in stroke volume/cardiac output for any level of right atrial pressure or end-diastolic volume, and hence shift the Starling curve upwards. Decreases in contractility cause a decrease in stroke volume/cardiac output for any level of right atrial pressure or end-diastolic volume and hence shift the Starling curve downwards.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 8
Incorrect
-
An 82 year old man taking warfarin as a maintenance medication comes in to your clinic because of an infection. Which antibiotic is the safest choice for this patient?
Your Answer: Doxycycline
Correct Answer: Cefalexin
Explanation:Alterations in the international normalized ratio (INR) brought about by the concurrent use of antibiotics and warfarin may result in either excessive clotting or excessive bleeding if they are deemed to have a high risk for interaction. As such, there should be careful consideration of the class of antibiotic to be used. Antibiotics from the following drug classes should generally be avoided as they have a high risk for interaction with warfarin, possible enhancing the anticoagulant effects of warfarin resulting in bleeding: Fluoroquinolones (e.g. ciprofloxacin, levofloxacin), Macrolides (e.g. clarithromycin, erythromycin, azithromycin), Nitroimidazoles (e.g. metronidazole), Sulphonamides (e.g. co-trimoxazole, a combination of trimethoprim and sulfamethoxazole), Trimethoprim, Tetracyclines (e.g. doxycycline). Low risk antibiotics that have low risk for interaction with warfarin includes cephalexin, from the cephalosporin class, and clindamycin which is a lincomycin.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 9
Incorrect
-
Which of the following best characterizes the correct administration of amiodarone for a shockable rhythm in adults on advanced life support:
Your Answer: Give 300 mg IV amiodarone after 3 - 5 minutes of onset of CPR
Correct Answer: Give 300 mg IV amiodarone after 3 shocks
Explanation:After three shocks, 300 mg IV amiodarone should be administered. After five defibrillation attempts, a further dose of 150 mg IV amiodarone may be considered. If amiodarone is not available, lidocaine may be used as a substitute, but it should not be given if amiodarone has previously been administered.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 10
Incorrect
-
Which of the following medications may lessen warfarin's anticoagulant effect:
Your Answer: Metronidazole
Correct Answer: Phenytoin
Explanation:Phenytoin will decrease the level or effect of warfarin by affecting hepatic/intestinal enzyme CYP3A4 metabolism.Metronidazole will increase the level or effect of warfarin by affecting hepatic enzyme CYP2C9/10 metabolism.NSAIDs, when given with Warfarin, increase anticoagulation.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 11
Incorrect
-
Which of the following increases the tendency for oedema to occur?
Your Answer: Increased plasma protein concentration
Correct Answer: Increased venous pressure
Explanation:When more fluid is filtered out of the capillaries than can be returned to the circulation by the lymphatics, oedema occurs. Changes that increase capillary hydrostatic pressure or decrease plasma oncotic pressure will increase filtration. Arteriolar constriction reduces hydrostatic capillary pressure and transiently increase absorption of fluid. Dehydration increases plasma protein concentration and therefore increases plasma oncotic pressure and absorption. Capillary hydrostatic pressure and filtration are increased when there is increased venous pressure.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 12
Correct
-
Mannitol is primarily indicated for which of the following:
Your Answer: Cerebral oedema
Explanation:Mannitol is an osmotic diuretic that can be used to treat cerebral oedema and raised intraocular pressure. Mannitol is a low molecular weight compound and is, therefore, freely filtered at the glomerulus and is not reabsorbed. It, therefore, increases the osmolality of the glomerular filtrate and tubular fluid, increasing urinary volume by an osmotic effect. It also does not cross the blood-brain-barrier (BBB).
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 13
Incorrect
-
For a tachyarrhythmia caused by hypovolaemic shock, which of the following is the first-line treatment:
Your Answer: Adenosine
Correct Answer: Synchronised DC shock
Explanation:If there are any adverse symptoms, immediate cardioversion with synchronized DC shock is recommended. If cardioversion fails to stop the arrhythmia and the symptoms persist, amiodarone 300 mg IV over 10–20 minutes should be administered before attempting another cardioversion. The loading dosage of amiodarone is followed by a 24-hour infusion of 900 mg administered into a large vein.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 14
Incorrect
-
Which of the following causes the first heart sound?
Your Answer: Opening of the semilunar valves
Correct Answer: Closing of the atrioventricular valves
Explanation:The heart sounds are as a result of the various parts of the cardiac cycle.Heart Sound – Phase of Cardiac Cycle – Mechanical Event:1st heart sound – Systole starts – there is closure of the atrioventricular (mitral & tricuspid) valves2nd heart sound – Systole ends – there is closure of the semilunar (aortic and pulmonary) valves3rd heart sound – Early diastole – this is caused by rapid flow of blood from the atria into the ventricles during the ventricular filling phase4th heart sound – Late diastole – this is caused by filling of an abnormally stiff ventricle in atrial systole
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 15
Incorrect
-
When an elderly dehydrated patient is moved from a supine to a standing position, her heart rate increases. Which of the following accounts for the increase in heart rate upon standing:
Your Answer: Increased contractility
Correct Answer: Decreased venous return
Explanation:On standing from a prone position, gravity causes blood to pool in veins in the legs. Central venous pressure (CVP) falls, causing a fall in stroke volume and cardiac output (due to Starling’s law) and thus a fall in blood pressure. Normally this fall in BP is rapidly corrected by the baroreceptor reflex which causes venoconstriction (partially restoring CVP), and an increase in heart rate and contractility, so restoring cardiac output and blood pressure. Impaired autonomic nervous activity in the elderly accounts for the greater likelihood of postural hypotension. Any symptoms of dizziness, blurred vision or syncope is due to a transient fall in cerebral perfusion that occurs before cardiac output and mean arterial pressure (MAP) can be corrected.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 16
Incorrect
-
Regarding endothelin-1, which of the following statements is INCORRECT:
Your Answer: Endothelin-1 (ET-1) is released from the endothelium.
Correct Answer: Endothelin-1 release is inhibited by noradrenaline.
Explanation:Endothelin-1 (ET-1) is an extremely potent vasoconstrictor peptide which is released from the endothelium in the presence of many other vasoconstrictors, including angiotensin II, antidiuretic hormone (ADH) and noradrenaline, and may be increased in disease and hypoxia.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 17
Correct
-
The mechanism of action of abciximab is by:
Your Answer: Blocking the binding of fibrinogen to GPIIb/IIIa receptor sites
Explanation:Abciximab is a glycoprotein IIb/IIIa inhibitors and prevents platelet aggregation by blocking the binding of fibrinogen to receptors on platelets.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 18
Correct
-
A patient who is taking ramipril for high blood pressure complains of a dry persistent cough. What is the mechanism of cough in ACE inhibitor therapy:
Your Answer: Decreased bradykinin breakdown
Explanation:Blocking ACE also diminishes the breakdown of the potent vasodilator bradykinin which is the cause of the persistent dry cough. Angiotensin-II receptor blockers do not have this effect, therefore they are useful alternative for patients who have to discontinue an ACE inhibitor because of persistent cough.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 19
Correct
-
Adenosine has a half-life of approximately:
Your Answer: 8 - 10 seconds
Explanation:Adenosine stimulates A1-adenosine receptors and opens acetylcholine sensitive K+ channels, increasing K+ efflux. This hyperpolarises the cell membrane in the atrioventricular node and, by inhibiting the calcium channels, slows conduction in the AVN. As it has a very short duration of action (half-life only about 8 – 10 seconds), most side effects are short lived.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 20
Correct
-
Regarding the heart sounds in the cardiac cycle, which of the following statements is INCORRECT:
Your Answer: The third heart sound is caused by filling of an abnormally stiff ventricle in atrial systole.
Explanation:Heart Sound – Phase of Cardiac Cycle – Mechanical Event:First heart sound – Start of systole – Caused by closure of the atrioventricular (mitral & tricuspid) valvesSecond heart sound – End of systole – Caused by closure of the semilunar (aortic and pulmonary) valvesThird heart sound – Early diastole – Caused by rapid flow of blood from the atria into the ventricles during the ventricular filling phaseFourth heart sound – Late diastole – Caused by filling of an abnormally stiff ventricle in atrial systole
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 21
Incorrect
-
Intracellular [Ca2+] rise in cardiac excitation-contraction coupling is mainly as a result of:
Your Answer: Ca 2+ influx by the Ca 2+ ATPase pump
Correct Answer: Ca 2+ release from sarcoplasmic reticulum
Explanation:Although Ca2+entry during the action potential (AP) is essential for contraction, it only accounts for about 25% of the rise in intracellular Ca2+. The rest is released from Ca2+stores in the sarcoplasmic reticulum (SR). APs travel down invaginations of the sarcolemma called T-tubules, which are close to, but do not touch, the terminal cisternae of the SR. During the AP plateau, Ca2+enters the cell and activates Ca2+sensitive Ca2+release channels in the sarcoplasmic reticulum allowing stored Ca2+to flood into the cytosol; this is called Ca2+-induced Ca2+release. The amount of Ca2+released is dependent on how much is stored, and on the size of the initial Ca2+influx during the AP.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 22
Incorrect
-
Which of the following does NOT predispose to digoxin toxicity in a patient taking digoxin:
Your Answer: Hypercalcaemia
Correct Answer: Hyponatraemia
Explanation:Hypoxia, hypercalcaemia, hypokalaemia and hypomagnesaemia predispose to digoxin toxicity. Care should also be taken in the elderly who are particularly susceptible to digoxin toxicity. Hypokalaemia may be precipitated by use of diuretics. Although hyponatremia can result in the development of other pathological disturbances, it does not potentiate digoxin toxicity.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 23
Correct
-
As a response to low blood pressure, the baroreceptor reflex will facilitate vasoconstriction by activating which receptor?
Your Answer: Alpha1
Explanation:The rate of baroreceptor firing slows down when blood pressure falls too low. This causes an increase in sympathetic stimulation of the heart, resulting in an increase in cardiac output. It also causes vasoconstriction by activating alpha 1 receptors in smooth muscle, which causes sympathetic stimulation of peripheral vessels. Alpha2 receptors can be found in both the brain and the peripheral nervous system. They control sympathetic outflow in the brain stem. Beta1 receptors, which are found on the cell membrane of cardiac muscle cells, stimulate heart rate and myocardial contractility. The smooth muscle cell membrane contains beta2 receptors, which promote smooth muscle relaxation in the lungs causing bronchodilation, GI tract, and peripheral blood vessels.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 24
Incorrect
-
Regarding autoregulation of local blood flow, which of the following statements is CORRECT:
Your Answer: Autoregulation is particularly important in the pulmonary circulation.
Correct Answer: An increase in blood flow dilutes locally produced vasodilating factors causing vasoconstriction.
Explanation:Autoregulation is the ability to maintain a constant blood flow despite variations in blood pressure (between 50 – 170 mmHg). It is particularly important in the brain, kidney and heart. There are two main methods contributing to autoregulation:The myogenic mechanism involves arterial constriction in response to stretching of the vessel wall, probably due to activation of smooth muscle stretch-activated Ca2+channels and Ca2+entry. A reduction in pressure and stretch closes these channels, causing vasodilation. The second mechanism of autoregulation is due to locally produced vasodilating factors; an increase in blood flow dilutes these factors causing vasoconstriction, whereas decreased blood flow has the opposite effect.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 25
Correct
-
By which of the following is mean arterial pressure (MAP) primarily determined?
Your Answer: Total peripheral resistance and cardiac output
Explanation:Mean arterial pressure (MAP) = Cardiac output (CO) x Total peripheral resistance (TPR). Cardiac output is dependent on the central venous pressure (CVP). CVP, in turn, is highly dependent on the blood volume. Any alterations of any of these variables will likely change MAP.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 26
Correct
-
Regarding alteplase, which of the following statements is INCORRECT:
Your Answer: Alteplase is commonly associated with hypotensive effects.
Explanation:Alteplase is a recombinant tissue-type plasminogen activator (tPA), a naturally occurring fibrin-specific enzyme that has selectivity for activation of fibrin-bound plasminogen. It has a short half-life of 3 – 4 minutes and must be given by continuous intravenous infusion but is not associated with antigenic or hypotensive effects, and can be used in patients when recent streptococcal infections or recent use of streptokinase contraindicates the use of streptokinase.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 27
Incorrect
-
What is the main mechanism of action of dobutamine as an inotropic sympathomimetic:
Your Answer: Alpha1-receptor agonist
Correct Answer: Beta1-receptor agonist
Explanation:Dobutamine directly stimulates the beta1-adrenergic receptors in the heart and increases contractility and cardiac output with little effect on the rate. In addition action on beta2-receptors causes vasodilation.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 28
Correct
-
When a person changes from a supine to an upright position, which of the followingcompensatory mechanismsoccurs:
Your Answer: Increased contractility
Explanation:On standing from a prone position, gravity causes blood to pool in veins in the legs. Central venous pressure (CVP) falls, causing a fall in stroke volume and cardiac output (due to Starling’s law) and thus a fall in blood pressure. Normally this fall in BP is rapidly corrected by the baroreceptor reflex which causes venoconstriction (partially restoring CVP), and an increase in heart rate and contractility, so restoring cardiac output and blood pressure. Impaired autonomic nervous activity in the elderly accounts for the greater likelihood of postural hypotension. Any symptoms of dizziness, blurred vision or syncope is due to a transient fall in cerebral perfusion that occurs before cardiac output and mean arterial pressure (MAP) can be corrected.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
-
Question 29
Incorrect
-
What is the correct adrenaline dose for a patient with pulseless ventricular tachycardia?
Your Answer: 0.5 ml of 1 in 10,000 adrenaline solution
Correct Answer: 10 ml of 1 in 10,000 adrenaline solution
Explanation:Ventricular fibrillation or pulseless ventricular tachycardia (VF/VT) are referred to as shockable rhythm. IV adrenaline 1 mg (10 mL of 1:10,000 solution) should be administered after 3 shocks and every 3 – 5 minutes/after alternate shocks thereafter for a shockable rhythm. For a non-shockable rhythm, 1 mg IV adrenaline should be administered as soon as IV access is obtained, and then every 3 – 5 minutes/after alternate shocks thereafter.
-
This question is part of the following fields:
- Cardiovascular
- Pharmacology
-
-
Question 30
Incorrect
-
Cardiac myocytes are connected to each other by which of the following:
Your Answer: Tight junctions
Correct Answer: Intercalated discs
Explanation:Adjacent cardiac myocytes are connected to each other by intercalated discs. The intercalated discs provide both a structural attachment by ‘glueing’ cells together at desmosomes and an electrical contact made up of proteins called connexons, called a gap junction, which essentially creates a low-resistance pathway between cells.
-
This question is part of the following fields:
- Cardiovascular
- Physiology
-
SESSION STATS - PERFORMANCE PER SPECIALTY
