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Question 1
Incorrect
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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.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 2
Incorrect
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Which of the following describes the pulse pressure:
Your Answer: Diastolic + systolic pressure/2
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.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 3
Incorrect
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What is the direct mechanism of action of digoxin as a positive inotrope:
Your Answer: Stimulation of Ca2+ ATPase
Correct Answer: Inhibition of Na+/K+ ATPase pump
Explanation:Digoxin directly inhibits membrane Na+/K+ ATPase, which is responsible for Na+/K+ exchange across the myocyte cell membrane. This increases intracellular Na+ and produces a secondary increase in intracellular Ca2+ that increases the force of myocardial contraction. The increase in intracellular Ca2+ occurs because the decreased Na+ gradient across the membrane reduces the extrusion of Ca2+ by the Na+/Ca2+ exchanger that normally occurs during diastole. Digoxin and K+ ions compete for the receptor on the outside of the muscle cell membrane, and so the effects of digoxin may be dangerously increased in hypokalaemia.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 4
Correct
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The Frank-Starling curve is shifted downhill in heart failure due to which of the following?
Your Answer: Decrease in contractility
Explanation:The Frank–Starling mechanism states that the left ventricle can increase its force of contraction and hence stroke volume in response to increases in venous return and thus preload. Changes in afterload or inotropy cause the Frank–Starling curve to rise or fall. In heart failure, the Frank–Starling curve is shifted downward (flattened), requiring higher venous return and filling pressure to enhance contractility and stroke volume.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 5
Incorrect
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All of the statements regarding vascular tone are correct except:
Your Answer:
Correct Answer: Most endogenous vasodilators act by decreasing levels of cAMP or cGMP.
Explanation:Most vasoconstrictors bind to G-protein coupled receptors. These mediate elevation in intracellular [Ca2+] which leads to vascular smooth muscle contraction. Important vasoconstrictors include noradrenaline, endothelin-1 and angiotensin II. Increased intracellular Ca2+ is as a result of the release of Ca2+from the sarcoplasmic reticulum and depolarisation and entry of Ca2+via L-type voltage-gated Ca2+channels. Most types of vascular smooth muscle do not generate action potentials – instead, the depolarisation is graded, which allows graded entry of Ca2+.sequestration by the sarcoplasmic reticulum Ca2+ATPase, removal from the cell by a plasma membrane Ca2+ATPase and Na+/Ca2+exchange decreases intracellular Ca2+, resulting in vasodilation. Relaxation is a result of most endogenous vasodilators when there is an increase in cyclic guanosine monophosphate (cGMP) like nitric oxide) or cyclic adenosine monophosphate (cAMP) like prostacyclin and beta-adrenergic receptor agonists. These activate protein kinases causing substrate level phosphorylation. Clinically effective vasodilators are L-type Ca2+channel blocker drugs.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 6
Incorrect
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Regarding cardiac excitation-contraction coupling, which of the following statements is CORRECT:
Your Answer:
Correct Answer: In relaxation, Ca 2+ is transported out of the cell using energy from a Na + gradient.
Explanation: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. In relaxation, about 80% of Ca2+is rapidly pumped back into the SR (sequestered) by Ca2+ATPase pumps. The Ca2+that entered the cell during the AP is transported out of the cell primarily by the Na+/Ca2+exchanger in the membrane which pumps one Ca2+ion out in exchange for three Na+ions in, using the Na+electrochemical gradient as an energy source. Increased heart rate increases the force of contraction in a stepwise fashion as intracellular [Ca2+] increases cumulatively over several beats; this is the Treppe effect. Factors that affect intracellular [Ca2+] and hence cardiac contractility are called inotropes.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 7
Incorrect
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If the ejection fraction increases, there will be a decrease in:
Your Answer:
Correct Answer: End-systolic volume
Explanation:An increase in ejection fraction means that a higher fraction of the end-diastolic volume is ejected in the stroke volume (e.g. because of the administration of a positive inotropic agent). When this situation occurs, the volume remaining in the ventricle after systole, the end-systolic volume, will be reduced. Cardiac output, stroke volume, and mean arterial pressure will be increased.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 8
Incorrect
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Regarding calcium channel blockers, which of the following statements is CORRECT:
Your Answer:
Correct Answer: Calcium channel blockers inhibit L-type voltage-sensitive calcium channels in arterial smooth muscle causing vasodilation.
Explanation:Calcium channel blockers inhibit L-type voltage-sensitive calcium channels in arterial smooth muscle, causing relaxation and vasodilation (reduction in peripheral vascular resistance). They also block calcium channels within the myocardium and conducting tissues of the heart which produces a negative inotropic effect by reducing calcium influx during the plateau phase of the action potential. They have a variety of uses, including:HypertensionAnginaAtrial fibrillationMigraineCalcium channel blockers have been found to be moderately useful in the prevention of migraines. The best evidence is for this is with verapamil. This may be due to the prevention of the arteriolar constriction that is associated with migraine. They are commonly used for this elsewhere in the world but are not currently licensed for this use in the UK.The following are common side effects of all calcium-channel blockers:Abdominal painDizzinessDrowsinessFlushingHeadacheNausea and vomitingPalpitationsPeripheral oedemaSkin reactionsTachycardiaVerapamil is highly negatively inotropic and reduces cardiac output, slows the heart rate and may impair atrioventricular conduction. It may precipitate heart failure, exacerbate conduction disorders, and cause hypotension at high doses and should not be used with beta-blockers. Nifedipine has less myocardial effects than verapamil and has no antiarrhythmic properties but has more influence on the vessels. Nimodipine is used solely for the prevention and treatment of vascular spasm following aneurysmal subarachnoid haemorrhage.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 9
Incorrect
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Regarding loop diuretics, which of the following statements is INCORRECT:
Your Answer:
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.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 10
Incorrect
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Blood flows from the left atrium into the left ventricle via:
Your Answer:
Correct Answer: The mitral valve
Explanation:Blood flows from the right atrium into the right ventricle via the tricuspid atrioventricular valve and from the left atrium into the left ventricle via the mitral atrioventricular valve. Blood is ejected from the right ventricle through the pulmonary semilunar valve into the pulmonary artery and from the left ventricle via the aortic semilunar valve into the aorta.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 11
Incorrect
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Which of the following drugs is first line treatment for a stable regular broad-complex tachycardia:
Your Answer:
Correct Answer: Amiodarone
Explanation:A regular broad-complex tachycardia is likely to be ventricular tachycardia or a regular supraventricular rhythm with bundle branch block. A ventricular tachycardia (or broad-complex tachycardia of uncertain origin) should be treated with amiodarone 300 mg IV over 10 – 60 min, followed by an infusion of 900 mg over the next 24 hours. If previously confirmed as SVT with bundle branch block, the patient should be treated as for narrow-complex tachycardia.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 12
Incorrect
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Which of the following statements is correct regarding the lymphatic system?
Your Answer:
Correct Answer: Lymphatic vessels contain both smooth muscle and unidirectional valves.
Explanation:Fluid filtration out of the capillaries is usually slightly greater than fluid absorption into the capillaries. About 8 L of fluid per day is filtered by the microcirculation and returns to the circulation by the lymphatic system. Lymphatic capillaries drain into collecting lymphatics, then into larger lymphatic vessels. Both of these containing smooth muscle and unidirectional valves. From this point, lymph is propelled by smooth muscle constriction and vessel compression by body movements into afferent lymphatics. It then goes to the lymph nodes where phagocytes remove bacteria and foreign materials. It is here that most fluid is reabsorbed by capillaries, and the remainder returns to the subclavian veins via efferent lymphatics and the thoracic duct. The lymphatic system has a major role to play in the body’s immune defence and also has a very important role in the absorption and transportation of fats.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 13
Incorrect
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Which of the following causes the first heart sound?
Your Answer:
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
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 14
Incorrect
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Which of the following conditions require IV Lidocaine administration?
Your Answer:
Correct Answer: Refractory ventricular fibrillation in cardiac arrest
Explanation:IV Lidocaine is indicated in Ventricular Arrhythmias or Pulseless Ventricular Tachycardia (after defibrillation, attempted CPR, and vasopressor administration)
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 15
Incorrect
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All of the following statement about the microcirculation are correct except:
Your Answer:
Correct Answer: Over the capillary bed, there is a net absorption of fluid.
Explanation:The hydrostatic pressure along the length of the capillary is usually greater than plasma oncotic pressure. As a result, there is a small net filtration of fluid from the capillary into the interstitial space. The regulation of blood flow into the microcirculation is via the vasoconstriction of small arterioles, which is activated by the sympathetic nervous system through numerous nerve endings in their walls. Unlike proteins, most ions and small molecules diffuse easily across capillary walls and thus the crystalloid osmotic pressure they exert is roughly the same on either side of the capillary wall. Because the plasma colloid osmotic pressure is higher than interstitial colloid osmotic, fluid is drawn intravascularly. A reduction of hydrostatic capillary pressure and transient increase in absorption of fluid is a result of arteriolar constriction.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 16
Incorrect
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Nifedipine commonly causes which of the following adverse effects?
Your Answer:
Correct Answer: Ankle oedema
Explanation:Most common adverse effects of Nifedipine include:Peripheral oedema (10-30%)Dizziness (23-27%)Flushing (23-27%)Headache (10-23%)Heartburn (11%)Nausea (11%)
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 17
Incorrect
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The QRS duration of a broad-complex tachyarrhythmia is:
Your Answer:
Correct Answer: Greater than or equal to 0.12 s
Explanation:It’s a broad-complex tachycardia if the QRS duration is 0.12 seconds or more. It’s a narrow-complex tachycardia if the QRS complex is shorter than 0.12 seconds. The QRS duration should be examined if the patient with tachyarrhythmia is stable.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 18
Incorrect
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Regarding autoregulation of local blood flow, which of the following statements is CORRECT:
Your Answer:
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.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 19
Incorrect
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Oedema can occur as a result of any of the following WITH THE EXCEPTION OF:
Your Answer:
Correct Answer: Increased interstitial hydrostatic pressure
Explanation:Oedema is defined as a palpable swelling produced by the expansion of the interstitial fluid volume. A variety of clinical conditions are associated with the development of oedema, including heart failure, cirrhosis, and nephrotic syndrome. The development of oedema requires an alteration in capillary dynamics in a direction that favours an increase in net filtration and also inadequate removal of the additional filtered fluid by lymphatic drainage. Oedema may form in response to an elevation in capillary hydraulic pressure (which increases the delta hydraulic pressure) or increased capillary permeability, or it can be due to disruption of the endothelial glycocalyx, decreased interstitial compliance, a lower plasma oncotic pressure (which reduces the delta oncotic pressure), or a combination of these changes. Oedema can also be induced by lymphatic obstruction since the fluid that is normally filtered is not returned to the systemic circulation.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 20
Incorrect
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What is the recommended dosing regime for amiodarone in the treatment of a stable regular broad-complex tachycardia:
Your Answer:
Correct Answer: 300 mg IV over 10 - 60 minutes, followed by an IV infusion of 900 mg over the next 24 hours
Explanation:A ventricular tachycardia (or broad-complex tachycardia of uncertain origin) should be treated with amiodarone 300 mg IV over 10 – 60 min, followed by an infusion of 900 mg over the next 24 hours.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 21
Incorrect
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What is the correct adrenaline dose for a patient with pulseless ventricular tachycardia?
Your Answer:
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.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 22
Incorrect
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Which of the following is NOT a typical side effect of digoxin:
Your Answer:
Correct Answer: Hypokalaemia
Explanation:Digoxin does not cause hypokalaemia, but hypokalaemia does potentiate digoxin toxicity. The adverse effects of digoxin are frequently due to its narrow therapeutic window and include: Cardiac adverse effects – Sinoatrial and atrioventricular block, Premature ventricular contractions, PR prolongation and ST-segment depressionNausea, vomiting and diarrhoeaBlurred or yellow visionCNS effects – weakness, dizziness, confusion, apathy, malaise, headache, depression, psychosisThrombocytopenia and agranulocytosis (rare)Gynaecomastia in men in prolonged administration
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 23
Incorrect
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Regarding hypertensive crises, which of the following statements is CORRECT:
Your Answer:
Correct Answer: In a hypertensive emergency, blood pressure should be reduced by 20 - 25% within 2 hours.
Explanation:A hypertensive emergency is defined as severe hypertension (blood pressure ≥ 180/110 mmHg) with acute damage to the target organs. Prompt treatment with intravenous antihypertensive therapy is generally required; over the first few minutes or within 2 hours, blood pressure should be reduced by 20 – 25%. Severe hypertension without acute target organ damage is defined as hypertensive urgency.; blood pressure should be reduced gradually over 24 – 48 hours with oral antihypertensive therapy. If blood pressure is reduced too quickly in the management of hypertensive crises, there is a risk of reduced organ perfusion leading to cerebral infarction, blindness, deterioration in renal function, and myocardial ischaemia.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 24
Incorrect
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Which of the following best characterizes the correct administration of amiodarone for a shockable rhythm in adults on advanced life support:
Your Answer:
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.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 25
Incorrect
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Which of the following statements is correct with regards to heparin-induced thrombocytopaenia (HIT)?
Your Answer:
Correct Answer: HIT typically develops 5-10 days after starting heparin.
Explanation:Heparin-induced thrombocytopenia (HIT) is a prothrombotic disorder caused by antibodies that recognize complexes of platelet factor 4 (PF4) and heparin. HIT is frequently considered in the differential diagnosis of thrombocytopenia occurring in patients on heparin therapy. HIT is a challenging diagnosis because of routine heparin use in hospitalized patients, the common occurrence of thrombocytopenia. The process of heparin dependent IgG antibodies binding to heparin/platelet factor 4 complexes activates platelets and produces a hypercoagulable state. This syndrome typically develops 5-10 days (range 4-15 days) after heparin is commenced. It can occur with unfractionated heparin, low molecular weight heparin, or, rarely, fondaparinux. The diagnosis of HIT requires the combination of a compatible clinical picture and laboratory confirmation of the presence of heparin dependent platelet activating HIT antibodies. Discontinuation of heparin alone or initiation of a vitamin K antagonist alone like warfarin, is not sufficient to stop the development of thrombosis in patients with acute HIT. If there is moderate clinical suspicion for HIT, all sources of heparin must be discontinued and there must be consideration of anticoagulant treatment with a non-heparin drug.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 26
Incorrect
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Which of the following increases the tendency for oedema to occur?
Your Answer:
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.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 27
Incorrect
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What is the primary mode of action of Enoxaparin?
Your Answer:
Correct Answer: Inhibits factor Xa
Explanation:Heparin acts as an anticoagulant by enhancing the inhibition rate of clotting proteases by antithrombin III impairing normal haemostasis and inhibition of factor Xa. Low molecular weight heparins have a small effect on the activated partial thromboplastin time and strongly inhibit factor Xa. Enoxaparin is derived from porcine heparin that undergoes benzylation followed by alkaline depolymerization.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 28
Incorrect
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Regarding cardiac excitation-contraction coupling, which of the following statements is CORRECT:
Your Answer:
Correct Answer: The Treppe effect refers to an increase in contractility secondary to an increase in heart rate.
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). In relaxation, about 80% of Ca2+is rapidly pumped back into the SR (sequestered) by Ca2+ATPase pumps. The Ca2+that entered the cell during the AP is transported out of the cell primarily by the Na+/Ca2+exchanger in the membrane. When more action potentials occur per unit time, more Ca2+enters the cell during the AP plateau, more Ca2+is stored in the SR, more Ca2+is released from the SR and thus more Ca2+is left inside the cell and greater tension is produced during contraction. Increased heart rate increases the force of contraction in a stepwise fashion as intracellular [Ca2+] increases cumulatively over several beats; this is the Treppe effect. Cardiac glycosides such as digoxin have a positive inotropic effect.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 29
Incorrect
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Adenosine is primarily indicated for which of the following:
Your Answer:
Correct Answer: Paroxysmal supraventricular tachycardia
Explanation:Adenosine is usually the treatment of choice for terminating paroxysmal supraventricular tachycardia including those associated with accessory conduction pathways e.g. Wolff-Parkinson-White syndrome.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 30
Incorrect
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At the start of the cardiac cycle, towards the end of diastole, all of the following statements are true EXCEPT for:
Your Answer:
Correct Answer: The semilunar valves are open.
Explanation:At the start of the cardiac cycle, towards the end of diastole, the whole of the heart is relaxed. The atrioventricular (AV) valves are open because the atrial pressure is still slightly greater than the ventricular pressure. The semilunar valves are closed, as the pressure in the pulmonary artery and aorta is greater than the ventricular pressures. The cycle starts when the sinoatrial node (SAN) initiates atrial systole.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
