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Question 1
Incorrect
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A patient who was put on low molecular weight heparin for suspected DVT and was scheduled for an ultrasound after the weekend, arrives at the emergency department with significant hematemesis. Which of the following medications can be used as a heparin reversal agent:
Your Answer: Dried prothrombin complex
Correct Answer: Protamine sulfate
Explanation:The management of bleeding in a patient receiving heparin depends upon the location and severity of bleeding, the underlying thromboembolic risk, and the current aPTT (for heparin) or anti-factor Xa activity (for LMW heparin). As an example, a patient with minor skin bleeding in the setting of a mechanical heart valve (high thromboembolic risk) and a therapeutic aPTT may continue heparin therapy, whereas a patient with major intracerebral bleeding in the setting of venous thromboembolism several months prior who is receiving heparin bridging perioperatively may require immediate heparin discontinuation and reversal with protamine sulphate. If haemorrhage occurs it is usually sufficient to withdraw unfractionated or low molecular weight heparin, but if rapid reversal of the effects of the heparin is required, protamine sulphate is a specific antidote (but only partially reverses the effects of low molecular weight heparins). Clinician judgment and early involvement of the appropriate consulting specialists is advised.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 2
Incorrect
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What is the main mechanism of action of dopamine as an inotropic sympathomimetic:
Your Answer:
Correct Answer: Beta1-receptor agonist
Explanation:Dopamine is a neurotransmitter and a metabolic precursor of the catecholamines. It acts on beta1-receptors in cardiac muscle increasing cardiac contractility, and increases renal perfusion by stimulating dopamine receptors in the renal vasculature. This is of benefit in cardiogenic shock where deterioration of renal function is common.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 3
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 4
Incorrect
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Myocardial contractility is best correlated with the intracellular concentration of:
Your Answer:
Correct Answer: Ca2+
Explanation:Contractility of myocardial cells depends on the intracellular [Ca2+], which is regulated by Ca2+entry across the cell membrane during the plateau of the action potential and by Ca2+uptake into and release from the sarcoplasmic reticulum (SR).
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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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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 6
Incorrect
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When a person changes from a supine to an upright position, which of the followingcompensatory mechanismsoccurs:
Your Answer:
Correct 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.
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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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Adenosine has a half-life of approximately:
Your Answer:
Correct 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.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 8
Incorrect
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Regarding the cardiac cycle, which of the following statements is INCORRECT:
Your Answer:
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.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 9
Incorrect
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Which of the following best describes the correct administration of adrenaline for a shockable rhythm in adult advanced life support?
Your Answer:
Correct Answer: Give 1 mg of adrenaline after the third shock and every 3 - 5 minutes thereafter
Explanation:The correct administration of IV adrenaline 1 mg (10 mL of 1:10,000 solution) is that it should be given after 3 shocks and 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 10
Incorrect
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Digoxin is predominantly used for which of the following:
Your Answer:
Correct Answer: Rate control in persistent and permanent atrial fibrillation
Explanation:Digoxin is most useful for controlling the ventricular response in persistent and permanent atrial fibrillation and atrial flutter. Digoxin is usually only effective for controlling the ventricular rate at rest, and should therefore only be used as monotherapy in predominantly sedentary patients with non-paroxysmal atrial fibrillation. It is now rarely used for rapid control of heart rate, as even with intravenous administration, response may take many hours. Digoxin is reserved for patients with worsening or severe heart failure due to left ventricular systolic dysfunction refractory to combination therapy with first-line agents. Digoxin is contraindicated in supraventricular arrhythmias 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 11
Incorrect
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The mechanism of action of abciximab is by:
Your Answer:
Correct 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.
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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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A 40-year-old man who has a history of asthma arrives at the emergency department complaining of palpitations that have been going on for 5 days. Which of the following beta-blockers is the safest for an asthmatic patient?
Your Answer:
Correct Answer: Atenolol
Explanation:Atenolol is a beta blocker, which is a type of medication that works by preventing certain natural substances in the body, such as epinephrine, from acting on the heart and blood vessels. This effect reduces heart rate, blood pressure, and cardiac strain. Atenolol, bisoprolol fumarate, metoprolol tartrate, nebivolol, and (to a lesser extent) acebutolol have a lower action on beta2 (bronchial) receptors and are thus cardio selective but not cardiac specific. They have a lower effect on airway resistance, although they are not without this adverse effect.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 13
Incorrect
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As a response to low blood pressure, the baroreceptor reflex will facilitate vasoconstriction by activating which receptor?
Your Answer:
Correct 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.
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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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What is the direct mechanism of action of digoxin as a positive inotrope:
Your Answer:
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 15
Incorrect
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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:
Correct 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.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 16
Incorrect
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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:
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.
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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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All of the following are indications for beta-blockers EXCEPT for:
Your Answer:
Correct Answer: Raynaud's disease
Explanation:Beta-blockers are contraindicated in Raynaud’s syndrome. Beta-blockers may be indicated in:HypertensionPheochromocytoma (only with an alpha-blocker)AnginaSecondary prevention after ACSArrhythmias including atrial fibrillationHeart failureThyrotoxicosisAnxietyProphylaxis of migraineEssential tremorGlaucoma
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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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In the treatment of bradyarrhythmias with adverse characteristics or risk of asystole, what is the initial suggested dose of atropine?
Your Answer:
Correct Answer: 500 micrograms
Explanation:Atropine 500 mcg IV bolus should be administered if there are any adverse features or risk of asystole. If the reaction is not adequate, repeat the steps every 3 to 5 minutes up to a maximum dose of 3 mg. In the case of acute myocardial ischemia or myocardial infarction, atropine should be taken with caution since the increased heart rate may aggravate the ischemia or increase the size of the infarct.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 19
Incorrect
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A 72 year old man is brought to ED by ambulance with sudden onset chest pain, palpitations and shortness of breath. His HR is 160 bpm and BP 90/65. ECG demonstrates new-onset fast atrial fibrillation. Which of the following is the first-line treatment option in this case:
Your Answer:
Correct Answer: Synchronised DC cardioversion
Explanation:All patients with adverse features suggesting life-threatening haemodynamic instability (shock, syncope, heart failure, myocardial ischaemia) caused by new onset atrial fibrillation should undergo emergency electrical cardioversion with synchronised DC shock without delaying to achieve anticoagulation.
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This question is part of the following fields:
- Cardiovascular
- Pharmacology
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Question 20
Incorrect
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Which of the following represents ventricular repolarisation on the ECG:
Your Answer:
Correct Answer: T wave
Explanation:P wave = Atrial depolarisationQRS complex = Ventricular depolarisationT wave = Ventricular repolarisation
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 21
Incorrect
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Arterial baroreceptors are located primarily in which of the following:
Your Answer:
Correct Answer: Carotid sinus and aortic arch
Explanation:Arterial baroreceptors are located in the carotid sinus and aortic arch, and detect the mean arterial pressure (MAP). A decrease in MAP (such as in postural hypotension, or haemorrhage) reduces arterial stretch and decreases baroreceptor activity, resulting in decreased firing in afferent nerves travelling via the glossopharyngeal nerve (carotid sinus) and vagus nerve (aortic arch) to the medulla where the activity of the autonomic nervous system is coordinated. Sympathetic nerve activity consequently increases, causing an increase in heart rate and cardiac contractility, peripheral vasoconstriction with an increase in TPR, and venoconstriction with an increase in CVP and thus an increase in cardiac output and blood pressure. Parasympathetic activity (vagal tone) decreases, contributing to the rise in heart rate.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 22
Incorrect
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Which of the following is NOT a benefit of low molecular weight heparin (LMWH) over unfractionated heparin therapy:
Your Answer:
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
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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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What is the main mechanism of action of flecainide:
Your Answer:
Correct Answer: Blocks Na+ channels
Explanation:Flecainide inhibits the transmembrane influx of extracellular Na+ ions via fast channels on cardiac tissues resulting in a decrease in rate of depolarisation of the action potential, prolonging the PR and QRS intervals. At high concentrations, it exerts inhibitory effects on slow Ca2+ channels, accompanied by moderate negative inotropic effect.
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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 describes digoxin:
Your Answer:
Correct 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).
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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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Regarding postural hypotension, which of the following statements is INCORRECT:
Your Answer:
Correct Answer: Postural hypotension usually causes a reflex bradycardia.
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.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 26
Incorrect
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On which of the following is preload primarily dependent?
Your Answer:
Correct Answer: End-diastolic volume
Explanation:Preload refers to the initial stretching of the cardiac myocytes before contraction. It is therefore related to muscle sarcomere length. The sarcomere length cannot be determined in the intact heart, and so, other indices of preload are used, like ventricular end-diastolic volume or pressure. The end-diastolic pressure and volume of the ventricles increase when venous return to the heart is increased, and this stretches the sarcomeres, which increase their preload.
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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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Intracellular [Ca2+] rise in cardiac excitation-contraction coupling is mainly as a result of:
Your Answer:
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.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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Question 28
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 29
Incorrect
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In adult advanced life support, which of the following best describes the correct administration of adrenaline for a non-shockable rhythm:
Your Answer:
Correct Answer: Give 1 mg of adrenaline as soon as intravenous access is achieved and every 3 - 5 minutes thereafter
Explanation:IV adrenaline 1 mg (10 mL of 1:10,000 solution) should be given after 3 shocks and 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 30
Incorrect
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Noradrenaline exhibits its positive inotropic effect by which of the following mechanisms:
Your Answer:
Correct Answer: Binds to beta1-receptors and causes increased Ca2+ entry via L-type channels during the action potential
Explanation:Noradrenaline (the sympathetic neurotransmitter) is a positive inotrope; it binds to β1-adrenoceptors on the membrane and causes increased Ca2+entry via L-type channels during the AP and thus increases Ca2+release from the SR. Noradrenaline also increases Ca2+sequestration into the SR and thus more Ca2+is available for the next contraction. Cardiac glycosides (e.g. digoxin) slow the removal of Ca2+from the cell by inhibiting the membrane Na+pump which generates the Na+gradient required for driving the export of Ca2+; consequently the removal of Ca2+from the myocyte is slowed and more Ca2+is available for the next contraction. Acidosis is negatively inotropic, largely because H+competes for Ca2+binding sites.
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This question is part of the following fields:
- Cardiovascular
- Physiology
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SESSION STATS - PERFORMANCE PER SPECIALTY
