Arrhythmias Quiz Part (1)
Questions and Answers
- 1.
When circulated blood returns to the heart via venous circulation, blood enters the right atrium. Right atrial contraction and changes in right ventricular pressure result in delivery of blood to the right ventricle through the tricuspid valve. Right ventricular contraction pumps blood through the pulmonic valve through the pulmonary arteries to the lungs, where blood becomes oxygenated. The blood then flows through the pulmonary veins into the left atrium. Left atrial contraction and changes in left ventricle (LV) pressure result in delivery of blood through the mitral valve into the LV. Contraction of the LV results in pumping of blood through the aortic valve and to the tissues of the body. Mechanical activity of the heart (contraction of the atria and ventricles) occurs as a result of the electrical activity of the heart.
- 2.
Reentry is often initiated as a result of an abnormal premature electrical impulse (abnormal automaticity); therefore, in these situations, the mechanism of the arrhythmia is both abnormal impulse formation (automaticity) and abnormal impulse conduction (reentry).
- 3.
The prevalence of sick sinus syndrome is approximately 1 in 600 individuals older than 65 years
- 4.
In patients with sinus bradycardia due to underlying correctable disorders (such as electrolyte abnormalities or hypothyroidism), management consists of correcting those disorders
- 5.
Nonpharmacologic Therapy : Long-term management of patients with sick sinus syndrome requires implantation of a permanent pacemaker
- 6.
Remember to 1- Monitor the patient’s heart rate and alleviation of symptoms. 2- Monitor for adverse effects of medications such as atropine (dry mouth, mydriasis, urinary retention, and tachycardia).
- 7.
The pacemaker of the heart is not the SA node
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
The pacemaker of the heart is the SA node, also known as the sinoatrial node. This small group of cells located in the right atrium of the heart initiates electrical impulses that regulate the heart's rhythm and rate. These impulses then travel through the atria and ventricles, causing them to contract and pump blood. Therefore, the correct answer is False.Rate this question:
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- 8.
The SA node has the greatest degree of automaticity
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The SA node, also known as the sinoatrial node, is located in the right atrium of the heart and is responsible for initiating the electrical impulses that regulate the heart rhythm. It has the highest degree of automaticity among all the cardiac cells, meaning it has the ability to generate electrical impulses spontaneously without any external stimulation. This automaticity allows the SA node to set the pace for the rest of the heart, making it the natural pacemaker of the heart. Therefore, the statement "The SA node has the greatest degree of automaticity" is true.Rate this question:
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- 9.
Ventricular myocyte resting membrane potential is usually –70 to –90 mV
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The resting membrane potential of ventricular myocytes is typically between -70 to -90 mV. This means that the inside of the cell is more negatively charged compared to the outside. This electrical gradient is important for the normal functioning of the heart, as it allows for the generation and propagation of action potentials, which are essential for cardiac contraction and rhythm.Rate this question:
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- 10.
During each action potential cycle, the potential of the membrane rapidly increases to a threshold potential due to a rapid influx of sodium into the cell
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Slow increase - Slow influxRate this question:
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- 11.
When the membrane potential reaches this threshold, the fast sodium channels open, allowing sodium ions to enter the cell rapidly
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
When the membrane potential reaches the threshold, it triggers the opening of fast sodium channels. This allows sodium ions to flow into the cell rapidly. This influx of positive ions depolarizes the cell and generates an action potential, which is a rapid change in the membrane potential. Therefore, the statement is true.Rate this question:
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- 12.
This rapid influx of positive ions creates a vertical upstroke of the action potential. This previous is considered as phase 0, which represents ventricular depolarization. At this point, the fast sodium channels become inactivated.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
During an action potential, the rapid influx of positive ions, particularly sodium ions, causes the depolarization of the ventricles. This depolarization is referred to as phase 0. As the positive ions enter the cell, the fast sodium channels responsible for their entry become inactivated. Therefore, the statement that the fast sodium channels become inactivated during phase 0 is true.Rate this question:
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- 13.
Ventricular depolarization begins, consisting of phases 1 through 3 of the action potential.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
repolarization not depolarizationRate this question:
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- 14.
Phase 1 repolarization occurs primarily as a result of an influx of potassium ions.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
efflux not influxRate this question:
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- 15.
During phase 2, potassium ions continue to exit the cell, but the membrane potential is balanced by an influx of calcium and sodium ions, transported through slow calcium and slow sodium channels, resulting in a plateau.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
During phase 2 of the cardiac action potential, the membrane potential is balanced by the exit of potassium ions from the cell. However, this exit is counteracted by the influx of calcium and sodium ions through slow calcium and slow sodium channels. This balanced movement of ions results in a plateau phase, which is a characteristic feature of phase 2. Therefore, the statement is true.Rate this question:
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- 16.
During phase 3, the efflux of potassium ions greatly exceeds calcium and sodium influx, resulting in the major component of ventricular repolarization.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
During phase 3 of the cardiac action potential, the efflux (outward movement) of potassium ions is much higher than the influx (inward movement) of calcium and sodium ions. This leads to the repolarization of the ventricles, which is the process of restoring the electrical potential of the heart muscle cells back to their resting state after contraction. Therefore, the statement that the efflux of potassium ions greatly exceeds calcium and sodium influx during phase 3, resulting in the major component of ventricular repolarization, is true.Rate this question:
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- 17.
During phase 4, Calcium ions gradually enter the cell, increasing the threshold again to –60 to –80 mV and initiating another action potential.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
sodium ions not calciumRate this question:
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- 18.
Cardiac arrhythmias are caused by
- A.
Abnormal impulse initiation
- B.
Abnormal impulse conduction
- C.
Both answers are correct
- D.
All of the above answers are wrong
Correct Answer
C. Both answers are correctExplanation
Cardiac arrhythmias can be caused by abnormal impulse initiation, meaning that the electrical signals that regulate the heartbeat are not generated properly. They can also be caused by abnormal impulse conduction, where the electrical signals are not transmitted correctly through the heart. Therefore, both of these factors can contribute to the development of cardiac arrhythmias.Rate this question:
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- 19.
Abnormal initiation of electrical impulses occurs as a result of abnormal automaticity
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Abnormal initiation of electrical impulses refers to the generation of electrical signals in the heart at irregular times or locations. This can lead to irregular heart rhythms or arrhythmias. Abnormal automaticity refers to the ability of certain cells in the heart to spontaneously generate electrical impulses, which can disrupt the normal electrical conduction system. Therefore, it is true that abnormal automaticity can result in abnormal initiation of electrical impulses.Rate this question:
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- 20.
Abnormal atrial automaticity will not result premature atrial contractions, atrial tachycardia or atrial fibrillation
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Abnormal atrial automaticity can result in premature atrial contractions, atrial tachycardia, or atrial fibrillation. This is because abnormal automaticity refers to the generation of electrical impulses by the atrial tissue outside of the normal pacemaker cells. These abnormal impulses can disrupt the normal electrical activity of the atria, leading to irregular or rapid heart rhythms such as premature contractions, tachycardia, or fibrillation. Therefore, the statement that abnormal atrial automaticity will not result in these conditions is false.Rate this question:
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- 21.
The mechanism of abnormal impulse conduction is traditionally referred to as :
- A.
Dog
- B.
Cat
- C.
Monkey
- D.
Reentry
Correct Answer
D. Reentry -
- 22.
These three conditions are (1) at least two pathways for the impulse to travel (2) a “unidirectional block” in one of the conduction pathways (3) slowing of the velocity of impulse conduction down the other conduction pathway.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The explanation for the given correct answer is that for reentry to occur, there must be at least two pathways for the impulse to travel. This allows the impulse to continue circulating in a circuit, leading to a sustained abnormal rhythm. Additionally, there must be a "unidirectional block" in one of the conduction pathways, meaning that the impulse can only travel in one direction in that pathway. Finally, the velocity of impulse conduction must be slowed down in the other conduction pathway, further promoting the reentry circuit. These three conditions together create the necessary conditions for reentry to occur.Rate this question:
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- 23.
Under normal circumstances, when a premature impulse is initiated, it cannot be conducted in either direction down either pathway because :
- A.
هههههههههههههه
- B.
هههههههههههههه
- C.
هههههههههههههه
- D.
The tissue is in its absolute refractory period from the previous impulse.
Correct Answer
D. The tissue is in its absolute refractory period from the previous impulse.Explanation
When a premature impulse is initiated, the tissue is in its absolute refractory period from the previous impulse. During this period, the tissue is unable to respond to any new stimulus and is temporarily unexcitable. As a result, the premature impulse cannot be conducted in either direction down either pathway. This refractory period allows the tissue to recover and reset its electrical properties before it can be stimulated again.Rate this question:
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- 24.
A premature impulse may be conducted down both pathways if it is only slightly premature and arrives after the tissue is no longer refractory
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
A premature impulse refers to an electrical signal that occurs earlier than expected in the heart. In this case, the explanation states that if the impulse is only slightly premature and arrives after the tissue is no longer refractory, it can be conducted down both pathways. This means that the electrical signal can travel through both normal and abnormal pathways in the heart. Therefore, the statement is true.Rate this question:
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- 25.
Myocardial ischemia does not alter impulse conduction velocity
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Myocardial ischemia refers to a condition where there is a lack of blood flow and oxygen supply to the heart muscle. This can result in various changes in the heart, including a decrease in the conduction velocity of electrical impulses. When the heart muscle is deprived of oxygen, it becomes less efficient in conducting electrical signals, leading to abnormalities in the heart's rhythm and potentially causing arrhythmias. Therefore, the statement that myocardial ischemia does not alter impulse conduction velocity is incorrect.Rate this question:
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- 26.
Class (I) drugs primarily increase ventricular automaticity and speed up conduction velocity.
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Class (I) drugs primarily decrease ventricular automaticity and slow down conduction velocity. These drugs are used to treat abnormal heart rhythms by suppressing the electrical activity in the heart. By reducing the automaticity and conduction velocity, Class (I) drugs help to stabilize the heart's rhythm and prevent arrhythmias. Therefore, the given statement that Class (I) drugs primarily increase ventricular automaticity and speed up conduction velocity is false.Rate this question:
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- 27.
He class I drugs are subdivided into classes IA, IB, and IC
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because class I drugs are indeed subdivided into classes IA, IB, and IC. Class I drugs are a category of drugs that affect the action potential of cardiac cells and are used to treat certain heart conditions. The subdivision into classes IA, IB, and IC is based on their specific effects on cardiac cells and their mechanisms of action. This categorization helps in understanding the different properties and therapeutic uses of these drugs.Rate this question:
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- 28.
The class IC drugs have the greatest potency for slowing ventricular conduction
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Class IC drugs are a type of antiarrhythmic medication that are known to have the greatest potency for slowing ventricular conduction. These drugs work by blocking sodium channels in the heart, which helps to slow down the electrical signals that control the heart's rhythm. By slowing ventricular conduction, these drugs can be effective in treating certain types of abnormal heart rhythms, such as ventricular tachycardia. Therefore, the statement that class IC drugs have the greatest potency for slowing ventricular conduction is true.Rate this question:
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- 29.
Class IA drugs have intermediate potency, and class IB drugs have the lowest potency
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
This statement is true because class IA drugs have intermediate potency, meaning they have a moderate level of effectiveness or strength. On the other hand, class IB drugs have the lowest potency, indicating that they have the least amount of effectiveness or strength compared to other classes of drugs. Therefore, the statement accurately describes the potency levels of class IA and class IB drugs.Rate this question:
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- 30.
Class II drugs are (Alpha) blockers
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
They are (Beta) blockers not (Alpha)Rate this question:
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- 31.
Class III drugs are those that inhibit ventricular repolarization and prolong refractoriness
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Class III drugs are a category of antiarrhythmic medications that work by inhibiting ventricular repolarization and prolonging refractoriness. This means that they delay the time it takes for the heart's ventricles to reset after each heartbeat, which can help to prevent abnormal heart rhythms. Therefore, the statement that class III drugs inhibit ventricular repolarization and prolong refractoriness is true.Rate this question:
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- 32.
Class IV drugs are the calcium channel blockers (CCBs), diltiazem and verapamil
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because class IV drugs, such as diltiazem and verapamil, are indeed calcium channel blockers (CCBs). These medications work by blocking the calcium channels in the heart and blood vessels, leading to relaxation of the smooth muscles and dilation of the blood vessels. This helps to lower blood pressure and reduce the workload on the heart. Diltiazem and verapamil are commonly used to treat conditions such as high blood pressure, angina, and certain heart rhythm disorders.Rate this question:
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- 33.
CARDIAC ARRHYTHMIAS Cardiac arrhythmias are classified into two broad categories: supraventricular (those occurring above the ventricles) and ventricular (those occurring in the ventricles).
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
The statement is true because cardiac arrhythmias are indeed classified into two broad categories: supraventricular and ventricular. Supraventricular arrhythmias occur above the ventricles, which include the atria and the atrioventricular node. Ventricular arrhythmias, on the other hand, occur in the ventricles of the heart. This classification helps in understanding the location and origin of different types of arrhythmias, which in turn helps in determining the appropriate treatment strategies.Rate this question:
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- 34.
Lidocaine & Mexiletin are classified into calss
- A.
Class II
- B.
Class II
- C.
Class IB
- D.
Class IA
Correct Answer
C. Class IBExplanation
Lidocaine and Mexiletin are classified as Class IB antiarrhythmic drugs. Class IB drugs primarily work by blocking sodium channels in the heart, which helps to decrease the excitability and conduction of electrical impulses. This class of drugs is particularly effective in treating ventricular arrhythmias, such as ventricular tachycardia and ventricular fibrillation. They have a fast onset of action and a short duration of effect. Class IB drugs have a moderate effect on the duration of the action potential and can help to stabilize the heart's electrical activity.Rate this question:
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- 35.
Amiodarone is a drug that is classified as :
- A.
Class IA
- B.
Class IC
- C.
Class IV
- D.
Class III
Correct Answer
D. Class IIIExplanation
Amiodarone is classified as Class III antiarrhythmic drug. Class III drugs primarily work by blocking potassium channels, which prolongs the action potential duration and refractory period of cardiac cells. This helps to stabilize the rhythm of the heart and prevent abnormal heartbeats. Amiodarone is commonly used to treat various types of arrhythmias, including atrial fibrillation and ventricular tachycardia. It has a broad spectrum of action and can affect multiple ion channels, which is why it is classified as Class III.Rate this question:
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- 36.
Sinus bradycardia, originating in the SA node, is defined by a sinus rate less than 50 beats/min
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
60 beatsRate this question:
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- 37.
Acute treatment of the symptomatic and/or hemodynamically unstable patient with sinus bradycardia includes administration of :
- A.
Bat
- B.
Hat
- C.
Cat
- D.
0.5 mg of IV Atropine
Correct Answer
D. 0.5 mg of IV AtropineExplanation
In the acute treatment of a symptomatic and/or hemodynamically unstable patient with sinus bradycardia, administering 0.5 mg of IV Atropine is recommended. Atropine is a medication that helps increase heart rate by blocking the action of the vagus nerve, which slows down the heart. By administering Atropine intravenously, it can quickly act on the body and increase the heart rate, improving symptoms and stabilizing the patient's condition.Rate this question:
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- 38.
Atropine should not be used cautiously in patients with myocardial ischemia or MI
- A.
True
- B.
False
Correct Answer
B. FalseExplanation
Atropine should be used cautiously in patients with myocardial ischemia or MI. This is because atropine can increase heart rate and worsen ischemia or MI by increasing the oxygen demand of the heart. Therefore, it is important to monitor these patients closely and use atropine with caution, if necessary.Rate this question:
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- 39.
In patients with hemodynamically unstable sinus bradycardia unresponsive to atropine, transcutaneous pacing may be initiated.
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
Transcutaneous pacing is a temporary method used to treat hemodynamically unstable sinus bradycardia. It involves the application of electrical impulses to the chest wall to stimulate the heart and increase the heart rate. Atropine is a medication commonly used to treat bradycardia, but if it is ineffective, transcutaneous pacing can be initiated as an alternative treatment option. Therefore, the statement is true.Rate this question:
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- 40.
In patients with hemodynamically unstable or severely symptomatic sinus bradycardia unresponsive to atropine and in whom temporary or transvenous pacing is not available you can use :
- A.
Isoproterenol
- B.
Dopamine
- C.
Epinephrine
- D.
All of the above
Correct Answer
D. All of the aboveExplanation
Patients with hemodynamically unstable or severely symptomatic sinus bradycardia may require immediate intervention when atropine and temporary or transvenous pacing are not available. Isoproterenol, dopamine, and epinephrine are all potential treatment options in such cases. Isoproterenol is a beta-adrenergic agonist that increases heart rate and cardiac output. Dopamine is a catecholamine that can stimulate beta-1 adrenergic receptors and increase heart rate. Epinephrine is also a catecholamine with similar effects on heart rate and cardiac output. Therefore, all three options can be used as alternatives in the management of hemodynamically unstable or severely symptomatic sinus bradycardia.Rate this question:
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- 41.
If the patient is taking any medication(s) that may cause symptomatic sinus bradycardia, they should be discontinued whenever possible. If the patient remains in sinus bradycardia after drug discontinuation and after five half-lives of the drug(s) have elapsed, then the drugs(s) can usually be excluded as the etiology of the arrhythmia
- A.
True
- B.
False
Correct Answer
A. TrueExplanation
If a patient is taking medication that is known to cause symptomatic sinus bradycardia, it is recommended to discontinue the medication whenever possible. This is because the medication could be the cause of the bradycardia. If the patient's heart rate remains slow even after stopping the medication and after a sufficient amount of time has passed (five half-lives of the drug), it is likely that the medication is not the cause of the bradycardia. Therefore, the statement "If the patient remains in sinus bradycardia after drug discontinuation and after five half-lives of the drug(s) have elapsed, then the drugs(s) can usually be excluded as the etiology of the arrhythmia" is true.Rate this question:
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- 42.
Which one do you like?
- A.
Option 1
- B.
Option 2
- C.
Option 3
- D.
Option 4
Correct Answer
A. Option 1 -
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