TheoryEKG Technician Practice Questions
Free EKG Technician practice questions with answers and plain-English explanations. Browse the PDF, video and online mock test.
EKG Technician Questions
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Q1Which structure is normally the primary pacemaker of the heart?
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✓ Correct answer: The sinoatrial (SA) node
The SA node in the right atrium has the fastest intrinsic rate (about 60-100 beats per minute) and therefore sets the normal heart rhythm, called sinus rhythm.
Q2Which chambers of the heart receive blood returning to the heart?
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✓ Correct answer: The atria
The atria are the upper receiving chambers; the right atrium receives deoxygenated blood from the body and the left atrium receives oxygenated blood from the lungs.
Q3The brief delay of the electrical impulse at the AV node primarily allows time for what to occur?
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✓ Correct answer: Ventricular filling as the atria contract
The AV node delays conduction so the atria finish contracting and fill the ventricles before ventricular contraction, optimizing stroke volume.
Q4Which valve separates the left atrium from the left ventricle?
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✓ Correct answer: The mitral (bicuspid) valve
The mitral valve, with two leaflets, lies between the left atrium and left ventricle and prevents backflow during ventricular contraction.
Q5Which side of the heart pumps blood to the lungs?
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✓ Correct answer: The right side
The right ventricle pumps deoxygenated blood through the pulmonic valve into the pulmonary arteries to the lungs for gas exchange.
Q6Depolarization of a cardiac cell is mainly caused by the rapid influx of which ion?
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✓ Correct answer: Sodium
The rapid upstroke of the cardiac action potential in working myocardium results from a fast inward sodium current through voltage-gated sodium channels.
Q7Repolarization of the ventricular myocyte is primarily driven by the movement of which ion?
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✓ Correct answer: Potassium leaving the cell
Repolarization occurs as potassium exits the cell, restoring the negative resting membrane potential after the depolarization and plateau phases.
Q8The plateau phase of the ventricular action potential, which prolongs contraction, is sustained mainly by the inflow of which ion?
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✓ Correct answer: Calcium
Slow inward calcium current balances potassium efflux to create the plateau, prolonging the action potential and supporting myocardial contraction.
Q9After leaving the AV node, the impulse travels next through which structure?
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✓ Correct answer: The bundle of His
From the AV node the impulse passes into the bundle of His, then divides into the right and left bundle branches, and finally reaches the Purkinje fibers.
Q10The terminal fibers that rapidly distribute the impulse throughout the ventricular muscle are called the:
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✓ Correct answer: Purkinje fibers
Purkinje fibers spread the impulse quickly across the ventricular walls so the ventricles contract in a coordinated way.
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