EKG Rhythms Practice
This is a free 15-question sampler on cardiac rhythms and what to do about each one. It covers the lethal arrest rhythms, shockable versus non-shockable, synchronized cardioversion versus defibrillation, the AV blocks and atrial fibrillation, mixing multiple choice, select all that apply and fill in the blank. Answer all 15 questions, then check your score and read the explanation for every question.
A monitored patient suddenly shows a chaotic waveform with no identifiable QRS complexes, and is unresponsive with no pulse. What should the nurse do first?
All Nursing & Health quizzes
- Practice test · 15 questions
EKG Practice Strips
- Practice test · 15 questions
EKG Practice Test
- Practice test · 15 questions
NCLEX Practice Questions
Now make your own
Upload your prep book, slides or notes, or just tell Bo what you want to learn. You do not need a document to start.
All 15 questions at a glance
Prefer to read before you play? Every question in the sampler is listed below. Answers and explanations stay collapsed until you open them.
1. A monitored patient suddenly shows a chaotic waveform with no identifiable QRS complexes, and is unresponsive with no pulse. What should the nurse do first?
- A. Give amiodarone through the existing IV
- B. Start CPR and call for the defibrillator
- C. Deliver a synchronized cardioversion
- D. Document the rhythm change and wait for the provider
Show answer and explanation
Answer: B. Start CPR and call for the defibrillator
Ventricular fibrillation is a lethal rhythm and the only two things that reverse it are early CPR and early defibrillation, so compressions start at once and continue until the pads are on and the machine is charged. If a defibrillator is already at the bedside in a witnessed arrest, the shock goes first, and drugs come later in the algorithm.
2. Complete the sentence.
In cardiac arrest, the two rhythms that a shock can treat are _____.
Options for blank 1: asystole and pulseless electrical activity, ventricular fibrillation and pulseless ventricular tachycardia, atrial fibrillation and atrial flutter, sinus bradycardia and first degree AV block
Show answer and explanation
Answer: ventricular fibrillation and pulseless ventricular tachycardia
Defibrillation works by stopping all electrical activity at once so the heart's own pacemaker can restart an organized rhythm, which only helps when the problem is disorganized ventricular activity. Asystole and pulseless electrical activity are non-shockable and get CPR, epinephrine and a search for the cause instead.
3. The monitor shows a flat line and the patient has no pulse. Which action is correct?
- A. Defibrillate as soon as the machine is charged
- B. Perform synchronized cardioversion
- C. Confirm the flat line in a second lead, continue CPR and give epinephrine
- D. Give adenosine by rapid IV push
Show answer and explanation
Answer: C. Confirm the flat line in a second lead, continue CPR and give epinephrine
Asystole is not shockable, so the work is high quality CPR, epinephrine and a hunt for a reversible cause. Checking another lead matters because a loose electrode, a disconnected cable or very fine ventricular fibrillation can all look like a flat line in one view.
4. During a code, compressions are paused for a rhythm check and the monitor shows a narrow, organized rhythm at about 70. What should the team do next?
- A. Deliver an unsynchronized shock
- B. Check for a pulse, and resume compressions at once if there is none
- C. Stop the code, since an organized rhythm means circulation is back
- D. Give adenosine to slow the rhythm down
Show answer and explanation
Answer: B. Check for a pulse, and resume compressions at once if there is none
An organized rhythm on the screen only proves that the conduction system is firing, so return of circulation is confirmed by a pulse and nothing else. No pulse with an organized rhythm is pulseless electrical activity, which is non-shockable and gets immediate compressions, epinephrine and a search for the cause such as blood loss or a tension pneumothorax.
5. Which of the following are reversible causes to look for in pulseless electrical activity?
Select all that apply.
- A. Hypovolemia
- B. Hypoxia
- C. Cardiac tamponade
- D. Hypertension
- E. Hyperglycemia
Show answer and explanation
Answer: A. Hypovolemia, B. Hypoxia, C. Cardiac tamponade
Pulseless electrical activity is treated by finding and fixing the cause, which resuscitation courses group as the Hs and Ts: hypovolemia, hypoxia, acidosis, low or high potassium, hypothermia, tension pneumothorax, tamponade, toxins and thrombosis in the lungs or the coronary arteries. High blood pressure and high glucose are not on that list and neither one takes away a pulse on its own.
6. Which patient needs synchronized cardioversion rather than defibrillation?
- A. A patient in ventricular fibrillation
- B. A patient in pulseless ventricular tachycardia
- C. A patient in atrial fibrillation at 180 who is hypotensive and confused
- D. A patient in asystole
Show answer and explanation
Answer: C. A patient in atrial fibrillation at 180 who is hypotensive and confused
Synchronized cardioversion times the shock to the R wave and is used for unstable tachycardias that still have a pulse, such as fast atrial fibrillation, atrial flutter and monomorphic ventricular tachycardia with a pulse. Defibrillation is unsynchronized and is used when there is no pulse, and the energy setting for either one comes from your device and your unit protocol.
7. Which findings mark a tachycardia as unstable and push the team toward immediate synchronized cardioversion?
Select all that apply.
- A. Hypotension with cool, clammy skin
- B. New confusion or a falling level of consciousness
- C. Ischemic chest pain or acute pulmonary edema
- D. A heart rate of 104 with a normal blood pressure
- E. Mild palpitations with no other symptoms
Show answer and explanation
Answer: A. Hypotension with cool, clammy skin, B. New confusion or a falling level of consciousness, C. Ischemic chest pain or acute pulmonary edema
Unstable means the fast rate is already causing poor perfusion, and the classic signs are hypotension or shock, altered mental status, ischemic chest discomfort and acute heart failure. A stable patient gets time for vagal maneuvers, drugs and a 12 lead first, so the number on the monitor never decides the plan by itself.
8. A patient in sinus bradycardia at 38 is dizzy, pale and hypotensive. Which drug is given first?
- A. Adenosine
- B. Atropine
- C. Amiodarone
- D. Magnesium sulfate
Show answer and explanation
Answer: B. Atropine
Atropine blocks the vagal slowing of the sinus and AV nodes, so it is the first drug for symptomatic bradycardia while pacing is being set up. If atropine does not work, the next steps are transcutaneous pacing or an infusion such as dopamine or epinephrine, with the exact doses taken from your current protocol.
9. A strip shows P waves and QRS complexes marching along at their own separate rates. The ventricular rate is 32 and the blood pressure is 78/40. What should the nurse prepare for?
- A. Defibrillation
- B. Transcutaneous pacing
- C. A rapid adenosine push
- D. Vagal maneuvers
Show answer and explanation
Answer: B. Transcutaneous pacing
P waves and QRS complexes with no relationship to each other describe third degree, or complete, heart block, where the atria and the ventricles beat independently. A slow escape rhythm with poor perfusion needs pacing, transcutaneous first and then transvenous or permanent, since atropine often fails when the block sits below the AV node.
10. On a rhythm strip the PR interval gets a little longer with each beat until one QRS is dropped, then the pattern starts over. Which rhythm is this?
- A. First degree AV block
- B. Second degree AV block type I, also called Wenckebach
- C. Second degree AV block type II
- D. Third degree AV block
Show answer and explanation
Answer: B. Second degree AV block type I, also called Wenckebach
A PR interval that stretches until a beat drops is the signature of Wenckebach, which usually sits in the AV node and is often tolerated well enough to just monitor. Type II drops beats with no PR lengthening at all and is far more dangerous, because it can slip into complete block and usually needs pacing.
11. A patient with a regular narrow QRS tachycardia at 190 is alert and comfortable with a blood pressure of 118/70. What is usually tried first?
- A. A vagal maneuver such as bearing down
- B. Immediate defibrillation
- C. Immediate synchronized cardioversion
- D. An atropine push
Show answer and explanation
Answer: A. A vagal maneuver such as bearing down
In stable supraventricular tachycardia the vagal maneuver comes first because it costs nothing and sometimes breaks the rhythm, and adenosine by rapid push with an immediate flush is the usual next step. Cardioversion is held back for patients who turn unstable, and atropine would only drive the rate higher.
12. Complete the sentence.
For torsades de pointes in a patient who still has a pulse, the drug given is intravenous _____.
Options for blank 1: magnesium sulfate, adenosine, atropine, furosemide
Show answer and explanation
Answer: magnesium sulfate
Torsades de pointes is a polymorphic ventricular tachycardia that twists around the baseline and grows out of a long QT, often from low magnesium or low potassium or from QT prolonging drugs. Magnesium is the treatment while there is a pulse, and if the pulse is lost the rhythm is defibrillated like any other pulseless ventricular rhythm.
13. Which of the following are standard parts of managing ongoing atrial fibrillation?
Select all that apply.
- A. Controlling the ventricular rate, often with a beta blocker or diltiazem
- B. Assessing stroke risk and starting anticoagulation when it is indicated
- C. Considering rhythm control with an antiarrhythmic or a planned cardioversion
- D. Scheduling a routine defibrillation every few months
- E. Holding all treatment for as long as the patient feels well
Show answer and explanation
Answer: A. Controlling the ventricular rate, often with a beta blocker or diltiazem, B. Assessing stroke risk and starting anticoagulation when it is indicated, C. Considering rhythm control with an antiarrhythmic or a planned cardioversion
Atrial fibrillation care stands on three legs: rate control, rhythm control and anticoagulation chosen from a stroke risk score rather than from how the patient feels. The fibrillating atria let blood pool and clot, which is why someone with no symptoms can still have a stroke, and defibrillation is never scheduled maintenance.
14. Complete the sentence.
When atrial fibrillation has lasted longer than _____ hours, or the duration is unknown, guidelines call for several weeks of anticoagulation, or a transesophageal echo to rule out a clot, before an elective cardioversion.
Options for blank 1: 12, 24, 48, 72
Show answer and explanation
Answer: 48
Clot can form in the fibrillating left atrium within about two days, and converting to sinus rhythm may push it loose and cause a stroke. Anticoagulation also continues for at least four weeks after a successful cardioversion, and longer when the patient's stroke risk score calls for it.
15. A post-op patient is in sinus tachycardia at 128, with a temperature of 102 F and pain rated 8 out of 10. What should the nurse do?
- A. Treat the causes, including the pain, the fever and any fluid loss
- B. Give adenosine to slow the rate
- C. Prepare for synchronized cardioversion
- D. Hold all fluids until the rate comes down
Show answer and explanation
Answer: A. Treat the causes, including the pain, the fever and any fluid loss
Sinus tachycardia is usually the heart responding correctly to something else, such as pain, fever, anxiety, bleeding, dehydration or low oxygen. The rate settles once the cause is treated, and forcing it down first can strip a patient of the compensation they are relying on.
What rhythm questions actually ask you to do
Rhythm recognition gets tested in two different places, and they ask for different things. A nursing dysrhythmia exam usually wants you to name the rhythm from a strip and then say what it means for the patient. A certification course such as ACLS cares much less about the name and much more about the branch you take next: is there a pulse, is the patient stable, is this rhythm shockable, what goes in first.
The questions in this sampler sit on the second side. They start from a rhythm you have already identified and ask what the nurse does about it. That split matters when you study, because you can be excellent at naming rhythms and still freeze at the bedside, and you can also know the algorithm cold and miss the rhythm that triggers it.
Be careful with the details that are not universal. Drug doses, joule settings, whether your unit has standing orders and how far a nurse can go before a provider arrives are all set by your facility protocol and by the current resuscitation guidelines, which are revised every few years. The parts that stay put are the ones tested here: which rhythms are lethal, which arrest rhythms a shock can fix, when a shock is synchronized and when it is not, and what causes each rhythm in the first place. Learn those, then read the exact numbers from your own protocol and your course's current handbook.
How to use this sampler
Take all 15 questions in one sitting without notes, around 60 to 90 seconds each. Then read the explanation for every question, including the ones you got right, because on a rhythm question the right answer for the wrong reason falls apart as soon as the scenario changes slightly.
A wrong answer points at a topic, not just a fact. If you missed the asystole question and the pulseless electrical activity question, review the whole non-shockable side of the arrest algorithm rather than memorizing two answers. If the AV block questions went badly, go back and sort first degree, both types of second degree and third degree by what happens to the PR interval and to the dropped beats, since that is the only thing that separates them on a strip.
Pair this with strip practice. Recognition and response are separate skills, so drill actual strips somewhere else: count the rate, check whether the rhythm is regular, look for a P wave in front of every QRS, measure the PR and the QRS, then say the rhythm out loud before you look at the answer. The two sibling quizzes linked below cover that side.
How StudyPDF builds full practice tests from your own materials
Fifteen questions can show you where you are shaky. They cannot get you ready on their own, and a generic bank has no idea which rhythms your instructor drills or which protocol your unit follows.
StudyPDF works from your material instead. You upload your cardiac lecture notes, your rhythm packet, your textbook chapter or the handbook from your course, and Bo, the study agent, builds full-length practice tests from those exact pages. Every question is grounded in your material and every explanation cites where the answer came from, so you can check the source when something looks off. You can regenerate fresh tests as often as you want, narrow one to a single area like AV blocks or arrest rhythms, and track which concepts you keep missing.
You do not need a file to start. If you have nothing to upload, name a topic instead, such as ventricular rhythms or atrial fibrillation management, and Bo builds the practice test from that. Starting is free.
Written by the StudyPDF team. Last updated 2026-08-19.