10 free Paramedic practice questions: Dysrhythmia Recognition and Management

The radial count ran over too short an interval to be valid: The pulse was counted for a full minute, which is exactly what an irregular rhythm requires. A shorter count would be unreliable, and that is not what happened here.

The monitor is counting artifact along with the true complexes: Artifact makes a tracing look messy and usually appears as spikes that do not fit the rhythm. An irregularly irregular rhythm with a clean complex count is not an artifact problem.

The patient converted between the two measurements: Conversion would change the rhythm rather than create two different rates for the same rhythm at the same moment.

Second degree atrioventricular block type I: Type I lengthens the PR interval a little more with each beat until one finally fails to conduct. The warning is the whole point of that pattern, and this strip has none.

First degree atrioventricular block: First degree block prolongs the PR interval and still conducts every single P wave. Nothing drops in first degree block.

Third degree atrioventricular block: Third degree block has no relationship at all between the P waves and the QRS complexes, with each marching at its own rate. This strip has a fixed relationship on every conducted beat.

Adenosine 6 mg by rapid push, since the rhythm is regular and stable: Adenosine works on rhythms that depend on the conducting node, which a wide complex tachycardia may not use at all. Giving it here treats a diagnosis that has not been established.

Verapamil, since the young age makes a supraventricular origin likely: Age is not a differential. Young patients have ventricular tachycardia, and a calcium channel blocker given on that assumption can drop the pressure out from under the rhythm.

Synchronized cardioversion, since any wide complex rhythm is unstable: Cardioversion is the answer when the patient is unstable. Alert, warm, dry, and 118 systolic is not unstable, and sedating and shocking a stable patient skips a step a drug can handle.

Albuterol by nebulizer at a high dose: Albuterol does move potassium into the cells, and it takes time to do it. Time is what this rhythm does not have while the QRS keeps widening.

Sodium bicarbonate by intravenous push: Sodium bicarbonate shifts potassium as well, and like the other shifting agents it is an adjunct rather than the opening move once the membrane is already destabilized.

Insulin with dextrose by slow infusion: Insulin with dextrose lowers the serum potassium effectively, and lowering the level is slower than protecting the heart from the level that is already there.

QRS width, PR interval, P waves, regularity, rate: All five components are present, but the sequence is inverted. It opens with the most granular measurement and ends with the one you can see from across the room. There is one setting where width does come first, the crashing tachycardic patient where wide versus narrow drives the treatment path, but that is a treatment shortcut, not the systematic strip analysis this question is asking about.

P waves, rate, QRS width, regularity, PR interval: Again all five components, scrambled. The tell is P waves in the lead position with regularity buried at fourth. Studying P-wave morphology before you know the rate means examining a detail without the context that tells you what the detail means.

Regularity, rate, PR interval, P waves, QRS width: This is the closest wrong answer and the one worth learning from: it swaps only the first two steps and moves the PR interval ahead of the P waves. Both errors matter. Rate is step one, and measuring a PR interval before confirming that P waves exist is measuring from a landmark you have not established yet.

A regular rhythm with a sawtooth baseline pattern: A sawtooth baseline with a regular ventricular response is atrial flutter, one organized reentrant circuit looping the atrium at a fixed rate and conducting in a set ratio like 2:1 or 3:1. Both rhythms are atrial and both can run fast; the split is organized versus chaotic. Flutter has a repeating pattern you can measure, fibrillation has none.

An irregular rhythm with P waves of changing shape before each QRS complex: An irregular rhythm with P waves that change shape from beat to beat describes a wandering atrial pacemaker: the pacemaker site drifts among different atrial foci, so each P wave looks different, but a P wave still precedes each QRS. That is the discriminator: atrial fibrillation has no P waves to find, so the presence of discrete P waves of any shape excludes it.

A narrow, regular rhythm at 180 with no visible P waves: This is the trap worth naming, because no visible P waves matches. A narrow, regular rhythm at 180 is supraventricular tachycardia (SVT), where the P waves are buried in or behind the QRS at that speed. The clinching differentiator is not the P waves at all, it is regularity: SVT is metronome-regular, atrial fibrillation never is.

Vagal maneuvers followed by reassessment before any further intervention: Vagal maneuvers are appropriate for a stable SVT patient, not an unstable one; relying on them here would delay needed intervention.

Adenosine administration only, with no further escalation planned: Adenosine is used for stable SVT; an unstable patient with the same rhythm should go to synchronized cardioversion rather than drug therapy alone.

Supportive care, oxygen, and transport with continuous monitoring only: Supportive management and monitoring alone is appropriate for a stable patient, not one with hypotension and altered mental status.

Aortic dissection: the answer to sudden tearing or ripping pain, often radiating to the back, with a blood pressure or pulse difference between the arms and sometimes a new murmur or a focal neurologic deficit. It has to be considered in any chest pain, but nothing here supports it, since the pain is sharp and clearly positional, it followed a viral illness rather than starting abruptly at maximum intensity, and the vital signs are unremarkable. The clinching separator is the positional quality, because dissection pain does not care what position the patient sits in, while pain that eases leaning forward points straight at the pericardium.

Anterior myocardial infarction: the right read when ST elevation is confined to the anterior precordial leads with reciprocal depression in the inferior leads, in a patient with pressure-like discomfort and a sympathetic response. Two findings rule it out here: the elevation crosses nearly every lead group, which no single coronary artery supplies, and there are no reciprocal depressions at all. This is the classic pair to separate, and the single clinching discriminator is reciprocal change, because regional injury produces it and diffuse inflammation cannot, since there is no uninvolved opposite wall.

Pulmonary embolism: produces sudden pleuritic pain with difficulty breathing, tachycardia, and hypoxemia, usually with a risk factor such as recent immobility, surgery, or malignancy, and pleuritic pain is a genuine overlap with pericarditis. This patient's lungs are clear, the neck veins are flat, the respiratory rate is 18, and the pain is positional rather than simply pleuritic. The key wins on the tracing, because diffuse elevation with depression of the segment between the P wave and the ventricular complex is an atrial-injury pattern an embolus does not create.

Amiodarone 150 mg over 10 minutes: Amiodarone belongs to a stable wide-complex tachycardia, or to ventricular tachycardia with a pulse, where the origin is below the atrioventricular node and a nodal blocking drug would accomplish nothing. The complexes here are narrow, which places the origin above the ventricles and puts this patient on a different branch of the algorithm entirely. The key also does something amiodarone cannot: it both treats and diagnoses, because interrupting the node either breaks the circuit or unmasks the underlying atrial rhythm within seconds, while amiodarone is a ten-minute infusion aimed at a ventricular origin this patient does not have.

Adenosine 12 mg rapid intravenous push: Twelve milligrams is the correct adenosine dose, just not the first one. It is what follows when a properly pushed 6 mg dose has failed to convert the rhythm, and skipping ahead to it delivers more drug than needed along with a larger burst of the unpleasant effects patients report, chest pressure, flushing, a brief sense of doom, and a several-second pause. This choice and the key are the same drug and the same mechanism, and the key wins purely on sequence, which is the point the item is testing.

Synchronized cardioversion at 100 J: Synchronized cardioversion is the answer for an unstable narrow-complex tachycardia, meaning hypotension, altered mental status, ischemic chest discomfort, or acute heart failure that is being caused by the rate. This patient is alert, with warm dry skin, clear lungs, and a blood pressure of 118/74, and mild lightheadedness at a rate of 186 does not meet the definition of instability. The stability question is what sorts this algorithm into its two branches, and the stable branch earns a trial of a drug before electricity and the sedation that goes with it.

Administer epinephrine 0.01 mg/kg intravenously: Epinephrine is genuinely indicated in this patient, just not yet, because it is the drug for pediatric bradycardia that persists despite oxygenation, ventilation, and compressions. This is a sequence error rather than a drug error: a drug pushed into a circulation that is not being circulated does not reach the coronary arteries in any useful concentration. The key restores the flow that carries the drug where it needs to go, which is why compressions come first and epinephrine comes next.

Administer atropine 0.02 mg/kg intravenously: Atropine is the answer to bradycardia caused by increased vagal tone or by a primary atrioventricular block, and in pediatrics the classic uses are the bradycardia that appears during an intubation attempt or deep suctioning, and organophosphate poisoning. This infant's bradycardia is hypoxic and metabolic, developing over three days of vomiting and poor feeding, so there is no vagal brake to release. Blocking vagal tone does nothing for a myocardium that is starved, while the key generates the circulation that starved myocardium needs.

Initiate transcutaneous pacing at 100: Transcutaneous pacing is the right tool when the conduction system is the problem and the muscle is healthy, meaning complete heart block or sinus node dysfunction. Pediatric bradycardia is almost never a conduction problem, it is the endpoint of hypoxia, and pacing a hypoxic acidotic myocardium commonly produces electrical capture with no mechanical output at all, which looks like success on the monitor and does nothing for the patient. The key perfuses a heart that cannot perfuse itself, which is what this infant's mottled skin and 5-second capillary refill are asking for.