One-Pager

NCLEX EKG Rhythms: What Nursing Students Need to Know

The rhythm strips NCLEX expects you to recognize, how to remember heart blocks, and the nursing action for each

Reviewed by Alex G, BSN, RN, CEN, CCRN, CMC, NREMT-P · Checked against current sources October 2026

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NCLEX EKG rhythms: read the client, then the strip

The NCLEX EKG rhythms to know are the sinus rhythms, atrial fibrillation and flutter, SVT, the four heart blocks, PVCs, ventricular tachycardia, ventricular fibrillation and asystole. The exam rarely asks you to measure a strip; it asks what you do next, and the answer starts with the client: pulse, blood pressure, breathing and symptoms.

Rate: about 60–100/min is normal.
Rhythm: regular or irregular.
P waves: one before every QRS?
PR interval: normal 0.12–0.20 s (3–5 small boxes) and the same each beat?
QRS: narrow (normally 0.10 s or less, 2½ small boxes) or wide (0.12 s or more)?

Sinus rhythms

Normal sinus rhythm: 60–100/min, regular, a P wave before every narrow QRS. No action; document.

Sinus bradycardia: under 60/min (here about 42). Normal in athletes and in sleep. Symptoms (dizziness, low BP, confusion): stay with the client, report; atropine is the first drug, pacing if it fails.

Sinus tachycardia: over 100/min (here about 128). Look for the cause: pain, fever, anxiety, bleeding, dehydration, low oxygen. Treat the cause, not the rate.

Atrial rhythms and SVT

Atrial fibrillation: irregularly irregular, no clear P waves, wavy baseline. Check the apical pulse and BP; new or fast AF: report. Stroke risk: expect anticoagulation, teach bleeding precautions.

Atrial flutter: sawtooth flutter waves between regular QRS complexes (here 4:1). Managed like AF: rate control and anticoagulation.

SVT: regular, narrow and very fast (here about 180), P waves hidden. Stable: vagal maneuver (bear down), then adenosine as a rapid IV push with a flush; warn of a brief pause. Unstable: synchronized cardioversion.

Heart blocks and how to remember them

First-degree: every P conducts, PR long (over 0.20 s) and constant. Usually no symptoms: monitor and review drugs that slow the AV node.

Second-degree type I (Wenckebach): PR gets longer, longer, then a P drops; the cycle repeats. Usually benign: monitor; report symptoms.

Second-degree type II: PR stays the same, then a P suddenly does not conduct. Dangerous: can progress to complete block. Report now; pacing pads ready.

Third-degree (complete): P waves and QRS complexes ignore each other; slow escape rhythm (here about 36). Assess perfusion, call for help, prepare to pace; atropine often does not work.

Ventricular and lethal rhythms

PVCs (here every other beat): early, wide, bizarre beats. Check potassium, magnesium and oxygen; report if new, frequent or in runs.

Ventricular tachycardia: wide, regular, fast (here about 165). Check the pulse first. No pulse: CPR and defibrillate. Pulse but unstable: synchronized cardioversion. Stable: report, 12-lead, antiarrhythmic per order.

Ventricular fibrillation: chaotic, no QRS, no pulse. Call a code, start CPR, defibrillate as soon as possible; epinephrine 1 mg every 3–5 min after the second shock.

Asystole: flat line, no pulse. Confirm in a second lead, call a code, CPR and epinephrine as soon as possible. Never shock. PEA (a rhythm on the screen, no pulse) is treated the same way.

Torsades de pointes: polymorphic VT that twists around the baseline, often with a long QT. Pulseless: defibrillate. With a pulse: IV magnesium per order; stop QT-prolonging drugs.

Which rhythm first?

Priority	Rhythm	Why
1	VF, pulseless VT, asystole, PEA	No cardiac output: CPR now
2	VT with a pulse, third-degree or type II block, symptomatic brady or SVT	Output at risk; can deteriorate
3	New AF with fast rate, frequent PVCs	Report; treat the cause
4	Sinus tachy or brady without symptoms, first-degree, type I	Monitor; find the cause

In depth

The one-page summary above is what the PDF prints. These sections go further.

What the RN does and what the provider orders

Scope varies by facility and state; follow your policy and training.
Situation	RN actions	Usually ordered or done by the provider or code team
Pulseless rhythm	Call a code, start CPR, attach AED or defibrillator per facility training, give epinephrine per protocol	Advanced airway, antiarrhythmics (amiodarone 300 mg, then 150 mg)
Unstable with a pulse (low BP, confusion, chest pain, shock)	Stay, oxygen if low, IV access, pads on, rapid response	Synchronized cardioversion, pacing, drugs
Symptomatic bradycardia	Assess, pads on, atropine per order	Pacing if atropine fails or for type II or complete block
Stable SVT	Coach a vagal maneuver; give adenosine fast with a flush, on a monitor	Adenosine order (6 mg, then 12 mg)
New AF	Apical pulse, BP, symptoms, 12-lead per order; stroke signs	Rate control, anticoagulation, cardioversion plan

Why each rhythm matters

AF: the atria quiver at about 300–500/min, so blood pools and can clot; AF is linked to about 2.4 times the stroke risk. That is why clients with AF are often on anticoagulants, and why sudden weakness or speech change in AF is a stroke until proven otherwise.
Type II and third-degree block: the block lies below the AV node, so atropine (which acts on the node) often does not help, and the rhythm can stop conducting at any time. A pacemaker is the treatment.
Type I (Wenckebach): usually at the AV node, often from drugs or high vagal tone; it rarely needs treatment.
VT and VF: the ventricles fire on their own; VF and pulseless VT are the shockable arrest rhythms. Asystole and PEA are not shockable: the fix is CPR, epinephrine and finding the cause.
SVT: adenosine briefly blocks the AV node; a few seconds of pause or asystole on the monitor is expected.

Telemetry tips for students

Confirm any alarm at the bedside. Loose leads, shivering and tooth brushing can look like VT or VF.
Before calling about a rhythm change, gather the client's symptoms, vital signs, recent potassium and magnesium, and drugs that affect rate (beta-blockers, calcium channel blockers, digoxin).
Report with SBAR: what the rhythm was, what it is now, how the client looks, and what you need.
Print or save a strip for the chart when the rhythm changes.

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Sources

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da Silva RMFL, de Souza Maciel A. Conduction Disorders: The Value of Surface ECG. Curr Cardiol Rev. 2021;17(2):173–181. Link
Joglar JA, Chung MK, Armbruster AL, et al. 2023 ACC/AHA/ACCP/HRS Guideline for the Diagnosis and Management of Atrial Fibrillation. Circulation. 2024;149(1):e1–e156. Link