The heart block poem is a four-line mnemonic that nursing students have used for decades to memorize the EKG patterns for all four types of atrioventricular (AV) heart block. Each line maps directly to a specific rhythm: one delayed signal, one progressively failing signal, one intermittently absent signal, and one completely dissociated signal.
If you can recite the poem and match each line to its EKG criteria, causes, and treatment, you have a solid foundation for rhythm strip interpretation in clinical and NCLEX settings alike.
The heart block poem
If the R is far from the P, then you have a First Degree.
If PR gets longer and longer before the QRS drop, it must be a Wenckebach.
If PR stays normal and QRS quits, it must be a Type II Mobitz.
If Ps and Qs beat independently, it must be a Third Degree.
Quick-reference table
| Block type | EKG finding | Memory key |
|---|---|---|
| First degree | PR interval > 200 ms (0.20 sec) | Far away P |
| Second degree Mobitz I (Wenckebach) | PR progressively lengthens, then QRS drops | Longer before drop |
| Second degree Mobitz II | PR constant, QRS drops unpredictably | QRS quits |
| Third degree (complete heart block) | P waves and QRS complexes fully dissociated | Beat independently |
Atrioventricular blocks occur when conduction from the atria to the ventricles through the AV node is delayed, intermittently blocked, or completely blocked. The four types represent a clinical spectrum from benign to immediately life-threatening.
Printable heart block poem
A one-page printable version of the poem and rhythm strip comparison table is available as a free PDF: download the heart block poem PDF. The PDF is sized for a single sheet of paper and works well taped inside a clinical binder or study notebook. It pairs the four poem lines with their matching EKG criteria so you can scan it during telemetry rotation or while drilling for NCLEX.
First degree heart block
Poem line: If the R is far from the P, then you have a First Degree.
What it is
First degree AV block is a conduction delay – not a true block – at the level of the AV node. Every atrial impulse still reaches the ventricles, but it takes longer than normal. Because no beats are dropped, first degree block is hemodynamically well tolerated in most patients.
EKG criteria
- PR interval greater than 200 ms (0.20 sec) on every beat
- Every P wave followed by a QRS complex – no dropped beats
- Normal QRS morphology (unless a coexisting bundle branch block is present)
- Regular rhythm
The normal PR interval is 120–200 ms. In first degree block, the interval is prolonged but consistent from beat to beat.
Causes
- Inferior wall MI or ischemia (the right coronary artery supplies the AV node in most patients)
- Increased vagal tone (athletes, during sleep, vagal maneuvers)
- Beta-blockers, calcium channel blockers, digoxin, amiodarone
- Lyme disease (the most common cardiac manifestation of Lyme disease is AV conduction disturbance)
- Hyperkalemia or hypokalemia
- Age-related fibrosis of the conduction system
Symptoms and nursing management
Most patients with first degree AV block are asymptomatic. It is frequently discovered incidentally on a routine 12-lead EKG. No specific treatment is required for isolated first degree block.
Nursing priorities:
- Identify and treat any reversible cause (medications, electrolyte imbalance, ischemia)
- Monitor for progression to higher-degree block, particularly if the underlying cause is an acute MI
- A markedly prolonged PR interval (> 0.26 sec) with symptomatic bradycardia may warrant atropine
No pacing is required for uncomplicated first degree block.
Second degree heart block: Wenckebach (Mobitz type I)
Poem line: If PR gets longer and longer before the QRS drop, it must be a Wenckebach.
What it is
Wenckebach block – also called Mobitz type I – is an intermittent conduction failure at the AV node. The AV node conducts progressively less efficiently with each beat until one impulse fails entirely and the QRS is dropped. After the pause, the AV node recovers and the cycle repeats.
The result is a characteristic grouped beating pattern on the rhythm strip sometimes described as the “footprint of a limping man”: each cycle’s QRS complexes get slightly closer together until one disappears, then a longer pause, then the pattern repeats.
EKG criteria
- Regular atrial rhythm (consistent P-P interval)
- Irregular ventricular rhythm
- PR interval progressively lengthens with each beat in the cycle
- Dropped QRS complex after the longest PR interval
- Shorter PR interval on the beat immediately following the dropped complex – then the lengthening resumes
- Group beating is the visual hallmark
Causes
- Inferior MI (the most common structural cause – the RCA supplies the AV node)
- Increased vagal tone
- Drug toxicity (digoxin, beta-blockers, calcium channel blockers)
- Acute rheumatic fever
- Post-cardiac surgery
Symptoms and nursing management
Many patients are asymptomatic. Some report palpitations, weakness, or lightheadedness, particularly when the ventricular rate drops significantly.
Wenckebach is generally considered the more benign of the two second-degree subtypes:
- If the heart rate is above 40 bpm and the patient is asymptomatic, observation is appropriate
- For symptomatic bradycardia: atropine 0.5 mg IV (can repeat up to 3 mg total)
- Temporary transcutaneous pacing if atropine fails and the patient is hemodynamically unstable
- Most cases resolve when the precipitating cause is treated
Key nursing action: monitor the rhythm continuously and reassess hemodynamics. The rhythm can fluctuate, especially in the setting of acute inferior MI.
Second degree heart block: Mobitz type II
Poem line: If PR stays normal and QRS quits, it must be a Type II Mobitz.
What it is
Mobitz type II is an infranodal block – the conduction failure occurs below the AV node, in the bundle of His or the bundle branches. The AV node itself conducts normally, which is why the PR interval stays constant. But the infranodal system fails intermittently, dropping QRS complexes without any warning.
This is the dangerous second-degree block. Because the site of block is below the AV node, the backup pacemaker cells (if needed) are slow, unreliable ventricular escape cells firing at 20–40 bpm. There is a significant risk of abrupt progression to third degree (complete) heart block.
EKG criteria
- Regular atrial rhythm
- Constant PR interval on conducted beats – no lengthening before the dropped beat
- QRS complexes absent intermittently and without predictable pattern
- QRS is often wide (≥ 0.12 sec) because the block is at the level of the bundle branches
- May occur as 2:1, 3:1, or higher ratios (two or more P waves for every QRS)
The constant PR interval with sudden QRS disappearance is the defining feature that distinguishes Mobitz II from Wenckebach.
Causes
- Anterior MI (the left anterior descending artery supplies the bundle branches – anterior MI can disrupt infranodal conduction)
- Severe coronary artery disease
- Structural heart disease (cardiomyopathy, calcific valve disease)
- Acute myocarditis
- Digoxin toxicity
Symptoms and nursing management
Patients may be asymptomatic if the ventricular rate remains adequate, but Mobitz II carries high risk of sudden hemodynamic collapse. Even an asymptomatic patient requires urgent management planning.
Nursing priorities:
- Continuous cardiac monitoring – watch for deterioration to third degree block
- Establish IV access and have atropine, transcutaneous pacemaker, and code cart at bedside
- Atropine is less reliable for infranodal blocks – it may paradoxically worsen the block in some cases
- Most patients with Mobitz II require a permanent pacemaker, regardless of current symptoms
- Discontinue digoxin if it is a contributing cause
- Dopamine or epinephrine infusion may be needed for hemodynamic support if deterioration occurs
The clinical priority with Mobitz II is anticipation: treat this rhythm as a precursor to complete heart block until proven otherwise.
Third degree (complete) heart block
Poem line: If Ps and Qs beat independently, it must be a Third Degree.
What it is
Third degree AV block – complete heart block – is the most severe conduction disturbance in the AV block spectrum. No atrial impulses reach the ventricles at all. The atria and ventricles beat completely independently, each driven by its own pacemaker: the SA node drives the atria, and a junctional or ventricular escape rhythm drives the ventricles.
Cardiac output depends entirely on the escape rhythm. Junctional escape rhythms (40–60 bpm, narrow QRS) are more reliable; ventricular escape rhythms (20–40 bpm, wide QRS) are slower and far less stable.
EKG criteria
- Regular atrial rhythm (consistent P-P interval)
- Regular ventricular rhythm (consistent R-R interval), but at a slower independent rate
- No fixed relationship between P waves and QRS complexes – the PR interval varies randomly across the strip
- P waves “march through” the QRS complexes without affecting them
- Ventricular rate 20–40 bpm (ventricular escape) or 40–60 bpm (junctional escape)
- QRS may be narrow (junctional escape, block at AV node) or wide (ventricular escape, block below the bundle of His)
The defining feature is complete AV dissociation: P waves and QRS complexes have no relationship to each other.
Causes
- Inferior MI (complete block at the AV node – more likely to have junctional escape, better prognosis)
- Anterior MI (infranodal complete block – ventricular escape, worse prognosis)
- Lyme disease (can cause complete heart block, often reversible with antibiotics)
- Surgical complication (valve surgery, septal defect repair)
- Digoxin toxicity
- Age-related conduction system fibrosis (Lev’s disease, Lenègre disease)
- Congenital complete heart block
Symptoms and nursing management
Third degree heart block with ventricular escape is a cardiac emergency. Patients typically present with:
- Syncope or near-syncope (Stokes-Adams attacks)
- Severe symptomatic bradycardia
- Hypotension and hemodynamic instability
- Signs of heart failure (dyspnea, pulmonary edema)
- Angina from reduced cardiac output
Nursing priorities – act immediately:
- Call for help and notify the physician or provider
- Apply transcutaneous pacing pads and initiate transcutaneous pacing – this is the emergent bridge
- Confirm mechanical capture – a palpable pulse with each pacing stimulus. Electrical capture alone (a QRS spike on the monitor) is not enough; if there is no pulse, increase the energy or reposition the pads
- Establish IV access; dopamine or epinephrine infusion for hemodynamic support
- Prepare for urgent transvenous pacemaker placement – the definitive bridge to permanent pacing
- Permanent pacemaker is the standard of care for acquired complete heart block
Note on atropine: atropine is ineffective for complete heart block and should not be relied upon as primary treatment. It may temporarily increase the atrial rate but cannot restore AV conduction.
Comparing the four types: clinical decision table
| Feature | First degree | Wenckebach (Mobitz I) | Mobitz II | Third degree |
|---|---|---|---|---|
| PR interval | Prolonged (> 200 ms), constant | Progressive lengthening | Constant, normal | Variable – no relationship |
| QRS pattern | Present after every P | Periodic drop after longest PR | Intermittent drop, no warning | Present at escape rate, unrelated to P |
| Dropped beats | None | Periodic (predictable pattern) | Intermittent (unpredictable) | All – complete dissociation |
| QRS width | Usually narrow | Usually narrow | Often wide | Narrow (junctional) or wide (ventricular) |
| Risk level | Low | Low to moderate | High | Critical |
| Location of block | AV node | AV node | Bundle of His / bundle branches | AV node or below |
| Typical treatment | Treat cause, monitor | Atropine if symptomatic; observe | Permanent pacemaker | Transcutaneous pacing → transvenous → permanent pacemaker |
| Key nursing action | Monitor for progression | Continuous telemetry, atropine ready | Code cart at bedside, pacemaker planning | Immediate transcutaneous pacing |
The heart block song
Some nursing students find a sung or chanted version easier to retain than spoken lines. A widely circulated version set to a simple chant rhythm goes:
If the R is far from P – first degree, first degree.
Longer, longer, longer, drop – Wenckebach, Wenckebach.
Constant PR, QRS quits – Mobitz II, Mobitz II.
P and QRS don’t agree – third degree, third degree.
The repetition of the block name at the end of each line turns the poem into a call-and-response format, which works well when studying with a partner. There is no single “official” heart block song; different nursing programs and NCLEX review courses use slightly different wording. What matters is the underlying logic each version encodes: prolonged PR for first degree, progressive lengthening then drop for Wenckebach, constant PR with sudden drop for Mobitz II, and complete dissociation for third degree.
Clinical urgency ladder
One of the most useful things the poem does is force you to rank the four types. From lowest to highest urgency:
| Block | Urgency | Typical intervention | When to call the provider |
|---|---|---|---|
| First degree | Routine monitoring | Identify and treat reversible causes | If PR > 0.26 sec with symptoms, or if progressing |
| Wenckebach (Mobitz I) | Monitor closely | Atropine if symptomatic; usually resolves | If rate drops below 40 bpm or patient becomes unstable |
| Mobitz II | Urgent | Permanent pacemaker planning; transcutaneous pacemaker on standby | Immediately – even if asymptomatic |
| Third degree | Emergency | Transcutaneous pacing now | Immediately – this is a code-level event |
Medications that cause or worsen AV blocks: digoxin (all four types, particularly second and third degree in toxicity), beta-blockers (slow AV conduction, worsen all types), calcium channel blockers (diltiazem and verapamil especially), and amiodarone (can prolong PR and cause higher-degree block). In any patient with a new AV block, check their medication list before assuming a structural cause.
How to measure the PR interval on a rhythm strip
Knowing the poem helps you name the rhythm. Knowing how to measure the PR interval is how you confirm it.
- Find a clear P wave with a QRS following it
- Mark the start of the P wave – where the waveform first lifts off the isoelectric line
- Mark the start of the QRS complex – where the first deflection (Q or R wave) begins
- Count the small boxes between those two marks: each small box = 40 ms on a standard strip running at 25 mm/sec
- Five small boxes = 200 ms = the upper limit of normal
If the interval is greater than five small boxes on every beat: first degree. If it lengthens across beats: Wenckebach. If it stays fixed while QRS complexes randomly disappear: Mobitz II. If P-to-QRS intervals vary with no pattern: third degree.
The key technique for spotting Wenckebach is to measure the PR on the first beat of each cycle, then the second, then the third. Each should be longer than the last. Then a QRS drops. Then the PR resets.
Distinguishing Mobitz I from Mobitz II: the most common NCLEX trap
Both Mobitz I and Mobitz II are second-degree blocks, both have dropped QRS complexes, and both can present with bradycardia. The question that trips students up: if you just see a dropped beat, how do you know which one it is?
The answer is the PR interval on the conducted beats:
- Wenckebach (Mobitz I): The PR interval on the conducted beats is not the same – it gets longer with each beat before the drop. Look at several consecutive PR intervals. If they are measurably different, it is Wenckebach.
- Mobitz II: The PR interval on every conducted beat is identical. If you measure three conducted beats and all three have the same PR, it is Mobitz II.
A 2:1 block – where every other QRS is dropped – is the hardest special case. When there is only one PR interval to measure before each drop, you cannot determine whether it is lengthening. In that situation, additional context (QRS width, the territory of any MI, whether the block improves with atropine) is needed to classify it. NCLEX will not usually require you to classify a 2:1 block from a strip alone; the question will give you enough context.
Common confusions
First degree vs. normal sinus rhythm: In normal sinus rhythm the PR interval is 120–200 ms. In first degree block it is greater than 200 ms. This is easy to overlook on a strip – measure, do not estimate.
Wenckebach vs. sinus pause: Both produce a pause in the rhythm. In Wenckebach, you can find the P wave before the dropped QRS if you look carefully – it is there, it just failed to conduct. In a sinus pause, the SA node itself did not fire, so there is no P wave at all during the pause.
Third degree vs. second degree with high block ratio: In high-ratio second degree block (3:1 or 4:1), most P waves do not conduct, and the ventricular rate is slow. The key difference from third degree: in second degree block the PR intervals on conducted beats are consistent (either lengthening as in Wenckebach or constant as in Mobitz II). In third degree block there are no consistent PR intervals – the relationship is entirely random.
NCLEX tips for heart blocks
NCLEX heart block questions test your ability to distinguish between the four types and identify the correct nursing priority. Here are the patterns most commonly tested:
-
Wenckebach vs. Mobitz II is the most common discrimination question. The key distinction: Wenckebach has a progressively lengthening PR before the drop; Mobitz II has a constant PR. If the question says “PR lengthens,” it’s Wenckebach. If it says “PR constant” or “PR unchanged,” it’s Mobitz II.
-
Mobitz II is always more dangerous than Wenckebach. If a question asks which patient to assess first or which rhythm requires more urgent intervention, choose Mobitz II. It can deteriorate to complete heart block without warning.
-
Complete heart block + hemodynamic instability = transcutaneous pacing first. NCLEX expects you to know that atropine is unreliable for complete heart block. The correct first intervention when a patient with third degree block is unstable is transcutaneous pacing, not atropine.
-
Inferior MI → Wenckebach or third degree (usually junctional escape, better prognosis). The right coronary artery supplies the AV node. Anterior MI → Mobitz II or infranodal complete block (ventricular escape, worse prognosis). The territory of infarction helps you predict the type of block.
-
When you see a strip with P waves and QRS complexes at different rates with no relationship – that is third degree. Don’t let NCLEX distract you with a normal-looking PR interval in part of the strip. If atrial and ventricular rates are independent, it’s complete heart block.
Heart block nursing care plans
Nursing care plans for AV heart block are organized around the hemodynamic impact of the conduction disturbance. The NANDA-I diagnoses below apply across the block spectrum; the severity and urgency of interventions escalate with block degree.
Care plan 1: decreased cardiac output
Nursing diagnosis: Decreased cardiac output
Related to: Altered electrical conduction (delayed, intermittent, or absent AV node transmission)
As evidenced by: Bradycardia, hypotension, fatigue, syncope or near-syncope, diminished peripheral pulses, reduced urine output, and hemodynamic instability (in Mobitz II and third degree)
Expected outcomes:
- Patient maintains adequate cardiac output as evidenced by heart rate within acceptable range, blood pressure within baseline, and absence of signs of low perfusion
- Patient remains free from progression to a higher-degree block during the monitoring period
- Patient verbalizes understanding of when to call the nurse for new symptoms
| Nursing intervention | Rationale |
|---|---|
| Continuous cardiac monitoring; obtain a rhythm strip every 4 hours and with any change in condition | Identifies rhythm changes promptly; documents progression to higher-degree block |
| Assess vital signs every 1–4 hours depending on block severity; more frequently during acute MI or hemodynamic instability | Provides early detection of deteriorating cardiac output |
| Assess level of consciousness, skin color, capillary refill, and peripheral pulses each shift | Peripheral perfusion signs reflect the adequacy of cardiac output |
| Assess for chest pain, dizziness, syncope, and shortness of breath at each assessment | Symptoms guide urgency of intervention and correlate with degree of output impairment |
| Review the medication administration record for AV-slowing agents (digoxin, beta-blockers, calcium channel blockers, amiodarone); hold and notify the provider if a new block is detected | Iatrogenic AV block resolves with drug discontinuation; continuing the offending agent risks progression |
| Obtain serum electrolytes (potassium, magnesium) and notify the provider of abnormal results | Hyperkalemia and hypomagnesemia prolong AV conduction; correction may restore normal rhythm |
| Administer atropine 0.5 mg IV as ordered for symptomatic bradycardia in first degree or Wenckebach block | Atropine blocks vagal tone at the AV node and increases the heart rate; effective for nodal (supranodal) blocks |
| For Mobitz II or third degree block: prepare transcutaneous pacing pads, have code cart at bedside, and notify the provider immediately regardless of current symptoms | Infranodal block carries risk of sudden deterioration; atropine is unreliable and transcutaneous pacing may be needed urgently |
| Administer supplemental oxygen as ordered and maintain SpO2 ≥ 94% | Hypoxemia worsens myocardial irritability and conduction dysfunction |
| Monitor urine output; output < 30 mL/hr suggests inadequate renal perfusion from low cardiac output | Oliguria is a sensitive early sign of hemodynamic compromise |
| Position patient in semi-Fowler’s; elevate legs if hypotensive and no evidence of pulmonary edema | Promotes venous return without increasing cardiac workload |
Care plan 2: risk for decreased cardiac output
Nursing diagnosis: Risk for decreased cardiac output
Risk factor: Potential progression from Wenckebach or first degree block to higher-degree block, particularly in the setting of acute inferior MI or drug toxicity
Expected outcomes:
- Patient remains hemodynamically stable throughout the monitoring period
- New rhythm changes are detected and reported within one telemetry cycle
- Reversible causes are identified and treated before progression occurs
| Nursing intervention | Rationale |
|---|---|
| Assign to a monitored telemetry bed; verify alarm parameters are set for rate below 50 bpm and rate above 120 bpm | Automated alarms provide a safety net between scheduled assessments |
| Perform a 12-lead EKG at baseline and with any new symptoms | A 12-lead captures the full conduction picture; changes in QRS morphology or axis can signal worsening infranodal disease |
| Assess for Lyme disease exposure, recent cardiac surgery, or acute myocarditis – document in nursing notes | These etiologies carry distinct timelines for resolution and affect pacemaker planning |
| Educate patient to call the nurse immediately for new dizziness, chest pain, or feeling of the heart “skipping” | Early patient-reported symptoms allow intervention before hemodynamic collapse |
Care plan 3: activity intolerance
Nursing diagnosis: Activity intolerance
Related to: Symptomatic bradycardia causing reduced cardiac output with exertion
As evidenced by: Fatigue, dyspnea on exertion, dizziness with position change, declining functional tolerance
Expected outcomes:
- Patient tolerates activities of daily living without significant vital sign changes or symptoms
- Patient demonstrates energy-conservation strategies before discharge
- Patient understands which activity symptoms require immediate reporting
| Nursing intervention | Rationale |
|---|---|
| Assess heart rate, blood pressure, SpO2, and patient-reported symptoms before, during, and after any activity | Exertion increases cardiac demand; bradycardia from AV block limits the ability to raise cardiac output, causing symptomatic intolerance |
| Implement activity restrictions during acute symptomatic phase; assist with ADLs as needed | Reduces myocardial oxygen demand while the rhythm is unstable |
| Cluster nursing care to allow uninterrupted rest periods of at least 90 minutes | Fragmented rest increases fatigue and prevents hemodynamic recovery between activities |
| Teach the patient to use the Borg scale or the “talk test” to pace exertion | Gives the patient an objective tool to self-limit activity before symptoms escalate |
| Collaborate with physical therapy for a gradual mobilization plan once rhythm is controlled or pacemaker is placed | Progressive ambulation prevents deconditioning without overloading a compromised conduction system |
Care plan 4: anxiety related to cardiac monitoring and pacemaker
Nursing diagnosis: Anxiety
Related to: Uncertainty about heart rhythm, potential pacemaker implantation, and dependence on cardiac monitoring
As evidenced by: Verbalized fear, restlessness, questions about device safety and lifestyle impact, increased heart rate
Expected outcomes:
- Patient verbalizes a reduction in anxiety by discharge
- Patient accurately describes the purpose of the monitor and/or pacemaker
- Patient demonstrates at least two coping strategies
| Nursing intervention | Rationale |
|---|---|
| Assess the patient’s current understanding of their diagnosis using open-ended questions | Knowledge gaps fuel anxiety; targeted education is more effective than generic reassurance |
| Explain the purpose of cardiac monitoring in plain language: “This monitor lets us catch any changes in your heart rhythm before you feel them” | Reframes monitoring as protective rather than alarming |
| Provide written and verbal education on the type of heart block, its cause, and the treatment plan | Informed patients report lower anxiety and greater compliance with monitoring and rest restrictions |
| If pacemaker is planned, describe the procedure, what the patient will experience, and how the device works; involve the family | Pre-procedural education reduces fear of the unknown and facilitates informed consent |
| Offer guided relaxation or controlled breathing exercises | Activating the parasympathetic nervous system reduces perceived anxiety without pharmacological intervention |
| Reassess anxiety level after education sessions using a 0–10 scale | Objective tracking identifies patients who need additional support or referral |
Care plan 5: deficient knowledge – pacemaker self-management
Nursing diagnosis: Deficient knowledge
Related to: New pacemaker implantation, unfamiliarity with device management, and activity restrictions
As evidenced by: Patient questions about device function, activity limits, and follow-up requirements; inability to state symptoms of device malfunction
Expected outcomes:
- Patient states the purpose and basic function of their pacemaker before discharge
- Patient identifies three signs of pacemaker malfunction requiring immediate reporting
- Patient demonstrates correct pulse-check technique
- Patient verbalizes understanding of activity restrictions and electromagnetic precautions
| Nursing intervention | Rationale |
|---|---|
| Teach the patient to check the radial pulse for one full minute daily at the same time each day; instruct them to report a pulse rate more than 5 bpm below the programmed minimum rate | The pacemaker sets a rate floor; a pulse below that rate signals a failure-to-pace situation requiring urgent evaluation |
| Explain the difference between electrical capture (a QRS on the monitor) and mechanical capture (a palpable pulse with each pacemaker stimulus) | Electrical capture without a pulse is a cardiac emergency; the distinction is critical for both patient self-monitoring and bedside nursing assessment |
| Teach the patient to avoid electromagnetic sources that can interfere with device function: MRI scanners (unless device is MRI-conditional), large industrial magnets, and anti-theft security systems if held directly against the chest | Electromagnetic interference can temporarily inhibit pacemaker output or cause inappropriate pacing |
| Instruct the patient not to raise the arm on the device side above shoulder height for two weeks; avoid heavy lifting on that side for four to six weeks | Arm elevation creates traction on the lead; the restriction allows fibrous encapsulation to stabilize the lead tip |
| Review signs and symptoms requiring immediate medical attention: hiccups or muscle twitching (lead dislodgement or diaphragm pacing), swelling, redness, or drainage at the wound site (infection), dizziness or syncope (failure to pace or sense), palpitations (inappropriate pacing) | Prompt recognition of complications shortens time to treatment and prevents device failure |
| Instruct the patient to carry their pacemaker identification card at all times and present it before any medical procedure, including dental procedures | The card documents device model and programmed settings; anesthesiologists and proceduralists need this to program appropriate precautions |
| Confirm a follow-up appointment with the device clinic before discharge | Pacemaker lead thresholds shift in the first weeks after implantation; outpatient device interrogation optimizes pacing output and battery longevity |
Pacemaker nursing considerations
When a patient with heart block progresses to pacemaker implantation – temporary or permanent – nursing priorities shift from rhythm monitoring to device function and complication surveillance.
Temporary transvenous pacemaker
A temporary transvenous pacemaker is the bridge between emergent transcutaneous pacing and permanent device implantation. The lead is placed through the subclavian, internal jugular, or femoral vein into the right ventricle and connected to an external pulse generator at the bedside.
Key bedside assessments:
- Capture: Each pacemaker spike on the monitor should be followed immediately by a wide QRS complex. Failure to capture (spike present, no QRS) indicates the lead has dislodged or the output threshold needs to be increased. Notify the provider immediately.
- Sensing: The pacemaker should detect intrinsic cardiac activity and withhold a stimulus when the patient’s own heartbeat occurs. Failure to sense (pacemaker fires into the T wave) risks R-on-T phenomenon and ventricular fibrillation.
- Rate and output settings: Verify the programmed rate matches the provider order. Do not adjust settings without an order. Document the settings every shift.
- Lead security: The external lead exits from an insertion site; secure it with a dressing and verify it has not migrated. Apply an arm sling on the affected extremity if a subclavian or IJ approach was used, to reduce lead tension.
- Threshold testing: The provider or device technician will periodically test capture threshold – the minimum output (milliamps) required to consistently capture the ventricle. This is done at the bedside; have resuscitation equipment available.
Nursing safety rule: Never allow any electrical equipment (IV pumps, call lights, ECG leads) to touch the exposed lead terminals. Stray current conducted directly to the heart can cause ventricular fibrillation.
Permanent pacemaker – post-implantation nursing
Most patients return from the catheterization lab or OR with a pressure dressing over the pocket (typically in the left pectoral region for right-handed patients). Standard post-procedure nursing includes:
| Assessment | Frequency | What to look for |
|---|---|---|
| Vital signs and rhythm | Every 15 min × 1 hour, then every 4 hours | Stable rate at or above programmed minimum; no pacing artifact without capture |
| Wound site | Every 4 hours | Hematoma formation (early), erythema and warmth (late infection), seroma |
| Extremity neurovascular | Every 4 hours × 24 hours | Adequate distal pulses, sensation, and movement on the pacemaker side |
| 12-lead EKG | Post-procedure and next morning | Confirms lead position; new RBBB morphology confirms right ventricular apical pacing |
| Chest X-ray | Post-procedure | Rules out pneumothorax (subclavian approach); confirms lead position |
Maintain the patient on bed rest for 2–4 hours post-procedure per protocol. Activity restrictions (no overhead reaching, no heavy lifting on pacemaker side) apply for the first four to six weeks.
Sources and references
- Dubin, D. — Rapid Interpretation of EKG’s (6th ed.) — foundational EKG reference used in nursing education. Cover Press, 2000.
- American Heart Association — 2019 AHA/ACC/HRS Focused Update of the 2014 AHA/ACC/HRS Guideline for the Management of Patients With Atrial Fibrillation. ahajournals.org
- National Institutes of Health / MedlinePlus — Atrioventricular block overview. medlineplus.gov
- NCSBN — NCLEX-RN test plan: cardiovascular system content area. ncsbn.org
Content reviewed by Lindsay Smith, AGPCNP-BC. Last reviewed: June 2026.
For details on how we review clinical content, see our editorial methodology.
Frequently asked questions
What is the nursing priority for a patient with third degree heart block? The immediate nursing priority is to establish transcutaneous pacing if the patient is hemodynamically unstable (hypotensive, altered mental status, chest pain, or severe bradycardia). Place the pacing pads, confirm mechanical capture with a palpable pulse – not just electrical capture on the monitor – and notify the provider. Atropine may be given while preparing for pacing but should not delay it; atropine is unreliable for complete heart block because the block is below the level where atropine has effect.
Why is atropine ineffective in Mobitz II and third degree heart block? Atropine increases heart rate by blocking vagal (parasympathetic) inhibition at the AV node. Mobitz II and infranodal complete heart block occur below the AV node, in the bundle of His or bundle branches. Because these sites are not under significant vagal influence, atropine produces little to no effect on the ventricular rate and may paradoxically worsen the block in some patients by increasing the atrial rate without improving ventricular conduction.
What does failure to capture mean in a pacemaker patient? Failure to capture means the pacemaker delivers a stimulus (visible as a spike on the rhythm strip) but the myocardium does not respond with depolarization – no QRS follows the spike. It means the pacemaker output is insufficient to reliably depolarize the ventricle, or the lead has displaced from its original position. Failure to capture in a pacemaker-dependent patient is a medical emergency: the patient’s underlying rhythm (often a slow escape rhythm) may not maintain adequate cardiac output. Notify the provider immediately, increase the pacing output if instructed, reposition the patient, and prepare for emergent lead repositioning.
Which type of heart block always requires a pacemaker? Mobitz type II (second degree, infranodal) and acquired third degree (complete) heart block are the two types that require permanent pacemaker implantation as standard of care, regardless of whether the patient is currently symptomatic. This is because both carry a high risk of sudden progression to complete asystole or fatal bradycardia. First degree and Wenckebach (Mobitz I) blocks do not require a pacemaker in the absence of symptoms or hemodynamic compromise.
How do you distinguish third degree heart block from a high-ratio second degree block on a rhythm strip? The key is PR interval consistency on conducted beats. In high-ratio second degree block (e.g., 3:1 or 4:1), the conducted beats have a consistent PR interval – either fixed (Mobitz II) or with the progressive lengthening pattern of Wenckebach. In third degree block, there are no conducted beats at all: the PR interval between every P wave and every QRS complex is different and follows no pattern, because the two are completely dissociated. If the PR intervals across the strip follow no discernible pattern, it is third degree.
Related resources
For a broader foundation in cardiac rhythm interpretation, the EKG interpretation cheat sheet covers normal intervals, common arrhythmias, and a systematic approach to reading rhythm strips. For care planning beyond the acute phase, see the cardiac arrhythmias nursing guide and pacemaker nursing care. Electrolyte disturbances – particularly hyperkalemia and hypokalemia – are a common cause of AV conduction changes; see electrolyte imbalances for nursing students for a full clinical reference.