Pacemaker & Cardiac Device Nursing

Indications for Cardiac Pacing

Symptomatic Bradycardia

Pacing is indicated when symptoms are directly attributable to a low heart rate. Symptoms include:

Syncope (sudden loss of consciousness)
Pre-syncope (near-fainting, lightheadedness)
Dizziness or persistent fatigue
Heart failure exacerbation due to low rate
Chronotropic incompetence (failure to raise HR with exertion)

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Key principle: Asymptomatic bradycardia rarely requires pacing. It is the symptom-rhythm correlation that drives the decision.

Sick Sinus Syndrome (SSS)

Dysfunction of the sinoatrial (SA) node resulting in abnormal impulse generation. Also known as sinus node dysfunction (SND).

Manifestation	ECG Feature	Significance
Sinus Bradycardia	HR <60 bpm, normal P-wave morphology	Symptomatic requires pacing
Sinus Arrest	Pause >3 sec, no P-wave	Syncope risk — pacing indicated
Sinoatrial Block	Dropped P-wave, pause = multiple of PP interval	Symptomatic requires pacing
Tachy-Brady Syndrome	Alternating SVT/AF then sinus pause	Drug therapy + pacing required
Chronotropic Incompetence	Failure to reach 85% max HR with exercise	Rate-responsive pacing (VVIR/DDDR)

AV Block Classification

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EMERGENCY: 3rd degree (complete) heart block requires urgent temporary pacing — do not delay for investigations.

Degree	ECG Criteria	Clinical Action
1st Degree	PR interval >200 ms (0.20 sec), all P-waves conduct	No treatment required. Monitor. Usually benign.
2nd Degree Mobitz I (Wenckebach)	Progressive PR lengthening → dropped QRS; then cycle resets. AV node level block.	Usually benign, often vagal/inferior MI. Atropine if symptomatic. Rarely requires pacing.
2nd Degree Mobitz II	Fixed PR interval with intermittent non-conducted P-waves. His-Purkinje level block. Unpredictable progression.	Permanent pacemaker indicated. Risk of progression to complete block. Temp pacing if acute.
3rd Degree / Complete Block	Complete AV dissociation — P-waves and QRS independent. Ventricular escape (wide) or junctional escape (narrow).	EMERGENCY pacemaker. Transcutaneous pacing immediately, bridge to transvenous/permanent.

NBG Pacing Code (NASPE/BPEG Generic)

A 5-letter code describing pacemaker programming. The first three positions are most commonly used clinically.

Chamber Paced

O, A, V, D

Chamber Sensed

O, A, V, D

III

Response to Sensing

O, I, T, D

Rate Modulation

O, R

Multisite Pacing

O, A, V, D

A=Atrium, V=Ventricle, D=Dual (both), O=None, I=Inhibited, T=Triggered, R=Rate responsive

Common Pacing Modes

Mode	Description	Use Case
VVI	Ventricular paced, ventricular sensed, inhibited. Single chamber backup pacing.	AF with bradycardia, SSS in AF
VVIR	VVI + rate responsive (accelerometer). Increases rate with activity.	Chronotropic incompetence, active patients
DDD	Dual chamber: tracks atrial rate, paces ventricle after AV delay. Physiological.	AV block with normal sinus function
DDDR	DDD + rate responsive.	AV block + chronotropic incompetence
VOO	Asynchronous ventricular pacing at fixed rate. Ignores intrinsic activity.	Magnet mode, EMI environments, pacemaker-dependent patients
AAI	Atrial paced/sensed/inhibited. Requires intact AV conduction.	SSS with normal AV conduction

Advanced Concepts

Hysteresis

A programmed feature where the escape interval after a sensed beat is longer than the basic pacing interval. Allows intrinsic rhythm to predominate while ensuring backup pacing activates at a slower rate. Preserves natural AV synchrony.

Example

Pacing rate = 60 bpm (1000 ms). Hysteresis rate = 50 bpm (1200 ms). The device waits 1200 ms for intrinsic beat but will pace at 1000 ms once pacing begins.

Rate-Responsive Pacing

The "R" suffix in VVIR/DDDR means the pacemaker uses a sensor to increase heart rate in response to physiological demand.

Accelerometer: detects body movement/vibration
Minute ventilation sensor: detects respiratory rate
Mixed sensors: more physiological response
Critical for patients with chronotropic incompetence
Rate response can be inappropriately triggered by vibration (air travel, road travel)

Indications for Temporary Pacing

Acute complete (3rd degree) heart block
Symptomatic 2nd degree Mobitz II block
Symptomatic bradycardia unresponsive to atropine
Post-cardiac surgery bradycardia (epicardial wires)
Drug toxicity (digoxin, beta-blocker, CCB)
Bridge to permanent pacemaker implantation
Overdrive pacing for refractory VT/torsades

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Post-MI consideration: Right coronary artery (RCA) infarction causes AV nodal ischaemia → inferior MI with complete block is a common indication for temporary pacing in GCC CCUs.

Transcutaneous Pacing (TCP)

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TCP is painful. Sedation/analgesia is mandatory unless patient is unconscious. Use IV morphine 2–4 mg + midazolam 1–2 mg titrated carefully.

Setup & Procedure

Apply pads in antero-posterior (AP) position: anterior pad left parasternal V3-V4 position; posterior pad left infrascapular
Set mode to DEMAND (synchronised to intrinsic activity) unless cardiac arrest → FIXED
Start output at 70–80 mA; increase by 10 mA increments until capture
Set rate 60–80 bpm (higher if haemodynamically compromised)
Typical capture threshold: 50–100 mA

Confirming Capture

✓

Electrical capture: Wide QRS after each pacing spike on ECG monitor.

Mechanical capture: Palpate a femoral or carotid pulse — do NOT rely on ECG alone due to muscle artifact. Use pulse oximetry waveform or arterial line if available.

Set output 10 mA above threshold once capture confirmed
Monitor BP, SaO2 and patient comfort continuously
Plan urgent transvenous pacing — TCP is a bridge only

Transvenous Pacing (TVP)

Vascular Access & Lead Placement

Preferred access: right internal jugular vein (IJV) — most direct route to RV
Alternatives: subclavian, femoral (higher displacement risk)
Lead advanced under fluoroscopy to RV apex
Position confirmed: lead tip at apex with slight curve, pacing threshold <1 V, R-wave >5 mV
Balloon-tipped (Swan-Ganz style) electrode can be floated without fluoroscopy

External Box Settings

Parameter	Initial Setting	Target
Rate	60–70 bpm	Haemodynamically appropriate
Output (mA)	5 mA	2–3× threshold mA
Sensitivity (mV)	2–3 mV	Adjust to suppress pacing with intrinsic beats
Mode	Demand (VVI)	VOO only if no intrinsic activity

Nursing Management of Temporary Pacing

Daily Threshold Assessment

Stimulation threshold: Reduce output slowly until capture is lost → threshold = last mA with capture. Set output at 3× threshold (safety margin)
Sensing threshold: Reduce sensitivity (increase mV value) until device starts pacing through intrinsic beats → threshold = mV at that point. Set at 50% of threshold
Document thresholds every shift and report rising thresholds (suggests lead dislodgement)

Lead & Connection Management

Secure external lead connections with tape — prevent accidental disconnection
Avoid kinking or tension on the pacing wire
Sterile dressing changes every 24–48 h
Limit patient mobility — educate patient on movement restrictions
Label lead clearly: "PACEMAKER WIRE — DO NOT REMOVE"

Electromagnetic Interference (EMI)

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EMI can inhibit temporary pacing → bradycardia/asystole. Keep patient away from strong electrical fields. Ensure proper patient grounding. Use demand mode unless pacemaker-dependent.

Emergency Responses

Loss of capture: Increase output → check connections → check lead position on CXR → consider reposition
Failure to pace (no spikes): Check battery, connections, sensing threshold (over-sensing inhibiting output)
Over-sensing: Reduce sensitivity (increase mV number) → reduces detection of extraneous signals
Under-sensing: Increase sensitivity (reduce mV number) → better detection of intrinsic beats

Pre-Operative Nursing Preparation

Consent & Risk Counselling

Document that patient/family understands the following risks:

Infection: ~1% (pocket infection to endocarditis)
Pneumothorax: 1–2% (subclavian approach higher)
Lead dislodgement: 2–5% (within first weeks)
Pericardial effusion/tamponade: <1%
Haematoma: pocket haematoma, especially with anticoagulation
Venous thrombosis at access site

Pre-Op Checklist

Antibiotics: Cephalosporin (cefazolin 1–2 g) IV 30 minutes pre-procedure — reduces pocket infection risk by ~50%
Anticoagulation: INR target <2.0 for warfarin; DOAC: hold 24–48 h depending on agent and CrCl
Skin preparation: Electrical hair clipper — NEVER razor (micro-abrasions increase infection risk)
NPO: 6 hours for solids, 2 hours for clear fluids
IV access: Contralateral arm to implant side
Baseline 12-lead ECG, CXR, FBC, U&E, coagulation screen
Consent signed and documented

Implantation Procedure Overview

Procedure Summary (for nursing knowledge)

Performed in catheter lab / EP lab under local anaesthesia ± sedation. Duration 45–90 minutes.

Step	Detail
Venous Access	Subclavian, cephalic, or axillary vein — left side preferred. Cephalic vein cut-down has lowest pneumothorax risk.
Lead Insertion	VVI: single RV lead. DDD: atrial lead (RA appendage) + ventricular lead (RV apex or RVOT for physiological pacing).
Fluoroscopic Guidance	Lead positions confirmed under X-ray. RV lead tip at apex shows left-lateral, inferior, and slightly anterior position.
Testing	Stimulation threshold, sensing amplitude, and impedance measured for each lead before securing.
Pocket Formation	Subcutaneous (subpectoral for thin patients) pocket in infraclavicular region. Device secured, wound closed in layers.
Device Implanted	Generator connected to leads, programmed to appropriate mode (DDD/VVI etc.).

Post-Operative Nursing Care

Monitoring (First 24 Hours)

Continuous cardiac monitoring — confirm pacing mode active, appropriate capture and sensing
CXR within 2 hours post-procedure: confirm lead position AND exclude pneumothorax
Vital signs every 30 min × 4, then hourly
Wound inspection: haematoma, bleeding, dehiscence
Observe for signs of cardiac tamponade: hypotension, JVP rise, muffled heart sounds

Arm Restriction (Critical)

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No arm elevation above shoulder level for 4–6 weeks. Lead dislodgement is the primary risk. Apply sling for first 24–48 hours. Educate patient before discharge.

Wound Management

Pressure dressing for first 12–24 hours
Keep wound dry for 5–7 days
Haematoma: manual compression first; if tense/enlarging → surgical drainage
Infection signs: redness, warmth, swelling, discharge, fever — escalate immediately
Wound review at 7–10 days

Discharge Preparation

Provide device identification card — patient carries at all times
Follow-up appointment at 4–6 weeks for device check
Arm restriction instructions written and verbal
Driving restriction: typically 1 week (non-commercial) — check local regulations
Electromagnetic interference (EMI) education
MRI labelling: MRI conditional vs MRI non-conditional

MRI & Electromagnetic Interference

MRI Considerations

MRI conditional: Can undergo MRI under specified conditions (1.5T, specific SAR, specific mode). Requires pre-MRI device programming by EP team.
MRI non-conditional / legacy devices: MRI contraindicated — risk of lead heating, reed switch activation, programming changes
Always check device documentation — patient card shows MRI status
All implant dates after ~2013: likely MRI conditional — verify with manufacturer

EMI Sources to Avoid

Retail anti-theft devices (EAS systems) — walk through quickly, do not linger
Strong industrial magnets, arc welding equipment
Airport security: inform staff, request manual screening (wand may be used briefly)
Mobile phones: hold to opposite ear, keep 15 cm from device
Cautery (surgical diathermy): inform surgical team — use bipolar/lowest effective setting
TENS machines, therapeutic ultrasound directly over device site

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Household appliances (microwaves, TVs, computers) are generally safe with modern pacemakers.

Implantable Cardioverter Defibrillator (ICD)

Indications

Category	Criteria
Secondary Prevention	Survived VF or haemodynamically unstable VT not due to reversible cause; sustained VT with structural heart disease
Primary Prevention	EF ≤35% despite ≥3 months optimal medical therapy (OMT); NYHA II-III; expected survival >1 year with good functional status
Channelopathies	Long QT, Brugada syndrome, HCM with risk factors, ARVC

ICD Therapies

✓

ATP (Anti-Tachycardia Pacing): Painless. A burst of rapid pacing stimuli delivered faster than VT rate to terminate it. First-line therapy for detected VT. No shock delivered.

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Shock Therapy: Extremely painful (up to 41 Joules). Delivered for VF or VT unresponsive to ATP. Patient typically experiences significant distress — provide psychological support and analgesia post-shock.

ICD Firing: Nursing Management

Single Appropriate Shock

VT/VF detected and terminated — confirm rhythm restored on monitor
Patient assessment: consciousness, BP, respiratory status
12-lead ECG immediately post-shock
Cardiac biomarkers (troponin, CK) — repeat at 3–6 hours
Reassure patient — explain what happened
Report to medical team; review trigger (electrolytes, ischaemia, HF exacerbation)
Device interrogation by EP team

Electrical Storm (≥3 Shocks in 24 Hours)

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EMERGENCY — Activate crash team / escalate immediately

IV amiodarone 150–300 mg bolus, then 900 mg/24h infusion
IV sedation (propofol/midazolam) to reduce sympathetic storm
Correct electrolytes: K⁺ >4.5 mmol/L, Mg²⁺ >1 mmol/L
Identify and treat precipitant: acute ischaemia, HF, electrolyte disturbance
Consider applying magnet over ICD to suspend therapy temporarily while arranging treatment
Anaesthesia support for intubation if refractory

Inappropriate Shocks

Shocks delivered for non-life-threatening rhythms. Causes and management:

Cause	Mechanism	Management
AF with fast ventricular rate	ICD detects rapid ventricular rates in AF zone, classifies as VT/VF	Rate control, reprogramming VT detection threshold
T-wave oversensing	Tall T-waves counted as R-waves, doubling apparent rate	Device reprogramming (sensing sensitivity adjustment)
Lead fracture / noise	Electrical noise from fractured lead mimics VF	Lead replacement; apply magnet temporarily
Sinus tachycardia	Rapid sinus rate falls in VT detection zone	Treat underlying cause (pain, infection); reprogram

ℹ

Applying a magnet over an ICD suspends tachycardia detection and therapy delivery. The device continues to pace for bradycardia. Magnet can be used to inhibit inappropriate shocks while definitive management is arranged. Remove magnet to restore ICD function.

Cardiac Resynchronisation Therapy (CRT)

Indications (ESC Guidelines)

Heart failure NYHA II–IV despite OMT
EF ≤35%
LBBB with QRS ≥130 ms (greatest benefit)
Sinus rhythm preferred (evidence weaker in AF)

Device Types

Device	Function
CRT-P	CRT + pacemaker. No defibrillation. For NYHA III–IV, elderly.
CRT-D	CRT + ICD. Defibrillates and resynchronises. For younger patients, EF ≤35%, primary prevention.

Left Ventricular Lead

LV lead placed via the coronary sinus into a lateral or postero-lateral cardiac vein
Sub-costal access approach allows CS cannulation
Most technically challenging component of the procedure
LV lead most prone to dislodgement

CRT Optimisation

AV delay optimisation: Adjusts timing between atrial and ventricular pacing to maximise ventricular filling
VV interval optimisation: Adjusts timing between RV and LV stimulation for optimal resynchronisation
Performed 4–8 weeks post-implant via echo-guided or device-based optimisation

Subcutaneous ICD (S-ICD)

Device placed subcutaneously — no transvenous leads entering the heart or veins
Sensing lead tunnelled subcutaneously from xiphoid to left parasternal region
Generator implanted in left lateral chest wall
Avoids risks of transvenous approach: venous occlusion, infection on leads inside heart
Preferred in young patients, those with congenital heart disease, or prior device infections

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Limitation: S-ICD CANNOT pace for bradycardia or deliver ATP for VT. It only provides defibrillation shocks. Patients requiring bradycardia pacing or ATP need a transvenous or leadless pacemaker in addition.

Requires pre-implant ECG screening (sense vector compatibility)
T-wave oversensing more common — requires careful programming
No MRI conditional versions currently available (as of 2025)

ECG Interpretation with Pacemakers

Identifying Pacing Spikes

Pacing spike: narrow, vertical deflection on ECG (may be very small with modern bipolar leads)
Atrial spike: precedes P-wave (or no visible P in atrial pacing)
Ventricular spike: precedes wide QRS (LBBB morphology for RV apex pacing)
DDD mode: may see both A spike → P-wave → V spike → wide QRS

Paced QRS Morphology

RV apex pacing produces LBBB-pattern QRS — dominant S in V1, R in V5/V6
RVOT pacing: inferior axis QRS
Biventricular (CRT) pacing: narrower QRS, more normal axis

Normal Pacemaker Function on ECG

          What to look for
          • Pacing spikes at appropriate rate
• Each spike followed by capture (P-wave or QRS)
• No spikes when intrinsic beats are present (in demand mode)
• AV interval constant in DDD mode

        

Pacemaker Malfunction: Systematic Approach

Problem	ECG Finding	Common Causes	Nursing Actions
Failure to Pace	No pacing spikes when expected (intrinsic rate below programmed rate without spikes)	Battery depletion; lead fracture; lead disconnection; over-sensing inhibiting output; programming error	Check connections; increase output; check battery indicator; reduce sensitivity; call cardiology urgently if pacemaker-dependent
Failure to Capture	Pacing spikes present but NOT followed by P-wave or QRS	Lead dislodgement; high pacing threshold (fibrosis); output too low; electrolyte imbalance (hyperK); exit block; lead fracture	Increase output; check electrolytes; reposition patient (may help temporarily); arrange urgent device check/CXR; call cardiology
Failure to Sense (Under-sensing)	Pacing spikes delivered during intrinsic beats (competitive pacing — R-on-T risk)	Sensitivity set too low; lead dislodgement; intrinsic signal amplitude too small; lead fracture; programming	Increase sensitivity (reduce mV threshold); call cardiology — R-on-T can precipitate VF
Over-sensing	Pauses — pacing inhibited inappropriately; no spikes when intrinsic rate is low	Sensitivity set too high; T-wave oversensing; myopotentials (diaphragm, pectoral); EMI; lead fracture noise	Decrease sensitivity (increase mV threshold); remove EMI source; call cardiology; apply magnet to convert to asynchronous mode if pacemaker-dependent

Special Syndromes

Pacemaker Syndrome

Occurs in VVI pacing when AV synchrony is lost. Retrograde VA conduction causes atria to contract against closed AV valves.

Symptoms: palpitations, presyncope, fatigue, neck pulsations (cannon A-waves), dyspnoea
Drop in BP ≥20 mmHg with VVI pacing compared to native rhythm
Management: reprogram to DDD (dual chamber) to restore AV synchrony

Pacemaker-Mediated Tachycardia (PMT)

Occurs in DDD pacemakers. Retrograde P-wave (from conducted ventricular beat) is sensed by atrial channel → triggers ventricular pacing → loop continues at upper rate limit.

ECG: tachycardia at upper rate limit with consistent AV pacing pattern
Management: apply magnet (converts to asynchronous — breaks re-entry loop)
Long-term: programme PVARP extension; increase post-ventricular atrial refractory period

Lead & Device Complications

Complication	Timing	Signs	Management
Lead Dislodgement	Early (<4 weeks)	Failure to pace/capture; new RBBB morphology for RV lead; CXR shows lead tip not at apex	Urgent repositioning in EP lab; bed rest; limit arm movement
Lead Fracture	Late (>months)	Intermittent sensing/pacing failure; noise on ECG; high impedance on interrogation	Lead replacement or extraction; avoid strenuous activity pending fix
Insulation Breach	Variable	Low impedance; inappropriate shocks (ICD); oversensing	Lead replacement
Pocket Infection	Days to months	Redness, warmth, swelling, fluctuance, discharge, fever, elevated CRP/WBC	IV antibiotics; lead extraction + device removal; reimplant contralateral side after adequate treatment
Device Endocarditis	Weeks to months	Fever, bacteraemia, vegetations on echo, positive blood cultures	IV antibiotics 4–6 weeks; complete lead extraction; multidisciplinary team decision on reimplantation
Pocket Haematoma	Early (24–72 h)	Swelling, bruising, tenderness over pocket	Manual compression; wound support; drain if tense or expanding; review anticoagulation
Pneumothorax	Immediate	Dyspnoea, pleuritic chest pain, reduced breath sounds, CXR confirmation	Small: observe; large/symptomatic: chest drain

Pacemaker & Cardiac Device Nursing

Example

Procedure Summary (for nursing knowledge)

What to look for

Pacemaker Function Analyser

Possible Causes

Immediate Nursing Actions

When to Call Cardiology / EP Team