BRADYARRHYTHMIAS – INDIA

CLINICAL MANAGEMENT GUIDELINE

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📋 For Healthcare Professionals Only | Not for Public Use

Scope: Diagnosis | Classification | Acute Management | Pacing Indications | Device Selection

Format: Stepwise, action-oriented

Note: This guideline covers sinus node dysfunction, AV conduction disorders, and related bradyarrhythmias.

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🔰 SYMBOL LEGEND

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SECTION 1: OVERVIEW AND DEFINITIONS

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1.1 DEFINITION

Bradyarrhythmia = Any cardiac rhythm with a heart rate < 60 bpm, or any rhythm that is inappropriately slow for the physiological circumstances.

Key Concept

Point

Bradycardia may be physiological (athletes, sleep) or pathological

Clinical significance depends on symptoms and hemodynamic status

Not all bradycardia requires treatment

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1.2 CLASSIFICATION

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1.3 ETIOLOGY

Intrinsic Causes (Disease of Conduction System)

Cause	Notes
Idiopathic fibrosis / Degenerative	Most common cause in elderly (Lenegre disease, Lev disease)
Ischemic heart disease	Acute MI (especially inferior); Chronic ischemia
Cardiomyopathy	DCM, HCM, Infiltrative (Amyloid, Sarcoid)
Myocarditis	Viral, Rheumatic, Chagas disease
Congenital	Congenital complete heart block (anti-Ro/La antibodies)
Collagen vascular disease	SLE, Scleroderma
Infectious	Lyme disease, Chagas, Diphtheria, Endocarditis with abscess
Post-surgical / Post-ablation	CABG, Valve surgery, Septal myectomy, Catheter ablation
Inherited channelopathies	SCN5A mutations (overlapping with Brugada, LQTS3)
Muscular dystrophies	Myotonic dystrophy, Emery-Dreifuss

Extrinsic Causes (Reversible)

Cause	Notes
Drugs	Beta-blockers, CCBs (Verapamil, Diltiazem), Digoxin, Amiodarone, Ivabradine, Clonidine, Lithium
Electrolyte disturbance	Hyperkalemia (most important), Hypokalemia (with digoxin), Hypermagnesemia
Hypothyroidism
Hypothermia
Hypoxia
Raised intracranial pressure	Cushing reflex (bradycardia + hypertension)
Obstructive sleep apnea	Nocturnal bradycardia; Sinus pauses
Vagal stimulation	Vasovagal syncope, Carotid sinus hypersensitivity, Vomiting, Coughing
Jaundice (Severe)	Bile salt effect

India-Specific Causes

Cause	Notes
Rheumatic heart disease	Carditis can affect conduction system
Chagas disease	In migrants from endemic areas (Latin America); Increasing awareness
Tuberculous pericarditis/myocarditis	Consider in endemic setting
Diphtheria	Rare but still seen; Myocarditis with AV block
Leptospirosis	Can cause myocarditis with conduction abnormalities
Enteric fever	Relative bradycardia

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1.4 ANATOMY OF THE CONDUCTION SYSTEM

Blood Supply

Structure	Blood Supply
SA node	SA nodal artery (60% RCA, 40% LCx)
AV node	AV nodal artery (90% RCA, 10% LCx)
Bundle of His	AV nodal artery + Septal perforators
Right bundle branch	Septal perforators (LAD)
Left anterior fascicle	Septal perforators (LAD)
Left posterior fascicle	Dual supply (LAD + RCA)

📌 Inferior MI (RCA) → AV nodal dysfunction (usually reversible)
📌 Anterior MI (LAD) → Bundle branch/fascicular block (often permanent)

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SECTION 2: SINUS NODE DYSFUNCTION

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2.1 OVERVIEW

Sinus Node Dysfunction (SND) = Inability of the SA node to generate impulses at a rate appropriate for physiological needs, or failure of impulse conduction to the atria.

Also Known As

Term

Sick Sinus Syndrome (SSS)

Sinoatrial Disease

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2.2 MANIFESTATIONS OF SND

2.2.1 Sinus Bradycardia

Definition	Sinus rhythm with rate < 60 bpm
ECG	Normal P wave morphology and axis; Regular rhythm; Rate < 60
Significance	Often physiological (athletes, sleep); Pathological if symptomatic

2.2.2 Sinus Arrest / Sinus Pause

Definition	Failure of SA node to generate impulse
ECG	Absent P waves for period NOT a multiple of PP interval
Significance	Pause > 3 seconds concerning; May cause syncope

2.2.3 Sinoatrial Exit Block

Definition	SA node fires but impulse fails to conduct to atrium
ECG	Pause IS a multiple of PP interval

Type	ECG Finding
First-degree SA block	Cannot be seen on surface ECG
Second-degree Type I	Progressive shortening of PP until dropped P
Second-degree Type II	Sudden dropped P; Pause = 2× PP interval
Third-degree SA block	No sinus P waves; Appears as sinus arrest

2.2.4 Tachy-Brady Syndrome

Definition	Alternating tachyarrhythmia (usually AF) and bradycardia
ECG	AF/AFL → Conversion → Long pause → Sinus bradycardia
Significance	Often symptomatic during pauses; Common indication for pacing

📌 Tachy-brady syndrome is the most common form of SND requiring pacemaker

2.2.5 Chronotropic Incompetence

Definition	Inability to increase heart rate appropriately with exercise
Diagnosis	Failure to achieve 80% of age-predicted maximum HR (220 - age) with exercise
Alternative	Failure to achieve heart rate reserve (HRR) > 80%
Significance	Causes exercise intolerance

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2.3 CLINICAL FEATURES OF SND

Symptoms

Symptom	Mechanism
Syncope / Pre-syncope	Prolonged pauses (especially post-tachycardia)
Dizziness / Lightheadedness	Bradycardia
Fatigue	Low cardiac output; Chronotropic incompetence
Exercise intolerance	Chronotropic incompetence
Dyspnea	Heart failure
Palpitations	Tachy-brady syndrome
Angina	Low diastolic perfusion
Cognitive impairment	Cerebral hypoperfusion

Natural History

Feature

Progressive condition

May develop AF (50% at 10 years)

AV conduction abnormalities develop in ~25%

Mortality depends on underlying heart disease

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2.4 DIAGNOSIS OF SND

ECG

Finding	Significance
Sinus bradycardia	< 60 bpm
Sinus pauses	> 3 seconds significant
SA exit block	Pause multiple of PP
AF/AFL with slow ventricular response	Without AV nodal blocking drugs
Escape rhythms	Junctional or ventricular

Holter / Ambulatory ECG Monitoring

Duration	Use
24-48 hour Holter	Frequent symptoms
7-14 day event recorder	Less frequent symptoms
Implantable loop recorder	Infrequent symptoms; Syncope workup

📌 Symptom-rhythm correlation is key – Document bradycardia during symptoms

Exercise Testing

Finding	Significance
Failure to increase HR adequately	Chronotropic incompetence
< 80% age-predicted max HR	Diagnostic

Electrophysiology Study (EPS)

Parameter	Normal Value
Sinus node recovery time (SNRT)	< 1500 ms
Corrected SNRT (cSNRT)	< 550 ms
Sinoatrial conduction time (SACT)	< 120 ms

Use of EPS

Not routinely needed

May help if diagnosis uncertain

Low sensitivity

Autonomic Testing

Test	Use
Carotid sinus massage	If carotid sinus hypersensitivity suspected
Tilt table test	If vasovagal syncope suspected
Atropine test	HR should increase > 90 bpm; Failure suggests intrinsic SND

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SECTION 3: AV CONDUCTION DISORDERS

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3.1 FIRST-DEGREE AV BLOCK

Definition

Prolongation of PR interval > 200 ms with all P waves conducted

ECG Features

Feature	Finding
PR interval	> 200 ms (> 5 small squares)
P waves	All conducted
QRS	Usually narrow

Clinical Significance

Point

Usually benign

No treatment required in isolation

May progress if PR very prolonged (> 300 ms)

May cause symptoms if PR very prolonged (”Pacemaker syndrome“ physiology with AV dyssynchrony)

Associated conditions should be evaluated

Causes

Cause

High vagal tone (athletes)

Drugs (Beta-blockers, CCBs, Digoxin, Amiodarone)

Ischemia

Degenerative conduction disease

Myocarditis

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3.2 SECOND-DEGREE AV BLOCK

3.2.1 Mobitz Type I (Wenckebach)

Definition

Progressive PR prolongation until a P wave fails to conduct

ECG Features

Feature	Finding
PR interval	Progressively prolongs
RR interval	Progressively shortens
Dropped beat	P wave not followed by QRS
Pause	< 2× shortest RR
QRS	Usually narrow (block at AV node)
”Footprints of Wenckebach“	Group beating pattern

Site of Block

Feature	Significance
Narrow QRS	Block usually at AV node
Wide QRS	Block may be at His-Purkinje level

Clinical Significance

Point

Usually benign

Block at AV node level

Often due to high vagal tone

May occur during sleep (normal)

Rarely requires pacing unless symptomatic

3.2.2 Mobitz Type II

Definition

Sudden failure of P wave conduction WITHOUT prior PR prolongation

ECG Features

Feature	Finding
PR interval	Constant before dropped beat
Dropped beat	Sudden; Not preceded by PR change
Pause	= 2× PP interval
QRS	Often wide (BBB present)

Site of Block

Feature	Significance
Below AV node	His bundle or bundle branches
Wide QRS	Confirms infranodal block

Clinical Significance

⚠️ IMPORTANT

High risk of progression to complete heart block

Unpredictable

Pacemaker usually indicated

More serious than Type I

3.2.3 2:1 AV Block

Definition

Every other P wave fails to conduct (2 P waves : 1 QRS)

ECG Features

Feature	Finding
P waves	Regular; Twice the QRS rate
Conduction	Alternate P waves conducted
PR interval	Constant for conducted beats

Distinguishing Type I vs Type II in 2:1 Block

Favors Type I (AV Node)	Favors Type II (Infranodal)
Narrow QRS	Wide QRS
PR prolonged (> 300 ms)	PR normal
Inferior MI	Anterior MI
Responds to Atropine	No response to Atropine
Worsens with carotid massage	May improve with carotid massage

📌 2:1 block cannot be definitively classified without longer rhythm strip showing Type I or Type II pattern

3.2.4 High-Grade (Advanced) AV Block

Definition

≥ 2 consecutive P waves fail to conduct (e.g., 3:1, 4:1 block)

Clinical Significance

⚠️ IMPORTANT

High risk of progression to complete heart block

Usually symptomatic

Pacemaker indicated

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3.3 THIRD-DEGREE (COMPLETE) AV BLOCK

Definition

Complete failure of conduction from atria to ventricles; Atria and ventricles beat independently (AV dissociation)

ECG Features

Feature	Finding
P waves	Regular; Independent of QRS
QRS	Regular; Independent of P waves
AV dissociation	PP interval ≠ RR interval; No relationship
Atrial rate	> Ventricular rate
Escape rhythm	Junctional or Ventricular

Escape Rhythm Characteristics

Escape Site	Rate	QRS Width
Junctional	40-60 bpm	Narrow
Ventricular	20-40 bpm	Wide

Clinical Significance

Point

Always significant

Usually symptomatic

Risk of asystole

Pacemaker required (unless reversible cause)

Congenital Complete Heart Block

Feature

Often due to maternal anti-Ro/La antibodies (SLE, Sjögren’s)

May be asymptomatic for years

Escape rhythm usually reliable (junctional)

Pacemaker if symptomatic, wide QRS escape, ventricular dysfunction

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3.4 BUNDLE BRANCH AND FASCICULAR BLOCKS

3.4.1 Right Bundle Branch Block (RBBB)

ECG Features

Feature	Finding
QRS duration	≥ 120 ms
V1-V2	rsR’ or rSR’ pattern (”M-shaped“)
V6, I	Wide S wave
ST-T	Secondary changes (discordant to terminal QRS)

Significance

Context	Significance
Isolated RBBB	Often benign (no structural HD)
With structural HD	Associated with worse prognosis
Acute RBBB	May indicate PE, MI
New RBBB in anterior MI	Risk of progression to complete HB

3.4.2 Left Bundle Branch Block (LBBB)

ECG Features

Feature	Finding
QRS duration	≥ 120 ms
V1-V2	QS or rS pattern
V5-V6, I, aVL	Broad monophasic R; No Q waves
ST-T	Secondary changes (discordant)
LAD	Common

Significance

Context	Significance
LBBB usually indicates structural HD	Always investigate
New LBBB + Chest pain	Treat as STEMI-equivalent
Chronic LBBB	CAD, HTN, Cardiomyopathy, Aortic valve disease
LBBB with HFrEF	CRT indication if QRS ≥ 130 ms

3.4.3 Left Anterior Fascicular Block (LAFB)

ECG Features

Feature	Finding
QRS duration	< 120 ms (usually)
Axis	Left axis deviation (-45° to -90°)
Lead I	qR
Lead II, III, aVF	rS

3.4.4 Left Posterior Fascicular Block (LPFB)

ECG Features

Feature	Finding
QRS duration	< 120 ms (usually)
Axis	Right axis deviation (> +90°)
Lead I	rS
Lead III	qR

⚠️ LPFB is rare – Must exclude RVH, Lateral MI, Pulmonary disease first

3.4.5 Bifascicular Block

Definition	Combination of two fascicles affected
RBBB + LAFB	Most common; RAD → LAD
RBBB + LPFB	Less common; LAD → RAD
Complete LBBB	Both left fascicles

Significance

Point

Increased risk of progression to complete HB

Annual risk ~1-2%

Pacemaker if symptomatic (syncope)

3.4.6 Trifascicular Block

Definition	Bifascicular block + First-degree AV block
Example	RBBB + LAFB + Prolonged PR
Significance	Suggests disease in third fascicle
Risk	Higher risk of complete HB

📌 Trifascicular block with syncope is indication for pacing

3.4.7 Alternating Bundle Branch Block

Definition	RBBB alternating with LBBB on same ECG or different ECGs
Significance	Very high risk of complete HB
Action	Pacemaker indicated

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3.5 AV DISSOCIATION

Definition

Atria and ventricles beating independently (not necessarily complete heart block)

Types

Type	Mechanism
Complete heart block	No conduction; Escape rhythm
Accelerated junctional/ventricular rhythm	Lower pacemaker faster than sinus (usurpation)
Sinus slowing	Sinus rate slows below escape rate
Interference dissociation	Combination of above

Key Point

📌 AV dissociation is NOT synonymous with complete heart block – It is a finding, not a diagnosis

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SECTION 4: CLINICAL ASSESSMENT

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4.1 HISTORY

Symptoms to Elicit

Symptom	Significance
Syncope	Most concerning; Suggests advanced block
Pre-syncope / Dizziness	May precede syncope
Fatigue	Bradycardia; Low cardiac output
Exercise intolerance	Chronotropic incompetence
Dyspnea	Heart failure; Pulmonary congestion
Chest pain	Ischemia; Angina
Palpitations	Tachy-brady syndrome; Escape beats
Confusion	Cerebral hypoperfusion (elderly)
Falls	Unwitnessed syncope (elderly)

Relevant History

Ask About

Duration and frequency of symptoms

Triggers (exercise, postural, micturition, coughing)

Previous cardiac history (MI, Heart failure)

Medications (Beta-blockers, CCBs, Digoxin, Amiodarone)

Family history of sudden death, pacemakers

Comorbidities (Thyroid, Sleep apnea, Renal disease)

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4.2 PHYSICAL EXAMINATION

Vital Signs

Parameter	Finding	Significance
Heart rate	< 60 bpm	Confirm bradycardia
Blood pressure	Low or Normal	Hemodynamic status
Respiratory rate	May be elevated	Pulmonary congestion

Cardiovascular Examination

Finding	Significance
Regular bradycardia	Sinus bradycardia; Complete HB
Irregular pulse	AF with slow response; Mobitz I; Sinus arrhythmia
Cannon A waves	AV dissociation (atria contracting against closed AV valves)
Variable S1 intensity	AV dissociation
Signs of heart failure	JVP elevation, Edema, Crackles

Look for Underlying Causes

Examination	Finding
Thyroid	Goiter; Signs of hypothyroidism
Jaundice	Severe liver disease
Cold peripheries	Hypothermia; Shock
Neurological	Signs of raised ICP; Muscular dystrophy

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4.3 INVESTIGATIONS

Essential Investigations

Test	Purpose
12-lead ECG	Diagnosis; Rhythm; Conduction defects
Continuous monitoring	Capture intermittent arrhythmia
Electrolytes (K⁺, Mg²⁺, Ca²⁺)	Hyperkalemia; Electrolyte disturbance
Renal function	Drug accumulation; Electrolyte context
TSH	Hypothyroidism
Troponin	If ischemia suspected
Drug levels	Digoxin if applicable

Additional Investigations

Test	Indication
Echocardiography	Structural heart disease; LV function
Holter / Ambulatory monitoring	Symptom-rhythm correlation
Implantable loop recorder	Infrequent symptoms; Unexplained syncope
Exercise stress test	Chronotropic incompetence; Exercise-induced block
Electrophysiology study	Selected cases; Risk stratification
Cardiac MRI	Infiltrative disease; Sarcoidosis; ARVC
Lyme serology	If epidemiologically indicated
Anti-Ro/Anti-La antibodies	Congenital CHB; Connective tissue disease

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4.4 AMBULATORY ECG MONITORING

Selection of Monitor

Monitor Type	Duration	Indication
Holter monitor	24-48 hours	Frequent symptoms (daily)
Extended Holter	7-14 days	Less frequent symptoms
Event recorder	2-4 weeks	Infrequent symptoms
Mobile cardiac telemetry	Up to 30 days	Unpredictable episodes
Implantable loop recorder (ILR)	Up to 3 years	Very infrequent; Unexplained syncope

Key Point

📌 Symptom-rhythm correlation is essential – Asymptomatic bradycardia may not need treatment

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4.5 CAROTID SINUS MASSAGE

Indication

Indication

Suspected carotid sinus hypersensitivity

Unexplained syncope (especially falls in elderly)

Technique

Step	Action
1	Patient supine; Continuous ECG and BP monitoring
2	IV access
3	Auscultate carotid (exclude bruit)
4	Firm massage over carotid body for 5-10 seconds
5	One side at a time
6	May repeat standing if negative supine

❌ Contraindications

Contraindication

Carotid bruit

History of stroke/TIA (recent)

History of VT/VF

Recent MI (< 3 months)

Diagnostic Criteria

Response	Definition
Cardioinhibitory	Asystole ≥ 3 seconds
Vasodepressor	SBP drop ≥ 50 mmHg
Mixed	Both

Carotid Sinus Syndrome

Definition	Abnormal response to carotid sinus massage + Reproduction of symptoms
Treatment	Pacemaker (if cardioinhibitory); Midodrine; Support stockings (if vasodepressor)

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SECTION 5: ACUTE MANAGEMENT

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5.1 INITIAL ASSESSMENT

Step 1: Assess Hemodynamic Stability

⚠️ UNSTABLE – Adverse Features

Hypotension (SBP < 90 mmHg)

Altered consciousness

Chest pain (ischemia)

Acute pulmonary edema

Signs of shock

Step 2: Identify Reversible Causes

Reversible Cause	Action
Drugs	Stop offending drug
Hyperkalemia	Treat urgently
Hypothyroidism	Thyroid replacement
Ischemia	Revascularization
Hypothermia	Rewarming

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5.2 ACUTE BRADYCARDIA ALGORITHM

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5.3 PHARMACOLOGICAL THERAPY

Atropine

Parameter	Details
Dose	500 μg (0.5 mg) IV bolus
Repeat	Every 3-5 minutes
Maximum	3 mg total
Mechanism	Vagolytic; Increases SA node automaticity and AV conduction
Most effective for	Sinus bradycardia; AV nodal block (Type I)
Less effective for	Infranodal block (Mobitz II, Complete HB with wide QRS)
⚠️ Caution	May worsen ischemia (↑ HR); Paradoxical slowing with < 500 μg doses

Isoprenaline (Isoproterenol)

Parameter	Details
Dose	2-10 μg/min IV infusion
Mechanism	Beta-adrenergic agonist; ↑ HR and AV conduction
Use	Bridge to pacing; Refractory bradycardia
⚠️ Caution	Proarrhythmic; ↑ Myocardial O₂ demand

Adrenaline (Epinephrine)

Parameter	Details
Dose	2-10 μg/min IV infusion
Mechanism	Alpha + Beta agonist
Use	Alternative to Isoprenaline; Hypotensive bradycardia
⚠️ Caution	Arrhythmogenic

Dopamine

Parameter	Details
Dose	5-20 μg/kg/min IV infusion
Mechanism	Dose-dependent dopaminergic, beta, alpha effects
Use	Alternative; Bradycardia with hypotension

Aminophylline

Parameter	Details
Dose	250 mg slow IV (over 20-30 min)
Mechanism	Adenosine antagonist
Use	May help in inferior MI with AV block

Glucagon

Parameter	Details
Dose	1-5 mg IV bolus; Then 2-10 mg/hr infusion
Mechanism	Increases cAMP independent of beta-receptors
Use	Beta-blocker or CCB overdose

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5.4 TEMPORARY PACING

Indications for Temporary Pacing

Indication

Hemodynamically significant bradycardia unresponsive to drugs

Bridge to permanent pacing

Reversible cause while awaiting resolution

Post-cardiac surgery bradycardia

During interventions (PCI of vessel supplying conduction system)

Overdrive pacing for torsades de pointes

Types of Temporary Pacing

Type	Description	Use
Transcutaneous	External pads; Quick; Painful; Standby/Bridge	Emergency; Standby
Transvenous	Wire in RV; More reliable	Sustained temporary pacing
Epicardial	Post-cardiac surgery	Post-operative

Transcutaneous Pacing

Step	Action
1	Apply pads (anterior-posterior or anterior-lateral)
2	Set rate (60-80 bpm)
3	Set output at max, then decrease until capture lost, then increase by 10%
4	Confirm electrical AND mechanical capture
5	Sedation/analgesia for conscious patient

Capture Confirmation

Pacing spike followed by wide QRS

Palpable pulse with each paced beat

Transvenous Pacing

Access	Internal jugular or Femoral vein
Position	RV apex under fluoroscopy
Rate	60-80 bpm
Output	Find threshold; Set at 2-3× threshold
Sensitivity	Adjust to sense native rhythm

Complications of Temporary Pacing

Complication

Failure to capture

Failure to sense

Lead displacement

Ventricular perforation / Tamponade

Infection

Venous thrombosis

Arrhythmias (VT from wire irritation)

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5.5 BRADYCARDIA IN SPECIFIC SETTINGS

5.5.1 Acute Myocardial Infarction

Inferior MI

Finding	Notes
Sinus bradycardia	Common; Vagal; Usually responds to Atropine
First-degree AV block	Usually transient
Mobitz Type I	Usually transient; Rarely needs pacing
Complete heart block	Usually narrow QRS; Escape reliable; Often resolves in 1-2 weeks
Management	Observation; Temporary pacing if hemodynamically unstable

Anterior MI

Finding	Notes
New RBBB / LBBB / LAFB	Suggests extensive infarct
Mobitz Type II	High risk; Often needs pacing
Complete heart block	Wide QRS; Unreliable escape; High mortality
Management	Early temporary pacing; Often needs permanent pacing

📌 Anterior MI with conduction block carries worse prognosis than Inferior MI

5.5.2 Drug Overdose

Beta-Blocker Overdose

Management

Atropine (often ineffective)

💊 Glucagon 1-5 mg IV (first-line)

Isoprenaline / Adrenaline

High-dose insulin euglycemic therapy

Temporary pacing

VA-ECMO if refractory

Calcium Channel Blocker Overdose

Management

💊 Calcium gluconate 10% 10-20 mL IV (or Calcium chloride)

Atropine

💊 Glucagon

High-dose insulin euglycemic therapy

Isoprenaline / Adrenaline

Temporary pacing

VA-ECMO if refractory

Digoxin Toxicity

Management

Stop Digoxin

Correct hypokalemia

💊 Digoxin-specific antibody fragments (Digibind/DigiFab)

Temporary pacing if needed

Avoid calcium (controversial – may worsen)

5.5.3 Hyperkalemia

Management

Calcium gluconate 10% 10-30 mL IV (cardioprotection)

Insulin 10 units + Glucose 50 mL 50% IV (shift K⁺ into cells)

Salbutamol nebulizer 10-20 mg (shift K⁺)

Sodium bicarbonate (if acidotic)

Furosemide (if volume overloaded)

Dialysis (definitive)

Temporary pacing if needed

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SECTION 6: PERMANENT PACING

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6.1 GENERAL PRINCIPLES

Indications for Permanent Pacing

Pacing is indicated when bradycardia causes symptoms or poses risk, and is not due to a reversible cause

Key Questions Before Pacing

Question

Is there symptom-rhythm correlation?

Is the cause reversible?

What is the natural history without pacing?

What pacing mode is optimal?

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6.2 INDICATIONS FOR PACING IN SND

Class I (Recommended)

Indication

SND with documented symptomatic bradycardia (including frequent sinus pauses)

Symptomatic chronotropic incompetence

Symptomatic sinus bradycardia due to required drug therapy

Class IIa (Reasonable)

Indication

SND with HR < 40 bpm when symptoms consistent with bradycardia present but not documented

Syncope of unexplained origin with major SND abnormalities on EPS

Class IIb (May Be Considered)

Indication

Minimally symptomatic patients with chronic HR < 40 bpm while awake

Class III (Not Indicated)

❌ Not Indicated

Asymptomatic SND

SND where symptoms are not related to bradycardia

Symptomatic bradycardia due to nonessential drug therapy

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6.3 INDICATIONS FOR PACING IN AV BLOCK

Third-Degree (Complete) AV Block

Class I (Recommended)

Indication

Complete AV block with symptoms

Complete AV block with arrhythmias requiring drugs that worsen bradycardia

Complete AV block with documented asystole ≥ 3 seconds or escape rate < 40 bpm (awake, asymptomatic)

Complete AV block post AV node ablation

Complete AV block post cardiac surgery (not expected to resolve)

Complete AV block with neuromuscular disease (even if asymptomatic)

Second-Degree AV Block

Class I (Recommended)

Indication

Mobitz Type II (with or without symptoms)

High-grade AV block (with or without symptoms)

Symptomatic second-degree AV block

Second-degree AV block with neuromuscular disease

Class IIa (Reasonable)

Indication

Asymptomatic Type II at intra- or infra-His level on EPS

Class III (Not Indicated)

❌ Not Indicated

Asymptomatic Mobitz Type I at supra-His (AV nodal) level

First-Degree AV Block

Class IIa (Reasonable)

Indication

Marked first-degree AV block (PR > 300 ms) with symptoms of pacemaker syndrome

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6.4 INDICATIONS FOR PACING IN BUNDLE BRANCH BLOCK

Class I (Recommended)

Indication

Alternating bundle branch block

Bifascicular/Trifascicular block with Mobitz Type II

Bifascicular/Trifascicular block with intermittent complete HB

Class IIa (Reasonable)

Indication

Syncope + Bifascicular block when other causes excluded

HV interval ≥ 100 ms on EPS (asymptomatic)

Pacing-induced infra-His block on EPS

Class IIb (May Be Considered)

Indication

Neuromuscular disease with any fascicular block

Class III (Not Indicated)

❌ Not Indicated

Asymptomatic fascicular block without AV block

Fascicular block with first-degree AV block (asymptomatic)

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6.5 INDICATIONS FOR PACING IN ACUTE MI

Class I (Recommended)

Indication

Persistent second-degree AV block in His-Purkinje system with alternating BBB OR third-degree AV block within or below His-Purkinje system post-STEMI

Transient advanced (second- or third-degree) infranodal AV block + associated BBB

Persistent symptomatic second- or third-degree AV block

Class IIb (May Be Considered)

Indication

Persistent second- or third-degree AV block at AV node level (even asymptomatic)

Class III (Not Indicated)

❌ Not Indicated

Transient AV block without intraventricular conduction defects

Transient AV block with isolated LAFB

Acquired LAFB without AV block

Persistent first-degree AV block with old or age-indeterminate BBB

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6.6 INDICATIONS FOR PACING IN SPECIFIC CONDITIONS

Carotid Sinus Syndrome

Class I

Recurrent syncope caused by carotid sinus stimulation with asystole > 3 seconds

Neurocardiogenic (Vasovagal) Syncope

Class IIa

Age > 40 years with recurrent syncope and documented cardioinhibitory response (asystole > 3 seconds or symptomatic bradycardia) AND failure of conventional treatment

Infiltrative / Inflammatory Disease (Sarcoidosis)

Indication

AV block (even first-degree) in cardiac sarcoidosis should prompt pacing consideration

Neuromuscular Disease

Indication

Lower threshold for pacing due to unpredictable progression

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6.7 SUMMARY TABLE: PACING INDICATIONS

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SECTION 7: PACEMAKER TYPES AND SELECTION

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7.1 PACEMAKER CODE (NBG CODE)

Common Pacing Modes

Mode	Description	Use
AAI®	Atrial pacing/sensing; Inhibited by atrial activity	SND with intact AV conduction
VVI®	Ventricular pacing/sensing; Inhibited by ventricular activity	AF with slow ventricular response; Backup pacing
DDD®	Dual chamber pacing/sensing; Dual response	SND with AV block risk; AV block
VDD	Atrial sensing, Ventricular pacing	AV block with intact SA node

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7.2 PACEMAKER SELECTION

Selection by Diagnosis

Diagnosis	Recommended Mode
SND with intact AV conduction	AAI® or DDD®
SND with AV block or risk of AV block	DDD®
AV block with intact sinus node	VDD or DDD®
AV block with chronotropic incompetence	DDD®
Chronic AF with slow ventricular response	VVI®
Carotid sinus syndrome	DDD
Vasovagal syncope	DDD (with rate drop response)

Benefits of Dual-Chamber Over Single-Chamber

Benefit

Maintains AV synchrony

Reduces risk of pacemaker syndrome

Reduces risk of AF (compared to VVI)

Better exercise capacity

Better quality of life

Pacemaker Syndrome

Definition	Symptoms from loss of AV synchrony (usually with VVI pacing in patients with sinus rhythm)
Symptoms	Fatigue, Dyspnea, Dizziness, Pulsations in neck (cannon A waves)
Treatment	Upgrade to dual-chamber pacing

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7.3 RATE-RESPONSIVE PACING

Indication

Indication

Chronotropic incompetence

Active patients

Sensors

Sensor Type	Mechanism
Accelerometer	Detects movement/vibration
Minute ventilation	Measures respiratory rate and tidal volume
QT interval	Shortens with catecholamines

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7.4 LEADLESS PACEMAKERS

Description

Feature

Self-contained device implanted directly in RV

No leads; No pocket

Single-chamber (VVI) currently available

Dual-chamber systems emerging

Advantages

Advantage

No lead-related complications

No pocket-related complications

Better cosmesis

Lower infection risk

Disadvantages

Disadvantage

Single-chamber only (VVI) – Currently

Cannot be removed easily

Limited battery life options

Higher cost

Indications (Current)

Indication

AF with AV block (VVI mode appropriate)

Patients with vascular access issues

Patients at high infection risk

Limited life expectancy

🇮🇳 India Availability

Status

Available but high cost

Limited centers

Micra (Medtronic) and Nanostim (Abbott)

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7.5 HIS BUNDLE PACING (HBP) AND LEFT BUNDLE BRANCH AREA PACING (LBBAP)

Concept

Pacing Type	Description
His Bundle Pacing	Lead placed at His bundle; Physiological activation
Left Bundle Branch Area Pacing	Lead placed in LV septum capturing left bundle; More reliable

Advantages

Advantage

Maintains normal ventricular activation

Avoids RV pacing-induced cardiomyopathy

May be alternative to CRT

Disadvantages

Disadvantage

Higher capture thresholds (HBP)

Technical challenges

Learning curve

Not suitable for all

🇮🇳 India Availability

Status

Increasing adoption in specialized centers

LBBAP gaining popularity

Cost similar to conventional

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7.6 CARDIAC RESYNCHRONIZATION THERAPY (CRT)

Indication

Criteria

LVEF ≤ 35%

Sinus rhythm

LBBB with QRS ≥ 150 ms (Class I) OR QRS 130-149 ms (Class IIa)

NYHA II-IV on optimal GDMT

CRT-P vs CRT-D

Type	Description	Indication
CRT-P	Biventricular pacing only	HF criteria met; No ICD indication
CRT-D	CRT + ICD	HF criteria + ICD criteria

Role in Bradycardia

Scenario

If patient needs pacing AND has HFrEF with LBBB, consider CRT

If patient needs pacing AND has HFrEF, consider CRT (to avoid RV pacing-induced cardiomyopathy)

If patient has ICD AND develops high RV pacing burden with deterioration, consider upgrade to CRT

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SECTION 8: PACEMAKER IMPLANTATION AND FOLLOW-UP

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8.1 PRE-IMPLANT CONSIDERATIONS

Pre-Procedure Checklist

Item

Informed consent

Review indications

Check renal function (contrast)

Review medications (anticoagulation)

Allergies (contrast, antibiotics)

Baseline labs (CBC, Coagulation, Electrolytes)

IV access

NPO for 6-8 hours

Anticoagulation Management

Scenario	Management
On Warfarin	Continue (INR 2-3) OR Bridge with LMWH
On DOAC	Omit 1-2 doses pre-procedure; Resume 24-48 hrs post
High thromboembolic risk	Heparin bridging OR Continue warfarin (pocket hematoma risk acceptable)

📌 BRUISE CONTROL Trial: Continuing Warfarin during PPM/ICD implant reduces pocket hematoma compared to bridging

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8.2 IMPLANT PROCEDURE

Standard Approach

Step	Action
1	Local anesthesia (± sedation)
2	Venous access (Subclavian, Axillary, or Cephalic vein)
3	Lead placement under fluoroscopy
4	Test parameters (Threshold, Sensing, Impedance)
5	Create pocket (subcutaneous or submuscular)
6	Connect leads to generator
7	Close wound
8	Post-procedure CXR

Lead Positions

Lead	Standard Position
Atrial	Right atrial appendage
Ventricular	RV apex or RV septum
LV (CRT)	Coronary sinus → Lateral/Posterolateral vein

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8.3 COMPLICATIONS

Early Complications (< 30 days)

Complication	Incidence	Management
Pneumothorax	1-2%	CXR; Observation vs Chest drain
Hemothorax	< 1%	Chest drain
Cardiac perforation / Tamponade	< 1%	Pericardiocentesis; Surgery
Pocket hematoma	2-5%	Conservative vs Evacuation
Lead dislodgement	1-3%	Repositioning
Infection (early)	< 1%	Antibiotics ± Extraction
Venous thrombosis	1-2%	Anticoagulation
Air embolism	Rare	Supportive

Late Complications

Complication	Notes
Infection (late)	May require complete extraction
Lead fracture	Lead revision
Lead insulation failure	Lead revision
Generator erosion	Reposition
Tricuspid regurgitation	Monitor
Venous stenosis/occlusion	May limit upgrade
Pacemaker syndrome	Upgrade to dual-chamber
RV pacing-induced cardiomyopathy	Consider CRT/LBBAP
Device malfunction	Troubleshoot
End of battery life	Generator replacement

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8.4 FOLLOW-UP SCHEDULE

What to Check at Follow-Up

Parameter	Purpose
Battery voltage	Estimate remaining life
Lead impedance	Detect lead fracture/insulation failure
Sensing	Ensure adequate sensing
Capture threshold	Ensure adequate capture
Pacing percentage	Assess pacing burden
Arrhythmia logs	Detect AF, VT
Patient symptoms	Ensure appropriate pacing

Battery Indicators

Status	Action
BOL (Beginning of Life)	New battery; Full function
MOL (Middle of Life)	Normal function
ERI (Elective Replacement Indicator)	Plan generator replacement within 3-6 months
EOL (End of Life)	Urgent replacement; May have backup pacing only

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8.5 REMOTE MONITORING

🇮🇳 India Status

Status

Increasingly available

Requires patient engagement and internet access

Cost considerations

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8.6 MRI SAFETY

MRI-Conditional Pacemakers

Feature

Most modern devices are MRI-conditional

Specific conditions must be met (field strength, SAR limits, lead positions)

Device must be reprogrammed to MRI mode before scan

Interrogate device after MRI

MRI-Non-Conditional (Legacy Devices)

Feature

MRI generally contraindicated

If MRI essential, can be done in specialized centers with precautions

Weigh risks vs benefits

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SECTION 9: SPECIAL SITUATIONS

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9.1 PACING IN ATRIAL FIBRILLATION

AF with Slow Ventricular Response

Scenario	Management
Symptomatic slow AF (without AV nodal blocking drugs)	VVI® pacemaker
Slow AF due to necessary AV nodal blocking drugs	VVI® pacemaker
AF with HFrEF	Consider CRT (if pacing expected > 40%)

”Ablate and Pace“ Strategy

Indication	Rate control failure in AF
Procedure	AV node ablation + Permanent pacemaker (preferably CRT if HFrEF)
Outcome	Excellent rate control; Improved symptoms
Caveats	Pacemaker-dependent; Anticoagulation continues

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9.2 PACING IN HEART FAILURE

RV Pacing-Induced Cardiomyopathy

Definition	LV dysfunction caused by RV apical pacing
Mechanism	Dyssynchronous activation similar to LBBB
Risk Factors	High pacing burden (> 40%); Pre-existing LV dysfunction
Prevention	Minimize RV pacing; Use physiological pacing (HBP/LBBAP); CRT if HFrEF

Upgrade to CRT

Indication

Pacemaker patient with LVEF ≤ 35% and RV pacing ≥ 40% with worsening HF

Consider HBP or LBBAP as alternative

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9.3 PACING IN PREGNANCY

Considerations

Point

Existing pacemaker: Generally safe in pregnancy

New implant: Can be done with minimal fluoroscopy; Lead positioning with echo/ECG guidance

Rate-response may need adjustment

Vaginal delivery generally safe

Avoid monopolar diathermy (can inhibit pacing)

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9.4 PACING IN INFILTRATIVE DISEASE

Cardiac Sarcoidosis

Point

High rate of progression of conduction disease

Lower threshold for pacing (even first-degree AV block if symptomatic)

Consider ICD if high arrhythmia risk

MRI important for diagnosis and monitoring

Cardiac Amyloidosis

Point

Conduction disease common

Consider pacing for symptomatic bradycardia

Often combined with AF

Prognosis depends on underlying amyloid type

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9.5 PACING IN NEUROMUSCULAR DISEASE

High-Risk Conditions

Disease

Myotonic dystrophy

Emery-Dreifuss muscular dystrophy

Limb-girdle muscular dystrophy

Kearns-Sayre syndrome

Key Points

Point

Unpredictable progression

May develop AV block suddenly

Lower threshold for pacing

Consider prophylactic pacing in high-risk patients

May need ICD for SCD risk

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9.6 BRADYCARDIA IN ATHLETES

Physiological vs Pathological

Physiological	Pathological
Resting HR 30-50 bpm (normal)	Symptomatic bradycardia
Mobitz Type I (during sleep)	Mobitz Type II
First-degree AV block	High-grade AV block
Junctional rhythm	Prolonged pauses (> 3 sec awake)
Asymptomatic	Syncope, Exercise intolerance

Evaluation

If symptomatic or concerning features

Detailed history

Holter monitoring

Exercise testing (HR response)

Consider underlying cause

Management

Management

Most athletic bradycardia needs no treatment

Detraining may be tried if suspected pathological

Pacing if symptomatic or high-risk features

Return to sport usually possible with pacemaker (avoid contact sports with conventional devices)

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SECTION 10: PATIENT EDUCATION

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10.1 GENERAL ADVICE FOR PACEMAKER PATIENTS

Daily Living

Topic	Advice
Wound care	Keep dry for 1-2 weeks; Watch for signs of infection (redness, swelling, discharge, fever)
Arm movement	Avoid raising arm above shoulder on implant side for 4-6 weeks
Driving	Usually 1 week restriction for PPM; Check local regulations
Return to work	Usually 1-2 weeks; Avoid heavy lifting for 4-6 weeks
Exercise	Avoid strenuous upper body exercise for 4-6 weeks; Then resume normal activity
Sexual activity	Usually safe after 1-2 weeks

Device Awareness

Topic	Advice
Carry pacemaker ID card	Always
Medical alert bracelet	Recommended
Inform healthcare providers	Always mention pacemaker before procedures
Airport security	Walk through metal detectors; Request hand search if concerned; Show ID card

Electromagnetic Interference

Device/Situation	Advice
Mobile phones	Keep > 15 cm from device; Use opposite ear
Household appliances	Generally safe
Microwave ovens	Safe
Anti-theft devices	Walk through normally; Don’t linger
MRI	Check if device is MRI-conditional; Inform MRI team
TENS machines	May interfere; Use with caution
Diathermy	Avoid monopolar; Bipolar safer
Welding	Arc welding may interfere; Caution
Strong magnets	Avoid close contact (can activate magnet mode)

When to Seek Medical Attention

⚠️ Contact Clinic If

Signs of wound infection

Device moving or eroding through skin

Return of original symptoms (dizziness, syncope, fatigue)

Palpitations

Hiccups or muscle twitching (diaphragmatic pacing)

Unexplained shortness of breath

Chest pain

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10.2 DRIVING REGULATIONS

🇮🇳 India

Condition	Recommendation
PPM for SND/AV block	1 week off driving after implant
PPM for syncope	1 week off driving
ICD (secondary prevention)	6 months off driving
ICD (primary prevention)	1 month off driving
After appropriate ICD shock	6 months off driving
Commercial driving	Generally not permitted with ICD

📌 Note: India does not have formal national regulations; Follow international guidelines (EHRA/ESC recommendations)

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10.3 END-OF-LIFE CONSIDERATIONS

Pacemaker Deactivation

Point

Legal and ethical to deactivate at patient’s request

Patient must be informed of consequences

Document discussion and decision

In pacemaker-dependent patient, deactivation will lead to bradycardia/asystole

Palliative care involvement recommended

ICD Deactivation

Point

More commonly discussed in end-of-life

Shocks at end-of-life can be distressing

Deactivate tachytherapy (shocks) while keeping pacing

Can be done with magnet or reprogramming

Advance care planning discussion recommended

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SECTION 11: INDIAN GUIDELINES AND CONSIDERATIONS

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11.1 CSI/IHRS RECOMMENDATIONS

Key Points from Indian Guidelines

Recommendation

Pacing indications aligned with international guidelines (ESC/ACC)

Dual-chamber pacing preferred when AV synchrony needed

Rate-responsive pacing for chronotropic incompetence

CRT for eligible HFrEF patients

HBP/LBBAP gaining acceptance as physiological pacing

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11.2 PRACTICAL CONSIDERATIONS IN INDIA

Cost Issues

Issue	Solution
Device cost	Basic devices more affordable; Premium features add cost
Insurance	Variable coverage; Many patients self-pay
Government schemes	Ayushman Bharat covers some procedures
Choice of device	Balance features vs cost; Essential features prioritized

Follow-Up Challenges

Challenge	Solution
Distance from center	Remote monitoring when available
Lost to follow-up	Patient education; Community health worker engagement
Limited centers	Develop regional pacing clinics

Generator Replacement

Issue

Patients may delay replacement due to cost

Education about ERI/EOL importance

Planning for replacement well in advance

Specific Indian Considerations

Consideration

Younger age at implant (compared to West)

Infective endocarditis risk in RHD patients

Chagas disease in migrants

Tropical infections affecting conduction

Adherence to follow-up

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11.3 DEVICE SELECTION IN RESOURCE-LIMITED SETTINGS

Pragmatic Approach

Scenario	Recommendation
Limited budget, AF + AV block	VVI® acceptable
Limited budget, SND without AV block	AAI® acceptable (if AV conduction definitely intact)
Young patient with expected long life	Invest in quality dual-chamber
Elderly with limited life expectancy	Simplest appropriate device
HFrEF needing pacing	CRT preferred; Consider LBBAP

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SECTION 12: SUMMARY TABLES

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12.1 AV BLOCK COMPARISON

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12.2 CAUSES OF AV BLOCK BY LEVEL

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12.3 PACING MODE SELECTION

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12.4 ACUTE BRADYCARDIA DRUG DOSES

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12.5 PACING INDICATIONS QUICK REFERENCE

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12.6 COMPLICATIONS OF PACING

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12.7 FOLLOW-UP SCHEDULE

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📚 ABBREVIATIONS

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📖 REFERENCES

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Document Version: 1.0

Last Updated: December 2025

For: Healthcare Professionals Only

Disclaimer: Clinical judgment must be exercised for individual patients. Local protocols and resource availability should guide management. This guideline integrates international and Indian recommendations. Do not self-medicate.

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