service de cardiologie hôpital militaire de tunis

MANAGEMENT OF ASYMPTOMATIC

BRADYCARDIA

Pr. HABIB HAOUALA

Service de Cardiologie

Hôpital militaire de Tunis

DISCLOSURESTATEMENT OF FINANCIAL INTEREST

Grant/research: Medtronic;Sanofi; Novartis

Consulting fees/ honoraria: SJMédical; Boston Scientific

BRADYCARDIA

Asystole Bradycardia < 50 bpm

Borderline 50-60 bpm

Normal (60-100 bpm)

Tachycardia > 100 bpm

Bradycardia < 50 bpm Borderline 50-60 bpm

bradycardia in child

Asymptomatic bradycardia

A condition in which a person has

bradycardia, or a slow heart rhythm, without

any of the classic symptoms of bradycardia

(dizziness, irregular heart beat, chest pain,

shortness of breath, fatigue, and light

headedness…)

Asymptomatic sinus bradycardia is usually

harmless and is often a sign of good

physical condition

Resting heart rate as a predictive

risk factor for sudden death

JOUVEN X Cardiovasc Res. 2001

May;50(2):373-8

Diagnosis of bradycardia

Carecterization of the

bradycardia Mechanism:

◦ Sinus node dysfunction

◦ Brady-arrythmia

◦ Atrio-ventricular block

Frequency

◦ Permanent

◦ Paroxysmal

General evaluation of

bradycardia Clinical evaluation

◦ Symptoms

◦ Drugs

◦ Daily activity

◦ Sports

◦ Familial history of bradycardia

General evaluation of bradycardia

Clinical evaluation

◦ Symptoms

◦ Drugs

◦ Daily activity

◦ Sports

◦ Familial history of bradycardia

Evaluation of the heart◦ Chest X ray

◦ Echocardiography

◦ MRI

◦ CT- Scan

◦ Angiography

Structural heart disease

(Valvular, ischaemic, congenital,

Hypertrophic, Dilated …)

Normal heart


Bradycardia evaluation

24-48 Hours ECG Monitoring

TREADMILL TEST

ATROPINE/ ISUPREL Test


ELECTROPHYSIOLOGY STUDY


24-48 Hours ECG Monitoring

• Long pauses

• Supraventricular arrhythmias

• Ventricular arrhythmias

• Chronotropic insufficiency



TREADMILL TEST

• Chronotropic

insufficiency

• Good exercise capacity



ATROPINE/ ISUPREL Test


Differentiation between intrinsic

and extrinsic bradycardia

ATROPINE/ISOPROTRENOL TEST

Europace. 2008 Oct;10(10):1176-

81



ELECTROPHYSIOLOGY STUDY

• Evaluation of sinus node function (Sinus node

recovery delay)

• Evaluation of the AV node conduction ( AH, HV,

LWC)

• Induction of arrhythmias

• May be useful in suspected ( not documented)

bradycardia

SINUS NODE DYSFUNCTION

Clinical case 1

22 years old man

Handball Player

W/H 120 Kgs/ 1,97m

He’s follwing an hypocaloric diet

No symptoms

Causes of sinus bradycardia

Physiologic extrinsic causes

Intrinsic causes

The athlete's heart

J Physiol. 2015 Apr 15; 593(Pt 8): 1749–1751.

Bradycardia in athletes is attributable to

High vagal tone J Physiol 593.8 (2015) pp 1745–1747

downregulation of a pacemaker

channel in the sinus node J Physiol. 2015 Apr 15; 593(Pt 8): 1749–1751.

Extrinsic causes of bradycardia

Drugs

◦ Digitalis glycosides, beta-blockers, and calcium channel-blocking agents.

◦ class I antiarrhythmic agents and Amiodarone

◦ lithium, paclitaxel, toluene, dimethyl sulfoxide (DMSO), topical ophthalmic

acetylcholine, fentanyl, alfentanil, sufentanil, reserpine, and clonidine

Pathologic conditions

◦ Hypothyroidism

◦ Hypothermia

◦ Hypoglycaemia

◦ Sleep apnoea

Infections

◦ Diphtheria

◦ Rheumatic fever

◦ Viral myocarditis

Intrinsic causes of sinus

bradycardia Sick Sinus Syndrome.

◦ Sinus bradycardia

◦ Sinus arrest

◦ Sino-atrial block

◦ Bradycardia tachycardia syndrome

Familial sinus bradycardia

Milanesi R et al. N Engl J Med 2006;354:151-157.

• Autosmal dominant

• Point mutation in the HCN4 cardiac ion channel

pore

• Genetic testing could play an important role in the

differentiation between benign and mailgnant

forms of familial sinus dysfunction

• Treadmill testing demonstrate normal

chronotropic and excercise capacity

Indications of Pacing in

patients with sinus node

dysfunction

BRADYARRYTHMIAS

Clinical case

84 Years old man

HTA, Type 2 Diabetes

Permanent atrial fibrillation

Moderate dyspnoea (NYHA class II)

No syncope, No dizziness

Sleep apnoea disorder

Sleep apnoea disorder

Long sinus pauses and AV block can

occur during sleep apnea in the

absence of symptoms these

abnormalaties are reversible and do

not require pacing

AV BLOCK

Atrio-ventricular block

Death in patients with untreated

atrioventricular (AV) block is due to:

◦ Heart failure (HF) secondary to low

cardiac output,

◦ Sudden cardiac death caused by

prolonged asystole or bradycardia-

triggered ventricular

tachyarrhythmia.

So, how should we manage

Asymptomatic AV block ?

First step◦ Is the AVB acute (reversible) or chronic

(irreversible) ?

Workup

Clinical evaluation

Drugs

Biology :Troponins, Serology diphtheria Lyme

disease typhoid , thyroid function

Imaging (TTE, MRI)

Coronary angiography

So, how should we manage

Asymptomatic AV block ?

Second step◦ What is the underlying heart disease ?

Structural heart disease

No structural heart disease

Indications of pacing in patients with

persistent bradycardia due to AV

block

Indications of pacing in patients with intermittent

documented bradycardia due to AV block

Asymptomatic chronic high degree/complete AV

block permanent or intermittent without structure

heart disease

Pacing indication in CAVB

A wide QRS escape rhythm, complex

ventricular ectopy, or ventricular dysfunction

I B

ventricular rate less than 55 bpm or with

congenital heart disease and a ventricular rate

less than 70 bpm.

I C

beyond the first year of life with an average

heart rate less than 50 bpm, abrupt pauses

ventricular rate that are 2 or 3 times the basic

cycle length, or associated with symptoms due

to chronotropic incompetence

II a B

in asymptomatic children or adolescents with

an acceptable rate, a narrow QRS complex,

and normal ventricular function. (II b B

II b B

Young people

Congenital AVBOld people

degenerative AVB

Pacemaker is

usually indicated

ACCF/AHA/HRS 2008 Guidelines

Asymptomatic chronic high

degre/complete AV block permanent or

intermittent with structure heart disease

Hypertrophic

cardiomyopathy




Hypertrophic

cardiomyopathy

Congenital heart disease




Hypertrophic

cardiomyopathy


Cardiac surgery/ TAVI




Hypertrophic

cardiomyopathy


Cardiac surgery/ TAVI

Muscular dystrophies

Implantation of

PM is encouraged

Conclusion

Asymptomatic bradycardia is diagnosed fortuitously

It’s often physiologically in athletes

It can be transient or permanent evolving on a paroxysmal or persistent mode

When asymptomatic bradycardia was diagnosed, a workup including heart imaging, ECG monitoring on rest and with exercise should be done to determine :◦ The underlying heart disease

◦ The mechanism exact of the bradycardia

Indication of the cardiac pacing depend on the two above conditions

THANK YOU FOR YOUR ATTENTION

service de cardiologie hôpital militaire de tunis

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