MANAGEMENT OF ASYMPTOMATIC BRADYCARDIA Pr. HABIB HAOUALA Service de Cardiologie Hôpital militaire de Tunis
DISCLOSURE STATEMENT 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
JOUVEN X Cardiovasc Res. 2001 May;50(2):373-8 Resting heart rate as a predictive risk factor for sudden death
Diagnosis of bradycardia
Diagnosis of bradycardia
Diagnosis of bradycardia
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
General evaluation of bradycardia Evaluation of the heart Chest X ray Echocardiography MRI CT- Scan Angiography Structural heart disease (Valvular, ischaemic, congenital, Hypertrophic, Dilated ) Normal heart
General evaluation of bradycardia Bradycardia evaluation 24-48 Hours ECG Monitoring TREADMILL TEST ATROPINE/ ISUPREL Test ELECTROPHYSIOLOGY STUDY
General evaluation of bradycardia Bradycardia evaluation 24-48 Hours ECG Monitoring Long pauses Supraventricular arrhythmias Ventricular arrhythmias Chronotropic insufficiency
General evaluation of bradycardia Bradycardia evaluation TREADMILL TEST Chronotropic insufficiency Good exercise capacity
General evaluation of bradycardia Bradycardia evaluation ATROPINE/ ISUPREL Test Differentiation between intrinsic and extrinsic bradycardia
ATROPINE/ISOPROTRENOL TEST Europace. 2008 Oct;10(10):1176-
General evaluation of bradycardia Bradycardia evaluation 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
ECG
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 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 Milanesi R et al. N Engl J Med 2006;354:151-157.
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 bradycardiatriggered 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 Young people Congenital AVB Old people degenerative AVB Pacing indication in CAVB A wide QRS escape rhythm, complex ventricular ectopy, or ventricular dysfunction ventricular rate less than 55 bpm or with congenital heart disease and a ventricular rate less than 70 bpm. 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 in asymptomatic children or adolescents with an acceptable rate, a narrow QRS complex, and normal ventricular function. (II b B I B I C II a B II b B 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
Asymptomatic chronic high degre/complete AV block permanent or intermittent with structure heart disease Hypertrophic cardiomyopathy Congenital heart disease
Asymptomatic chronic high degre/complete AV block permanent or intermittent with structure heart disease Hypertrophic cardiomyopathy Congenital heart disease Cardiac surgery/ TAVI
Asymptomatic chronic high degre/complete AV block permanent or intermittent with structure heart disease Hypertrophic cardiomyopathy Congenital heart disease Cardiac surgery/ TAVI Implantation of PM is encouraged Muscular dystrophies
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
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