Summary
Definition
History and exam
Key diagnostic factors
- presence of risk factors
- age >50-60 years
- syncope
- heart rate <40 bpm
- pre-syncope
Other diagnostic factors
- male sex
- fatigue
- dyspnoea
- chest pain, palpitations, and nausea or vomiting
- high (less commonly, low) blood pressure
- cannon A waves
- hypoxaemia
- family history of AV block
- features of Lyme disease
Risk factors
- age-related degenerative changes in the conduction system
- increased vagal tone
- AV-nodal blocking agents
- chronic stable CAD
- acute coronary syndrome
- CHF
- hypertension
- cardiomyopathy
- left ventricular hypertrophy
- recent cardiac surgery
- acid-base or electrolyte disturbance
- neuromuscular disorders
- sarcoidosis
- myocarditis
- infective endocarditis
- hypoxemia
- blunt cardiac injury
- some indigenous medicines
Diagnostic investigations
1st investigations to order
- 12-lead ECG
- serum troponin
- serum potassium
- serum calcium
- serum pH
- serum digitalis level
Investigations to consider
- 24-hour ambulatory monitoring or event monitoring
- chest x-ray
- transthoracic echocardiogram
- serological testing for Lyme disease
- implantable loop recording
- tilt-table testing
- electrophysiological study
- cardiac stress testing
- coronary angiography
- serum CK-MB
Treatment algorithm
Contributors
Authors
Consultant Cardiologist/Electrophysiologist
Royal Wolverhampton NHS Trust
Heart and Lung Centre
New Cross Hospital
Wolverhampton
UK
Disclosures
SP has received speaker's honoraria from Bayer, Bristol-Myers Squibb, MSD, and Pfizer. SP has received hospitality and/or accommodation from Bayer, Medtronic, St Jude, and Boston Scientific for attending conferences or meetings.
EP and Devices Fellow
New Cross Hospital
Wolverhampton
UK
Disclosures
JP declares that he has no competing interests.
Specialty Registrar Cardiology
New Cross Hospital
Wolverhampton
UK
Disclosures
AA declares that he has no competing interests.
Dr Petkar, Dr Pathiraja, and Dr Aziz would like to gratefully acknowledge Dr Susan S. Kim, Dr John F. Beshai, and Dr Stephen L. Archer, previous contributors to this topic. Dr Petkar would also like to gratefully acknowledge the assistance of Dr Arka Das. AD, SSK, JFB, and SLA declare that they have no competing interests.
Peer reviewers
Professor of Medicine
Section of Cardiology
Director
Cardiac Electrophysiology
University of Chicago Medical Center
Chicago
IL
Disclosures
BPK declares that he has no competing interests.
Associate Professor of Medicine
Section of Cardiology
Cardiac Electrophysiology
University of Chicago Medical Center
Chicago
IL
Disclosures
MCB declares that he has no competing interests.
Consultant Cardiologist
King’s College Hospital
London
UK
Disclosures
NG declares that he has no competing interests.
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