Summary
Definition
History and exam
Key diagnostic factors
- age >50-60 years
- underlying cardiovascular factors
- syncope
- heart rate <40 bpm
- presyncope
Other diagnostic factors
- male gender
- fatigue
- dyspnea
- chest pain, palpitations, and nausea or vomiting
- high (less commonly, low) blood pressure
- cannon A waves
- hypoxemia
- 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 coronary artery disease
- acute coronary syndrome
- recent cardiac surgery, intervention, or ablation
- congestive heart failure (CHF)
- hypertension
- cardiomyopathy
- left ventricular hypertrophy
- acid-base or electrolyte disturbance
- neuromuscular disorders
- sarcoidosis
- giant cell myocarditis
- cardiac tuberculosis
- lyme disease
- infective endocarditis
- hypoxemia
- blunt cardiac injury
- some indigenous medicines
Diagnostic tests
1st tests to order
- 12-lead ECG
- serum troponin
- serum potassium
- serum calcium
- serum pH
- serum digitalis level
Tests to consider
- 24-hour ambulatory monitoring or event monitoring
- chest x-ray
- transthoracic echocardiogram
- serologic testing for Lyme disease
- tilt-table testing
- electrophysiology study
- cardiac stress testing
- coronary angiography
- serum CK-MB
Treatment algorithm
first-degree AV block or type I second-degree AV block
type II second-degree AV block or third-degree AV block
Contributors
Authors
Sanjiv Petkar, MD, FRCP
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.
Dibbendhu Khanra, MD, DM Cardiology
International Clinical Fellow in Electrophysiology and Devices
Royal Wolverhampton NHS Trust
Heart and Lung Centre
New Cross Hospital
Wolverhampton
UK
Disclosures
DK declares that he has no competing interests.
Gaurav Panchal, MBBS, MRCP
Specialist Registrar in Cardiology/Electrophysiology
Royal Wolverhampton NHS Trust
Heart and Lung Centre
New Cross Hospital
Wolverhampton
UK
Disclosures
GP declares that he has no competing interests.
Acknowledgements
Dr Petkar, Dr Khanra, and Dr Panchal would like to gratefully acknowledge Dr Pathiraja, Dr Aziz, Dr Susan S. Kim, Dr John F. Beshai, and Dr Stephen L. Archer, previous contributors to this topic. JP, AA, SSK, JFB, and SLA declare that they have no competing interests.
Peer reviewers
Bradley P. Knight, MD
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.
Martin C. Burke, DO
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.
Nick Gall, MSc, MD, FRCP
Consultant Cardiologist
King’s College Hospital
London
UK
Disclosures
NG declares that he has no competing interests.
Thomas A. Dewland, MD
Associate Professor of Medicine
University of California
San Francisco
CA
Disclosures
TAD declares that he has no competing interests.
Differentials
- Junctional rhythm
- Supraventricular tachycardia (SVT)
- Atrial fibrillation or multifocal atrial tachycardia (MAT)
More DifferentialsGuidelines
- 2022 AHA/ACC/HFSA guideline for the management of heart failure
- 2021 ESC guidelines on cardiac pacing and cardiac resynchronization therapy
More GuidelinesPatient information
Atrial fibrillation
Heart attack
More Patient information
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