Last reviewed: 7 Apr 2021
Last updated: 12 Jan 2021

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 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
  • serologic testing for Lyme disease
  • tilt-table testing
  • electrophysiology study
  • cardiac stress testing
  • coronary angiography
  • serum CK-MB

Treatment algorithm

Contributors

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.

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.

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.

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 reviewersVIEW ALL

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.

Use of this content is subject to our disclaimer