Last reviewed: 1 Nov 2022
Last updated: 18 Nov 2021



History and exam

Key diagnostic factors

  • pulse rate <50 bpm
  • age >70 years
  • use of known causative medications
  • presence of known underlying cause
  • dizziness/lightheadedness
  • syncope
  • fatigue
  • exercise intolerance
  • shortness of breath
  • cannon a-waves in jugular venous pulse
  • jugular venous distension
More key diagnostic factors

Other diagnostic factors

  • increased intracranial pressure
  • abnormal heart sounds
  • abdominal or lower extremity oedema
  • hypotension
  • mental status changes
  • pallor
  • extremities cool to touch
  • hypothermia
  • chest pain
  • rashes
  • thyroid goitre
Other diagnostic factors

Risk factors

  • use of known causative medications
  • age >70 years
  • recent myocardial infarction
  • surgery
  • percutaneous valve replacement procedures
  • hypothyroidism
  • electrolyte disorders
  • acidosis
  • infections
  • exposure to toxins
  • hypothermia
  • infiltrative diseases
  • sleep apnoea
  • epilepsy
More risk factors

Diagnostic investigations

1st investigations to order

  • 12-lead ECG
  • Holter monitoring
  • event monitor/mobile cardiac telemetry
  • exercise testing
  • carotid sinus massage
  • echocardiogram
  • thyroid function tests
  • basic metabolic panel
  • arterial blood gas
  • cardiac biomarkers
  • serum digoxin level
  • serum creatinine
More 1st investigations to order

Investigations to consider

  • implantable-loop recorder
  • tilt-table testing
  • Lyme titres
  • electrophysiology testing
  • nocturnal pulse oximetry or overnight polysomnography
More investigations to consider

Treatment algorithm


haemodynamically unstable

haemodynamically stable: sinus node dysfunction

haemodynamically stable: acquired atrioventricular block

hemodynamically stable: congenital atrioventricular block

haemodynamically stable: vagally mediated bradycardia

haemodynamically stable: bradycardia associated with neurological disorders



Brian Olshansky, MD, FAHA, FACC, FHRS, FESC
Brian Olshansky

Professor Emeritus

University of Iowa

Iowa City

Adjunct Professor

Des Moines University


Mercy Hospital North Iowa

Mason City

Covenant Hospital




BO is a national research study coordinator for Boehringer Ingelheim. He is a consultant and speaker for Lundbeck. He is a consultant for Amarin and was chair of the DSMB of REDUCE-IT He is a consultant for Sanofi Aventis and Respicardia.

Sandeep Saha, MD, MS, FACP, FACC

Cardiologist and Cardiac Electrophysiologist

Oregon Heart Center

Consultant, Cardiology and Cardiac Electrophysiology

Salem Health Hospitals and Clinics




SS declares that he has no competing interests.

Rakesh Gopinathannair, MD, MA, FAHA, FACC, FHRS
Rakesh Gopinathannair

Director, Cardiac Electrophysiology Laboratories

Kansas City Heart Rhythm Institute and Research Foundation

EP Medical Director

Research Medical Center, HCA Midwest Health

Overland Park


Clinical Professor of Medicine

University of Missouri-Columbia



Associate Professor of Medicine (adjunct)

University of Louisville




RG is a consultant for St. Jude Medical, Biotrionik, and Boston Scientific. He is on the speakers' bureau for Pfizer Inc. and Zoll Medical. He serves as a physician advisor for HealthTrust PG and AltaThera Pharma, and PaceMate. None of these activities are relevant to the content of this topic.


Professor Brian Olshansky, Dr. Sandeep Saha, and Professor Rakesh Gopinathannair would like to gratefully acknowledge Dr Giselle Statz for her contributions to this version of the topic. They would also like to acknowledge Dr Renee M. Sullivan, Dr Weiwei Li, Dr Alexander Mazur, and Dr Chirag M. Sandesara, previous contributors to this topic.


GS, RMS, WL, AM, and CMS declare that they have no competing interests.

Peer reviewers

Nora Goldschlager, MD

Professor of Clinical Medicine

University of California


Clinical Cardiology

San Francisco General Hospital


Coronary Care Unit

ECG Laboratory and Pacemaker Clinic

San Francisco



NG declares that she has no competing interests.

Paul Heidenreich, MD

Associate Professor of Medicine

Stanford University




PH declares that he has no competing interests.

Juan M. Sztajzel, MD

Cardiology Center and Medical Polyclinics

University Hospital Geneva




JMS declares that he has no competing interests.

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