Summary
Definition
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
Other diagnostic factors
- increased intracranial pressure
- abnormal heart sounds
- abdominal or lower extremity edema
- hypotension
- mental status changes
- pallor
- extremities cool to touch
- hypothermia
- chest pain
- rashes
- thyroid goiter
Risk factors
- use of known causative medications
- age >70 years
- recent myocardial infarction
- surgery
- hypothyroidism
- electrolyte disorders
- acidosis
- infections
- exposure to toxins
- hypothermia
- infiltrative diseases
- sleep apnea
Diagnostic investigations
1st investigations to order
- 12-lead ECG
- Holter monitoring
- event monitor
- exercise testing
- carotid sinus massage
- echocardiogram
- thyroid function tests
- basic metabolic panel
- arterial blood gas
- cardiac biomarkers
- serum digoxin level
- serum creatinine
Investigations to consider
- implantable-loop recorder
- tilt-table testing
- Lyme titers
- electrophysiology testing
- nocturnal pulse oximetry or overnight polysomnography
Treatment algorithm
Contributors
Authors
Professor Emeritus
University of Iowa
Iowa City
Adjunct Professor
Des Moines University
Electrophysiologist
Mercy Hospital North Iowa
Mason City
Covenant Hospital
Waterloo
IA
Disclosures
BO is a national research study coordinator for Boehringer Ingelheim. He is a consultant and speaker for Lundbeck.
Cardiologist and Cardiac Electrophysiologist
Oregon Heart Center
Consultant, Cardiology and Cardiac Electrophysiology
Salem Health Hospitals and Clinics
Salem
OR
Disclosures
SS declares that he has no competing interests.
Director, Cardiac Electrophysiology Laboratories
Kansas City Heart Rhythm Institute and Research Foundation
EP Medical Director
Research Medical Center, HCA Midwest Health
Overland Park
KS
Clinical Professor of Medicine
University of Missouri-Columbia
Columbia
MO
Associate Professor of Medicine (adjunct)
University of Louisville
Louisville
KY
Disclosures
RG is a consultant for St. Jude Medical and Boston Scientific. He is on the speakers' bureau for Pfizer Inc., Bristol Myers Squibb, and Zoll Medical. He serves as a physician advisor for HealthTrust PG and Abiomed. 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.
Peer reviewers
Professor of Clinical Medicine
University of California
Chief
Clinical Cardiology
San Francisco General Hospital
Director
Coronary Care Unit
ECG Laboratory and Pacemaker Clinic
San Francisco
CA
Disclosures
NG declares that she has no competing interests.
Associate Professor of Medicine
Stanford University
Stanford
CA
Disclosures
PH declares that he has no competing interests.
Cardiology Center and Medical Polyclinics
University Hospital Geneva
Geneva
Switzerland
Disclosures
JMS declares that he has no competing interests.
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