Sinus Bradycardia

Sinus Bradycardia Overview

Sinus rhythm with a resting heart rate of < 60 bpm in adults, or below the normal range for age in children.

Normal heart rates in children

• Newborn: 110 – 150 bpm
• 2 years: 85 – 125 bpm
• 4 years: 75 – 115 bpm
• 6 years+: 60 – 100 bpm

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Causes of bradycardia

Non-pharmacological

Pharmacological

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Differential Diagnosis

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ECG Example

Sinus bradycardia secondary to anorexia nervosa

• Sinus bradycardia (35 bpm) in a 15-year old girl with anorexia nervosa.
• Note the prominent U waves in the precordial leads, a common finding in sinus bradycardia.

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Advanced Reading

Online

Textbooks

• Zimmerman FH. ECG Core Curriculum. 2023
• Mattu A, Berberian J, Brady WJ. Emergency ECGs: Case-Based Review and Interpretations, 2022
• Straus DG, Schocken DD. Marriott’s Practical Electrocardiography 13e, 2021
• Brady WJ, Lipinski MJ et al. Electrocardiogram in Clinical Medicine. 1e, 2020
• Mattu A, Tabas JA, Brady WJ. Electrocardiography in Emergency, Acute, and Critical Care. 2e, 2019
• Hampton J, Adlam D. The ECG Made Practical 7e, 2019
• Kühn P, Lang C, Wiesbauer F. ECG Mastery: The Simplest Way to Learn the ECG. 2015
• Grauer K. ECG Pocket Brain (Expanded) 6e, 2014
• Surawicz B, Knilans T. Chou’s Electrocardiography in Clinical Practice: Adult and Pediatric 6e, 2008
• Chan TC. ECG in Emergency Medicine and Acute Care 1e, 2004

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LITFL Further Reading

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