Bradycardia in children refers to a heart rate unusually slow for their age. Unlike adults, a child’s normal heart rate varies significantly by developmental stage, making a universal definition challenging. Knowing what constitutes a slow heart rate in pediatric patients helps parents and caregivers recognize potential concerns. This means the heart pumps blood at a reduced pace, potentially impacting the body’s ability to receive sufficient oxygen and nutrients.
Defining Bradycardia by Age
Defining pediatric bradycardia requires considering the child’s age, as normal heart rates change from infancy through adolescence. For newborns (0-28 days), a resting heart rate below 100 bpm is typically bradycardia. In infants (1 month-1 year), a heart rate consistently below 90 bpm at rest may indicate bradycardia.
As children grow, normal resting heart rates generally decrease. For toddlers (1-3 years), bradycardia is often defined as less than 80 bpm; for preschoolers (3-5 years), it’s below 60-65 bpm. School-aged children (6-12 years) typically have a normal resting heart rate between 70 and 100 bpm; anything below 60 bpm is bradycardic. Adolescents (13-18 years) generally have adult-like heart rates; a resting rate below 50 bpm is often classified as bradycardia.
Factors Affecting Pediatric Heart Rate
A child’s heart rate naturally fluctuates due to physiological factors, sometimes leading to temporary decreases not indicative of true bradycardia. During sleep, heart rate typically slows considerably compared to waking hours. Physical activity, while generally increasing heart rate, can sometimes be followed by a temporary reduction as the body recovers.
Emotional states, such as relaxation or mild distress, can influence heart rate. Hydration status plays a role, with severe dehydration potentially affecting cardiovascular function. Fever, while often increasing heart rate, can sometimes be associated with relative bradycardia where the heart rate does not increase as expected.
Recognizing Symptoms
When a child experiences bradycardia, their body may not receive enough blood flow, leading to observable symptoms. Parents or caregivers might notice the child appears unusually tired or lethargic, lacking typical energy. In infants, poor feeding or difficulty suckling can be a sign. Respiratory issues, such as difficulty breathing or unusually slow and shallow breaths, can also be present.
Older children might report feeling dizzy or lightheaded, especially when standing quickly. In more severe cases, a child might faint or temporarily lose consciousness. Other signs include unusual paleness of the skin or a bluish tint to the skin. These symptoms, especially when occurring together, warrant prompt medical evaluation.
Common Causes
Pediatric bradycardia can stem from various underlying medical conditions or external factors. Congenital heart defects are a frequent cause, particularly those affecting the heart’s electrical system, like congenital heart block. Certain infections, like myocarditis, can impair the heart’s ability to beat effectively. Metabolic imbalances, such as severe electrolyte disturbances or hypothyroidism, can also slow the heart rate.
Certain medications can also induce bradycardia. Drugs like beta-blockers can intentionally lower heart rate. Accidental ingestion of toxins or exposure to extreme cold can also depress cardiac function. Head injuries or conditions that increase pressure within the brain can also manifest with a slowed heart rate.
Seeking Medical Attention
Knowing when to seek medical attention for suspected bradycardia is important. If a child exhibits concerning symptoms like severe lethargy, fainting, difficulty breathing, or bluish discoloration, immediate emergency medical attention is necessary. These signs suggest a critical reduction in blood flow and oxygen delivery. Parents should also seek urgent care if a child’s heart rate is consistently below the normal range for their age, even without other severe symptoms.
For less acute but persistent concerns, consulting a pediatrician is advisable. This includes situations where a child seems unusually tired over several days, has unexplained dizziness, or if a slow heart rate is detected incidentally. A medical professional can assess the child’s heart rate, conduct diagnostic tests, and determine if the bradycardia is a temporary physiological variation or indicative of an underlying condition requiring intervention.
References
1. Bradycardia. Cleveland Clinic. [https://my.clevelandclinic.org/health/diseases/21625-bradycardia](https://my.clevelandclinic.org/health/diseases/21625-bradycardia)
2. Bradycardia in Children. Children’s Hospital of Philadelphia. [https://www.chop.edu/conditions-diseases/bradycardia-children](https://www.chop.edu/conditions-diseases/bradycardia-children)