From the Guidelines
Bradycardia in young patients is most commonly caused by athletic conditioning, but can also result from various other factors including medication effects, hypothyroidism, structural heart conditions, neurological causes, electrolyte disturbances, infectious diseases, and genetic conditions. The causes of bradycardia in young patients can be diverse, ranging from benign explanations such as athletic conditioning to more serious underlying conditions.
- Athletic conditioning is a common cause of physiologic bradycardia in young athletes due to increased vagal tone and cardiac efficiency from regular training 1.
- Medication effects from beta-blockers, calcium channel blockers, or certain antiarrhythmics can also slow heart rate in young individuals.
- Hypothyroidism is another potential cause of bradycardia, even in younger patients.
- Structural heart conditions like congenital heart disease, myocarditis, or cardiomyopathies may present with bradycardia.
- Neurological causes include increased intracranial pressure, vasovagal responses, or autonomic dysfunction.
- Electrolyte disturbances, particularly hyperkalemia or hypocalcemia, can affect cardiac conduction.
- Infectious diseases like Lyme disease or viral infections may cause transient bradycardia.
- Certain genetic conditions such as congenital long QT syndrome or sick sinus syndrome can manifest in youth.
- Sleep apnea should also be considered, as it can cause nocturnal bradycardia even in young people. Evaluation should include a thorough history focusing on symptoms, medication use, and family history, along with appropriate cardiac testing such as ECG, echocardiogram, and possibly Holter monitoring depending on clinical presentation 1. The primary criterion for pacemaker implantation in young patients with sinus bradycardia is the concurrent observation of a symptom, such as syncope, with bradycardia 1. In the context of real-life clinical medicine, it is crucial to prioritize the evaluation and management of bradycardia based on the most recent and highest quality evidence, focusing on symptomatic bradycardia and its direct attribution to clinical manifestations 1.
From the Research
Causes of Bradycardia in Young Patients
- Bradycardia can be caused by various factors, including sinoatrial node dysfunction and atrioventricular (AV) conduction disturbances 2
- In young patients, bradycardia can occur in a structurally normal heart or in association with congenital heart disease 3
- Genetic variants in multiple genes have been described to contribute to the pathogenesis of inherited sinus node dysfunction or progressive cardiac conduction disorders 3
- Reversible causes of bradycardia include medication toxicity and hyperkalemia 4
- Pathology that produces bradycardia may occur within the sinus node, atrioventricular (AV) nodal tissue, and the specialized His-Purkinje conduction system 5
Types of Bradycardia in Young Patients
- Sinus bradycardia
- Junctional bradycardia
- Atrioventricular block 3
Management of Bradycardia in Young Patients
- Management and eventual prognosis of bradycardia in the young are entirely dependent upon the underlying cause 3
- Reasons to intervene for bradycardia are the association of related symptoms and/or the downstream risk of heart failure or pause-dependent tachyarrhythmia 3
- Early diagnosis and appropriate management are critical in order to prevent sudden death 3
- Treatment should rarely be prescribed solely on the basis of a heart rate lower than an arbitrary cutoff or a pause above certain duration 5