Can a brain bleed cause bradycardia (abnormally slow heart rate)?

From the Guidelines

A brain bleed can indeed cause bradycardia, particularly when it leads to increased intracranial pressure, triggering the Cushing reflex. This reflex is a physiological response to the pressure, characterized by a triad of increased blood pressure, irregular breathing, and a reduction in heart rate 1. The Cushing reflex is a critical body response aimed at maintaining cerebral perfusion pressure in the face of rising intracranial pressure. Key factors that influence the development of bradycardia in the context of a brain bleed include the location and severity of the hemorrhage. For instance, brainstem hemorrhages are more likely to affect the autonomic nervous system's control over heart rate, potentially leading to more pronounced bradycardia.

Some of the neurologic disorders associated with bradycardia, as outlined in the 2018 ACC/AHA/HRS guideline 1, include those that increase intracranial pressure, such as hemorrhagic strokes or traumatic brain injuries with bleeding. The management of bradycardia in these settings may involve treating the underlying cause, such as relieving the increased intracranial pressure, and supportive care to maintain adequate heart rate and blood pressure. The guideline also discusses the importance of considering permanent pacing in patients with progressive neurologic disorders that affect heart conduction 1.

In clinical practice, the presence of bradycardia in a patient with a brain bleed should prompt immediate evaluation and management to address both the cardiac and neurological issues. This may involve a multidisciplinary approach, including neurologists, cardiologists, and possibly neurosurgeons, depending on the nature and severity of the brain bleed. The goal is to stabilize the patient, prevent further neurological deterioration, and manage the bradycardia appropriately to ensure adequate cerebral and systemic perfusion.

Key considerations in managing such patients include:

• Prompt recognition of the Cushing reflex and its implications for patient management
• Close monitoring of heart rate, blood pressure, and neurological status
• Appropriate use of medical therapies to support heart rate and blood pressure as needed
• Consideration of the need for urgent neurosurgical intervention to relieve increased intracranial pressure
• Long-term management strategies for patients with persistent neurological deficits or cardiac conduction abnormalities.

From the Research

Brain Bleed and Bradycardia

• A brain bleed, also known as intracranial hemorrhage, can lead to increased intracranial pressure (ICP) which may cause bradycardia (abnormally slow heart rate) as part of Cushing's reflex 2.
• Cushing's reflex is characterized by hypertension, bradycardia, and apnea secondary to raised ICP, and is a protective mechanism to preserve cerebral perfusion pressure 2.
• Space-occupying lesions, such as subdural hematoma, can compress the brain parenchyma and lead to bradycardia 2.
• Intracranial pressure monitoring is crucial in managing patients with brain insults, including traumatic brain injury, subarachnoid hemorrhage, and malignant stroke, as it can help identify expanding intracranial mass lesions and prevent herniation events 3.
• The management of bradycardia in patients with brain bleed includes identification and treatment of the underlying cause, anti-cholinergics, and cardiac pacing if necessary 2.

Pathophysiology and Monitoring

• Intracranial hemorrhage can lead to increased ICP, which can impede nutrient delivery to the brain and cause cerebral perfusion pressure to decrease 3, 4.
• Monitoring of ICP is essential in managing patients with brain insults, and can help identify patients at risk of developing bradycardia and other complications 3.
• The pathophysiology of intracranial hemorrhage is complex and involves multiple factors, including the type and location of the hemorrhage, as well as individual patient characteristics 4, 5.

Diagnosis and Treatment

• The diagnosis of intracerebral hemorrhage involves imaging studies, such as CT or MRI, and laboratory tests to identify the underlying cause of the hemorrhage 6.
• Treatment of intracerebral hemorrhage includes medical and surgical interventions, such as controlling blood pressure, reversing anticoagulation, and surgical evacuation of the hematoma 6.
• Bradycardia can be a warning sign of increased ICP and brain herniation, and prompt treatment is essential to prevent further complications 2, 3.