What are the EKG findings in bradysinus (bradyarrhythmia)?

From the Guidelines

Bradycardia-tachycardia syndrome, also known as sick sinus syndrome, is typically diagnosed on an EKG by alternating periods of abnormally slow heart rates (bradycardia) and fast heart rates (tachycardia), and management involves pacemaker implantation and medications to control tachyarrhythmias, as recommended by the 2019 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.

Key Diagnostic Features

• Sinus bradycardia with heart rates below 60 beats per minute
• Sinus pauses or arrests lasting more than 3 seconds
• Sinoatrial exit block
• Episodes of supraventricular tachycardias like atrial fibrillation or atrial flutter
• Prolonged sinus pauses when tachyarrhythmias terminate before normal rhythm resumes

Management

• Pacemaker implantation to prevent bradycardia
• Medications to control tachyarrhythmias, such as:
  • Beta-blockers like metoprolol (25-100 mg twice daily)
  • Calcium channel blockers like diltiazem (120-360 mg daily in divided doses)
• Anticoagulation with drugs like apixaban (5 mg twice daily) or warfarin (dose adjusted to INR 2-3) if atrial fibrillation is present to prevent stroke, as supported by the 2012 ACCF/AHA/HRS focused update incorporated into the ACCF/AHA/HRS 2008 guidelines for device-based therapy of cardiac rhythm abnormalities 1.

Pathophysiology

• The sinoatrial node, the heart's natural pacemaker, becomes dysfunctional and cannot consistently generate appropriate electrical impulses, leading to these alternating rhythm disturbances.

From the Research

Bradysinus EKG

• Bradysinus, also known as sinus bradycardia, is a condition where the heart rate is slower than normal, typically less than 50-60 beats per minute (bpm) 2.
• Sinus bradycardia can be a normal phenomenon in young athletic individuals, and in patients as part of normal aging or disease 2.
• The evaluation and management of bradycardia should focus on the assessment of symptoms, rather than solely on the heart rate 2.
• Treatment for bradycardia should rarely be prescribed solely on the basis of a heart rate lower than an arbitrary cutoff or a pause above certain duration 2.

Causes of Bradysinus

• Certain medications, such as beta-adrenergic receptor antagonist drugs (beta-blockers) and non-dihydropyridine calcium-channel blockers (non-DHP CCBs), can cause sinus arrest or severe sinus bradycardia 3.
• The combination of beta-blockers and non-DHP CCBs can have additive effects, increasing the risk of profound bradycardia 3.
• Other factors, such as age, renal or hepatic disease, and the presence of other medications, can also contribute to the development of marked bradycardia with hypotension 3.

Management of Bradysinus

• Patients with permanent mild sinus bradycardia and syncope as an isolated symptom should undergo tilt testing and electrophysiological study 4.
• In the presence of a positive tilt test without very prolonged sinus node recovery time, the patient should be managed as patients with neurally mediated syncope and normal sinus rate 4.
• The management of bradycardia should be individualized, taking into account the underlying cause and the presence of symptoms 5, 2.