What is the diagnosis and treatment for Tachy-Brady (Tachycardia-Bradycardia) syndrome?

From the Guidelines

Tachy-Brady syndrome should be treated with implantation of a permanent pacemaker to manage the bradycardia component, and additional medications such as beta-blockers may be prescribed for patients who also experience tachyarrhythmias, as recommended by the 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay 1.

Treatment Overview

The treatment of Tachy-Brady syndrome typically involves a combination of permanent pacemaker implantation and medication therapy. The goal of treatment is to alleviate symptoms, prevent complications, and improve quality of life.

• Permanent pacemaker implantation is the primary treatment for managing the bradycardia component of Tachy-Brady syndrome.
• Additional medications, such as beta-blockers (e.g., metoprolol 25-100 mg twice daily) or calcium channel blockers (e.g., diltiazem 120-360 mg daily), may be prescribed to control tachyarrhythmias.
• Anticoagulation therapy, such as warfarin (target INR 2-3) or direct oral anticoagulants like apixaban (5 mg twice daily), may be necessary to prevent stroke in patients with atrial fibrillation.

Pathophysiology and Diagnosis

Tachy-Brady syndrome, also known as sick sinus syndrome, is a cardiac condition characterized by alternating episodes of bradycardia and tachycardia. The condition results from age-related degenerative changes in the conduction system, fibrosis of the sinoatrial node, or sometimes from medications that affect heart rate. Diagnosis is typically made based on symptoms, electrocardiogram (ECG) findings, and Holter monitoring results.

• The pathophysiologic link between sick sinus node dysfunction and atrial fibrillation remains incompletely understood, and is an active area of investigation 1.
• The severity of symptoms is often related to the length of pause, and patients may experience syncope, fatigue, dizziness, or more serious complications like heart failure or stroke.

Guideline Recommendations

The 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay recommends permanent cardiac pacing for patients with symptomatic bradycardia, including those with Tachy-Brady syndrome 1.

• The guideline also recommends treatment of atrial tachyarrhythmias with ablation or medication therapy, as appropriate.
• Regular monitoring with ECGs and Holter monitoring is necessary to assess treatment efficacy and adjust therapy as needed.

From the FDA Drug Label

Flecainide acetate should be used only with extreme caution in patients with sick sinus syndrome because it may cause sinus bradycardia, sinus pause, or sinus arrest.

The FDA drug label mentions Sick Sinus Syndrome (Bradycardia-Tachycardia Syndrome), which is also known as Tachy-Brady syndrome.

• Flecainide acetate should be used with extreme caution in patients with this condition.
• It may cause sinus bradycardia, sinus pause, or sinus arrest in these patients 2.

From the Research

Definition and Characteristics of Tachy Brady Syndrome

• Tachy-brady syndrome (TBS) is a complication of sick sinus syndrome (SSS) characterized by alternating tachycardia and bradycardia 3
• It is also known as tachycardia-bradycardia syndrome, and is marked by the heart's inability to perform its pacemaking function 4
• TBS is predominantly affecting older adults, and comprises various arrhythmias, including bradyarrhythmias with or without accompanying tachyarrhythmias 4

Diagnosis and Treatment of Tachy Brady Syndrome

• Diagnosis of TBS may be challenging, and is ultimately made by electrocardiographic identification of the arrhythmia in conjunction with the presence of symptoms 4
• Treatment of TBS includes removing extrinsic factors, when possible, and pacemaker placement 4
• Pacemakers do not reduce mortality, but they can decrease symptoms and improve quality of life 4
• Rate control is also an important aspect of managing TBS, and can be achieved through the use of various medications, such as calcium-channel blockers, digoxin, and beta blockers 5

Electrophysiological Mechanisms and Future Therapeutic Approaches

• The electrophysiological mechanisms of TBS involve dysfunction of ion channels responsible for initiation or conduction of cardiac action potentials 3
• Alternatives to electronic pacemakers, such as gene-based bio-artificial sinoatrial node and cell-based bio-artificial pacemakers, are promising techniques whose long-term safety and efficacy need to be established 3
• The role of adenosine in treating TBS is also being explored, and may provide a new approach to managing this condition 6

Clinical Implications and Management

• TBS patients who receive pacemakers for bradycardia may still experience atrial tachyarrhythmias, and require rate or rhythm control 5
• Inappropriate rate control in patients with pacemaker can lead to increased hospitalizations and symptoms, highlighting the need for improved rate control strategies 5
• A significant proportion of TBS patients succeed to maintain sinus rhythm using an anti-arrhythmic drug with a significant pacing use, suggesting preventive pacemaker implantation might be advantageous in these cases 7