What are the treatment options for conduction disease?

Treatment Options for Conduction Disease

Permanent pacing is the primary treatment for symptomatic conduction disease, with the specific approach determined by the type and severity of the conduction disorder. 1

Evaluation of Conduction Disorders

• Transthoracic echocardiogram is recommended for patients with newly detected left bundle branch block (LBBB) to exclude structural heart disease 1
• Ambulatory electrocardiographic monitoring is essential in symptomatic patients with conduction system disease to document suspected atrioventricular block 1
• Electrophysiology studies (EPS) are reasonable in patients with symptoms suggestive of intermittent bradycardia with conduction system disease identified by ECG 1
• Advanced imaging (cardiac MRI, CT, or nuclear studies) should be considered in selected patients with LBBB when structural heart disease is suspected but echocardiogram is unrevealing 1

Treatment Indications for Permanent Pacing

Class I Indications (Strongly Recommended)

• Patients with syncope and bundle branch block who have an HV interval ≥70 ms or evidence of infranodal block at EPS 1
• Patients with alternating bundle branch block 1

Class IIa Indications (Reasonable)

• Patients with Kearns-Sayre syndrome and conduction disorders 1
• Patients with marked first-degree or second-degree Mobitz type I (Wenckebach) atrioventricular block with symptoms clearly attributable to the block 1
• Patients with lamin A/C gene mutations with PR interval >240 ms and LBBB 1
• Patients with infiltrative cardiomyopathies (cardiac sarcoidosis or amyloidosis) and high-grade atrioventricular block 1

Class IIb Indications (May Be Considered)

• Patients with Anderson-Fabry disease and QRS prolongation >110 ms 1
• Patients with neuromuscular diseases (e.g., myotonic dystrophy type 1) with PR interval >240 ms, QRS duration >120 ms, or fascicular block 1
• Patients with heart failure, mildly to moderately reduced left ventricular ejection fraction (36%-50%), and LBBB (QRS ≥150 ms) 1

Class III (Not Recommended)

• Asymptomatic patients with isolated conduction disease and 1:1 atrioventricular conduction 1

Pacing Modalities

• Conventional Right Ventricular Pacing: Traditional approach but may lead to pacing-induced cardiomyopathy with chronic use 2
• Conduction System Pacing (CSP): Novel approach that preserves physiological ventricular activation 3, 2
  • Left bundle branch area pacing (LBBAP) has shown high success rates (93%) in patients with AV conduction disease 3
  • LBBAP success rates remain high across the spectrum of AV conduction disease with stable lead parameters during follow-up 3
• Cardiac Resynchronization Therapy (CRT): Should be considered in patients with heart failure, reduced ejection fraction, and LBBB 1
• Atrioventricular node ablation with CRT: Should be considered in severely symptomatic patients with permanent atrial fibrillation and at least one hospitalization for heart failure 1

Special Considerations

• In patients with conduction disease and suspected bradyarrhythmias, the choice of cardiac monitoring should be based on symptom frequency and nature 1
• Antiarrhythmic drug therapy is not recommended in patients with advanced conduction disturbances unless antibradycardia pacing is provided 1
• Pediatric patients with restrictive cardiomyopathy require aggressive ECG monitoring for conduction system disease, as they are at risk for acute high-grade heart block 4
• Patients with congenital complete atrioventricular block or congenital heart disease may benefit from conduction system pacing to preserve ventricular synchrony 2

Monitoring and Follow-up

• Regular monitoring of pacemaker function and lead parameters is essential 3
• Patients with progressive conduction disorders (e.g., neuromuscular diseases, infiltrative cardiomyopathies) require closer follow-up due to risk of disease progression 1, 4
• Ambulatory electrocardiographic monitoring can detect clinically significant arrhythmias even in asymptomatic patients with conduction system disease 1

Pitfalls and Caveats

• Conduction disorders may be the first manifestation of underlying structural heart disease or cardiomyopathy 1, 4
• Exercise-induced conduction disorders, particularly LBBB, are associated with increased risk of death and cardiac events 1
• True alternating bundle branch block indicates significant infranodal disease with high risk for sudden onset of complete heart block 1
• Progression of conduction disease can be unpredictable, especially in infiltrative or genetic disorders 5, 4