Conduction Disease Management

Evaluation and Diagnosis

The American College of Cardiology recommends transthoracic echocardiogram for patients with newly detected left bundle branch block to exclude structural heart disease 1, 3
Ambulatory electrocardiographic monitoring is essential in symptomatic patients with conduction system disease to document suspected atrioventricular block 2, 4
Electrophysiology studies are reasonable in patients with symptoms suggestive of intermittent bradycardia with conduction system disease identified by ECG 1, 5
Advanced imaging should be considered in selected patients with LBBB when structural heart disease is suspected but echocardiogram is unrevealing 1, 5

The American College of Cardiology recommends permanent pacing for patients with syncope and bundle branch block who have an HV interval ≥70 ms or evidence of infranodal block at EPS 1, 6
Patients with alternating bundle branch block are indicated for permanent pacing 1, 6
Patients with Kearns-Sayre syndrome and conduction disorders may be considered for permanent pacing 1, 6
Patients with marked first-degree or second-degree Mobitz type I atrioventricular block with symptoms clearly attributable to the block may be considered for permanent pacing 5, 3
Patients with lamin A/C gene mutations with PR interval >240 ms and LBBB may be considered for permanent pacing 5, 3
Patients with infiltrative cardiomyopathies and high-grade atrioventricular block may be considered for permanent pacing 5, 3

Cardiac Resynchronization Therapy should be considered in patients with heart failure, reduced ejection fraction, and LBBB 6, 3
Atrioventricular node ablation with CRT should be considered in severely symptomatic patients with permanent atrial fibrillation and at least one hospitalization for heart failure 7

In patients with conduction disease and suspected bradyarrhythmias, the choice of cardiac monitoring should be based on symptom frequency and nature 2, 4
Antiarrhythmic drug therapy is not recommended in patients with advanced conduction disturbances unless antibradycardia pacing is provided 7
Patients with progressive conduction disorders require closer follow-up due to risk of disease progression 5

Ambulatory electrocardiographic monitoring can detect clinically significant arrhythmias even in asymptomatic patients with conduction system disease 1

Conduction disorders may be the first manifestation of underlying structural heart disease or cardiomyopathy 1
Exercise-induced conduction disorders, particularly LBBB, are associated with increased risk of death and cardiac events 6
True alternating bundle branch block indicates significant infranodal disease with high risk for sudden onset of complete heart block 6