Electrophysiologic studies in patients with ventricular inversion and "corrected transposition"

Area of Science:

• Pediatric Cardiology
• Electrophysiology
• Congenital Heart Disease

Background:

• Ventricular inversion and transposition of the great arteries are complex congenital heart defects.
• Intracardiac conduction abnormalities can occur in these patients, impacting cardiac function.
• Accurate assessment of the conduction system is crucial for management.

Purpose of the Study:

• To evaluate intracardiac conduction intervals using His bundle recordings in pediatric patients with ventricular inversion and transposition of the great arteries.
• To localize the site of atrioventricular (AV) block in these patients.
• To determine the safety and utility of His bundle recording in this population.

Main Methods:

• His bundle recordings were performed in 40 patients with ventricular inversion and transposition of the great arteries.
• Patients were assessed for atrioventricular (AV) conduction status (1:1 AV conduction, first-degree AV block, complete AV block).
• The location of AV block was determined relative to the His bundle recording site.

Main Results:

• Twenty-nine subjects exhibited 1:1 atrioventricular (AV) conduction; 15 had normal conduction intervals comparable to healthy individuals.
• Among 14 patients with first-degree AV block, the block was localized to various sites within the conduction system.
• Eleven patients had complete AV block, with the block site identified in relation to the His bundle in most cases. Complete block below the His recording site was linked to syncope and sudden death in two patients.

Conclusions:

• His bundle recording is a safe and effective method for studying intracardiac conduction in children with ventricular inversion and transposition of the great arteries.
• This technique allows for precise localization of atrioventricular block, which is essential for understanding disease progression and guiding treatment.
• Identifying the site of block aids in risk stratification, particularly for severe conduction abnormalities associated with adverse outcomes.