Electrophysiologic studies in tricuspid atresia

Area of Science:

• Cardiology
• Electrophysiology
• Pediatric Cardiology

Background:

• Tricuspid atresia is a congenital heart defect affecting right ventricular development.
• Understanding conduction abnormalities is crucial for managing tricuspid atresia.
• His bundle studies provide insights into the cardiac conduction system.

Purpose of the Study:

• To investigate electrophysiological characteristics in patients with tricuspid atresia.
• To correlate His bundle study findings with conduction patterns and axis deviation.
• To assess the functional integrity of the atrioventricular node and bundle branches.

Main Methods:

• His bundle electrophysiological studies were performed in five patients with tricuspid atresia.
• Catheter placement near the mitral valve ring.
• Right atrial pacing and measurement of refractory periods in three patients.

Main Results:

• Prolonged intraatrial conduction time observed in all patients, attributed to right atrial dilation and hypertrophy.
• Normal A-H intervals noted in all patients.
• Short H-V intervals in three patients and normal H-V intervals in two patients.
• Left axis deviation correlated with short H-V intervals (early posterior left bundle branch activation) and normal H-V intervals (anomalous left bundle course).
• Normal responses to atrial pacing and normal refractory periods, indicating functional AV node and bundle branch integrity.

Conclusions:

• Prolonged intraatrial conduction is a consistent finding in tricuspid atresia, linked to right atrial remodeling.
• Variations in H-V intervals contribute to differing patterns of left ventricular activation and axis deviation.
• The atrioventricular conduction system generally maintains functional integrity despite tricuspid atresia.