Dual-loop circuits in postoperative atrial macro re-entrant tachycardias

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Surgery

Background:

• Dual-loop re-entrant atrial arrhythmias can occur late after open-heart surgery.
• Mapping and catheter ablation of these arrhythmias are challenging, even with advanced computer-assisted mapping.

Purpose of the Study:

• To determine the prevalence and characteristics of dual-loop re-entrant arrhythmias post-cardiac surgery.
• To define an optimal mapping and catheter ablation strategy for these complex arrhythmias.

Main Methods:

• Studied 40 patients with intra-atrial re-entrant tachycardia (IART) post-open-heart surgery.
• Defined dual-loop IART by identifying two simultaneous atrial circuits.
• Used entrainment mapping and electroanatomical mapping to localize circuits and guide radiofrequency ablation.

Main Results:

• Dual-loop IART was found in 20% of patients, involving atrial flutter and atriotmy scar re-entry.
• Successful radiofrequency ablation was achieved in 88% of patients.
• Lower success rates were observed in dual-loop IART cases due to difficulties in ablating the second circuit.

Conclusions:

• Dual-loop IART is relatively common following heart surgery with right atriotomy.
• Abrupt tachycardia changes and specific entrainment mapping maneuvers are key to demonstrating these circuits.
• Electroanatomical mapping is vital for successful catheter ablation of periatriotomy circuits.