Right atrial collision time (RACT): A novel marker of propensity for typical atrial flutter

Area of Science:

• Cardiology
• Electrophysiology
• Medical Diagnostics

Background:

• Typical atrial flutter (AFL) risk correlates with right atrial (RA) size and scarring, which reduce conduction velocity.
• These factors facilitate macro re-entrant wave propagation, crucial for AFL development.
• The time taken for a wave to traverse the re-entrant circuit may serve as a novel marker for AFL propensity.

Purpose of the Study:

• To investigate right atrial collision time (RACT) as a potential marker for existing typical AFL.
• To assess the diagnostic accuracy of RACT in differentiating patients with and without typical AFL.

Main Methods:

• A prospective, single-centre study involving 98 patients (41 with typical AFL, 57 controls) in sinus rhythm.
• Right atrial collision time (RACT) was measured by pacing the coronary sinus ostium and mapping activation times to find the latest collision point.
• RACT quantifies the conduction velocity and distance from the coronary sinus to the lateral right atrial wall collision point.

Main Results:

• Patients with typical AFL were older and more frequently male than controls.
• The mean RACT was significantly longer in the AFL group (132.6 ± 17.3 ms) compared to controls (99.1 ± 11.6 ms) (p < .001).
• A RACT cutoff of 115.5 ms demonstrated high diagnostic accuracy (92.7% sensitivity, 93.0% specificity) for typical AFL, with an AUC of 0.96.

Conclusions:

• Right atrial collision time (RACT) is a novel and promising marker for identifying propensity to typical AFL.
• These findings support the potential of RACT as a diagnostic tool for typical AFL.
• Further larger prospective studies are warranted to validate these results.