Time matters: adenosine testing immediately after pulmonary vein isolation does not substitute a waiting period

Aims Adenosine testing can reveal dormant pulmonary vein (PV) conduction after PV antrum isolation (PVAI). However, the optimal timing for adenosine administration is unknown. We hypothesized that adenosine testing immediately after PVAI reliably reveals PV reconnection and thereby eliminates the need for an observation period. Methods and results Fifty patients underwent PVAI. Immediately after isolation of a PV pair, adenosine was administered. Both PV pairs were separately tested. If adenosine restored PV conduction, PVs were re-isolated. During a ≥30 min observation period after immediate adenosine-guided isolation, spontaneous reconnection was assessed and reconnected PVs were re-isolated. After the observation period, adenosine testing was repeated. Immediate adenosine testing revealed dormant conduction in 10.4% of the left PVs and 16.3% of the right PVs. All PVs were successfully re-isolated. During a mean observation period of 36 ± 10 min, spontaneous reconnection occurred in 8.2% of the left and 16.3% of the right PVs. None of these PVs had shown reconnection during immediate testing. Late adenosine testing revealed dormant conduction in 12.5% of the left and 16.3% of the right PVs. In patients without reconnection during immediate adenosine testing, 14.6% of the left PVs and 30.6% of the right PVs showed either spontaneous reconnection or restored PV conduction during late adenosine testing. Conclusion Adenosine testing immediately after PVAI does not reliably exclude later spontaneous or adenosine-induced PV reconnection. Adenosine testing should be performed after an appropriate observation period to reduce risk of PV reconnection.