Impact of Low‐Dose Dipyridamole Injection on Adenosine Test after Pulmonary Vein Isolation

Abstract

Dipyridamole increases the levels of extracellular adenosine. The study investigates the impact of low-dose intravenous dipyridamole on adenosine test after pulmonary vein (PV) isolation (PVI). This prospective study included 12 paroxysmal atrial fibrillation (AF) patients (61 ± 12 years; nine men) who underwent PVI at the first procedure. Transient PV reconnection was provoked by adenosine test in 4/48 PVs. In 44 PVs without reconnection, intravenous infusion of low-dose (10 mg) dipyridamole preceded the adenosine test. Additional six patients (PVs) with transient dormant conduction were included. Among the total 10 PVs with transient reconnection, it was eliminated by radiofrequency (RF) application(s) until no dormant conduction was exposed by adenosine test(s) in five PVs. Then, dipyridamole potentiated adenosine test was undertaken to provoke dormant conduction (group 1). In the remaining five PVs, dipyridamole potentiated adenosine test was followed by RF elimination of conduction gap and repeat adenosine test to confirm complete elimination (group 2). Low-dose dipyridamole prolonged the duration of adenosine-induced atrioventricular block without vasodilatatory hypotension. There was no evidence of reconnection in 44 PVs without dormant conduction and in group 1 wherein transient reconnection was eliminated by 4.8 ± 3.2 RF applications in 8.8 ± 3.0 minutes and adenosine injected 3.1 ± 1.8 times. In group 2, dipyridamole plus adenosine test revealed the same dormant conduction that persisted longer than during adenosine alone. It was eliminated by single RF application in 3.4 ± 0.9 minutes, and adenosine was injected once. Low-dose dipyridamole safely prolongs the electrophysiological effects of adenosine test without provoking additional PV reconnection. This allows sustained visualization and facilitates complete RF elimination of the electrical conduction gap.