Distinctive Electrophysiological Properties of Pulmonary Veins in Patients With Atrial Fibrillation
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Background— Atrial fibrillation (AF) is frequently initiated from pulmonary veins (PVs), but little is known of the electrophysiological properties of PVs.
Methods and Results— Two groups were studied: 28 patients (49±13 years old) with paroxysmal AF and 20 control patients (49±14 years old) without AF. Effective and functional refractory period and conduction time from PV to left atrium (LA) were compared in the 2 groups by use of programmed stimulation with a single extrastimulus in the PVs and LA. In the AF group, the venous effective refractory periods (ERPs) were shorter than that of the LA: 185±71 versus 253±21 ms, P<0.001, whereas in the control group, they were longer (282±45 versus 253±41 ms, P=0.009). The venous ERPs and functional refractory periods in patients with AF were also shorter than that observed in control subjects (185±71 versus 282±45 ms and 210±77 versus 315±43 ms, respectively, P<0.001), whereas LA ERPs were not significantly different. Decremental conduction in PVs was more frequent (93% versus 56%, P=0.01) and had a greater increment (102±65 versus 42±40 ms, P<0.001) in patients with AF. Finally, AF was more frequently induced when pacing was performed in PVs (22 of 90) versus LA (1 of 81) in patients with AF (P<0.001).
Conclusions— The PVs of patients with AF exhibited distinctive electrophysiological properties, which were strikingly different from those of patients devoid of AF, potentially explaining their arrhythmogenicity.
Received June 12, 2002; revision received August 23, 2002; accepted August 24, 2002.