WAVELENGTH AND ATRIAL VULNERABILITY - AN ENDOCAVITARY APPROACH IN HUMANS

If atrial vulnerability parameters are well defined, wavelength (WL) m easurement (conduction velocity x refractory period), has never been a ssessed through an endocavitary electrophysiological exam. We investig ated 30 patients (14 female, mean age 63.4 +/- 13 y.o.), 10 with parox ysmal atrial fibrillation (PAF group), 10 with ischemic cerebral injur y (ICI group) by comparison with 10 controls (C group). The upper to l ower right atrium conduction time and velocity were measured in the ri ght atrium with a decapolar electrode catheter applied along the free wall. Others parameters correlated to atrial excitability were also ta ken into account: effective (ERP) and functional refractory periods (F RP); spontaneous or paced atrial electrogram (Al) or extrastimulated a trial electrogram (A2) widths, ERP/A2 ratio, provocative atrial testin g. Measurements were taken in sinus rhythm and in 600-460 ms paced cyc le lengths. If ERP, FRP, Al widths are the same in the 3 groups, PAF a nd ICI groups have a significant increased conduction time and lower c onduction velocity, leading to a shorter Al WL during 600 and 460 ms p aced rhythms (p<0.05) and A2 WL during 460 ms paced rhythm. The provoc ative testing was positive in 60% of PAF and ICI groups, and there is a significant correlation between arrhythmia induction and 60 ms Al WL or 460 ms A2 WL. This electrophysiological study suggests the possibi lity of an approach in humans of wavelength concept and proves the pre sence of correlation between a short wavelength and atrial spontaneous or induced arrhythmias. A no-arrhythmia bond (Al WL > 17 cm during 60 0 ms paced rhythm, Al WL > 16 cm or A2 WL > 12 cm during 460 ms paced rhythm) and a fibrillation-band (Al WL < 12 cm during 600 and 460 ms p acing, A2 WL < 7 cm during 460 ms pacing) can be defined. Therefore, t he ICI group has the same atrial pattern as the AF group.