PMC:6019327 / 137761-140106 JSONTXT

{"project":"2_test","denotations":[{"id":"28506916-12687831-29307850","span":{"begin":466,"end":469},"obj":"12687831"},{"id":"28506916-12687831-29307850","span":{"begin":466,"end":469},"obj":"12687831"},{"id":"28506916-22683746-29307851","span":{"begin":747,"end":750},"obj":"22683746"},{"id":"28506916-22683746-29307851","span":{"begin":747,"end":750},"obj":"22683746"},{"id":"28506916-23461559-29307852","span":{"begin":751,"end":754},"obj":"23461559"},{"id":"28506916-23461559-29307852","span":{"begin":751,"end":754},"obj":"23461559"},{"id":"28506916-24763464-29307853","span":{"begin":862,"end":865},"obj":"24763464"},{"id":"28506916-24763464-29307853","span":{"begin":862,"end":865},"obj":"24763464"},{"id":"28506916-24446022-29307854","span":{"begin":866,"end":869},"obj":"24446022"},{"id":"28506916-24446022-29307854","span":{"begin":866,"end":869},"obj":"24446022"},{"id":"28506916-23918789-29307855","span":{"begin":870,"end":873},"obj":"23918789"},{"id":"28506916-23918789-29307855","span":{"begin":870,"end":873},"obj":"23918789"},{"id":"28506916-23778249-29307856","span":{"begin":1206,"end":1209},"obj":"23778249"},{"id":"28506916-23778249-29307856","span":{"begin":1206,"end":1209},"obj":"23778249"},{"id":"28506916-12435181-29307857","span":{"begin":1304,"end":1307},"obj":"12435181"},{"id":"28506916-12435181-29307857","span":{"begin":1304,"end":1307},"obj":"12435181"},{"id":"28506916-22683746-29307858","span":{"begin":1371,"end":1374},"obj":"22683746"},{"id":"28506916-22683746-29307858","span":{"begin":1371,"end":1374},"obj":"22683746"},{"id":"28506916-23778249-29307859","span":{"begin":1375,"end":1378},"obj":"23778249"},{"id":"28506916-23778249-29307859","span":{"begin":1375,"end":1378},"obj":"23778249"},{"id":"28506916-22385041-29307860","span":{"begin":1379,"end":1382},"obj":"22385041"},{"id":"28506916-22385041-29307860","span":{"begin":1379,"end":1382},"obj":"22385041"},{"id":"28506916-26960977-29307861","span":{"begin":1383,"end":1386},"obj":"26960977"},{"id":"28506916-26960977-29307861","span":{"begin":1383,"end":1386},"obj":"26960977"},{"id":"28506916-22385041-29307862","span":{"begin":1577,"end":1580},"obj":"22385041"},{"id":"28506916-22385041-29307862","span":{"begin":1577,"end":1580},"obj":"22385041"},{"id":"T15948","span":{"begin":466,"end":469},"obj":"12687831"},{"id":"T29531","span":{"begin":466,"end":469},"obj":"12687831"},{"id":"T48992","span":{"begin":747,"end":750},"obj":"22683746"},{"id":"T72384","span":{"begin":747,"end":750},"obj":"22683746"},{"id":"T93781","span":{"begin":751,"end":754},"obj":"23461559"},{"id":"T76025","span":{"begin":751,"end":754},"obj":"23461559"},{"id":"T3169","span":{"begin":862,"end":865},"obj":"24763464"},{"id":"T3378","span":{"begin":862,"end":865},"obj":"24763464"},{"id":"T49447","span":{"begin":866,"end":869},"obj":"24446022"},{"id":"T53075","span":{"begin":866,"end":869},"obj":"24446022"},{"id":"T55780","span":{"begin":870,"end":873},"obj":"23918789"},{"id":"T23359","span":{"begin":870,"end":873},"obj":"23918789"},{"id":"T11482","span":{"begin":1206,"end":1209},"obj":"23778249"},{"id":"T49085","span":{"begin":1206,"end":1209},"obj":"23778249"},{"id":"T21914","span":{"begin":1304,"end":1307},"obj":"12435181"},{"id":"T50909","span":{"begin":1304,"end":1307},"obj":"12435181"},{"id":"T36053","span":{"begin":1371,"end":1374},"obj":"22683746"},{"id":"T10416","span":{"begin":1371,"end":1374},"obj":"22683746"},{"id":"T75789","span":{"begin":1375,"end":1378},"obj":"23778249"},{"id":"T80170","span":{"begin":1375,"end":1378},"obj":"23778249"},{"id":"T96078","span":{"begin":1379,"end":1382},"obj":"22385041"},{"id":"T71006","span":{"begin":1379,"end":1382},"obj":"22385041"},{"id":"T95219","span":{"begin":1383,"end":1386},"obj":"26960977"},{"id":"T74726","span":{"begin":1383,"end":1386},"obj":"26960977"},{"id":"T62235","span":{"begin":1577,"end":1580},"obj":"22385041"},{"id":"T94895","span":{"begin":1577,"end":1580},"obj":"22385041"},{"id":"T36879","span":{"begin":466,"end":469},"obj":"12687831"},{"id":"T56722","span":{"begin":466,"end":469},"obj":"12687831"},{"id":"T2772","span":{"begin":747,"end":750},"obj":"22683746"},{"id":"T67777","span":{"begin":747,"end":750},"obj":"22683746"},{"id":"T73829","span":{"begin":751,"end":754},"obj":"23461559"},{"id":"T54063","span":{"begin":751,"end":754},"obj":"23461559"},{"id":"T86488","span":{"begin":862,"end":865},"obj":"24763464"},{"id":"T30471","span":{"begin":862,"end":865},"obj":"24763464"},{"id":"T77139","span":{"begin":866,"end":869},"obj":"24446022"},{"id":"T81132","span":{"begin":866,"end":869},"obj":"24446022"},{"id":"T24564","span":{"begin":870,"end":873},"obj":"23918789"},{"id":"T42172","span":{"begin":870,"end":873},"obj":"23918789"},{"id":"T38959","span":{"begin":1206,"end":1209},"obj":"23778249"},{"id":"T82327","span":{"begin":1206,"end":1209},"obj":"23778249"},{"id":"T62459","span":{"begin":1304,"end":1307},"obj":"12435181"},{"id":"T7123","span":{"begin":1304,"end":1307},"obj":"12435181"},{"id":"T59067","span":{"begin":1371,"end":1374},"obj":"22683746"},{"id":"T27754","span":{"begin":1371,"end":1374},"obj":"22683746"},{"id":"T18823","span":{"begin":1375,"end":1378},"obj":"23778249"},{"id":"T20235","span":{"begin":1375,"end":1378},"obj":"23778249"},{"id":"T59745","span":{"begin":1379,"end":1382},"obj":"22385041"},{"id":"T25658","span":{"begin":1379,"end":1382},"obj":"22385041"},{"id":"T14267","span":{"begin":1383,"end":1386},"obj":"26960977"},{"id":"T76316","span":{"begin":1383,"end":1386},"obj":"26960977"},{"id":"T23715","span":{"begin":1577,"end":1580},"obj":"22385041"},{"id":"T39162","span":{"begin":1577,"end":1580},"obj":"22385041"}],"text":"Exit Block\nAlthough the demonstration of entrance conduction block is the standard endpoint of PVI procedures, permanent PV exit conduction block (or the “stable absence of PV-LA conduction”) is the ultimate goal for prevention of PV-induced AF. Exit block can be demonstrated either by spontaneous discharges recorded circumferentially around the PV or by continuing arrhythmia within the PV, which are dissociated from sinus rhythm or by pacing from within the PV.476 In the case of PV pacing, it is imperative to demonstrate local PV capture without conduction to the LA to prove exit block. It is also important to avoid inadvertent capture of adjacent far-field structures, which would result in misinterpretation of apparent exit conduction.477,478 The presence of entrance block appears to be effective in predicting bidirectional block across CPVA lines.141,142,143 Mechanistically, the most likely explanation is source–sink mismatch, which is defined as delay or block of conduction observed when the size of a given excited region supplying depolarizing current (the current source) is insufficient for the amount of depolarizing current necessary to excite the regions ahead (the current sink).479 Although an initial report has observed unidirectional entrance block in more than 40% of PVs,445 the incidence was much lower in more recent studies (1.5%–16%).477,479,480,481 Interestingly, in one of these studies, the presence of PV discharges conducted to the LA (exit conduction) was followed by recovery of entrance conduction during a 30-minute waiting period.480 None of the reported studies compared success rates of PVI using only verification of PV entrance block vs bidirectional PV conduction block.\nThe above data would suggest that demonstration of exit block is feasible, and is a reasonable endpoint for AF ablation when combined with the presence of exit block. A survey of the writing group members shows that 60% routinely pace in the PV and employ exit block as an endpoint during AF ablation using RF energy, and 46% routinely pace in the PV and employ exit block as an endpoint during CBA. Based on this information, the published literature, and group experience, the writing group recommends that demonstration of exit block may be considered following PVI with RF or CB energy (Class IIb, LOE B-NR) (Table 3)."}