Buxton, A.E.

Campo, R.A.

Hsia, H.H.

Miller, J.M.

Panas, G.

Rothman, S.A.

Thome, L.M.

Elsevier - Publisher Connector 

laser dakvary will pmvonl IISSUQ superheaflng and charnng nnd allow d~rt?ct 
v~s~~l~~at~on of leston formalron dunng ablnlmn 
Methods In 4 nncsthellz6d dogs. Ihe stun over th6 IhIgh muscle was 
tnclsod and ratsed lo fan a cradle whtch was sup&used with hopannlroa 
cantno bled (3?‘C) A 10 F lumen ciilnator with a salme tntioted balloon (12 
mm m dInmeter) al Iho lip. A laser fiber (L300 II diamslar) and @n Imag!ng 
optic fibw (1200 11) WA% held perpendicular lo the thigh musclo. 44 le81ons 
were prndwxd by Qlkwtng Nd:YAG law energy. 1Q mm tom the surface 
at 1h~ thigh mwle. baser enqv was applied at % watts (for M) or 120 8~) 
and 10 wwa (for 3Q ar f3Q a%) In pulrrod mude (4 set onQ 90~ offI, Tissue 
tpmpemlure was mo~~umd al depth6 of 3.5 mm and 7 mm 
RGWIW 
y;; l6W al 7 mm demh 
10 5 GO ai;0 l.vlO 43 t e Qftt15 67112 
10 5 120 800 1:10 46 i 7 103tP1 rot 10 
t2 10 30 Oil2 &I2 49 1 e 1031t7 72?06 
t2 10 e0 002 lit2 52 t R’ 1151 13’ ?Bt10’ - 
“. 005 
Dunng ablabon. the margm of Iha lesson was caslly recogntzed by the 
darkencd color. Charting occurred anly when blood mhltrated between the 
balloon and trssue in path dthe laser. The bssue temperature at 3.5 mm depth 
quickty decreased by &tS*C betwean each laser pulse, while temperature 
al 7 mm depth steadtly rncreased 
Imagemg , k, 
cm Laser F&r 
F&f 
Laser 
Aadlabon 
Q 
@!ood 
Saflne 
‘\ lnfla!ed 
, i woon . 
Lesion 
Thigh r”tuscte 
Conc~r~s~ons: IntermRtent cookng ot ttssue by pulsmg the laser energy 
allows deep leston formatton wllhout steam tormahon and pop. Leston for- 
mation and tissue chamng can be marstored rvlth direct WSuallZ3tlOn 
j_l 1046 169 Ventricular Fusion During Auricular Entrainment of ldiapathic Fascicular Tachycardias. 
Implications on Ventricular Tachycardia Circuit 
J. Martmez-Atday' , J.M. Ormaetxe’ , J. Atmendral. E. Castellanos. 
R. Pemado. A. Pastor, A. Arena?. J. Villacastin. M.F. Arkotxa’ ‘Hosprfa/ de 
Basurto. f3rlbao. Spain: Hospital Gregono Maration. Madrid, Span 
/nlmducti&x ldiopathlc fascicular tachycardlas (IFT) are due to a macroreen- 
Iran? mochantsm. The presence of a muscular band (MB) and the lelt postenor 
hemibranch (LPH) as integral parts of the circuit IS controversial. 
Theoretical Model (TA!j: We propose two TMs 01 a MB connecting IO 
the LPH: A) stnctly muscular cucuit cunnectmg MB and LPH m a smgle 
attachment and B) MB conrtecfecl to LPB by hw arrachmenrs In which the 
MB could be either the antegrade (91) or the retrograde limb (82). If Ihe slow 
conduction zone (SCZ) were localized in the LPH. during atrial pacing in sinus 
rhythm at the tachycardla rate the QRS morphology would maintam a LP 
hem!block morphology. In models A and 82 during atnal entrainment (AE) the 
QRS morphology would be nanowed until its total normalization; However. 
in model B1 during AE we could demonstrate constant and progressive 
82 
Ven?nCUlar f?IslOn because O? COltIs1On through lefi antenor hr?nNbranch (w 
tcgure). 
&%farral WO studrod 7 p (6 M/Z F 0129 + 18 yo ) wtth IFT and a mean 
cycle length 01 388 x 51 ms.. 
~esurfs. Dunng pacmg m smus rhylhm none 01 the patlenta rtaed a LP 
hemlblock Panem auwal that Ihe SC2 18 not local~red In the LPH Dunng 
AE four p nonnalired the QRS morphology and three p. showed constant 
and progressive fusion suggest model 81 
Conc/usrons- mts stucfy shows for the l~rst lrme ventncutar tflton dunng 
AE In ?FT and suggcsls that the SCZ 1s not localized m the LPti but m the 
MB. howover tho attachment between the MB and the LPH could be dw+%se 
1046-l 70 Anlsc’mpic Reentry aa a MsChanlrm at 
Ventrlcutar Tachycardia in Patients 
M.J. Schaltf. F.P van Rugge. M.A. Siezenga. E.Y. van der Velde 
Deparimenf of Cardrology Unrversrry Hospffal Leaden. L&en, rhfl 
Netherlands 
BacQround- Previous work has suggested that reentrant circuits causing 
ventncular tachycardla (VT) m patents (pts) are relatively large, wrth an tm- 
pulse circulatmg amtxl scar trssue, and pantally propagating Through a zone 
of slow c mductron wlthm survwmg subencrocard~al cellayers. However fl IS 
hypothetued. that because o? mcreased tissue amsotropy. reentry may oc- 
cur wlthm such an area of survwmg aubendocardtal cellayw . . Cunsequemty 
these clrcu~ts will be relatively small Th!s study was conducted to test fhls 
hVpo?hests dunng sustamed VT m pts 
Methods. A basket-shaped 32.bipolar electrode catheter (BMC), mte- 
grated with a comptienzed mapping system, was used to reconstruct en- 
d,Yardtal acllvatlon maps and to study local endocarckal actlvallon V? was 
Induced usmg programmed electrical stlmulatlon applymg up to 3 extmstlm- 
UII. 
Results Eighteen post mycczirdtal mfarctlon (MI) pts with drugrefractory 
VT were stildrsd The I& ventncular etectlon tractlon was 34 : 15% Cycle 
length of VT was 305 t 79 ms. fartrest end@cardlal aCtNatIOn dunng VT 
was recorded 49 I 43 ms pnor to the onset of the surfacg ECG. Due 10 
lhe limited resotut!on of Me mappmg catheler n?constNcttOn at a reentrant 
circuit was posstble m only E/18 pts. In 2 pts a large nXn?~~r mop clrculatIn9 
around a left ventncular aneurysm caused VT. Based on the locally recorded 
ECG’s. a small reentrant cmxlt could be reconstructed in 6 pts. Elecrrograms 
recorded around the lme of block exhibited erther double potentiats. reflectIn 
acttvatron of two l!mbs nf the reentrant circuit or fragmented local activity 
a; the plvotmg pomts of the circuit It appeared Mar these reertt~nt Circuits 
could be confined vnthin an area 01 -4 r’n*, SIimu!ation al these SlteS pmvlde 
evidence for the role of Increased tissue anisotropy m 416 PtS. oUrin9 pacfn9 
SIOW conduct!on. as reflected by fragmented local eleclricat actI%‘. Over a 
considerable dlslance was recorded. 
Conc/usrons AnIsotropIc leentry may be a mechamsm of some sustaIned 
VT In co:: Ml pts High resolution mapprng studies are mandatory to study 
areas of increased anisotropy m letall. 
t 1046 171 “PoppIng” During Radiofrequerry Catheter Ablation: An In Vitro Model - New Observations 
S.A. Rothman. H H Hsla. L.M. Thome. R.A Campo. G. Panas. 
A.E Buxton. J M Miller. Temple Unrvers~y Hosp,fa/. Phrladelphra. PA. USA 
Background: An audible ‘popping’ sound (produced by sudden subendocar- 
dial steam release) dunng ad!ofrequency catheter (RF) ablation has been 
observed m the past but more rarely m the era of temperature (Tlcontmtled 
RF appltcatton. 
Methods: We performed T-contmlled RF appl!catton (70% Set point. 
N-60 set application. n = 153 tnals) In freshly-explanted human left v&I- 
tricles obtained at transplant, and noted the ocCum?nCe and teahrres Of an 
audible pop. Catheter tip (endocardial surface) and !hermocouple needle (2 
mm deep) T were momtored. 
I ‘OA AHSTRhC’l’S - Puhter 
Results: Pops wore obsotvod In 35% 01 trlnls overall, occurring altar 17 i 
9 (mnga, 6-66) sac of powor dollvory. The moan Ihormocoupla tamparattrro 
at the llma of popping wns 82 t 25%. 
S~riqoc@ afsruptlan wns aoan In 11% of pope (bath normnl nnd acnr), anty 
wllh loud pop& nnd olwnya cmta tha ando(lnrdlal audnoa. 
Canclu.a/onn: 1) Rnpld slenm lamWon landing lo fludden vonllng (papa) 
In cqmmon In thla In vllt~ modal. acourrlnQ in 96% af bmpQrilfrr~confrP//Od 
RF nppllcallona. 2) Tha “popping” phnnomanon mny ba mom cammon clur- 
InQ cllnlcRl RF flblnlltm than la wzaanlxad (IA-I., honrd). 3) I”opplnQ Cnn bo 
praducad wan In araas al donao endocnrdlnl nonr, 4) loud popplng Is asso. 
clmed with andaoardlnl dlsruptlon nnd cauld rnsull In debris ambollxnllon. 
Radlofrequanoy Ablation In Patlente With 
Coronary Okwnna and lnconennt or Frequently 
Raourrlng Ventrlculnr Tachycnrdla 
R. Caynn, 9, Zndo, 8. Snder. R. Man, D. Cnllans, J. Fnntnino C. Goltliob, 
F. Mamhllnskt. Abghany Unlwrarty M~pltafs, Ph~lad~lphm PA, USA 
Bockgra~md: PWVI~UR dnto f~flqonl rndtalrequoncy nbloltan (WA) in uaolul 
tn trentlng VT nsaaciolod wllh coronary nrtory dlaonsa (CAD). Howovar, liltto 
dnln rrxlet dercrlblng ~cula BUCCBRR and tdn Mla~up nflar RFA In the CAD 
patlonl (pl) subaal wllh Incaraanl [I) or trqquontty raaurrlna (FR) VT, daflnod 
RR :$X3 agtradaa al VT avnr lha peat manlh and~or multtpta daily aplsadas. at 
VT over tha pnal wnak unmapanalvP to IV antlnrrhylhmlc ngonls. 
MrWtrxY$~ T\Nanly-nsvm pla undargolng pmcoduros tar ECG~dacumonlod 
IVT/FAVTcomprlr~oci lho nludy group. All but 2 pla hnd ICDa oftor RFA. RFA 
was bnaod on nnlmlnmsnt crilorin, dlnalollo polentlnls. flnd/ar onntomic gutd. 
ante. We datlnnd ncule pmoodrtrnl success (APS) RS lnnblkty to Induce the 
c!mfcal VT nl lha lennlnnllon at lho last RPA pmcoduro. Followup andpomts 
Included ]l] recurmnco ot IVT/FRVT nnd [2] reourmnca 01 nny sporadic VT 
Resu~fs; Sovan pta undonvant mom than ono RF/\ pmcodum; 24 of 27 
phi (69%) had APS IallowIng lho Ins1 RFA procedure. In lollowup (moan 11 
months) 01 the 24 pts with APS. no pt had recurrenl IVTIFRVT. fourteen pts 
(56%) had only sporadic VT, ond ton pts (42%) hnd no VT Tablo depicts the 
VT mcurrenca In follow-up nnd whother any VT was mduclblo lollowing APS 
In lho 24 pts wtth APS. 
Conc/usrans: [l] RFA IS elloct~vo lhorapy lor IVTlFRVT associated wtlh 
CAD; mare lhnn ono RFA procedure may bo noodod for APS. [2] A mmonty 
of pnllonts with APS have no VT in fallow-up. [3] Racause non-lnducibilily 01 
VT fallowing APS doos not predict headorn horn recurrent sporadic VT, ICD 
implantation is @lied 
110471 Lead Extraction: Mechsnlsrns of 
Defibrillatlon/AWID 
Monday. March 30.1998, Noon-2:OO p.m. 
Georgia World Congress Center, West Exhibit Hall Level 
Presentation Hour: 1:00 p.m.-200 p.m. 
b 047-l 73 1 The Spectranetlcs laser Sheath Reduces 
Extraction Time for Nonthoracotomy 
Deflbrlllator Leads 
M.J. Nrebauer, A. Al-Khadra. M.K. Chung. G.A. Kidwetl. V. Morant. 
H. Smith. P.J. Tchou. B.L. Wilkoff. The CleveBnd Clinrc Foundahon. 
ClevelandOH. USA 
Background: Extraction of nonlhoracotomy delibrillator leads (NTL) can be 
pedoned rekably using pacemaker lead extraction tools. Recently. the Spec- 
tranetics t2P laser sheath has become available which dissolves the scnr 
Itssue around the lead using Eximer Laser energy directed via fiber optics. 
Methods: We report the results of 62 NTL extractton procedures performed 
at the Cleveland Clinic Foundation between 1991 and 1997 using the Cook 
Pacemaker Corporation Lead Extraction tools. Data were obtained from 
patient records and the Cook Lead Extraction Database. Forty-five patients 
undarwonl NTL axlrocllon u&g slondnrd locking style& and Tollon dilator 
shonths. Seventoan patlonts undetwontsxtractlon using the slandnrdlocklng 
atylbte and tho lnsor dllalor sheath. Procedure time. extmcllon limo and 
lluaroscopy time ware compared between Iho two dllatar shoalh groups. 
Procedure llmo Includes the lime requlmd lo petlorm Ihe NTI. extracllon 6s 
wall a8 the adWknal tlma mqulred ta debride IXCBT tlsaus (fer lead kMtc(lon 
cseea) bind lmplanl any now leadsldovlces (for lead lallun, crises))) 
Tbtlan 6kealh Lanr 6heath -,aIi_ 
Ptocadurn ltma tmmt 1ar.7 1 474 135.3 * 44.4 P-079 
Ruoroasapy Tlma 
6xtrsclkx-r Tlmo 
7.0 t 6.1 76 t45 P-OR1 
47.0 . 71 ? 187t.286 I. 
~~scu~slofl: Thoao mftulls ahaw lhst, nllhough 911aroscopy lima and total 
pmccdum tlmal da na\ d{Har between the two gmupa, lhe oxfmctkart tane 
Is aubatanllally roducsd wnen Iha laser dilntar ahealhe ars uae4 IO aid 
NTC axlmctlon. Tha atmtlar lluomscapy nnd pracodum times ap(roar to ba 
ralntod la tha addilionnl ltmos noodod lar ttasuo debralament anjlor new 
loed implantation. 
a 
1047-l 74 Flht8$; arlenea Wlth a Lassr Shwth to &tract 
kuwvpnous C)eflbrlltator Leads 
9 C. Knshnan, Q. Vassolas’, CM. Epstom. 8efh MaeI Deaconess A@&al 
Confer. Hnrvard Me&a/ School, Lloston. 44A. USA- ‘E/OS Hosprtal. 
Schenecta~ NK USA 
Background: Lead lractum and mtcclion are not uncommon cemptttatiens 
ot tmplontabla csrdtoverler/do!~bnllator (ICD) lhorapy. Wdb the recent rutpan, 
slon al mdtcattons physictans watt ba hmed wilh lhts prqbtom mere often 
Conventtonal tachniquos of load extraction am associated with limned cl- 
kcncy and styniltcant morbidky. Tho use at a laser shunth (Spactranatics 
Corp.) hns improved the etticacy al pacemaker load extaclton. 
Methods: Load oxtraction was nltomplod in 5 patients with chrontc transve 
nous ICD leads (Endotak, CPt G&ant). Two patients had a pnor unsuccess- 
lul nllompl at land mmoval tn analhor mshtulran usmg standard technrques. 
Once lha lead was hoed in tho pock01 a locking style1 was placed. It tha lead 
was nOI mmovod wllh gorilla traction a laser sheath was employed. 
Rcsub: All Fivo paltcnlo underwent successful extractron wtlhoul cem- 
pkcalion horn lho subctavian appmach. 
Despite lho mlabvely short rmplant duralron (2.7 k 1.5 years) extensiue 
scarring. especially of Ihe dtslal coil was noted in 415 patients requsing the 
use ol the laser (16 F 3. 14 F 1). The mean time lo lead removal alter the 
lockmg stylet was placed was 6.8 i 3.9 minutes. Four ol the 5 patients 
recewed a new ICD and were dtschargeci within 36 hours. One pakont 
remained hospitalized for IV antibiotics. 
Conclusion; The use of a Laser sheath offers a saie and effectwe approach 
for the extraction of chronic lransvenous ICD leads. 
11047-l 751 Shock Induced tiyperpolarlration Activates 
Sodium Channels 
M.R. Uthelyr. X. Zhou. T.L. Creazzo. Universrfy of Geoqra and Medical 
College of Georgra. Augusta GA: Unlverslty of Alabama at Birmmngham. 
Brmmgham Al. US4 
Computer models suggest that hyperpolanzmg dekbriltalron shocks (HPS) 
can reackve sodium channels, and that this may be a mechantsm by whtch 
a shock can extend relractormess. These studtes. however, have not been 
tested in a biological model. Isolated chick ventricular myocyles (n = 6) 
were voltage Clamped to quantitate whole cell Inward Na* current. The 
voltage clamp protocol mimicked experimentally determmed transmembrane 
potentials rVm) recordsd from a cell stimulated with a 17 V/cm shock strength 
delivered during action potential (AP) plateau. A prepulso pmtocol mimicked 
AP upstroke and plateau. The test pulse was delivered 50 ms or 60 ms 
later in 10 mv steps to mimick make and break HPS (10 ms pulse width). 
rospectwely. Figure 1 shows protocol and current tracing for make and break 
HPS. Figure 2 shows IV curves for step potentials from - 60 Vm holding 
(Control) and step polonlials for brook HPS. The IV curve from break HPS is 
shined lo more positive Vm. while peak Na’ current induced by break HPS is 
~25% of baseline current. Make HPS did not produce any inward or outward 
current. 


“Popping” during radiofrequency catheter ablation: an in vitro model — new observations 

file:///data/remote/core/dit/data/elsevier/pdf/cb0/aHR0cDovL2FwaS5lbHNldmllci5jb20vY29udGVudC9hcnRpY2xlL3BpaS9zMDczNTEwOTc5ODgxMTYzNw==.pdf

“Popping” during radiofrequency catheter ablation: an in vitro model — new observations

Abstract

Similar works

Full text

Available Versions

Elsevier - Publisher Connector

Elsevier - Publisher Connector