A DAO TAO LIEN T t C
Tham do dien sinh ly tim
ThS. Phan fMnh Phong - TS. Pham Quoc Khanh
;ier T T Tiach '\%=r '.5T
LGIOniHEU
N ^ e n cflu dien sinh ly tim la mot phtf d i ^ p h ^ t h d i ^ tim die biet nhim phin deh mdt cich cd h | tfadi^ cic h i ^ ttfdng dien sinh ly tim d benh nhin trong tinh trang cd sd vi dip flr^
ciia tim vdi cic kich thich dien cd chtfdi^ trinh.
Sau 30 nam tfl khi dtfdc tien hanh lan dau tien, tham dd dien sinh ly dm ngay nay da tixf thanh mpt phtfdng p h ^ thim dd quan t r p i ^ khdng the thilu trong tim mach hpe, die biet trong linh vtfc rdi loan n h ^ tim, giup chin doin chinh xac cac ed chi gay rdi loan nhip tim va tao nen mpt cupe cich mang trong dieu tri cac rdi loan nhip dnL
Thim do dien sinh ly tim ciu^ vdi triet ddt cac rdi loan nhip tim bang nang Itfdng sdng tan sd radio qua dtfdng dng didng drfdc trien khai lin diu tien dnrfdeta vio nam 1998 vi hien nay d i trd thanh mpt ^ thuit thtfcfiig quy tai mdt sd tnmg tim tim mach Idn tren c i ntfde I . CAU TAO, BAC TMH BEN SINH Lt HOC CO TIM VA HL THONG DAN TRUYEN TIM
1. CIn tao ctf tim va he tfamig dan t m y ^ tim Cmt tqo ctf tim
Cd tim c6 cau tao dac biet gom nhuiig thd cd vin dan ching chit vdi nhau ma chflc nang cua chui^ li co bop khi drfdc kich thick Ben
eanh cic sdi co bdp, cdn cd cic sdi biet hoa vdi nhiem vu t^o ra va d i n truyen x m ^ dpng din cac sdi cxi cua dnL
Hi 0t6ng ddn truyen thn
• Nut xoang: Dtfdc Keith va Flack tim ra nam 1907, co hinh d i u phay, dai tfl 10 - 35 mm va rpng tfl 2 - 5 mm, n i m d v i u ^ tren nhl phai giiia chd d6 vio eua tinh maeh chu tren va tiiu nhiphaL Cac t l bao chinh cua niit xoai^drfdc gpi l i t l b i o P cd tinh trf dpng eao nhit nen li chu nhip chinh cua tim.
- Diidng lien ndi: gdm cic te b i o biet hda dm ylu li cd khi n i i ^ din truyin xur^ d p i ^ nhiing ciii^ cd mdt sd t l bao cd kha nang ttf ddng phat xung. Cic dtfdng nay noi tfl nut xoang den nut nhi tiiit (Tawara) gdm dtfdng trtfdc cd mpt nhinh di sang nhi trii (Bachman), dtfdi^ gifla (bd Wenckebach) va dtfdi^ sau (bd Thorel).
- Nut nhi thdt: Dtfdc Tawara tim ra tfl nam 1906, cd hinh bau due, mat phai lom, mat trii loi, dii 5 - 7 mm, rpng 2 - 5 mm, day 1,5 - 2 mm, nam d mat phai phan dtfdi vich hen nhl gifla la vich van ba l i va xoang vinh. Nut nhl that gdm nhieu t l bao biet hda dan vdi nhau chang chit lam cho xung d p i ^ qua day bi cfaam lai va dl bi bide. Niit nhi that chu yeu lam nhiem vu dan truyen va ehi ed it te bao ttf dpng.
- Bd His: Dtfdc His m6 ta tfl nam 1893, rpng 1 - 3 mm, ndi tilp vdi nut nhi that, cd dtfdng di trong vich hen that ngay dtfdi mat 58 iTAPCHlTIMMACH HOCVIET NAM-S663.2013
DAO TAO LIEN TUC k
phii cua vich dii khoing 20 mm, bd His chia 2 nhanh phii va trai. Ciu tao bd His gdm eac sdi dan tiruyin nhanh di song song va ed t l bao cd dnh ttf dpng eao. Vi bd His va nut nhT thit ndi tiep vdi nhau khdng ed ranh gidi rd ret, rat khd phan biet ve mft td ehfle hpe nen diXdc gpi chung la b$ ndi nhi that.
- Cdc nhdnh vd mgng ludi Purkinje: Bd His chia ra 2 nhanh: nhinh phai va nhanh trii, nhinh phai nhd vi manh hdn, nhanh trii Idn chia ra 2 nhanh nhd l i nhanh trtfdc trin trii vi sau dtfdi trii. N h i n h phai va trii chia nhd va dan vio nhau nhtf mpt Itfdi bpe hai tim that.
Mang nay di ngay dtfdi ming trong tim thit va di sau vii mihmet vao be day eua Idp cd. Hai nhinh bd His v i mang Purkinje rat giiu cic t l b i o cd tinh ttf ddng cao co the tao nen cac chu nhip t i m that.
- Cdc S0 Kent: Sdi tilp ndi giiia nhi va that.
- Cdc sgi Mahaim: Cae sdi di tfl nut nhi thit tdi cd thit, tfl bd His tdi ed thit, tfl nhinh trii tdi cd that.
Cd tim va he thdng dan truyen dtfdc nudi dtfdng bdi h^ thdng dpng msieh vanh. He thdng d i n truyin tim chiu ehi phdi bdi eac nhinh than kinh giao cam, phd giao cim ed nhiem vu dilu hda ho^t ddng cua tim.
Hinh 1: H$ thdng ddn truyen trong tim
2. D i e tinh dien sinh li hoc cd tim va h e thdng d i n truyen tim
Tinh Uf ddng: La thupc tinh quan trpng nhat cua td ehfle biet hda ed tim, ed t h i phit ra nhflng xung dpng nhip nhing vdi nhflng tan sd nhat dinh, dim bao cho tim dap chii ddng.
Tinh ttf dpng nay hoan toin dpe lip vdi he thin kinh, nen khi eat bd h i t cac nhanh than kinh tim van dip,
Tinh ddn truyin: Cd ca d thd ed biet hda va thd cd co bdp. Ca hai loai cd tim khi dtfdc kieh thich diu cd t h i din truyin xung d^ng tdi cae thd ed khic.
Binh thtfdng, xung ddng phat ra tfl nut xoang dan truyen trong he thdng din truyin cua tim vdi van tdc khac nhau. Qua bd lien niit:
1000 mm/s, d phia tren mit nhl that: 50 mm/s, qua nut nhi thit: 100 - 200 mm/s, bd His 800 - 2000 mm/s, mang Itfdi Purkinje: 2000 - 4000 mm/s, ed tim 300 mm/s. He thdng din truyin ed the din truyin xung dpng theo hai chieu xudi v i ngtfdc.
Tinh chiu kich thich: Cd tim dap flng theo dinh luat "tit ci hoae khong" nghia la khi tim nhan kieh thich du manh (ngtfdng) thi cd tim eo bdp d mflc tdi da, dtfdi ngtfdng do tim khdng dap flng, tren ngtfdng dd tim cung khdng eo bdp manh hdn.
Tinh trd: Cd tim chi dap flng theo nhip kich thich den mdt ehu ky nhit dinh, kich thieh den dung lue tim dang co thi khdng dtfdc dap ling, kieh thich din vao thdi ky tim gian thi ed dap flng. Ngfldi ta ehia ra thdi ky trd tuyet ddi, thdi ky trd ttfdng ddi va cdn cd khii niem thdi ky trd hilu qua, day la giai doan ma mpi kich thieh len sdi ed tim deu khdng gay dtfdc dap flng cd hpe du manh de lan truyen ra cae sdi xung quanh. Thdi ky trd hieu qua gdm thdi TAP CHi TIM MACH HOC VIET NAM-SO 63.20131 59
A DAO TAO LIEN TUC
ky trd tuyet ddi cpng vdi phan diu eua thdi I^
trd ttfdng ddi. Ngoii ra cdn ed thdi ky tren binh thtfdng (supernormal phase) nghia l i dap flng de dang vdi kich thich ttfdng ddi nhd.
3. Dien t h i hoat dpng
- Khi nghi ngdi, eic te b i o ed tim va he thdng din truyin d trang thii phan ctfc vdi diln t h i (-t-) d phia ngoii va dien t h i (-) d phia trong mang te bio. Trung binh dien die i m d trong ming so vdi ngoai mang te b i o la -90 mV, diln t h i nay bat ngudn tfl stf chenh lech ndng dp eua cic ion Na'^, K*, C a " va eac ion khae d dieh trong va ngoai ming t l bao.
- Khi t l bao hoat dpng, do stf van chuyin cac ion qua mang te bio, dien t h i (+) ngoai mang t l b i o se dtfdc thay t h i bang dien t h i (-), day la h i | n ttfpng khfl eflc (depolarization).
- Cac hi In ttfdng tren xay ra khi t l bio dtfdc kich thich bang bit ky tic nhan nao. Mudn ed di?n t h i boat dpng, kich thich d i n t l bao phai Iim ha diln t h i trong ming tdi mdt ngtfdng nhat dinh, khi dd se xay ra stf thay ddi vl tinh tham thiu eua mang t l bao, cac ion Na' d at ehui vio trong t l bao, ha dien the trong mang xudng 0 mV va edn niy qua da trd nen (-^) khoang 20 mV.
- Di|n the boat ddng gdm cic pha sau:
H- Pha 0: Khfl etfc nhanh. Ddng Na* nhanh tfl ngoai vao trong te bio.
Tilp dd d i n tai c\(c gom 4 pha:
-t- Pha 1: Tai eflc nhanh sdm. Ddng Na* tiX ngoai vio trong t l bao dpt ngpt ddng lai. Ddng Ca** bit diu vio trong te bao.
+ Pha 2: Cao nguyen tii eflc, dien t h i trong ming vin {+), Na* tilp tyc vao trong mang t l b i o nhtfng cham hdn, Ca** ciing vao trong ming va K* thoit ra ngoii mang.
+ Pha 3: Tii eflc nhanh mupn, K" thu ddng
thoit ra ngoai mang t l bao, dien t h i trong mang trd nen am tinh hdn.
+ Pha 4: Phin c}^c, d dau giai doan nay cac ion Na* ehu dpng di chuyen ra ngoai mang t l bio, cdn K* lai chuyin vio trong. Khi dien thi mang dat dat d i n mflc eao nhat, t l b i o trd lai trang thii phin eflc nhtf khi ngh! (trtfdc giai doan 0 cua di?n the hoat dpng).
Hinh 2: Biin thihogt d^ng
' O sdi cd CO bdp, diln t h i tdi da trong mang dtfdc duy tri, giai doan 4 se keo dii cho din khi cd mdt kieh thich tii ngoai d i n Iim ha dien t h i tdi ngtfdng rdi khdi dpng dien t h i ho?t dpng vdi cic giai doan nhtf da md ta d tren.
a te bao biet hda ciia he thdng d i n truyin thi hoan toin khac. Trong trang thai nghi, t l bao ttf khfl eflc: ion Na* xim nhip dan din vao trong t l bao lam ha dan dien t h i trong mang, do la sfl khfl ctfc cham tam trfldng, mpt die trtfng eua te bao tfl ddng. Khi dien t h i trong mang ha tdi ngtfdng se khdi dpng mpt dien t h i boat dpng. Tan sd tao ra nhu:ng diln the hoat dpng phy thudc vio tdc dp khfl etfc ehim tim trtfdng d giai doan 4. Binh thtfdng, t l bao ttf d^ng cua nut xoang cd tin sd tii khfl ctfc Idn nhit vi viy dien t h i trong ming cua cic ndi khic chfla xudng d i n ngfldng d l tao ra mdt dien t h i ho^t I ITAPCHITIMMACH HOCVIET NAM-S063 2013
DAO TAO LIEN TUC k
dpng thi xung ddng tfl nut xoang da dan tdi xoa nhflng xung ddng dang hinh thinh tfl cac ndi dd va do viy no ehi huy nhip dap cua tim.
IH. CHI DINH THAM DO Dl|N SINH Lt TIM
Cae chi djnh tham dd dien sinh ly tun ed t h i tham khao ehi tilt trong phan phu lye vl Chi dinh tham do dien sinh ly tim, khuyin cdo cda Hgi Tim mgch hoc Hoa Ky/TrUdng mon Tim mgch hgc Hoa Ky ndm 1996 (ACC/AHA). Tuy nhien, nhin chung cd t h i ehia lam ba nhdm: rdi loain nhip cham, rdi loan nhip nhanh vi ngat.
1. Cac rdi lo^n nhip e h i m : bao gdm hpi chflng suy mit xoang, rdi logn dan truyin qua nut nhl that hoac dtfdi mit nhi that. Nhin chung, chi dinh trong nhdm nhip ehim khdng phai la thtfdng quy do chi dinh tao nhip tim chfl ylu dtfa vio mdi lien quan gifla nhip cham va tri?u chflng hoae ed hay khdng rdi loan nhip cham nang hay tinh trang vd tim thu keo dai. Tham dd dien sinh ly tim trong nhdm nhip cham ehi khi cic phtfdng phip khdng xim Ian nhtf kham Iim sang, dien tim dd thtfdng quy, ghi dien tim dd lien tue (Holter), may ghi biin c6 (event recorder)... chtfa t h i cho ehan doin xac dinh.
Tham dd dien sinh ly tim giiip phit hien cae rdi loan d i n truyin cd t h i giy biin cd nguy hilm ma cic phtfdng phap ehan doin khie khdng phit hi^n dtfpc, ehang han nhtf tinh trang rdi loan d i n truyin ning dtfdi nut nhi thit (khoang HV keo dai).
2. Ngat: Tham dd dien sinh ly tim cd t h i giup phit hien eic rdi loan nhip ehim la nguyen nhin giy ngat. Do vay, nhflng trtfdng hdp ngat sau khi da loai trfl cac nguyin nhin khdng phii rdi loan nhip tim can dtfdc ehi dinh thu thuit.
3. rdi loan nhip nhanh: tham dd dien sinh ly
tim ed gii tri die biet trong nhdm cic rdi loan nhip nhanh nhat l i nhiing rdi loan nhip giy ra do cd ehi vao lgi. Cho phep xie dinh cd chi giai phau sinh ly giy ra eae rdi loan nhip, lip ban dd dien hpe (trinh ttf hoat hoi dien hoc), dinh gia cac bien ddi huyet dpng trong cdn tim nhanh va dac bilt la giup dinh hfldng dieu tri (bing thii thuat ctfdng p h i vi, thudc chdng loan nhip, triet ddt bang nang Itfpng cd tan so radio hay ciy may p h i rung tim - ICD).
lU CAC THIET B! CAN THIET CHO MOT LABO THAM DO BIEN SINH LY TIM
1. May v i dien crfc
Hi thong mdy cht^p mgch ky thudt so:
He thdng may chup maeh xoa nIn ky thuit sd giiip cho vile dtfa cie diln cd-C vio eic vi tri can thilt trong budng tim eung nhtf cho viee lap bin dd dien hpe thdng qua eac man hinh tang sing. He thdng edn eho phep ehup vi ghi hinh cae giai doan cua thu thuit.
^ • "^i 1 -.
Hinh 3: Hi thSngmdy chup mgch ky thudts6xoa nin
Mdy kich thich tim cd chUdng trinh May cd chtfdng trinh kich thieh tim tfl tan sd 50 ck/ph din 800 ck/ph va cd the kich thich vdi nhieu khoang ghep khae nhau (S1, S2, S3...).
TAPCHITIMMACH HOC VIET NAM - 5063 20131 61
DAO TAO LIEN TUC
Hi thong tham do diin sinh ly tim EP Tracer-70
He thdng cd the ghi ddng thdi dien tim dd h i mat 12 chuyin dao va nhilu chuyin dgo trong budng tim khac nhau, ddn etfc hoac Itfdng ctfc.
Phin mim deh hdp he thdng ed t h i cho phep do dac cie khoing thdi gian vdi eic tdc dp ghi khae nhau: 25, 50,100,150, 300 mm/s hoac eao hdn va do biin dp cac dien dd d cac mflc dp khulch dgi khie nhau. Cae kit qui nay cd t h i in ra giay qua he thdng miy in laser hoac chuyen thanh dang Itfu gifl dien tfl.
He thdng eho phep lap ban dd trinh tfl hoat hda npi mac trong eac budng tim qua do giup xie dinh dfldc chinh xie ed ehi giy rdi loan nhip tim cung nhtf vi tri khdi phat cae rdi loan nhip tim.
Hmh 4: He thdng thdm do diin sinh ly tim vd mdy kich thich tim theo chUOng trinh
Mdy phdt nang hidng song tdn s6 radio Miy cd cdng suit phat nang lrf(^g toi da li 50-75W.
Cd khi nang ki€m soit nang Itfdng va nhiet dp vdi nhilu ehi dp dilu tri khie nhau. - —
Hmh S: Mdy phdt ndng hi^ng tdn sd radio Mdy soc diin va thuoc cdp cdu roi logn nhip:
Ciing nhtf cae thu thuit tim mach can thiep khie. Thim dd dien sinh if tim ludn d i m tang giy ra cac rdi loan nhip tim phflc tap, nguy hilm nhtf nhanh thit, n m g that... Di d i m b i o an toin cho ngtfdi benh, phdng tham dd dien sinh ly tim ludn phai ed may pha rung v i cie thudc cap cflu rdi loan nhip nhtf Adrenalin, Atropin...
vdi cie bic si, dilu dfldng vien cd kinh n ^ l m ve cap cflu tim mach.
Cflc diin cue thdm do (diagnostic EP catheter):
Dien ctfc tham dd ditfdng dtfdc sfl dung la logi 4 ctfc de ghi dien d i l v i kich thieh thit phii, nhi phai, bd His (dtfdng kinh 4F, 5F v i 6F).
D i l n ctfc xoang vanh tbridng dung loai 4 hoac 10 ci^c, kich thtfdc SF hoac 6F. Khoang c i c h gifla c i c vdng dien ctfc l i 2-5-2 mm
Diin ciic Idp bdn do diin hgc vd triit dot rdi logn nhip (Mapping and ablation catheter)
62 ITAPCHITIMMACH HOC VIET NAM-5063.2013
DAO TAO LIEN TUC -.
Chilu dai dau dien ctfc: 4 nmi Dtfdng kinh dien cflc: 7F
Cd loai gap dudi 1 htfdng (unidirectional) va 2 htfdng (bi-directional).
La dien etfc chuyin biet cho vile triet ddt bang nang Itfdng sdng radio. Tuy nhien cie dien ctfc ddt cung cd vai trd rat quan trpng trong thu diuit tham dd dien sinh ly tim, tham gia vao vile lip b i n dd dien hpe (thtfdng dtfpc d i n hanh ngay trtfdc khi triet ddt rdi loan nhip). Die tinh cd t h i gap dudi dtfpc mdt htfdng va hai htfdng cd t h i giup eho viec dtfa dau dien etfc vao nhflng vi tri khd trong budng tim ma di?n eflc thim do thfldng quy khdng t h i lii vao dfldc.
Hinh 6: Dien ciic thdm do (trdi) vd dien cUc ddt (phdi)
u cAc Birdc TI£N HANH THAM DO BIEN SINH LtTIM
1. Chu^n bi b e n h nhan
- Giai thich b?nh nhin hoae ngfldi nhi benh n h i n ve stf cin thilt, nhflng lpi ich cung nhtf eac nguy cd, tai bien cd t h i cd cua thu thuit, ky giiy cam kit.
- Trong phan Idn trtfdng hdp la thu thuit cd ehuin bj, benh nhan trong tinh trang dn dinh vl lam sing va xet nghiem. Cac rdi logn n l u cd phii dddc dieu chinh tdt trtfdc do. Cac thudc chdng logn nhip thtfdng dtfdc ngflng trtfdc thii diuat trong didi gian it nhit bang
5 lan thdi gian b i n huy efla thudc (ngoai trfl amiodarone).
- Giam dau bang gay tl tai chd, cd t h i cho thudc an thin nhe.
- BN dtfdc theo ddi vl diln tim d6 va huylt dpng hen tuc trtfdc va trong sudt thdi gian thfl t h u i t
2. Dat cac catheter d i l n ctfc
- Cic di|n ctfc tham dd diln sinh ly tim thtfdng dtfdc dtfa qua dtfdng tinh mach dui ben phii trfl khi ed nhflng chdng chi dinh nhtf huylt khdi tinh mgch sau chi dtfdi hoac b?nh nhin dang dtfpe dat filter tinh mach chu dtfdi.
- Cac trtfdng hdp cin thdng tim trai (dtfdng din truyin phu ben trai hogc tim nhanh that nguon gdc tfl thit trii...), dien ctfc d\i(yc dtfa vao cie budng tim trii ngtfpc ddng qua ddng mach chu hoac dtfa xuyin qua vich lien nhi tfl dtfdng thdng tim b i n phii.
- Thdng thtfdng, d l tham dd dien sinh ly tim can ed ba catheter di^n ctfc: mdt dgt d vimg cao nhi phai (thtfdng dtfdc dtfa ttfa vao thanh ben cao ciia nhl phai); mpt dat d mom thit phai va mdt d vi tri bd His (dien cdc dtfdc dtfa vao that phai qua vung trtfdc vach cua van ba la, sau do catheter dtfpe nit ra tfl tfl va xoay nhe theo chilu kim dong hd eho den khi ghi dtfpc dien the bd His nim gifla diln the nhi va that vdi ti II thich hdp).
- Dien etfc xoang vanh eho phep ghi dien do cua cac budng tim b i n trai m i khdng can ehpe ddng maeh, thtfdng dtfdc sfl dung trong ehan doin eac edn tim nhanh tren thit hoac eae rdi loan nhip cd ngudn gdc tfl cae budng tim ben trii. Dien etfc xoang vanh dtfdc dtfa vao qua tinh mgch dui hoae tinh mgch dtfdi ddn trii, thtfdng cd 10 din 12 etfc vdi cap dien ctfc dau gin nim ngay d 15 xoang vanh.
TAP CHi TIM MACH HOC VIET NAM - SO 63.20131 i
^ DAO TAO LIEN TUC
bd His. Khoang HV it chiu i n h farfdng cua than kinh ttf ehu, binh thrfdng gidi ban ti( 35 - 55 ms.
- Thdi gian QRS: do tCT khdi dau song Q, (hoac R) den diem k£t thuc sdng S.
Hinh 7: Sd do vitri dgt cdc catheter Sin cUc.
3. Danh gja dien sinh ly tim trong tinh t r ^ g c d s d
Cac thdng sd dien sinh ly hpe cd sd (tinh bang ms) ditfdng dtf<?c do dac bao gdm:
- Thdi gian chu ky cd sd trong luc nhip xoang.
- Khoang PA: la thdi gjan din truyen trong nhi phii, do tfl chin sdng P (thtfdng d chuyin dao DU) tren DTD b l mat tdi dilm khdi dau sdng A tren dien dd His. Khoar^ PA binh thtfdng cd gidi hgn tfl 25 - 55 ms.
- Khoang AH: l i thdi gian din truyen tfl vimg drfdi nhi phai d i n vich hen nhi qua nut nhi thit d i n bd His, do tii khdi diu sdng A din khdi dau sdng H tren dien dd His. Khoang AH ehiu anh htfdng bdi nhilu yeu td, dac biet la thin kinh ttf chu, binh thtfdng gidi ban tfl 55 - 125 ms.
- Dp rgng diin thi His (HH); do tfl diem khdi diu din dilm kit thuc sdng H tren d i | n dd His. Binh thfldng dp r p i ^ di?n the His gidi han tfl 15-25 ms.
- Khoang HV: la thdi gian din truyen tfl phan dau gin bd His tdi cd that, do tfl dilm khdi dau sdng H tren dien dd His den ndi khdi dau sdm nhit boat d p i ^ that tren DTD b l mat nhilu chuyin dao hoae dien dd thit trong ^u.
Hmh 8: Cdc khodng ddn truyin trong tim trong trgng thdi ctJ sd.
Hmh 9: Cdch do cdc khodng ddn truyin trong tim trong trgng thdi ctf sd.
4. Kich thich tim co chtfdng trinh (programmed stimulation)
Bao gdm kich thich tim vdi t i n sd ting 64 TAPCHITIMMACH HOC VIET NAM-5063.2013
DAO TAO LIEN TUC k
dan hoac vdi mdt hoae nhilu xung kich thich sdm dan trong liic nhip xoang hogc khi dang tgo nhip. Kieh thieh tun co chtfdng ti-inh nham muc dieh:
• Xac djnh nhflng die tinh dien sinh ly hpe cua he thong d i n truyen nhi that, tam nhi va tim that.
- Tao ra va phan tieh ed che rdi loan nhjp tim.
• Danh gii ei tie dting cua thudc v i can thiep dien d i n dac tinh dien sinh 1^ hpe cua he thdng dan truyin nhi that, tam nhi va tam thit va hieu qui ddi vdi dilu tri rdi loan nhjp tim.
Kich thich nhl
Kich thich nhi vdi tdn s6 tang ddn
' Bat dau vdi tin sd kieh thich nhi cao hdn tin sd tim cd sd it nhit 10 nhip/ phut. Sau dd tang d i n tan sd kich thich mdi lin 10 nhjp/
phut hoac thdi gian chu ky kich thieh sau ngin hdn ehu ky trtfdc 10 - 20ms. Ngflng kich thieh khi dgt tan sd 180 nhjp/ phut (nlu d l xie dinh chflc nang nut xoang) hoae eao hdn (nlu de xie dinh dan truyin nhi thit hoae dtfdng phtf).
Thdi gian kich thieh d mdi mfle tin s6 thtfdng tfl 30 - 60 giay di bao dam sfl dn djnh eiia eie khoang d i n truyin sau do nghi 1 phut rdi tilp tuc kich thieh mflc tan so sau.
- D i p flng binh thtfdng vdi phtfdng phap kieh thich nhl vdi tan so tang dan la khoang AH keo dai d i n eho tdi khi xuit hien bide nhi thit cip 2 kilu chu ky Wenckebach. Dan truyen dtfdi nut (khoing HV) khdng bj inh htfdng.
Hau h i t eic benh nhin d tmh trang ed sd se xuit hien bide nhi that kilu chu ky Wenckebach d thdi gian chu ky tgo nhip nhi tfl 500 - 350ms.
- Phfldng phap kich thieh nhi vdi tin sd ting din cho phep danh gii:
-I- Thdi gian phuc hdi nut xoang (tPHNX) va thdi gian phtfc hdi nut xoang dilu chinh (tPHNXd): kich thich nhl vdi cae tin sd khie nhau vi eao hdn nhip cd sd trong vdng 30 giay sau dd ngflng kich thieh.
tPHNX dtfdc tinh tfl xung kieh thieh nhi cudi eung d i n sdng P hoac dien dd nhi dau tien xuit hi^n sau khi ngifng kich thich. tPHNXd dtfdc tinh bang cich lay tPHNX trfl di thdi gian chu ky nhip xoang ed sd.
-t- Dan truyin nhi that vdi thdi dilm xuit hien bide nhi that dp 2 kilu chu ky Wenckebach (dilm Wenckebach nhi-that).
-(- Dan truyen chilu xudi qua dtfdng phtf vdi dilm xuit hien bide d dtfdng phy.
-I- Giy edn tim nhanh tren that.
Kich thich nhi vdi mdc do sdm ddn
Cd hai phtfdng phip: ( l ) Kich thieh nhi sdm tren ed sd nhan cam nhi (sensed extra stimulus): may kich thieh tim nhin cim nhip edban eua benh nhin, sau d-10 nhip nhan cam, miy se phat xung kich thieh nhi sdm tao ra mdt ngogi tim thu nhi, tflc khoang ghep kich thich ngan hdn thdi gian ehu ky nhip ed sd. Cfl nhtf vay, khoing ghep kich thich ngin din 10 - 20 ms cho moi mot Ian kieh thich eho d i n khi ed
^ 4 \ ^ - M \ ^ - W s / ^ M s / - M ^ . ^ U ^ . . ^ ^ ^ ''^f^ 4-^^—H^
Hmh 10: Kich thich nhi vd tinh thdi gian phuc hoi nut xoang
TAP CHi TIM MACH HOC VIET NAM - 5063.2013 I 65
^ DAO TAO LIEN TUC
nhi trd khdng cdn dap flbg vdi kidi diich sdm.
(2) Kieh thich nhi sdm tren cd sd tao nhip nhi (paced extra stimulus): miy kieh thich dm vdi mpt didi gian chu ky ed dinh trong 8 nhip ( S i ) sau dd phat ra mpt xung tilp theo ideh thich sdm hdn (S2) va S1S2 cung giam dan cho d i n khi ed nhi trd. Kieh thich nhi vdi mflc dp sdm dan nhim:
+ Xac dinh thdi gian trd hilu qua cd nhi: la khoing ghep dai nhit ma cd nhi khdng d i p ling
vdi xung kich thich sdm.
+ Xie dinh thdi gian d i n truyin xoang nhi (tDTXN) bang phtfdng phap Strauss.
-I- Danh gii ed hay khdng bang chflng dfldng d i n truyin kep qua nut nhi diat (btfdc nhay AH): la sfl tang dpt ngpt khoing AH >
SO ms so vdi khoing AH cua lin h'eh thieh nhi sdm trtfdc dd khi S1S2 giam di 10 ms.
+ Gay cdn tim nhanh bang phtfdng phap kich thich sdm vdi mot hoac nhilu khoing g^ep.
Hinh 11: kich thich nhi sdm ddn tim bang chdng ddn truyen kep qua nut nhi thdt (budc nhdy nhi-thdt).
VdiSlSl:S00msvdSlS2:280ms,khodngAHld250ms; vdiSlS2:280ms,khodngAHtdnglin360 ms. NhUvgy budc nhdy HA: 360 ms -250 ms = J J 0 ms.
Kich thich nhl vdi tdn sd co dinh 8 nhip Cdn gpi li phtfdng p h ^ Narula. Phtfdi^
phip nay dtfa tren n g u ^ n tie Idch du'ch nhi vdi tan sd cao hdn tin sd tim cd sd 10 nhip/ phut, mdi lin Idch thich hin 8 nhip rdi ngflt^. Phtfdng phap Narula eho phep dnh toin thdi gian din
truyin xoang nhl (tDTXN), theo cdr^ thflc sau:
tDTXN = ( A 2 A 3 - A L A l ) / 2 Trong dd: A2A3 la thdi gian tfl xung kich thich eudi eimg d i n sdng P xoang diu tien sau khi ngiftig kich thich; A l A l l i thdi gian cua khoing PP cd sd.
i ITAPCHITIMMACH HOCVIET NAM-S663.2013
DAO TAO LIEN TUC k.
Hmh 12: Kich thich nhivd tinh thdi gian ddn Kich thich thdt
Kieh thich thdt vdi tdn sd tdng ddn
- Bit dau vdi tan sd kieh thich that cao hdn tan sd tim cd sd it nhat 10 nhip/ pbut. Sau dd tang dan tin sd kich thieh mdi lan 10 nhip/
phut hoac thdi gian chu ky kich thieh sau ngan hdn chu ky trflde 10 - 20ms. Ngflng kieh thich khi thdi gian chu ky kich thieh giam din 300 ms. Thdi gian ehu ky kieh thich cd t h i ngin hdn 300 ms trong mpt s6 trtfdng hdp nhtf de dinh gii mflc dp din truyin ngtfpc cua dtfdng din truyin phy nhi-thit.
- Dip flng binh thtfdng vdi phtfdng phap kich thieh thit vdi t i n sd ting d i n li thdi gian dan truyin thit-nhi keo dai dan rdi xuat hien
truyen xoang nhi
bide diit-nhi chieu ngtfdc. Kieu bloc d i n truyin thit nhi (V-A) cd t h i la chu ky Wenckebach hoac mflc cao hdn. Bide thit-nhi kieu ehu ky Wenckebach thtfdng bilu thi stf cham tri d i n truyin trong nut nhi that.
- Phtfdng phip kich thieh that vdi tan sd tang dan eho phep danh gia:
+ Mfle hide thit-nhi qua dtfdng din truyen His-Purkinje-niit nhl that.
+ Xac dinh sfl tdn tai dtfdng din truyin phu nhi thit va diem bide dan truyen chieu ngfldc thit-nhi qua dtfdng din truyen phu.
-I- Giy edn tim nhanh that, tim nhanh vio lgi nhi that.
. ^vyv^^j\^yvjVJVJWU\JVAJ\JVA
U^MO-
Jl—l~Ji^—J-M)—[-M'—pvX—l-/i^ — I - ' * -
I-HH4-
Hinh 13: Kich thich thdt sdm ddn vdi SI SI: 300 ms gdy phdn ly thdt-nhi
TAPCHITIMMACH HOCVIET NAM - 50 63.20131 67
A DAO TAO LIESTLC
Kich thich Adt vdi mdc do sdm ddn
- Kidi thich that sfei dan cung dtfdc thtfe hien gidng nhtf kich thich nhi sdm dan dieo 2 phtfdng phip: ( l ) Kieh thieh diat sdm trin cd sd nhan cam that (sensed extra stimulus): miy kich thich nhin cim nhip cd sd, sau 8 nhip si phit ra mot xung sdm va khoing g^ep ciia xung sdm nay giam dan 10 - 20m5 cho din khi cd that trd, hoae (2) kich thich thit sdm tren cd sd tao nhip thit (paced extra stimulus): thtfdng dtfdc ti^ hanh vdi 2 ehu ky tao nhip that la 600 ms (Si) tiong 8 nhip v i 400 ms (S2), S1S2 giim dan 10 - 20 ms cho den khi cd that trd.
- Ngoai ra, cdn cd phtfdng phap kich thich thit sdm vdi nhilu khoang ^ e p \ ' 2 , V3, \'4.
T r o i ^ ddi V2: xung kich thich thit sdm difl nhat; V3: xung kidi thich that sdm thfl hai vi
\4: xung kich diich that sdm thfl 3 vcS khoang
^ e p V1V2 > V2V3 > V3V4 ( V I : xung tao nhip thatcdsd).
Phtfdng phip kich diich thit sdm d i n cho phep danh gii:
- Xie dinh ihcA gian trd hieu qui cd that:
la khoing ghip dai nhit m i cd that khdng d ^ flng vdi xung Idch thich sdm.
- Giy cic cdn dm nhanh thit, tim nhanh
\'ao lai nhi-that
Xie dinh thdi gian trd cua dtfdi^ phi;
theo chieu ngtfdc hoac thdi gian trd cua bd His theo chilu ngtfdc
Hmh 14: Kich thidt thdt sdm dan xdc dinh thdi gian tro hieu qud ctf thdt. SI S2: 220 ms (trdi) vdn cdn gdy sdng khd aic thdt; SI S2:200 ms (phdi) khong cdn gdy sdng khU cUc thdt. Nhti vay 0idi gUin trtf kOu qud CO thdt Id 200 ms.
I TAP CHi TIM MACH HOC VIET NAM - 5063.2013
DAO TAO LIEN TUC
\-^\^-^\-A,
r'\''^^j'^-j^^r\r\r\rv
*~r\
-rj~-*-^~j 1"—^—f—f^—f'—^—f—^H~-i~
U U ^ ^ L W^,\^^|^^W^l^^
—jL^— f—jy—^ k 1^ u k — > _ _ _ | — k . 1, ^—
Hmh 15: Kich thich thdt sdm ddn gdy can tim nhanh thdt
5. Mpt sd thudc dtff^fc sut dung trong tham do dien sinh ly tim
- Isoproterenol: lilu tif 0,5 d i n 5 t^g/kg/
phut, thudc ed tic dung tang tinh ttf ddng, tang dnh dSn truyen, thay ddi thdi gian trd ciia cae md tim do vgy tao thuan ldi cho vile kich thieh tim giy cac cdn tim nhanh.
- Atropin: lilu tfl 0,5 den 1 mg tiem TM, thudc huy phd giao cam vdi c i c t i c dung dien sinh ly hpe ttfdng tfl va cd the dung thay t h i Isoproterenol.
- Procainamid: lilu tfl 10 d i n 15 mg/kg, thudc cd tic dung lam cham din truyin dtfdi nut nhl thit va klo dii khoang HV do vay ddi khi dddc sfl dung trong danh gii rdi loan din truyen dfldi niit nhi thit hoae de dfl phong xiy
ra rung nhi khi kich thich tim ed chfldng trinh.
- Adenosin: lieu tfl 6 den 18 mg, thudc giy bide nhi that thoang qua, thfldng dddc diing trong dinh gii cic cdn tiin nhanh tren that nhtf cdn cd phu thudc nut nhi that hay khdng, ed hay khdng bang chflng dtfdng din truyin phu ngoai niit nhi that.
VI. CAC BIEN C H O N G
Thii thuit tham dd di?n sinh ly tim cd the CO cac biin chflng sau:
I. Biin chflng mach man
Cd the nhe nhfl tu mau dtfdi da hogc hinh thanh khdi miu tu ngay tai vj tri chpc mgch, gap trong 1 - 5% sd ca. Nang hdn li cae biin ehfliig TAP CHI TIM MACH HOCVIET NAM - SO 63.20131 (
A DAO TAO LIEN T t C
nhtf huylt khdi ddng, (mh mgch, thdi^ ddng &ih mgch hoac gii phinh maeh, gap trong < 1% sd ea.
1. C i c b i i n chfling chung lien quan d i n tham do Tfam nhap tiin mach
Tran khi ming phoi, tran miu mang ngoii tim, dot qu^ nhdi mau ed dm, tfl vong.
3. Cac bien chntng dac thu Uen quan den tham do dien sinh ly tim
- Tdn thtfdng nut nhi that gay bide nhi that
hoan toin can phii cay may tao nhip dm.
- Rdi logn nhjp tim, gap trong 10% sd ca, thtfdng nhe va ttf h i t Tuy nhien, mdt sd rdi logn nhip nang nhtf tim nhanh that ben bi hoae nmg that ed the gap khi kich thich that cd chtfdng trinh.
- Huyet khdi tic mgch lien quan den tdn thtfdng md tim gay ra bdi nang Itfdng ed tin sd radio dimg de triet bd eic rdi loan nhip.
TAI LIEU THAM KHAO
1. Andrea Xatale (2007) Handbook ojCardiac Electrophysiology. Informa Healthcare.
2. Frauds D.Murgatroyd (2002) Hflndboofco/Cardiac£/ecfrophysio/ogy-Apractica/^ide to i/ivasive^P studies and Catheter Ablation. Remedica Pulishing.
3. Mark E. Josephson (1993) Clinical cardiac dectrophysiology 2°^ Edition. Lea & Fibiger Company.
4. Masood Akhtar (2001) Techniques of electrophysiologic evaluation - Hurst's The Heart 10* edition, vol 1. McGraw-Hill medical publishing division.
5. Zainnl Abedin, Robert Conner (2007) Essential Cardiac Electrophysiology. Blackwell-Futura 70 I TAP CHi TIM MACH HOCVIET NAM - 5063.2013