KHOR HOC - CONG NGHC Vfl B6\ M O I
MAY DIEN TIM BO Tdi - HO TRO TICH CIIC
TRONG CHAN DOAN S ( M VA DIEO TRI RENH TliVJ NIACH
• I • CAO TH! VAN OIEM, PHAM MINH QUAN, CHO QUY Dl/ONG, PHAN QUANG OQ
Vi§n N ^ n aiu che tao va chjyen 03o cbnq n ^ tliet bj y t^f
SU ra dcri cua may dien tim, dac biet la may dien tim bo tui da mang lai nhieng tien icti I(h6ng nhd cho cac benh nhan tim mach, dap iFng nhu cau ghi lai va theo doi nhjp tim cj!ia benh nhSn trong cu3c sd'ng hang ngay, gop ph^n ch^n doan va hd trof dieu trj hieu qui cac trUcrng hap benh nhan chira co bieu hien ro benh hoac cac b§nh nhSn da hOi phuc, cd t h i sinh hogt b'inh thirdng nhirng vin cin phai theo ddi.
Tai Vi$t Nam, cac nha khoa hpc thudc Vidn Nghidn ctfu chd'tao va chuyen giao cdng ngh| thid't bj y te'da lam chu diftfc cdng nghe thie't ke'va che'tao thanh cdng may didn tim bd tui, vdi khi ndng ghi va phdn tfch ctf ban dif lidu, btfdc dau suf dung cac cinh bao va sang lpc ctf bin mot sd'trieu chifng cua benh tim mach.
Sir ra doii ciia may di^n tim
Mpt trong nhDng thiet bj thdng dung va pho bien nhat trong ede cP sd y t l hien nay la may didn tim. Thie't bj nay dupc si!f dgng trong d p cUu, hdi sDc bdnh nhdn, giup bac sTtheo doi nhQng d i l n b i l n tUc thdi eua benh nhdn. May didn tim d i u tien do nhd bde hpe Einthoven (ngUdi Hd Lan) sang ehe nam 1901 vdi ten gpi la dien ke day, cho phep ghi tin hieu dien tim hoac cac tfn hieu bien doi theo thdi gian. T h i l t bj (gom mot dien k l day, bdng den eong, he thd'ng c h i l u vd camera) ndng khodng 300 kg va can 5 ngudi vdn hdnh. Sau dd, nhieu edng ty da tim each t h i l t k l Igi he thong nay de ed the dUa ra thj trudng, mpt trong cde thiet ke dupe nhieu ngudi biet tdi nhat la san pham cija Cdng ty Cambridge Scientific Instrument (Anh) vao ndm 1911.
hAiy di$n tim dgng bin cua Cdng ty Cambridge Scientific Instrument nim 1911
Nam 1914, nha khoa hoe My Horatio Williams da t h i l t ke ra may dien tim dau tien eua My, cd the do rd't chinh xac nhDng xung dien nhd gay ra bdi mpt so trieu chUng tim maeh. Thdi diem dd, y hge da dua tren chiec may dien tim nay de ghi nhdn va phdt trien he thdng ly thuyet chan dodn vd dieu tri y hpc. TD dd den nay, eae thiet bj theo doi dien tim dupc che tao theo hUdng ngay edng nhd gpn ve kfch thude, TU khoi lUpng hang tram kg, cac t h i l t bj dien tim chi cdn nang vai tram gam, tham ehf vai chue gam.
Nam 1948, nhd bac hpe ngUdi My Norman Jeff Holter da thiet ke mdy dien tim bd tui (Holter ECG) vdi trpng lupng chi 40 g. Thiet bj nay ed the ghi lai tin hieu dien tim va truyen tfn hieu. Day Id tien de cho sU phdt then he thd'ng theo doi dien tim sau nay. Dac biet, su ra ddi cua may dien tim bd tui da dap Ung nhu eau ghi lai va theo ddi nhjp tim cua benh nhdn tim mach trong eudc song hang ngay, gdp phan ehan doan va h5 trp dieu tri rat hieu qud cac trudng hpp benh nhan ehua ed bieu hien benh ro rang hoac cac benh nhan da hoi phue, cd the smh hoat binh thudng nhung vdn can phdi theo ddi.
Ctf che hoat dong cna may dien tim
Cd tim dupc vi nhu mdt te bao. Luc nghi, eae ion dUdng 6 ngoai mang te bao, edn eae ion am bj giD d trong mdng te bao de edn bang luc hut tTnh dien, Khi mpt t l bao b\kich thfeh se xuat hien hien tUpng khD cUc, cac ion am k h u l c h tan ra ngoai mang, cdn cdc ion dUdng khuech tan vao trong mang. Sau dd te bao dan lap l^i the can
So 17 nam 2014 TapcN KHOfl HQf 11
CONnv"' N)dr
KHOR HOC - CONG NGHG VH DOI MOI
bang ion lue nghi, dien t h i mat ngodi trd lai dUdng tfnh tUdng doi, ngUdi ta gpi dd la hien tupng tai eUc. Ddi vdi tim eon ngUdi, ed e h l hoat ddng phUc tgp hdn mdt chut so vdi t l bao. Tim dUde kich hoat hoat ddng bdi mdt xung dien truyen qua h§ thong than kinh tU dpng eua tim. Day Id xung ta dpng, khdng the dieu khien bdi nao bp con ngUdi.
Xung dpng di tU nut xoang tda ra ed nhT vd lam cd nhT khD cue trude. Cd nhT bop day mdu xuong tam that. Sau dd nut nhT that Tawara tilp nhdn xung dpng truyin qua bd nhT that HIS xuong tdm that de khCf eUc tam that. Tam that tiep nhan toan bp mau se bop manh day mau ra ngoai bien.
Sau khi thuc hien nhiem vu co bop, eac cd tim se trd lai trang thai ban dau, tUdng tU nhU doi vdi te bdo qua hien tupng tdi cue. Hien tupng nhT va that khCf cue lan lupttrUde va sau nhu the de duy tri qua trinh huylt dpng binh thudng cOa he thong tuan hoan. Do vdy, dien tam do bao gom ba phan: khCf cUe tam nhT, khCf cue va tai cUc tam that. Sdng dien tim trong mpt nhip cd the chia thdnh sdng P dai dien cho khi!f cue tam nhT, phUe bd QRS dai dien eho khLf eUc tam that va sdng T dgi dien cho tai cue tam that.
De thu dUdc ddng dien tim, eac dien cue eua may dien tim can phai mac vao cd the. Tijy vao chd ddt cde dien eUe, hinh dang dien tam do se khae nhau. Ngudi ta thud_ng dat dien cue theo 12 each, bao gom 3 chuyen dao mau, 3 chuyen dao ddn egc cdc chi va 6 ehuyen dao trude tim.
6 moi chuyen dao, hinh dang sdng dien tim khac nhau. 3 chuyen dao mlu dupe mdc bao gom: 1. Chuyen dao 1 (D,):
dien cue dm d eo tay phai, dien cUc dUdng d eo tay trai (thue chat, chuyen dao nay dUdc mac de do dien cUc d vai phai va vai trai, la nhij'ng chd khd gdn dien cUe, hai tay ehi lam nhiem vg Id ddn dien, true chuyen dao la dudng thang noi tu vai phai (R) den vai trdi (L)); 2. Chuyen dao 2 (DJ: dien cue am dat d ed' tay phdi, dien cue dUdng dat d eo chan trdi, true chuyen dao se Id dudng thang ditU vai phai (R) xuong goe ehan trdi (F) va chieu dUdng Id chilu tU R den F;
3. Chuyen dao 3 (D3): dien eUc am d tay trdi va dien cue dUdng d chan trai, dudng chuyen dao la LP.
3 chuyen dao ddn cue ede chi dupe sii dung de nghien eUu dien the rieng biet eua mpt diem. Trong each mdc ehuyen dao ddn, ngudi ta noi dien cue dd (dien cue am) ra mpt cue trung tam gpi tdt Id CT (central terminal) ed dien t h i bdng 0 (trung tfnh), vi nd la tdm cua mpt mang dien hinh sao
mdc vao ba dinh cua tam giac Einthoven (Wilson). Con dien eUc thdm dd cdn lai (didn cUc dUdng) thi dem dat Ign vung can tham dd: co tay phdi (ta dUdc chuyen dgo VR, day la dien the 6 me ben phdi va ddy tim, true chuyen dgo la dudng thang noi tam diem (0) ra vai phai (R)); co tay trai (ta dupc chuyen dgo VL, day Id dien thi ve phia that trai, true chuyin dgo la dudng thang OL);
CO chan trdi (ta dupe chuyen dgo VF, ddy Id chuyin dao ddc nhat "nhin"
thay dupc thanh sau dudi day tim, tryc ehuyen dao la dudng thang OF).
6 chuyin dao trudc tim dupc ky hieu bang ehU V kem theo so tU 1 den 6. Day la cac chuyen dao dPn cue vdi mdt dien cUe trung tfnh va mdt dien cUc tham dd dUdc dat lanlUPttrenGdiem vung trude tim. VI la khoang lien sUdn 4 ben phai sat bd xUPng Uc; V2 Id khodng lien sudn 4 bdn trdi, sat bd xUdng Ue;^V3 la diem giOa dudng thang nil V2 va V4; V4 la giao diem ei!ia dudng dpc di qua diem giQa
xUdng ddn trai vdi dudng ngang di qua mdm tim; V5 la giao diem cCia dudng naeh trifdc r^-&'Y^-"'-/r--' \ vdi dudng ngang ' ' ' di qua V4; V6 la
giao diem glQ'a dudng naeh giii'a vdi dudng ngang di qua V4, V5.
Tuy theo cdch mac, eac tfn hieu dien tim thu dUdc se khac nhau vd dupe sCf dgng de ehan dodn cac logi benh tim mach. Trong ky thuat chan dodn va sang Igc benh tim, thdi gian vd bien dp cua cdc sdng la cd s6 de xac dinh benh. Sdng P thudng ed bien dd tU 1-3 mm (1 6 ntifi
= 1 mm - 0,1 mV). Thdi gian cija sdng P khodng 0,08 giay. Sdng PQ (hodc PR n l u khdng cd sdng Q) bieu thj thdi gian khCf cue nhT va truyin xung ddng tU nhT xuong that. Thdi gian cua sdng RQ tU 0,12-0,18 gidy. Phi3c b6 QRS la thdnh phan quan trpng nhat ci!ia sdng dien tim, bieu hien sU lan truyen xung dpng ngang qua cd that (quS trinh khii eUc vd tdi cue). Thdi gian keo ddi etia phiJc b^
QRS la 0,05-0,1 giay. Dogn QRS Idn hdn 0,12 gidy IS
bieu hien bat thudng. Bien dp cua QRS dupc coi la bat
thudng n l u nho hdn 0,5 mV ddi vdi cac chuyin dgo chi
KHOR HOC - C O N G NGHG VA B6\ M O I
va 0,1 mV ddi vdi cdc c h u y i n dao trudc tim. Doan ST Id khodng thdi gian cd tam that cdn trong giai doan khCr eUc.
D i l m c i n luu y n h l t cua doan ST chinh Id sM thay doi vi trf cOa no so vdi dUdng dang dien vd hinh dang cua doan ST. Thdng thudng doan ST nam ngang vdi dudng dang d i l n hodc chenh rat it. Sdng T Id sdng b i l u hidn thdi gian phgc hdi cda tam thap. Thdi gian ciJa sdng T khdng cd vai trd quan trpng ndn khdng dupc sii dung, tuy nhien hinh dgng va dp cao cua sdng T thudng dUdc dung de chan dodn n h i l u benh ly nguy hiem nhu ddng mgch vanh, tang Kali._ Ngodi ra, cdn n h i l u tham c h i l u de chan doan benh dUa tr§n sdng didn tim.
May dien tim bd tui khdng dUdc dung de theo ddi trong qua trinh can thiep, ma dupe sii dung de theo doi benh nhdn 24/24 h. Cac benh nhan dupe theo doi bdng mdy didn tim bd tDi thudng dupc yeu cau ghi lai nhat ky hoat ddng trong ngdy d l tien cho viec chan doan. Sau mot khodng thdi gian (vdi ngdy), cdc bdc sT se thu nhan tin hieu dien tim vd t i l n hdnh sdng Ipc sCf dung phan mem sang Ipe tfn hieu dien tim. P h i n m I m dupc lap trinh dua trdn ede thuat todn va cdc dau hieu y hoe ve cac benh tim mgch qua phan tieh tfn hieu dien tim. Todn bp dd iieu se dupe Kis ly va khu tni ede vj trf, diem cd dau hieu bat thudng v l tim mach nhu loan nhjp, sdng bat thudng... K i t hpp vdi nhdt ky hogt dpng eua benh nhdn, bdc sTed the dua ra nhOng chan doan ve benh. Qud trinh xii ly phan tfch tfn hidu dupc thuc hien qua eae giai doan ddnh gid va xdc dinh sau: xdc djnh nhjp va loan nhjp; xac djnh nhip tim; k i l m tra thdi gian cCia sdng P, PR, QRS va QT; xdc djnh ede tryc c h u y i n dgo va danh gid rieng Id doi vdi tdng dao trinh ( n l u ed t h i ) ; kiem tra sdng P, 0 , R, S, T va ede doan ECG; xdc djnh va danh gia trung binh cdc sdng trong hai hode n h i l u nhjp; danh gid tong quan hinh dang sdng. Doi vdi mdi logi benh khde nhau, qud trinh xde djnh benh ly dUa trdn tin hieu dien tim can mgt ehu trinh danh gia khae nhau. Hidn nay tren the gidi hau nhU chUa ed p h i n mem hodn ehinh cd the sang Ipe 100% so benh tim mgch dya tren mdy didn tim bo tui. He thd'ng thuat todn vd ehu trinh danh gid lien tye dupc cap nhat de dap Ung nhu c l u c h i n dodn mdi.
Nghien cufn che tao may di$ii tim bo tni ol Vi9l Nam
Vi$n Nghidn cUu c h i tgo vd chuyen giao cdng nghe t h i l t bj y t l - Hdi t h i l t bj y te Viet Nam hien dang thue hidn d i tdi d p Bd Y t l : Nghien cdu thie't k l , c h i tgo may di$n tim bd tui, vdi mye tidu chfnh la lam chu edng nghe vd c h i tgo thdnh cdng thiet bj nay. Hien tai, ede nhd khoa hpc ciia Vi§n da t h i l t k l hodn chinh may dien tim bd tui vdi khd ndng ghi vd phdn tich cd bdn dU lieu.
Ddc biet, mdy dien tim bd tui eua de tdi dd budc dau sii dgng eac canh bao va sang loc cd bdn cho mdt so trieu chdng benh. Giao dien ngudi sis dgng dUde t h i l t k l bang tieng Viet, bao gom ndi dung hien thi sdng dien tim vd chpn ngudng canh bao.
Ngudng do^n ST NgUdng phUc bd QRS NgUdng do?n PR
San pham may dien tim bd tui cGa de tai co cac thdng so cd bdn nhu sau:
- Tdc dp ghi: 250 tin hieu/gidy,
- May hiln thi cac thong so tim quan trpng (tan s6 tim, phUc bo QRS va doan ST) va luu giO lai hinh dnh dien tim (30 ket qua) theo ngdy gid.
- Thdi gian do: 30 giay.
- Hien thj: man hinh LCD, hien thj hinh dnh dien tim lien tuc.
- So' dao trinh hien thj: 2 dao trinh.
- Tin hieu vdo: tU dien cUe khd ngay tren may hoac day dien cue ldp ngoai.
- Cong tin hieu ra: VGA, WIFI.
- Nguon dien: 2 pin AAA (1,5 V).
- Trong IUdng < 250 g bao gom ca pin.
- Nhiet do hoat dgng: 10-40°C.
- Dp am hoat dgng 25-95%.
Tuy nhien, d l cd the sdn xuat hang loat va dUa vao sii dung, phyc vy tdt hdn eho eong tae ehan doan va dieu tri cac benh tim mach, san pham eua de tai can dupc tiep tyc hoan thien, cap nhat cdc phan mem, thuat toan va ehu trinh danh gia mdi de dap Ung nhu eau trong en."'" doen ..-
So 17 nam 20'
