in tim trong NMCT v TMCTA. Nhi mu c tim (NMCT) I. Khi nim 1. nh ngha: NMCT ( NMCT ) l hin tng hoi t mt vng c tim do nguyn nhn gim hay ngng cung cp mu t ngt ca mt hay nhiu nhnh ng mch vnh gy ra. 2. Gii phu h ng mch vnh:

Right coronary artery: ng mch vnh phi Left coronary artery: ng mch vnh tri Anterior interventricular artery: ng mch gian tm tht trc 2.1 ng mch vnh phi : Phn chia cc nhnh ca ng mch vnh phi nh sau : 1. on u (nm ngang) ca ng mch vnh P 2. on 2 (nm dc) ca ng mch vnh P 3. on 3 (nm ngang) ca ng mch vnh P 4. ng mch lin tht sau 5. ng mch qut ngc tht 6. ng mch chp 7. ng mch nt xoang 8. ng mch b P 9. ng mch tht P 10. ng mch nt nh tht 11. ng mch c honh 12. Cc nhnh vch di

T th chch trc P 45o

T th chch trc T 45o

2.2 ng mch vnh tri : Phn chia cc nhnh ca ng mch vnh tri nh sau : 1. Thn chung ng mch vnh T 2. Nhnh lin tht trc on gn 3. Nhnh lin tht trc on gia 4. Nhnh lin tht trc on xa 5. Nhnh ng mch vnh m 6. Nhnh ng mch b T 7. Nhnh cho th 1 8. Nhnh cho th 2 9. Nhnh vch th lang=VI 1 10. Cc nhnh vch 11. Cc nhnh tm nh ca ng mch ch 12. Nhnh ng mch b th 2

T th chp chch trc P 30o

T th chp chch sau

II. Hnh nh v c ch : 1. Hnh nh tn thng in hnh: Tn thng trong NMCT bn cp tnh c 3 vng - Vng hoi t (infarction) : c trng bi sng Q, ngi ta gi l sng Q hoi t - Vng tn thng (injury) : c trng bi ST chnh ln, ngi ta gi l ST ca vng tn thng - Vng thiu mu cc b (ischemia): c trng bi T m, ngi ta gi l T vnh

Tn thng trong NMCT cp tnh c 2 vng : Vng tn thng v vng thiu mu cc b. Lc ny sng T ha ln vo on ST nn ta ch thy ST chnh cao, dng vm m khng thy sng T vnh

Tn thng trong NMCT mn tnh c 2 kh nng: vng tn thng hoi t thm 1 phn lm tng kch thc tn thng, hoc vng tn thng hi phc 1 phn lm gim kch thc tn thng. Sau khi n nh, trn in tim s c hnh nh sng Q su v rng, cn ST c xu hng tr v ng ng in, T c xu hng tr v bnh thng nhng dt hn.

2. C ch cc sng trong NMCT 2.1 Giai on cp tnh : Giai on ny cha c hoi t, c tim mi ch tn thng nn vn cn kh nng dn truyn in. Tuy nhin thi gian kh cc ca c tim vng tn thng ny mun dn n hin tng khi cc vng c tim bnh thng kh cc xong ( in tch -), vng tn thng vn cha hon thnh (in tch +). Nm na l vecto kh cc s c chiu t vng lnh ti vng bnh. Bn c li c ch tng bin sng R trong dy tht dy nh s thy bin sng R o trnh tng ng s tng cao. ng thi thi gian xut hin nhnh ni in mun ( do thi gian kh cc lu hn) s ln mt thi gian ti cc. Kt qu on ST s chnh cao hn bnh thng

V mc tn thng ca nhi mu c 3 loi: - NMCT xuyn thnh (t ni tm mc n thng tm mc). - NMCT di thng tm mc. - NMCT di ni tm mc. Mi mc tn thng s c hnh nh khc nhau mt xu.

D thy trong trng hp NMCT di ni tm mc, ST s chnh xung ( vecto kh cc theo hng t thng tm mc v ni tm mc). Tng t vi NMCT di thng tm mc, ST s chnh ln ( vecto kh cc theo hng t ni tm mc v thng tm mc). V tn thng xuyn thnh ST cng chnh ln ( ch lc ny vecto kh cc i t cc vng lnh khc hng v vng tn thng ch khng cn i theo hng t ni tm mc ra ngoi tm mc) 2.2 Giai on bn cp : giai on ny c hin tng hoi t c tim, tc tn thng khng hi phc. Vng c tim ny khng cn kh nng dn truyn in, ng thi gradien in th mng cng gim hn so vi bnh thng. Nu so snh vi cc vng c tim bnh thng, vng ny s tr nn m in hn. Do vecto kh cc s c chiu i t vng tn thng n cc vng lnh ( theo quy lut chung i t m n dng ch on ny d long ngong vi on trn v sng kh cc y i t vng bnh ti vng lnh ). Th hin qua sng Q su, rng. Tuy nhin iu ny ch ng trong trng hp nhi mu di thng tm mc v nhi mu xuyn thnh. Sng Q khng bao gi xut hin trong trng hp nhi mu di ni tm mc. C ch c gii thch nh sau: + Phn di ni tm mc chim khong 2/3 b dy ca thnh c tim pha trong, y cha mng purkinje, s dn truyn xy ra rt nhanh chng, cc vect kh cc xy ra t nhiu pha lm chng trit tiu nhau v vy trn in tm kh cc vng ny khng c i din bng sng no c. Ngi ta cn gi vng ny l Vng cm in hc. Mt hoi t xy ra vng cm ny cng s khng gy bin i g v phc b QRS (cho nn ta khng thy sng Q hoi t bnh nhn NMCT di ni tm mc) + Phn di thng tm mc chim khong 1/3 ngoi b dy ca thnh c tim. y s hot ng ca cc vng tng i c lp vi nhau do s phn b mng li dn truyn tha tht. Khi c NMCT vng ny th s kh cc n s c phn nh trn in tim (Sng Q hoi t). ST chnh nhng khng nhiu nh giai on cp. Nh ta bit, cc t bo c tim hoi t c in tch b mt m hn so vi cc t bo bnh thng, m hn c nhng t bo thuc vng tn thng. Do ln ca vecto kh cc lc ny nh hn so vi giai on cp tnh. T m. Nu NMCT thng tm mc s khin o ln vng ti cc, ngha l ni tm mc ti cc trc, thng tm mc ti cc sau. Do sng T m. Nu NMCT xuyn thnh, cc vng khc ti cc trc, vng tn thng ti cc sau. Do vecto kh cc s c chiu t vng tn thng (in tch m) n vng lnh (in tch dng sau khi ti cc xong).

Trn o trnh i vi o trnh tng ng ca vng tn thng, cc sng in tim c hng ngc chiu nhau to nn hnh nh soi gng 2.3 Giai on mn Lc ny vng c tim tn thng thnh so. in tch vng ny rt m so vi nhng vng khc. Trn in tim s c hnh nh Q su v rng. III. nh v tr tn thng * NMCT mt trc: trc vch, mm, bn, bn cao, rng. * NMCT mt sau: sau di (cn gi l di hoc honh); sau thc * NMMCT tht phi Tng ng vi cc vng l cc ng mch vnh chi phi - Vng trc vch (50%) do tn thng ng mch lin tht trc. - Vng sau di (25%) do tn thng ng mch vnh phi. - Vng trc bn (15%) do tn thng ng mch m tri. - Vng trc rng (10%) do tn thng ng mch lin tht trc v nhnh m ca ng mch vnh tri.

- Cc chuyn o chi: + Vng sau di: DII, DIII, aVF. + Vng trc bn: DI, aVL. - Cc chuyn o ngc: + Vng trc vch: V1, V2. + Vng trc mm: V3, V4. + Vng trc bn: V5, V6. + Trc vch mm: V1 V4. + Trc rng: V1 V6. - c bit: + Vng sau thc: Chuyn o thc qun hoc da vo hnh nh soi gng V1, V2, V3. + Tht phi: Cc chuyn o kho st tht phi V3R, V4R (i xng vi V3, V4). + im J: im ni gia phc b QRS v on ST 1. NMCT trc vch:

2. NMCT trc mm :

3. NMCT trc bn :

4. NMCT bn cao :

5. NMCT trc rng :

6. NMCT sau di :

7. NMCT sau thc :

B. Thiu mu c tim (TMCT): Sau khi hiu r bn cht ca NMCT, ta nhn thy TMCT ch l 1 trng hp nh ca NMCT, s bin i cc sng v s lng ln cht lng cng khng phc tp nh trong NMCT. Nm na c th hiu in tim TMCT lc ny tng t nh in tim phn nh vng thiu mu (ischemia) ca c tim tn thng trong NMCT, mi c ch v hnh nh mi bn xem mc giai on cp tnh ca NMCT. Trn hnh nh in tim ta c th thy: - T o chiu vi QRS, i xng cc chuyn o tng ng vi vng ng mch vnh b hp - ST c th bnh thng, i ngang hoc chnh th hin tn thng nng hn so vi ch c sng T vnh n thun