Izvo, chii chinokosha
The atrioventricular (AV) node ndiyo chikamu chinokosha chemagetsi emwoyo. Inodzora chikamu chemhepo yemagetsi yemhepo kubva kuAria kusvika kumhepo.
Chii Chirevo cheAV?
Iyo node yeAV inongo "duku" yemasero anozivikanwa (anenge anenge 3 ne5 mm muupamhi) iri pedyo nechepakati pemwoyo, kurudyi kweearic atriyamu pamaganho eatriya uye mhepo.
Basa rayo nderokubatsira kurongedza kushandiswa kweatria uye mhepo inofanirwa kutarisana nemutsara wemagetsi emwoyo.
Chii Chinodiwa neAV?
Iyo nhamba yeAV inodzora chikamu chechiratidzo chemagetsi emwoyo kubva kuAria kusvika kumhepo.
Mushure mokufungira magetsi kunoumbwa node ye sinus , inopararira nechepamusoro peAria, zvichiita kuti atria irove. Iyo nhamba yeAV iyo "inounganidza" iyo inokonzerwa nemagetsi uye, mushure mekurumidza kunonoka, inobvumira kuti ipfuurire kusvika kumhepo.
Zviratidzo zveKliniki yeAV Node
Chirongwa cheAV chinowanzokosha chakakosha pakushanda kwemoyo. Kuzononoka kwenguva pfupi pamusana pemagetsi anokonzerwa neAV node inoita kuti mwoyo uite basa. Kuzononoka kunobvumira kuti atria ipedze kurova, kuitira kuti mhepo inobhururuka izere neropa, vasati vashandisi vatange kurova.
Uyezve, zvakasiyana zvikuru nedzimwe nhengo dzemhepo yemagetsi, kunyanya kuwanda kweAV kukurudzirwa nemagetsi emagetsi, inononoka inoita magetsi.
Ichi chinozivikanwa - icho chinonzi "kumira kwekutengesa" - chinova chakakosha zvikuru ((somuenzaniso) yefriday fibrillation , apo iyo node yeAV inoputirwa nemazana emagetsi emagetsi neminiti. Iko kurairirwa kwemaitiro kunodzivisa zvizhinji zvezvinangwa izvi kusvika pakuvhura, uye inoita kuti mwoyo urege kuva usina ngozi.
Iyo nhamba yeAV inowanikwa zvakakwana neve vagus nerve . Kuwedzera kwevusus nerve tone (yakadai inogona kutsamwiswa neValsalva mufambiro ) inogona kuvhara kutengesa kwemasimba emagetsi kuburikidza neAV node. Izvi zvinobatsira pakuisa marudzi akawanda e- supraventricular tachycardia (SVT) .
Vamwe vanhu vanoberekwa vane nzira mbiri dzakasiyana dzemagetsi kuburikidza neNode yeAV, iyo inogona kuita kuti ive nyore kuurmimia inonzi AV nodal reentrant tachycardia, kana AVNRT. Iwe unogona kuverenga pano nezveAVNRT .
Zvirwere zveAV node zvinogona kuita kuti kunonoka, kana kuti chikamu chisina kukwana kana chakakwana, pakuparidzirwa kwemagetsi emagetsi kubva kuAria kusvika kune mhepo-mamiriro ezvinhu anozivikanwa se " moyo block ".
Kunonoka kuitisa nehutachiona hweVV kunoonekwa paEECG sokuwedzera kwe "PR interval." (Nguva yeP PR inotarisa nguva pakati pekuregererwa kwepanyika uye kuputika kwemhepo.) Nguva yakareba PR, yakabudiswa nekuderera muAV nodal conduction, inonzi "first degree AV block." Yokutanga digita AV block kazhinji haina kunyanya kukosha.
Kana AV nodal conduction inonoka zvakakwana, mwoyo inogona kugadzirisa. Ne "yechipiri digiti AV block" mamwe mafungiro akavharwa kubva pakusvika pamhepo. Ne "yechitatu digiti AV block" zvose zvido zvinodziviswa.
Dzimwe nguva AV nodal block inokosha zvakakwana kuti ibudise girdycardia yakasimba, uye kuiswa kwechigadziro chemhepo chinogona kudiwa. Zvisinei, bhokisi remwoyo rinokonzerwa neAV nodal kutadza kunowanzoenderana nemishonga (zvakadai se beta blockers kana calcium channel blockers ), kana nezvinetso zvezvehutano zvinowedzera vagal verve tone (zvakadai sokunyunyutira uye kurutsira), uye inogona kunge inogara ichingorapwa isina kuti tishandise pacemaker.
Zvisinei, chimwe chinokonzera AV nodal block chingada kuti pacemaker isingagumi, iyo inonzi, myocardial infarction (kurwisa mwoyo) . Iyo nhamba yeAV inogamuchira ropa rayo kubva kuAV nodal artery, iyo in 90% yevanhu ibazi rekodhoni yakakodzera .
Saka AV nodal block nekuda kwekurwadziwa kwemoyo inonyanya kuonekwa nekakanaka yekoniyiti yepamwoyo inorwadza. Nenzira yakanaka, kunyange mumatambudziko aya AV node inowanzodzorera zvakakwana mumazuva mashomanana kuitira kuti pacemaker isakoshi.
Sources:
Epstein AE, DiMarco JP, Ellenbogen KA, et al. ACC / AHA / HRS 2008 Nhungamiro yeChirongwa-Based Based Therapy yeCardiac Rhythm Kusakanganiswa: mushumo weAmerican College of Cardiology / American Heart Association Task Force pamusoro pekushandisa mazano (Komiti Yokunyora Kuongorora ACC / AHA / NASPE 2002 Nhungamiro Yekutsvaga Kwekugadzirisa yeCardiac Pacemakers uye Antiarrhythmia Devices): yakagadziriswa pamwe chete neAmerican Association for Thoracic Surgery uye Society of Thoracic Surgeons. Circulation 2008; 117: e350.