Yaki da Ciwon Zuciya: Taimakawa Zuciya Fada

Eugene Braunwald, MD (1929-) ana ɗaukarsa a matsayin babban likitan zuciya na shekaru 100 da suka gabata. An haife shi a Vienna, Austria, shi da danginsa da kyar suka tsere daga sansanin tattara 'yan Nazi. Braunwald ya shahara saboda aikinsa a kan aikin al'ada na zuciyar ɗan adam, da tasirin bugun zuciya wanda ke haifar da sabbin jiyya. Ya fara aikinsa na ilimi a Cibiyar Kiwon Lafiya ta Ƙasa a shekarun 1950, kuma shekaru da yawa ya kasance Shugaban Magungunan Ciki a Brigham da Asibitin Mata na Makarantar Kiwon Lafiya ta Harvard. Littafinsa na Ciwon Zuciya ya kasance "ma'aunin zinare" don maganin cututtukan zuciya na kusan shekaru 40.

A cikin 1968, sabon kayan aiki a Yammacin Tekun, Braunwald da tawagarsa ¹ yayi bincike mai zurfi kan tasirin hawan jini akan aikin zuciya ta al'ada da kuma bugun zuciya sakamakon bugun zuciya. Hawan jini shine juriya a cikin jijiyoyin da ventricle na hagu yana buƙatar buguwa don tura jini don isa ga kyallen takarda; mafi girman juriya, wato mafi ƙuntata jijiyoyin jini, da wuya ƙwayoyin tsokar zuciya su buƙaci yin aiki. Ana kiran juriya ga kwararar jini “afterload.” Ƙasan abin da aka ɗora bayan, bugun jini na jijiyar jijiyoyin jini na wurare dabam dabam, mafi sauƙi shine don ventricle na hagu don yin famfo da kyau. Amma binciken ya nuna cewa akwai nau'in bugun jini wanda ya fi dacewa don aikin zuciya. Idan magunguna sun rage juriya a cikin jijiyoyin jini da yawa, to, zuciya ba zata iya isar da isasshen jini da iskar oxygen ga gabobin ba.

Me game da ɗayan kewaya? Jijiyoyin ba su da jini a gefen dama na zuciya inda ake huda shi ta huhu ya koma gefen hagu. Braunwald ya san cewa matsin da ke cikin jijiyoyin jini da gefen dama na zuciya dole ne ya yi tasiri sosai kan yadda za a iya “ɗora” jini a cikin ɓangaren hagu na zuciya don a tura shi gaba. Idan babu isasshen jini da matsin lamba a cikin zuciyar da ta dace, da akwai ƙarancin jini don “fifita famfo” a gefen hagu na zuciya sannan rage fitar da zuciya. Anan akwai misalin injin - injin silinda na injin na iya zama lafiya, amma idan famfon mai ya lalace, silinda ba za su iya yin aikin su da kyau ba. Wannan tasirin jijiyoyin akan zuciya ana kiransa "preload." Preload, kamar yadda aka ɗora, yana da wayo. Adadin adadin jinin da ke shiga zuciya daga jijiya zai ƙara ƙara ƙwayoyin ƙwayoyin tsokar zuciya da ƙirƙirar ƙarin gadoji na actin da myosin. ² Zuciya tana kama da bututun roba - shimfida madaidaicin tazara kuma zata sake dawowa da ƙarfi. Amma kar a ƙara miƙa shi.

Idan tsokar zuciya ta raunana daga cututtuka, sau da yawa akwai jini ko ruwa mai yawa a cikin jijiyoyin. A cikin ɗan gajeren lokaci, wannan riƙewar ruwa yana da fa'ida; tsokar zuciya na mikewa kuma tasirin yana taimakawa inganta aikin zuciya. Amma wannan haɓaka aiki yana zuwa da tsada: yayin da ventricle na hagu ke faɗaɗa, rufin ciki na sel na ventricle yana amfani da ƙarin iskar oxygen. Ƙwaƙwalwar ajiyar zuciya kamar balon filastik ce; mafi girma yana ƙaruwa, ana ƙara matsa lamba akan sel ɗin sa. Wannan “tashin hankali na bango” shine babban direba na uku na buƙatar zuciya don iskar oxygen. Bukatar ba wai kawai daga bugun zuciya bane da maƙasudin kwangilar sarcomeres. A cikin mutanen da ke da zukatan da suka lalace, galibi gefen dama da hagu na zuciya sun isa iyakar daidaitawa, kuma ruwa mai yawa yana ƙarewa a cikin huhu a matsayin “huhun huhu” ko kuma a ɓangaren ƙasa na jiki kamar “edema,” kumburin kafafu da ciki. Likitoci sun san wannan tasirin kowane nau'in cututtukan zuciya tsawon ƙarnuka, amma yanzu tare da gwaje -gwajen dabbobi masu inganci, Braunwald da abokan aikinsa sun nuna yadda kuma me yasa waɗannan binciken na zahiri suka tashi.

2 Wannan tasirin ƙarar jini akan zuciya shine ake kira Frank-Starling Relationship, wanda masana ilimin lissafin jiki suka gano a ƙarshen karni na sha tara.