Rangarira ndima iri pasi apa uye ipapo pindura mubvunzo gare gare mumutauro mumwe chetewo sechikamu:  Kupfuura: Kazhinji, marudzi maviri ezvinetso anoguma nebradycardias: zvinetso zve sinoatrial node (SA node), uye zvinetso zveatrioventricular node (AV node).  Mubvunzo: Zita rakakwana rokuti SA node nderipi?
sinotirial node