Avtor/Urednik		Knap, Bojan; Južnič, Gojmir; Južnič, Susara
Naslov		Cilindrikacija kot mehanizem kvalitete akcije levega prekata
Prevedeni naslov		"Cylindricality" as a mechanism of quality of left ventricle action
Tip		članek
Vir		Med Razgl
Vol. in št.		Letnik 35, št. 2
Leto izdaje		1996
Obseg		str. 213-20
Jezik		slo
Abstrakt		The endocardial surface and the volume of the left ventricle were determined experimentally by an original noninvasive method with the goal of understanding the mechanism of the influence of the change of left ventricle shape on the execution of its pumping function. The chore parameters were studied by Echocardiography and ECG at the end of diastole and systole. Three groups of patients (sportsmen, subjects taking part in no sports and dialysis-patients) were evaluated. The change in the volume of left ventricle represents the frame of the left ventricle pumping action, while the change of surface can be interpreted as an indicator of the axis' dynamics. A spherical and the cylindrical shapes of the volume ejecting left ventricle during the heart cycle and that can be understood as a principle, called "cylindricality". In diastole the left ventricle is more spherical, in systole more tube like. This mechanism is in pathological conditions changed. The term of cylindricality encompasses the fact, that two bodies whith the same volume can have different surface areas. The experimentally determined value of the cylindrical form of surface deviates from the mathematically determined spherical form of surface. Cylindricality of a normal left ventricle in diastole is 7%, and systolic cylindicality 24%; diastolic cylindricality of the dialysis patients is 16%, in systole 24%. The results obtained suggest, that in pathological conditions the principle of cylindricality is replaced by the law of Laplace, which can explain the consequences of the lost of the cylindricality, principle for the left ventricle function and its prognosis.
Izvleček		Z originalno neinvazivno metodo smo eksprimentalno določili endokardno površino levega prekata z namenom razumeti mehanizem vpliva spremembe oblike levega prekata na izvedbo njegove pogonske funkcije. Uporabili smo ehokardiografijo in elektrokardiografijo koncem diastole in sistole; preiskali smo 3 skupine (športniki, nešportniki in dializni bolniki). Sprememba prostornine levega prekata predstavlja okvir njegove poganjalne akcije, površino levega prekata pa lahko razumemo kot indikator za dinamiko osi. Sferična in cilindrična oblika prostornine, ki jo izžene levi prekat, se v srčnem ciklusu izmenjujeta in to lahko razumemo kot princip "cilindrikacije". V diastoli je prekat bolj podoben krogli, v sistoli pa bolj cevast. Ta mehanizem je v bolezenskih razmerah spremenjen. Pojem cilindrikacije vključuje dejstvo, da imata dve telesi lahko isto prostornino, a različno površino. Eksperimentalno določena cilindrična oblika površine levega prekata se razlikuje od matematično določene sferične oblike. Cilindrikaličnost normalnega levega prekata znaša v diastoli 7%, v sistoli 20%; dializni bolniki imajo v diastoli 16%, v sistoli pa 24%. Iz meritev, ki so opisane v tem članku, lahko sklepamo, da se v izjemnih razmerah princip cilindrikaličnosti lahko spremeni v Laplaceov zakon. To dejstvo nam pojasnjuje, kakšne posledice ima izguba principa cilindrikaličnosti za funkcijo levega prekata in za njegovo prognozo.
Deskriptorji		HEART VENTRICLE VENTRICULAR FUNCTION, LEFT CARDIAC VOLUME ELECTROCARDIOGRAPHY ECHOCARDIOGRAPHY SPORTS HEMODIALYSIS