doktorska disertacija
Igor Krajnc (Author), Andreja Sinkovič (Mentor), Ivan Krajnc (Thesis defence commission member), Franjo Naji (Co-mentor)

Abstract

Uvod Ehokardiografska meritev iztisnega deleža (EF) levega prekata predstavlja večinoma dober in uporaben označevalec sistolične funkcije levega prekata (LP), vendar s pomembnimi omejitvami. Uporaba doplerskih tehnik nam omogoča natančno merjenje hitrosti krvi v srčnih votlinah in hitrosti miokarda, vključno z meritvami trajanja posameznih časovnih intervalov. Cilji Cilj naše raziskave je bil, da s pomočjo doplerske ehokardiografije, natančneje s sintezo pulznega in tkivnega doplerja, izmerimo pospešek krčenja LP pri zdravih preiskovancih in pri simptomatičnih bolnikih s kroničnim srčnim popuščanjem (SP). Upoštevaje pospešek krčenja LP in dimenzije LP smo izračunali indeks akceleracije levega prekata 1 (AccLV1) in indeks akceleracije levega prekata 2 (AccLV2). Indeks AccLV1 je premosorazmeren z doseženo maksimalno hitrostjo v času iztisa v iztočnem delu LP (Vmax LVOT) v cm/s in obratno sorazmeren s časovnim intervalom (dt) od začetka izovolumetrične kontrakcije LP do dosežene maksimalne hitrosti v LVOT, merjenim v sekundah in s končnim diastoličnim volumnom LP (EDV) v mililitrih. Indeks AccLV2 pa je premosorazmeren z V max LVOT in obratno sorazmeren s dt in s končnim diastoličnim premerom LP (LVEDD), merjenim v cm. Oba indeksa imata potencial doplerskih pokazateljev globalne sistolične disfunkcije, oziroma okvare LP. V nadaljevanju raziskave smo oba indeksa primerjali s standardno oceno sistolične funkcije LP z merjenjem EF. Bolniki in metode V prospektivno, opazovalno raziskavo smo vključili 121 preiskovancev, 76 (62,8 %) zdravih preiskovancev in 45 (37,2 %) bolnikov z znanim kroničnim SP. Pri vseh smo opravili standardne ehokardiografske meritve in izračunali AccLV1 po formuli: AccLV1=Vmax LVOT / dt x EDV [cm/s2 ml] in AccLV2 po formuli: AccLV2=Vmax LVOT / dt x LVEDD [1/s2]. Preiskovance smo nato opazovali dve leti in spremljali pojav končnih opazovanih dogodkov, ki kažejo na poslabšanje SP. Rezultati Celotni vzorec preiskovancev je zajemal 65 (53,7 %) moških in 56 (46,3 %) žensk, od teh je bilo v skupino zdravih uvrščenih 76 preiskovancev (46,1 % moških), v skupino bolnikov pa 45 preiskovancev (66,7 % moških). Med zdravimi in bolniki smo ugotovili statistično pomembno razliko v povprečnih vrednostih EF (65,4 ± 6,7 % vs 38,6 ± 18,0 %; p < 0,001), AccLV1 (12,1 ± 2,8 cm/s2 ml vs 4,4 ± 2,1 cm/s2 ml; p < 0,001) in AccLV2 (217,8 ± 43,8 1/s2 vs 110,5 ± 43,7 1/s2; p < 0,001). ROC krivulja, ki ločuje zdrave preiskovance od bolnikov s kroničnim SP, ne glede na pridruženo MR, je pokazala višje vrednosti AUC za AccLV1 in AccLV2 v primerjavi z EF (0,996 vs 0,897 in 0,969 vs 0,897). V skupini bolnikov smo prav tako potrdili nekoliko močnejšo korelacijo indeksov AccLV1 in AccLV2 s funkcijskim razredom po NYHA (r = - 0,657; p < 0,001 in r = - 0,569; p < 0,001), glede na korelacijo EF z NYHA (r = - 0,539 p < 0,001). V toku dve-letnega opazovanja smo pri 16 preiskovancih ugotovili končne opazovane dogodke. Vseh zabeleženih dogodkov je bilo 31 in vsi v skupini bolnikov. Določeni preiskovanci so doživeli končni opazovani dogodek, čeprav so imeli EF nad povprečjem EF preiskovancev brez zapleta (nad 58,1 %). Noben preiskovanec ni doživel končni opazovani dogodek, če je njegov indeks AccLV1 presegel povprečje indeksa AccLV1 preiskovancev brez zapleta (nad 10,1 cm/s2 ml ) ali če je njegov indeks AccLV2 znašal nad povprečjem indeksa AccLV2 preiskovancev brez zapleta (nad 190,1 /s2). Zaključek Z izračunom indeksov AccLV1 in AccLV2 lahko v primerjavi z meritvami EF z večjo natančnostjo razlikujemo med zdravimi in bolniki s simptomatičnim SP, prav tako vrednosti AccLV1 in AccLV2 dobro, oziroma bolje kot EF, korelirajo s funkcijskim razredom NYHA v skupini bolnikov. Oba indeksa nakazujeta prav tako boljšo napovedno vrednost za klinično poslabšanje SP v primerjavi z EF.

Keywords

srčno popuščanje;srčni prekat;iztisni delež;neinvazivna diagnostika;kontrakcija;akceleracija;

Data

Language: Slovenian
Year of publishing:
Typology: 2.08 - Doctoral Dissertation
Organization: UM - University of Maribor
Publisher: I. Krajnc]
UDC: 616.124-073.4-8(043.3)
COBISS: 290240256 Link will open in a new window
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Secondary language: English
Secondary title: Non-Invasive measuring of the acceleration of contraction of the left ventricle with the doppler echocardiography
Secondary abstract: Introduction The echocardiographic measurement of the left ventricle ejection fraction (EF) is usually a good and useful marker of the left ventricle (LV) systolic function, but with important limitations. With doppler echocardiography it is possible to perform a precise measurement of the blood flow velocities as well as the measurement of time intervals. Objectives The study investigates the use of Doppler echocardiography to assess the global systolic function of LV. For this purpose we combined the pulsed-wave (PW) doppler and tissue doppler technique to measure the acceleration of contraction of the LV in healthy subjects and patients with symptomatic CHF. By taking into account the acceleration of LV contraction and LV dimensions we calculated the acceleration index of the left ventricle 1 (AccLV1) and the acceleration index of the left ventricle 2 (AccLV2). The AccLV1 index is proportional to the V max LVOT (peak systolic velocity in LV outflow tract in cm/s) and inversely proportional to dt (time interval from the onset of isovolumetric LV contraction to the point when V max LVOT is reached, measured in seconds) and EDV (end diastolic volume of the LV in millilitres). The AccLV2 index is proportional to Vmax LVOT and inversely proportional to dt and LVEDD (left ventricle end diastolic diameter measured in cm). Both indices could serve as doppler indicators of global systolic dysfunction in patients with CHF. We compared both indices with the standard evaluation of the LV systolic function by determining EF. Patients and methods This prospective and observational study included 121 subjects, 76 (62.8%) healthy subjects and 45 (37.2%) patients with a known chronic heart failure. In all subjects we performed standard echocardiographic measurements and calculated AccLV1 using the following formula: AccLV1=Vmax LVOT/dt x EDV [cm/s2 ml] and AccLV2 using the following formula: AccLV2=Vmax LVOT/dt x LVEDD [1/s2]. The subjects were followed-up for two years and observed for the occurrence of endpoints indicating the deterioration of HF. Results The entire sample of subjects included 65 (53.7 %) men and 56 (46.3 %) women, among which 76 subjects were in the healthy group, and 45 subjects in the patient group. A statistically significant difference was established between healthy subjects and patients in the average values of EF (65.4 ± 6.7 % vs 38.6 ± 18.0 %; p < 0.001), AccLV1 (12.1 ± 2.8 cm/s2 ml vs. 4.4 ± 2.1 cm/s2 ml; p < 0.001) and AccLV2 (217.8 ± 43.8 1/s2 vs. 110.5 ± 43.7 1/s2; p < 0.001). The ROC curve, which separate healthy subjects and patients, has indicated higher values of AUC for AccLV1 and AccLV2 compared to EF (0.996 vs. 0.897 and 0.969 vs. 0.897). We also confirmed better correlation of AccLV1 and AccLV2 indices with the function class NYHA (r = - 0.657; p < 0.001 in r = - 0.569; p < 0.001), regarding the correlation EF with NYHA (r = - 0.539 p < 0.001). During follow-up period, we observed endpoints in 16 subjects and all were in the patient group. Certain subjects reached the endpoints, despite having EF above the EF average of subjects without complications (above 58.1 %). None of the subjects reached the endpoints if their AccLV1 index exceeded the average AccLV1 index of subjects without complications (above 10.1 cm/s2 ml) or if their AccLV2 index was above the average AccLV2 index of subjects without complications (above 190.1 /s2). Conclusion By calculating the AccLV1 and AccLV2 indices, we can precisely distinguish (compared to EF) between healthy subjects and patients with symptomatic CHF, whereby the AccLV1 and AccLV2 values correlate better than EF with the function class NYHA. Both indices indicate a better predictive value for clinical indicators of deteriorating HF compared to EF.
Secondary keywords: Levi srčni prekat;Disertacije;Sistola;Dopplerska ehokardiografija;Ventricular function, left;Physiology;Echocardiography, Doppler;Methods;Myocardial contraction;Acceleration;Delovanje levega prekata;Fiziologija;Doplerski ultrazvok srca;Metode;Krčenje miokarda;Akceleracija;
URN: URN:SI:UM:
Type (COBISS): Dissertation
Thesis comment: Univ. v Mariboru, Medicinska fak.
Pages: 90 str.
ID: 9247564