Author/Editor		Kermavnar, Melita K; Grad, Anton; Meglič, Bernard
Title		Razmerje med aktivnostjo simpatika in parasimpatika pri testu z nagibno mizo
Translated title		The ratio between sympathetic and parasympathetic activity during head-up tilt table test
Type		članek
Source		Med Razgl
Vol. and No.		Letnik 42, št. 1
Publication year		2003
Volume		str. 17-28
Language		slo
Abstract		Introduction: Neurocardioagenic syncope is the most frequent transitional form of loss of consciousness, which is caused by inappropriate triggering of the Bezold-Jarisch reflex. Most commonly, the triggering agent is an upright posture. With the help of spectral analysis, researchers have demonstrated that there is a large increase in sympathetic activity just before"syncope, while at the moment of syncope a paradox inhibition of this activity occurs with consequential vasodilatation and bradycardia, which result in loss of consciousness. The objective of our study was to discover whether there are differences in autonomic nervous system activity between patients and control subjects in their responses to head-up tilt table testing and whether these differences are greater in a tilt table test with nitroglycerine. Subjects and methods. A group of 30 subjects who received nitroglycerine during the test (NTG+) was compared with another group of 30 who were tested without nitroglycerine (NTG-). In half of the patients in each group, syncope occurred during the test (SIN+) while in the other half it did not (SIN-). Spectral analysis of heart rate variability was used to determine the ratio of medium- (SF) and high-frequency (VF) bands (SF/VF), which represents the balance between the sympathetic and parasympathetic nervous systems: The results were compared using t-test for dependent samples for changes within each group, and with Student's t-test for comparison between the groups. A statistically significant difference was one with p <_ 0.05. (Abstract truncated at 2000 characters)
Summary		Uvod. Nevrokardiogena sinkopa je najpogostejša oblika prehodne izgube zavesti, ki nastane zaradi neustreznega proženja Bezold-Jarischovega refleksa. Vzrok je najpogosteje pokončni položaj telesa. S tehniko spektralne analize variabilnosti srčnega ritma so dokazali, da je tik pred sinkopo aktivnost simpatika močno povečana, ob sinkopi pa pride do paradoksne inhibicije simpatika, kar privede do vazodilatacije in bradikardije ter posledične izgube zavesti. Ugotoviti smo želeli, ali se pri testu z nagibno mizo odzivi avtonomnega živčevja med preiskovanci z nevrokardiogeno sinkopo in brez nje razlikujejo in ali so te razlike pri testiranju z nitroglicerinom večje. Preiskovanci in metode. Primerjali smo skupino 30 preiskovancev, testirariih z nitroglicerinom (NTG+) in skupino 30 preiskovancev, testiranih brez nitroglicerina (NTG-). V vsaki skupini smo pri polovici preiskovancev s testom izzvali sinkopo (SIN+), pri drugi polovici pa ne (SIN-). S spektralno analizo variabilnosti srčnega ritma smo izračunali količnik SF/VF med srednje- (SF) in visokofrekvenčnim (VF) pasom spektralne analize srčnega ritma, ki predstavlja ravnovesje med simpatikom in parasimpatikom. Rezultate znotraj skupine smo primerjali s testom t za parne vzorce, med skupinami pa s Studentovim testom t. Za statistično pomembno razliko smo upoštevali vrednost p <_ 0,05. Rezultati. V vseh skupinah, razen v skupini NTG-/SIN-, se vrednosti SF/VF statistično pomembno povečajo po dvigu preiskovanca iz ležečega položaja na nagibni kot 60 stopinj. Količnik SF/VF se poveča: p < 0,001 (NTG+/SIN+), p < 0,005 (NTG+/SIN-), p < 0,05 (NTG=/SIN+), NS (NTG-/SIN-). Statistično pomembno povečanje smo našli tudi med ležečim položajem in dodatkom nitroglicerina za spremembo SF/VF (skupina NTG+/SIN+: p < 0,01, skupina NTG+/SINp < 0,001). Med skupinami nismo našli statistično pomembnih razlik. (Izvleček skrajšan na 2000 znakov)
Descriptors		SYNCOPE, VASOVAGAL TILT-TABLE TEST NITROGLYCERIN ELECTROCARDIOGRAPHY HEART RATE