IntroductionThe oxidative stress associated with glucose variability might be responsible for neuronal damage while autonomic neuropathy (AN) has a detrimental effect on metabolism. The aim of the study was to find relationship between AN and GV in type 1 diabetic patients and to identify further factors that affect GV.Patients and methodsTwenty type 1 diabetic patients were involved (age: 39.5 ± 3.4 years, duration of diabetes: 17.5 ± 2.5 years; HbA1c: 8.1 ± 0.2%, mean ± SE). AN was assessed by the cardiovascular reflex tests. The interstitial glucose levels were determined following insertion of a subcutaneous electrode during the continuous glucose monitoring (CGM) method on six consecutive days. GV was characterized by calculation of four parameters.ResultsSD of interstitial glucose values correlated positively with the overall AN score and the degree of the orthostatic reduction of systolic blood pressure (AN-score-SD ρ = 0.47, p < 0.05; orthostasis-SD: ρ = 0.51, p < 0.05). Mean absolute glucose (MAG) correlated with three parameters of AN (AN-score-MAG: ρ = 0.62, p < 0.01; 30/15 ratio-MAG: ρ = −0.50, p < 0.05; orthostasis-MAG: ρ = 0.59, p < 0.01). The HbA1c also correlated with two parameters of GV (HbA1c-continuous overlapping net glycemic action: ρ = 0.56, p < 0.05; HbA1c-MAG: ρ = 0.45, p < 0.05). The frequency of hypoglycemia did not exhibit any correlation with measures of GV.ConclusionSeverity of glucose variability but not overall glucose load correlates with both parasympathetic and sympathetic dysfunctions in type 1 diabetes. Higher HbA1c is associated with more severe glucose variability. The observed correlation between increased glucose variability and the severity of AN necessitates the further exploration of this relationship.
Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Research, Development and Innovation Office Introduction Polycystic ovary syndrome (PCOS) is a multifactorial, endocrine disease associated with metabolic disturbances (e.g. hyperinsulinemia, insulin resistance) and increased cardiovascular risk. Recent data strongly suggest that different QT variability parameters characterizing cardiac repolarization instability represent novel markers in proarrhythmic risk assessment. Purpose In the present study we investigated ECG repolarization parameters, including QT variability parameters in patients with polycystic ovary syndrome. Methods Fifty-five PCOS patients (age: 29±6 years) and 55 age-matched healthy volunteers (age: 29±10 years) were enrolled in the study. Five-minute 12-lead resting electrocardiograms were recorded, the ECGs were digitized and evaluated off-line using the Cardiosys-A01 system (Cardiosys-A01). The following parameters were determined: the frequency corrected QT interval (QTc) using Bazett’s, Fridericia, Framingham and the Hodges formulas; QT dispersion (QTd) and T wave peak-to-end distance (Tpeak-Tend). Among QT variability parameters we analyzed the QT variance (QTv), the QT variability index (QTVI), the short-term beat-to-beat QT and RR interval variability (STV-QT, STV-RR) based on constructed Poincaré plots and the variability ratio (VR). Results The RR interval did not differ significantly in PCOS patients compared to controls (821±129 ms vs. 847±99 ms), however the QT interval (373±30 ms vs. 391±27 ms, p<0.01), the QTc calculated with Bazett’s, Framingham, Fridericia and Hodges correction formulas (QTc Bazett’s: 413±18 ms vs. 426±21 ms, p<0.01) and the Tpeak-Tend intervals were significantly shorter (76±10 ms vs. 83±12 ms, p<0.01). The QTd, QTv, and STV-RR did not differ significantly. However, the VR (0.3±0.4 vs. 0.2±0.2, p<0.05), the QTVI (-0,9±0.5 vs. -1,3±0.4, p<0.001), and importantly, the STV-QT were significantly higher in PCOS patients compared to controls (4.0±0.9 ms vs. 3.2±0.9 ms, p<0.0001). Conclusion Some of the alterations in repolarization parameters and the significant increase in the short-term beat-to-beat QT interval variability and the QT variability index may indicate increased repolarization instability in patients with polycystic ovary syndrome compared to age-matched controls, however, further studies are needed to establish the exact relation of this finding to increased arrhythmia propensity in this population.
Bevezetés: A szénhidrát-anyagcsere súlyos instabilitása csökken inzulinpumpa bevezetése után 1-es típusú diabetesben. A glükózanyagcsere zavara autonóm neuropathiát okozhat, azonban az autonóm károsodás is felelős lehet az anyagcsere romlásáért. Felmerül a kérdés, hogy milyen mértékű az autonóm idegrendszer érintettsége a pumpakezelés indikációjának megfelelő rossz anyagcsere mellett, továbbá a neuropathia javulása akár rövid időn belül bekövetkezik-e a pumpakezelés megkezdése után. Célkitűzés: Vizsgálataink célja a kardiovaszkuláris autonóm funkció jellemzése volt pumpakezelés megkezdésekor, majd a kezelés bevezetése után 2 hónappal. Betegek, módszerek: Vizsgálatainkba 1-es típusú diabeteses beteget vontunk be (38 beteg, 23 nő, 15 férfi, életkor: 29,5±1,3 év, betegségtartam: 13,8±1,5 év; BMI: 23,2±0,6; átlag±SE). A kontrollcsoportba 10 nem diabeteses személy került (életkor: 27,8±2 év). Az autonóm neuropathia (AN) vizsgálatát az inzulinpumpa felhelyezése előtt és azt követően 2 hónappal kardiovaszkuláris reflextesztek (CRT) segítségével végeztük el. Eredmények: A betegcsoportban a legérzékenyebb paraszimpatikus teszt, a belégzésre bekövetkező szívfrekvencia-változás az egészséges kontrollhoz képest szignifikánsan kórosnak bizonyult a kezelés kezdetén (belégzés: 32,6±3,8 vs. 18,6±1,5 ütés/min., p<0,001). A paraszimpatikus károsodás mértéke annál kifejezettebb volt, minél hosszabb volt a bólus-bázis inzulinkezelés időtartama az inzulinpumpa felhelyezése előtt a betegekben (AN score–tartam: r=0,51, p<0,05; belégzés–tartam: r=−0,63, p<0,001). A két hónapos pumpakezelés mellett az AN összesített súlyossága csökkent (AN score: 2,2±0,2 vs. 1,5±0,2, p<0,05), a belégzésre bekövetkező szívfrekvencia-változás pedig szignifikánsan javult (belégzés: 18,6±2,1 vs. 22,4±2 ütés/min., p<0,05). Az átlagos HbA1c a két hónapos kezelés alatt 0,7%-ot csökkent (8,7±0,2% vs. 8,0±0,3%, p=0,125). Következtetés: A pumpakezelés megkezdésekor a fiatal 1-es típusú diabeteses betegekben a paraszimpatikus idegrendszeri diszfunkció dominált, ami már két hónapos pumpakezelés mellett javulást mutatott. Az idegrendszeri érintettség súlyossága szoros összefüggést mutatott a pumpakezelést megelőző bólus-bázis inzulinkezelés időtartamával. Adataink 1-es típusú diabetes mellitusban megerősítik azt a megfigyelést, hogy kóros szénhidrát-anyagcsere esetén a paraszimpatikus idegrendszer károsodik elsőként, ami eredményeink szerint a pumpakezelés elkezdését követően már rövid időn belül is javulhat.
Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Research, Development and Innovation Office Introduction Polycystic ovary syndrome (PCOS) is a multifactorial, endocrine disease associated with metabolic disturbances (e.g. hyperinsulinemia, insulin resistance) and increased cardiovascular risk. Recent data strongly suggest that different QT variability parameters characterizing cardiac repolarization instability represent novel markers in proarrhythmic risk assessment. Purpose In the present study we investigated ECG repolarization parameters, including QT variability parameters in patients with polycystic ovary syndrome. Methods Fifty-five PCOS patients (age: 29±6 years) and 55 age-matched healthy volunteers (age: 29±10 years) were enrolled in the study. Five-minute 12-lead resting electrocardiograms were recorded, the ECGs were digitized and evaluated off-line using the Cardiosys-A01 system (Cardiosys-A01, MDE Heidelberg GMBH, Heidelberg, Germany). The following parameters were determined: the frequency corrected QT interval (QTc) using Bazett’s, Fridericia, Framingham and the Hodges formulas; QT dispersion (QTd) and T wave peak-to-end distance (Tpeak-Tend). Among QT variability parameters we analyzed the QT variance (QTv), the QT variability index (QTVI), the short-term beat-to-beat QT and RR interval variability (STV-QT, STV-RR) based on constructed Poincaré plots and the variability ratio (VR). Results The RR interval did not differ significantly in PCOS patients compared to controls (821±129 ms vs. 847±99 ms), however the QT interval (373±30 ms vs. 391±27 ms, p<0.01), the QTc calculated with Bazett’s, Framingham, Fridericia and Hodges correction formulas (QTc Bazett’s: 413±18 ms vs. 426±21 ms, p<0.01) and the Tpeak-Tend intervals were significantly shorter (76±10 ms vs. 83±12 ms, p<0.01). The QTd, QTv, and STV-RR did not differ significantly. However, the VR (0.3±0.4 vs. 0.2±0.2, p<0.05), the QTVI (-0,9±0.5 vs. -1,3±0.4, p<0.001), and importantly, the STV-QT were significantly higher in PCOS patients compared to controls (4.0±0.9 ms vs. 3.2±0.9 ms, p<0.0001). Conclusion Some of the alterations in repolarization parameters and the significant increase in the short-term beat-to-beat QT interval variability and the QT variability index may indicate increased repolarization instability in patients with polycystic ovary syndrome compared to age-matched controls, however, further studies are needed to establish the exact relation of this finding to increased arrhythmia propensity in this population.
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