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Age- and gender related differences in QTc-interval are most likely the result of changes in sex-specific hormones. Although the exact mechanisms and pathophysiology of sex hormones on the QTc-interval are not known, testosterone appears to shorten the QTc-interval. In females, however, there is a more complex interaction between progesterone and e...
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... and progesterone levels fluctuate during the men- strual cycle. Estrogen and progesterone levels are lowest at the onset of menses (menstrual phase). After the cessation of the menstrual flow, there is a gradual increase in estrogen (follicular phase). Estrogen levels peak in the middle of the menstrual phase during ovulation (ovulation phase) and after ovulation the estrogen levels gradually decrease during the luteal phase. Progesterone levels, in contrast, are low during the menstrual and follicular phase and increase after ovula- tion through the luteal phase (Fig. 2). In healthy females, there are no clear QTc-interval differences between the different phases of the menstrual cycle [55][56][57][58][59]. Hulot et al. [55] found no relationship between the level of estrogen and the length of the QTc-interval (P ? 0.92). In the study by Nakagawa et al. [56], the uncorrected QT-interval was shorter in the luteal phase compared to the follicular phase, although no difference in QTc-interval was seen. They found no statistically significant difference in estrogen level between these phases, while progesterone (P o 0.001) and noradrena- line levels (P o 0.05) were higher in the luteal phase suggest- ing a role of progesterone and/or autonomic tone on the uncorrected QT-interval. When double autonomic blockade was given consisting of atropine and propranolol adminis- tration, QTc-interval differences between the phases of the menstrual cycle were seen. Burke et al. [57] found a shorter QTc-interval in the luteal phase compared to the menstrual and follicular phase, whereas Endres et al. [58] observed a significantly longer QTc-interval during the follicular phase compared to the menstrual and luteal phase. Both studies indicate the important role of autonomic tone in alternations in the QTc-interval during the menstrual cycle. Rodrigues et al. [59] showed that ibutilide infusion, a known I Kr blocker mimicking LQTS, causes differences in QTc-interval between the phases of the menstrual cycle, whereas the luteal phase seemed to be protective against the drug-induced QTc-inter- val prolongation. Hence, since there is an effect of the menstrual cycle on the QTc-interval during administration of QTc-interval prolonging medication, it could be argued that this effect also is present in patients with ...
Citations
... Однако, согласно исследованиям S.B. Clur и A.S. Vink (2018), у плодов с LQTS было обнаружено, что время изоволюметрического расслабления левого желудочка (L-IVRT) значительно увеличено по сравнению с контрольной группой на всех стадиях гестации. Это увеличение L-IVRT коррелирует с удлинением интервала QT на постнатальной ЭКГ [50] (рис. 6). ...
Timely prenatal diagnosis of various pathological conditions of the fetal heart is a particularly important problem of obstetric practice. For this purpose, the most frequently used are innovative ultrasound diagnostic technologies that give the opportunity to timely detect various fetal arrhythmias. Clinically significant arrhythmias are established to develop in fetuses and newborns in 1 out of 4,000 live births and are one of the causes of morbidity and mortality. About 10% of fetal arrhythmias require intrauterine treatment or constant monitoring, and they may also indicate the presence of serious hereditary syndromes associated with cardiac rhythm disorders and the likelihood of sudden infant death. The purpose of the review is to study the material of literature sources devoted to the primary prenatal ultrasound diagnosis of clinically significant fetal arrhythmias and dynamic echographic control in the management of pregnant women with fetal tachyarrhythmia. During the research, available domestic and foreign sources were used, which presented the features of the course of fetal cardiac arrhythmias, their types, and the possibilities of prenatal ultrasound diagnosis of this pathology. The search for publications is performed in databases eLIBRARY.RU , RSCI, PubMed, Embase. Based on the results of the analysis and generalization of the studied publications, it was found that ultrasound examination of the fetal heart plays a key role in the diagnosis of arrhythmias, it helps to determine the main mechanism of rhythm disturbance, assess the effect of arrhythmia on the fetal heart's functioning, exclude possible structural changes in the fetal heart, as well as enables to monitor the fetal condition during antiarrhythmic therapy. If fetal arrhythmias are suspected, an urgent ultrasound examination with ultrasound Dopplerography is recommended with an extension of the standard protocol for examining the fetal heart with an assessment of the frequency of atrial and ventricular contractions.
... UQTS düzensiz kalp atışına neden olarak bayılma, boğulma, nöbet veya ani ölümlere neden olabilir (8). UQTS egzersiz veya stres tarafından tetiklenebilir (Şekil 1) (9)(10)(11). ...
... Ayrıca kadınlarda QT uzaması görülme sıklığı erkeklere göre fazladır (16). Araştırmacılar bu farklılığın nedeninin cinsiyet hormonlarının iyon kanalları üzerindeki etkileri olduğunu bildirmektedir (11). ...
... Age has been acknowledged to influence several clinical aspects in LQTS patients. For example, is the QTc interval influenced by age, sex, and genotype (Vink et al., 2017(Vink et al., , 2018. Additionally, age is known to influence the risk of cardiac events and patients with LQTS often experience their first cardiac event before the age of 16 (Zareba et al., 1995). ...
Objectives
This study aimed to retrospectively assess cardiac autonomic activity in children with LQTS, considering genotype, symptoms, sex, age, and beta‐blocker therapy (BB) and compare it to healthy controls.
Methods
Heart rate variability (HRV), using power spectrum analysis, was analyzed in 575 Holter recordings from 116 children with LQTS and in 69 healthy children. The data were categorized into four age‐groups and four heart rate (HR) ranges.
Results
In LQT1 and LQT2, increasing HR corresponded to significantly lower low (LF) and high frequency (HF) compared to controls. Total power (PTOT) was lower in all LQT1 age‐groups compared to controls at HR 120–140 bpm (1–15 years: p < .01; 15–18 years: p = .03). At HR 80–100, LQT1 patients aged 1–10 years had lower HF than LQT2 patients (1–5 years: p = .05; 5–10 years: p = .02), and LQT2 patients aged 15–18 years had lower HF than LQT1 patients (p < .01). Symptomatic patients aged 10–15 years had lower PTOT at HR 100–120 bpm than asymptomatic patients (p = .04). LQT1 girls aged 10–15 and 15–18 years had a lower PTOT (10–15 years: p = .04; 15–18 years: p = .02) than boys.
Conclusion
This study shows a correlation between HR and changes in HRV parameters. At higher HRs, LQTS patients generally had lower HRV values than controls, suggesting an abnormal autonomic response. These results may strengthen the link between physical activity and arrhythmias in LQTS.
... QT prolongation has two main aetiologies: congenital (i.e., inherited long-QT syndrome) [4] and acquired. Different factors have been related to the acquired long-QT, including demographic risk factors, pollution, drugs, cardiovascular risk factors, electrolyte disorders, stroke, altered autonomic tone, and structural heart diseases [5][6][7][8][9]. The QT interval, according to HR, changes: it increases at a low HR and decreases at a high HR. ...
Background: The study aimed to compare the prognostic importance of the heart rate (HR) and QT—corrected (QTc) according to Fridericia, Framingham, and Bazett with respect to all-cause mortality in a large non-selected population. Methods: The analysis of digital electrocardiograms archived from 2008 to 2022 in the metropolitan area of Modena, Italy, was carried out. The population under study was divided into three groups based on age, and survival analysis was performed. Results: 131,627 patients were enrolled and, during the follow-up (mean 1641.4 days), all-cause mortality was 8.9%. Both HR and QTc were associated with mortality. All-cause mortality significantly increased with HR values greater than 81 BPM and QTc values greater than 440 msec in young subjects and 455 msec in old subjects (values of the 75th percentiles/optimal operating point). A Cox analysis confirmed the better prognostic value of Bazett’s QTc and HR in the whole population and in the three age-groups. Conclusion: Bazett’s method performed better than the others, but, unexpectedly, the HR had the same or an even better correlation with all-cause mortality. Since the HR is simple and readily available, its evaluation should be improved. However, QTC and HR values are difficult to define, causing many confounding factors, and further population studies are required.
... Different factors have been Disclaimer/Publisher's Note: The statements, opinions, and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions, or products referred to in the content. 2 related to the acquired long-QT, including demographic risk factors, pollution, drugs, cardiovascular risk factors, electrolyte disorders, stroke, altered autonomic tone and structural heart diseases [5][6][7][8][9]. The estimation of the QT interval on surface ECG may be difficult, as the beginning of the QRS complex and/or the end of the T wave may not be easy to identify but the digitalization of ECG traces could help clinicians. ...
Background: the study aimed at comparing the prognostic importance of Heart Rate (HR) and of QT corrected (QTc) according to Fridericia, Framingham and Bazett methods, in a large non-selected population. Methods: the analysis of digital Electrocardiograms archived from 2008 to 2022 in the metropolitan area of Modena, Italy, was made. The population under study was divided into three age-groups and survival analysis was performed. Results: 131.627 patients were enrolled and during the follow-up (mean 1641.4 days), all-cause mortality was 8.9%. Both HR and QTc were associated with mortality. All-cause mortality significantly increased from HR values greater than 81 BPM and from QTc values greater than 440 msec in young subjects and 455 msec in old subjects (values of the 75th percentiles/optimal operating point). Cox analysis confirmed the better prognostic value of Bazett’s QTc and of HR in the whole population and in the three age-groups. Conclusion: Bazett’s method performed better than other methods but unexpectedly HR had the same or a better correlation with all-cause mortality. Since HR is simple and readily available, its evaluation should be improved. However, reference values for QTc and for HR are difficult to define causing many confounding factors and further population-study are required.
... Moreover, female gender is well recognized in the literature to be an independent risk factor for LQTS. Additionally, females with LQTS, whether inquired or congenital have a higher risk of tachyarrhythmias and SCD 12,13 . Although an association between QT-interval and mortality has been established in North American Indigenous people 14 , there is a scarcity of literature examining the outcomes of LQTS amongst Indigenous women specifically. ...
... At assessment, sex (female to male, 415 to 401 ms) was a strong covariate, while phosphate levels were a weak (Spearman 0.151, p < 0.05) covariate of the QT c-Bazett time interval. Both can be expected, as it is generally known that both sex and electrolytes, including calcium/phosphate balance, have been reported as significant covariates of the QT c-Bazett time interval, as also reflected in the FDA guidance and EMA guidelines [14,15,18]. Although evidence is inconsistent, a higher BMI in adults was associated with a longer QT c-Bazett in some studies [19,20]. ...
Introduction:
Although relevant for precision pharmacovigilance, there are conflicting data on whether former preterm birth is associated with QTc-Bazett prolongation in later life.
Methods:
To explore QTc-Bazett interval differences between former preterm and/or extremely low birth weight (ELBW) cases and term-born controls in adolescence and young adulthood, we analyzed pooled individual data after a structured search on published cohorts. To test the absence of a QTc-Bazett difference, a non-inferiority approach was applied (one-sided, upper limit of the 95% confidence interval [CI] mean QTc-Bazett difference, 5 and 10 ms). We also investigated the impact of characteristics, either perinatal or at assessment, on QTc-Bazett in the full dataset (cases and controls). Data were reported as median and range.
Results:
The pooled dataset contained 164 former preterm and/or ELBW (cases) and 140 controls born full-term from three studies. The median QTc-Bazett intervals were 409 (335-490) and 410 (318-480) ms in cases and controls. The mean QTc-Bazett difference was 1 ms, with an upper 95% CI of 6 ms (p > 0.05 and p < 0.01 for 5 and 10 ms, respectively). In the full dataset, females had a significantly longer QTc-Bazett than males (415 vs. 401 ms; p < 0.0001).
Conclusions:
QTc-Bazett intervals are not significantly different between former preterm and/or ELBW cases and term-born controls, and we rejected a potential prolongation > 10 ms in cases. When prescribing QTc-prolonging drugs, pharmacovigilance practices in this subpopulation should be similar to the general public (NCT05243537).
... It is known that, in patients with LQT-2, cardiac events are characteristically triggered by situations involving sudden heart rate acceleration 1 and that women with LQTS have a higher risk for cardiac events during adulthood compared with men with LQTS. 31 Hence, this implies a potential role for the standing test in the risk stratification of patients with LQTS. ...
Background
An elegant bedside provocation test has been shown to aid the diagnosis of long‐QT syndrome (LQTS) in a retrospective cohort by evaluation of QT intervals and T‐wave morphology changes resulting from the brief tachycardia provoked by standing. We aimed to prospectively determine the potential diagnostic value of the standing test for LQTS.
Methods and Results
In adults suspected for LQTS who had a standing test, the QT interval was assessed manually and automated. In addition, T‐wave morphology changes were determined. A total of 167 controls and 131 genetically confirmed patients with LQTS were included. A prolonged heart rate–corrected QT interval (QTc) (men ≥430 ms, women ≥450 ms) at baseline before standing yielded a sensitivity of 61% (95% CI, 47–74) in men and 54% (95% CI, 42–66) in women, with a specificity of 90% (95% CI, 80–96) and 89% (95% CI, 81–95), respectively. In both men and women, QTc≥460 ms after standing increased sensitivity (89% [95% CI, 83–94]) but decreased specificity (49% [95% CI, 41–57]). Sensitivity further increased ( P <0.01) when a prolonged baseline QTc was accompanied by a QTc≥460 ms after standing in both men (93% [95% CI, 84–98]) and women (90% [95% CI, 81–96]). However, the area under the curve did not improve. T‐wave abnormalities after standing did not further increase the sensitivity or the area under the curve significantly.
Conclusions
Despite earlier retrospective studies, a baseline ECG and the standing test in a prospective evaluation displayed a different diagnostic profile for congenital LQTS but no unequivocal synergism or advantage. This suggests that there is markedly reduced penetrance and incomplete expression in genetically confirmed LQTS with retention of repolarization reserve in response to the brief tachycardia provoked by standing.
... There is solid evidence showing that adequate and regular physical activity can have positive cardiovascular, endocrine, metabolic and neurological effects. 19,20 However, it has also been shown that excessive and strenuous physical training forms can generally damage the cardiovascular system. 21 In our study, hemoglobin level was found to be significantly higher in the group with pathology. ...
... 22 Also, in our study, it was found that QTc shortening with increasing age was consistent with the literature. 20 Therefore, it can be said that age is an independent risk factor for athletes. However, it was understood that these findings did not predict the important pathologies that would prevent the individuals from continuing their sports life. ...
... Although the exact mechanism and pathophysiology of sex hormones on the QT interval is unknown, testosterone appears to shorten the QT interval in males. And in women there is a more complex interaction between progesterone and estrogen due to the influence of the menstrual cycle, pregnancy and menopause (Vink et al., 2018). ...
The QT interval is a picture of the activity of the heart's ventricles, starting from depolarization to ventricular repolarization which can be influenced by several factors, namely drugs, gender, inflammatory conditions, obesity, heart failure, and others. Basic Health Research Data in 2018, states that in Indonesia there are around 2,784,064 individuals who suffer from heart disease and every year this number will continue to increase. The purpose of this study was to find out whether there was a relationship between sex and intravenous administration of drugs with QT prolongation. This research is a type of descriptive research. With a total sample of 118 respondents, it was carried out by observing medical records. The results of statistical tests on the sex variable with QT prolongation showed ρ = 0.007, and on the intravenous drug administration variable with QT prolongation showed ρ = 0.002. The conclusion of this study was that there was a relationship between gender and intravenous drug administration with QT prolongation. It is necessary to pay attention to the side effects of drug administration given to patients. And for future researchers, it is hoped that this study can become a reference by using other variables related to QT interval prolongation such as drug side effects and conditions of electrolyte disturbances.