Search

Background: Heart rate variability (HRV) is the fluctuation in the time intervals between adjacent heartbeats. HRV is a measure of neurocardiac function that is produced by dynamic autonomic nervous system (ANS) processes and is a simple measure that estimates cardiac autonomic modulation. Methods: The study included 108 patients admitted to the Coronary Intensive Care Unit with acute myocardial infarction (AMI) who did not undergo primary percutaneous transluminal coronary angioplasty (PTCA) or systemic thrombolysis and followed conservative management. All patients underwent detailed clinical, biological, and paraclinical assessments, including evaluation of HRV parameters and echocardiographic measurements. The analysis of RR variability in both time and frequency domains indicates that the negative prognosis of patients with AMI is associated with an overall imbalance in the neuro-vegetative system. The HRV parameters were acquired using continuous 24 h electrocardiogram (ECG) monitoring at a baseline, after 1 month, and 6 months. Results: Our analysis reveals correlations between alterations in HRV parameters and the increased risk of adverse events and mortality after AMI. The study found a significant improvement in HRV parameters over time, indicating better autonomic regulation post-AMI. The standard deviation of all RR intervals (SDNN) increased significantly from baseline (median 75.3 ms, IQR 48.2–100) to 1 month (median 87 ms, IQR 55.7–111) and further to 6 months (median 94.2 ms, IQR 67.6–118) (p < 0.001 for both comparisons). The root mean square of successive difference of RR (RMSSD) also showed significant increases at each time point, from baseline (median 27 ms, IQR 22–33) to 1 month (median 30.5 ms, IQR 27–38) and from 1 month to 6 months (median 35 ms, IQR 30–42) (p < 0.001 for all comparisons), indicating enhanced parasympathetic activity. Moreover, changes in HRV parameters have been associated with impaired left ventricle ejection fraction (LVEF) and global longitudinal strain (GLS), indicating a relationship between autonomic dysfunction and myocardial deformation. GLS values improved from a baseline median of −11% (IQR 5%) to −13% (IQR 4%) at 6 months (p < 0.001), reflecting better myocardial function. Conclusions: HRV parameters and cardiac performance analysis, especially using GLS, offer a solid framework for evaluating recovery and predicting adverse outcomes post-MI. [ABSTRACT FROM AUTHOR]

(1) Background: Pregnancy induces significant physiological adaptations with substantial impacts on the cardiovascular system. Hypertensive disorders of pregnancy (HDPs) are connected to significant risks of maternal and fetal complications, contributing significantly to morbidity and mortality across the globe. This study focuses on evaluating autonomic dysfunction by analyzing heart rate variability (HRV) and assessing cardiac performance through global longitudinal strain (GLS) using speckle tracking echocardiography, as well as examining diastolic function in pregnant women with HDP compared to healthy pregnant controls. (2) Methods: A case–control study was conducted involving pregnant women diagnosed with gestational hypertension (GH), preeclampsia (PE), or severe preeclampsia (SPE) as the case group, and healthy pregnant women as the control group. HRV was measured to evaluate autonomic function, GLS was assessed using speckle tracking echocardiography, and diastolic function was evaluated through standard echocardiographic parameters. Data were analyzed to compare cardiac performance and autonomic regulation between the HDP and control group, as well as among the different HDP subgroups. (3) Results: The HDP group exhibited significantly reduced HRV parameters compared to healthy controls, indicating notable autonomic dysfunction. Speckle tracking echocardiography revealed lower GLS among women with HDP, particularly in those with SPE, compared to the control group. Diastolic dysfunction was also present in the HDP group. (4) Conclusions: HRV and GLS are valuable non-invasive tools for detecting autonomic dysfunction and cardiac performance impairments in pregnant women with hypertensive disorders. These findings suggest that autonomic and cardiac dysfunctions are prevalent in HDP. [ABSTRACT FROM AUTHOR]

Thyroid hormones have a pivotal role in controlling metabolic processes, cardiovascular function, and autonomic nervous system activity. Hypothyroidism, a prevalent endocrine illness marked by inadequate production of thyroid hormone, has been linked to different cardiovascular abnormalities, including alterations in heart rate variability (HRV). The study included 110 patients with hypothyroid disorder. Participants underwent clinical assessments, including thyroid function tests and HRV analysis. HRV, a measure of the variation in time intervals between heartbeats, serves as an indicator of autonomic nervous system activity and cardiovascular health. The HRV values were acquired using continuous 24-h electrocardiogram (ECG) monitoring in individuals with hypothyroidism, as well as after a treatment period of 3 months. All patients exhibited cardiovascular symptoms like palpitations or fatigue but showed no discernible cardiac pathology or other conditions associated with cardiac disease. The findings of our study demonstrate associations between hypothyroidism and alterations in heart rate variability (HRV) parameters. These results illustrate the possible influence of thyroid dysfunction on the regulation of cardiac autonomic function. [ABSTRACT FROM AUTHOR]