Sympathetic overactivity in patients with rheumatic mitral stenosis

Long-Term Outcomes of Children and Adolescents With Postural Tachycardia Syndrome After Conventional Treatment

Objectives: To explore the long-term outcomes of children and adolescents with postural tachycardia syndrome receiving conventional interventions. Materials and Methods: A total of 121 patients were recruited, but 6 (5.0%) of them were lost at follow-up. The detailed clinical data were collected, and the reoccurrence and frequency of orthostatic intolerance symptoms were evaluated with a mean followed-up period of 18.7 months (range, 14-74 months). The Kaplan-Meier curve was used to show the cumulative symptom-free rate of patients over time. Factors influencing the long-term outcomes were examined using the Cox's proportional hazards models. Results: The cumulative symptom-free rate was gradually increased over time. It was 48.4% at the 1-year follow-up and increased to 85.6% at the 6-year follow-up. The duration of symptoms before treatment and the maximum upright heart rate in standing-up test were identified as independent indicators for the long-term outcomes. Each 1-month prolongation in the duration of symptoms before treatment was associated with a 1.2% decrease in the cumulative symptom-free rate. However, each 1-bpm increase in the maximum upright heart rate in standing-up test was associated with a 2.1% increase in the cumulative symptom-free rate. Conclusions: The long-term outcomes of postural tachycardia syndrome patients who received conventional interventions are benign and the cumulative symptom-free rate was gradually increased over time. The prolonged duration of symptoms before treatment and the reduced maximum upright heart rate in standing-up test are the independent risk indicators.

Heart rate variability in children with acute rheumatic fever

OBJECTIVE

Acute rheumatic fever is a systemic inflammatory disease occurring after acute streptococcal tonsillopharyngitis. The PR prolongation in these patients is thought to be due to increased vagal activity. There has been no previous study investigating the autonomic balance in patients with acute rheumatic fever. In this study, we aimed to investigate the balance of the autonomic nervous system in children with acute rheumatic fever by analysis of heart rate variability.

METHODS

We evaluated the heart rate variability parameters in 50 patients with acute rheumatic fever and 37 comparable control subjects. Both groups underwent 24-hour electrocardiography monitoring, and time- and frequency-domain heart rate variability parameters were calculated. A total of 39 patients (78%), with (n = 28) or without (n = 11) other major findings, had carditis, and the remaining 11 (22%) did not. The PR interval was found to be prolonged in 10 (20%) of the patients at the beginning.

RESULTS

In the study group, the time- and frequency-domain heart rate variability parameters showed a sympathetic dominance compared with the control group, with a p-value less than 0.05. When compared with the control group, the time- and frequency-domain heart rate variability parameters showed a significant sympathetic dominance in patients with both prolonged PR and normal PR intervals in the acute period, with a p-value less than 0.05. When compared with patients with normal PR interval, mean normalised low frequency and normalised high frequency parameters suggested a relatively lower sympathetic dominance in patients with prolonged PR interval, with a p-value less than 0.05.

CONCLUSION

Our results indicated that in the acute period of rheumatic fever, sympathetic dominance is apparent; in patients with prolonged PR interval, sympathetic dominance is relatively lower when compared with the patients with normal PR interval.

The increase in sympathetic nerve density in the atrium facilitates atrial fibrillation in patients with rheumatic heart disease

BACKGROUND

Atrial fibrillation (Af) is frequently observed in patients with rheumatic heart disease (RHD). The hyperactivity of autonomic nervous system is known to contribute to the occurrence of Af in RHD patients. This study investigated the association between the autonomic density and the risk of Af in RHD patients.

METHODS

Seventy-five patients were enrolled: (1) RHD patients with Af (N = 25, Group 1); (2) RHD patients without Af (N = 25, Group 2); (3) congenital heart disease patients without Af (N = 25, Group 3). The baseline characteristics and the blood concentrations of renin, C-reaction protein and angiotensin II were collected from all patients. The tissues were obtained from the right atrial appendage during the open-heart surgery and then stained using immunohistochemical methods with autonomic antibodies.

RESULTS

The sympathetic nerve density was significantly higher in RHD patients with Af than RHD patients without Af and congenital heart disease patients, both endocardially and epicardially. The parasympathetic nerve density did not show significant difference among the three groups. The left atrial diameter was larger in RHD patients with Af than the other two groups. The blood concentrations of renin and angiotensin II were higher in RHD patients with Af than the other two groups. The erythrocyte sedimentation rate and blood concentrations of C-reaction protein did not show significant change among the three groups.

CONCLUSION

This study provided direct evidence of the increase in sympathetic nerve density in atrium in patients with RHD. This phenomenon may be associated with the development of Af in RHD patients.

Analysis of 24-hour heart rate variations in patients with epilepsy receiving antiepileptic drugs

OBJECTIVE

The goal of the study described here was to evaluate interictal heart rate variability (HRV) in young patients with epilepsy, a patient population in whom sudden unexpected death in epilepsy (SUDEP) is known to be more common.

METHODS

Twenty-four-hour ambulatory ECG Holter recordings of 37 patients (15-40 years old) and 32 healthy controls were compared.

RESULTS

All of the time domain indices (SDNN, SDANN, RMSSD, and HRV triangular index) were significantly suppressed (P<0.001), and there was a marked reduction in parasympathetic tone (reduced HF(nu,)P<0.001) and an increase in sympathetic tone (increased LF(nu) and LF/HF ratio, P<0.001) in the patient group. Stepwise linear regression analysis revealed that polytherapy and epilepsy duration >10 years were independent variables associated with a reduction in SDNN.

CONCLUSION

Our data suggest that the major determinants of suppressed SDNN are polytherapy and epilepsy duration >10 years. Analysis of spectral measures of frequency domain indices suggests that an increased sympathetic tone in association with a decreased parasympathetic tone may constitute the mechanism underlying SUDEP in young people with epilepsy.

Sympathetic overactivity in patients with pulmonary stenosis and improvement after percutaneous balloon valvuloplasty

OBJECTIVE

Percutaneous balloon valvulotomy (PBV) is the procedure of choice for the treatment of valvular pulmonary stenosis (PS) with similar results comparable to surgical valvotomy but less invasive.

METHODS AND RESULTS

Twenty-seven consecutive patients with PS being evaluated for PBV were enrolled in the study. Peak instantaneous transvalvular gradient, right ventricle (RV) diameter, mean atrial pressures, RV systolic pressure (RVSP), pro-brain natriuretic peptide (proBNP) levels significantly decreased immediately after PBV. Regarding heart rate variability (HRV) parameters, mean HR (heart rate), LF (low frequency) day and night, LF/HF day and night significantly decreased and standard deviation of all NN intervals (SDNN), root mean square of successive differences (RMSSD), P number of NN intervals that differed by more than 50 ms from adjacent interval divided by the total number of all NN intervals (PNN50), HF (High frequency) day and night significantly increased 1 day after PBV and these changes were shown to be preserved at the first month. The increase in SDNN was correlated with the decrease in right atrial pressure (RAP) (r =-0.5, P = 0.04); the increase in standard deviation of the 5-minute mean RR intervals (SDANN) was correlated with the decrease in proBNP (r =-0.4, P = 0.03).

CONCLUSIONS

Sympathetic overactivity and increased proBNP levels were associated with the symptomatic status of patients with PS. Associated with a decrease in atrial pressures and proBNP levels, PBV yielded a decrease in adrenergic overactivity in the patients with PS.