QT wave dispersion in patients with panic disorder

Objective QT dispersion (QTd), defined as the maximal inter-lead difference in QT intervals on 12 leads of the surface electrocardiogram (ECG), reflects the regional heterogeneity of ventricular repolarization and has been suggested as an important marker for risk of arrhythmia in addition to the QT interval. Some investigators proposed that it might be a predisposing factor for arrhythmic events and sudden death. Thus, we aimed to investigate whether QTd differs in patients with panic disorder from that in healthy controls. Methods In 40 panic disorder patients and 40 healthy controls, Qmax, Qmin, and QTd values were measured. In addition, the Hamilton depression rating scale and the panic agoraphobia scale were scored for both patients and healthy volunteers. Results Qmax and Qmin values in the panic disorder patients were significantly higher than those in healthy controls. The mean corrected QTd was significantly greater in the patients than in the controls. One-way analysis of covariance (ANCOVA; using left atrial size, age and heart rate as covariates) also corrected the significant difference. In addition, ANCOVA revealed a significant main effect for the diagnosis, indicating a significantly higher QTd for patients compared with controls. Conclusion QTd might be associated with panic disorder. Future studies in larger samples evaluating the effects of treatment are required.     

支架置入与冠状动脉粥样硬化性心脏病患者QT离散度及校正QT离散度变化

目的：探讨支架置入临床应用特点及其对冠状动脉粥样硬化性心脏病患者QT离散度及校正QT离散度的影响。方法：应用万方数据库和中国期刊全文数据库(CNKI),由第一作者以“支架置入,QT离散度,校正QT离散度”等检索1998/2010时限内与支架置入对冠状动脉粥样硬化性心脏病患者QT离散度影响有关的文献。排除重复研究或较陈旧文献。结果：依据纳入排除标准共保留文献22篇。常用支架为金属裸支架与药物支架。金属裸支架置入操作简便易行,并具有形状记忆效应及良好的生物相容性等临床应用优势,但术后早期再狭窄发生率高;药物支架有效降低术后再狭窄发生率,但远期安全性尚不明确。同时因经济投入高、置放技术要求严格等不易进行临床推广。从临床应用效果来看,支架置入显著缩短冠心病患者QT离散度以及校正QT离散。结论：支架置入显著缩短QT离散度以及校正QT离散,有效改善心肌再灌注,降低恶性心血管事件发生率,改善患者长期预后。但不同类型支架置入引起QT离散度的对应性变化,尚需进一步研究。     

Comparison of heart rate variability in patients with chronic fatigue syndrome and controls

Recent studies have reported a close association between chronic fatigue syndrome and neurally mediated hypotension. We hypothesized that this association may result from an abnormality in autonomic function among patients with chronic fatigue syndrome, which may be detectable using an analysis of heart rate variability. We prospectively studied 19 patients who fulfilled the Centers for Disease Control criteria for chronic fatigue syndrome and 11 controls. Each subject underwent a two-stage tilt-table test while wearing a Holter monitor. Heart rate variability was assessed in the supine baseline position and during upright tilt using frequency domain parameters. In the baseline supine position, high frequency (HF) power, low frequency (LF) power, and the ratio of low frequency power to high frequency power (LF/HF ratio) were similar. In both patient groups, upright tilt resulted in a similar decrease in HF power, increase in LF power, and increase in the LF/HF ratio. In conclusion, autonomic function, as assessed using an analysis of heart rate variability, does not differ in the baseline supine state, nor in response to upright tilt among patients with chronic fatigue syndrome and healthy controls.     

Effects of caffeine on heart rate and QT variability during sleep

Administration of caffeine in the evening produces poor sleep. Patients with insomnia have characteristic electrocardiogram (ECG) changes, including increased heart rate (HR), increased sympathetic activity, and decreased parasympathetic activity. Fifteen young adult normal subjects slept in the laboratory for several nights prior to randomization into a caffeine protocol where subjects received caffeine 400 mg 30 min prior to one night of sleep and placebo randomly prior to another night. ECG was sampled at a rate of 500 Hz and recorded onto a PC. Data samples of 256-s periods of the ECG trace were taken from wake (before sleep), stage II, and REM for placebo and caffeine conditions. A peak detection algorithm was used to identify the R-R intervals (in milliseconds) from the ECG. A common QT variability algorithm was used to find the QT interval for each beat using the time-stretch model. The powers for HR and QT series were integrated in the bands of LF (low frequency: 0.04-0.15 Hz) and HF (high frequency: 0.15-0.5 Hz) bands. There was a significant caffeine by sleep stage interaction for LF/HF ratios (F = 4.0; df = 2, 18; P = .04). LF/HF ratios were significantly higher during REM following caffeine administration. There was also a significant caffeine by sleep stage interaction for QTvi (QT variability normalized for mean QT interval divided by HR variability normalized for mean HR; F = 5.6; df = 2, 12; P = .02). QTvi was also significantly higher during REM following caffeine administration. The higher LF/HF ratios and QTvi during REM are most likely due to the sympathetic effects of caffeine. These findings suggest that excessive caffeine intake may result in adverse cardiovascular events in vulnerable subjects.     

Ketogenic diet in patients with Dravet syndrome

PURPOSE: The ketogenic diet (KD) has been used as a therapeutic alternative to antiepileptic drugs (AEDs) for refractory epilepsy. Severe myoclonic epilepsy in infants or Dravet syndrome (DS) is one of the most malignant epileptic syndromes. In this retrospective study, we evaluated the efficacy and tolerability of the KD in patients with diagnostic criteria of DS. METHODS: Between March 1, 1990, and August 31, 2004, 52 patients who met diagnostic criteria for DS were enrolled in a study at our department. Twenty of them were placed on the KD with the Hopkins protocol and followed up for a minimum of 1 year. RESULTS: Three of the 20 original children stayed on the diet for 12 months, four children for 2 years, four children for 3 years, and two children for 4 years. One year after initiating the diet, 13 (65%) of the initial patients remained on the diet. Two (15%) patients were seizure free, eight (61.7%) children had a 75-99% decrease in seizures, and the remaining three (23%) children had a 50-74% decrease in seizures. Thus 1 year after starting the diet, 10 (77%) children had achieved a >75% decrease in their seizures. Four patients have been off the diet for >2 years; one of them is seizure free, two have sporadic seizures, and one, who abandoned the diet after 2 years of adhering to it, relapsed. No differences in seizure control when compared with age, sex, or seizure type were found. CONCLUSIONS: Considering the severity and intractability of seizures in patients with DS, the fact that 10 of the 13 children who remained on the diet had a significant reduction in number of seizures shows that the KD is at present an interesting therapeutic alternative. Even in patients in whom seizure reduction was not dramatic, quality of life improved, and in all of them, the number of AEDs was reduced to one or two. We consider that children with DS should be offered the KD immediately after three adequate trials of AEDs have failed.     

Effect of posture and isoproterenol on beat-to-beat heart rate and QT variability

RATIONALE: Recent literature emphasizes the utility of QT variability to study ventricular electrophysiologic function. In this investigation, we sought to test the hypothesis that beat-to-beat fluctuations in QT intervals are mediated by sympathetic activity in normal subjects using postural challenge and isoproterenol infusions. SUBJECTS AND METHODS: We obtained ECG in the supine and standing postures during spontaneous breathing, at 12, 15 and 20 per minute controlled breathing (n = 19), and before and after infusions of isoproterenol, a beta-adrenergic agent, in the supine posture during spontaneous breathing (n = 11) using lead II configuration in healthy human adult subjects. Heart rate (HR) and QT time series data were analyzed by spectral analysis of 256 s of real-time data. Beat-to-beat QT intervals were measured by automated analysis of ECG. A QT variability index (QT(vi)) was calculated for each subject as the logarithm of the ratio of normalized QT variance to normalized HR variance. We also calculated fractal dimensions of QT time series during spontaneous breathing. RESULTS: QT(vi) was significantly higher in the standing than in the supine posture (-1. 93 +/- 0.27 vs. -1.47 +/- 0.41; p = 0.0001), and also during isoproterenol infusions in the supine posture (-1.83 +/- 0.39 vs. -1. 27 +/- 0.43; p = 0.0001). Fractal dimensions of QT time series were also significantly higher during standing (p = 0.00001) and isoproterenol infusions (p = 0.0002). Respiratory rate or tidal volume did not account for the increased QT variability seen in the standing posture. CONCLUSIONS: A change from the supine to the standing posture as well as infusion of isoproterenol significantly increased the absolute as well as normalized QT variability, which appears to be due to an increase in sympathetic activity associated with these conditions.     

脑中风患者心率变异的初步分析

目的：探讨中风后植物神经的变化规律及其变化机制。方法：采用反映植物神经功能折心率变异指标，对其时域指标进行分析、应用方差分析及ｔ检验，比较了健康对照组与中风组的心率变异情况。结果：（１）中风组ＳＤＮＮ及ＨＲＶＩ均明显低于健康对照组。（２）中风组随病程的处长，其心率变异逐渐增高，到半年后基本恢复到对照组的水平。     

Metabolic syndrome and short-term heart rate variability in adults with intellectual disabilities

Metabolic syndrome (MetS) increases the risk of cardiovascular events. Heart rate variability (HRV) represents autonomic functioning, and reduced HRV significantly increases cardiovascular mortality. The aims of the present paper are to assess the prevalence of MetS in adults with intellectual disabilities (ID), the difference in short-term HRV between the healthy and ID population, and the association of short-term HRV with MetS. In this study, we analyzed 129 ID subjects who participated in routine health check-ups in October 2010. We measured their metabolic components and evaluated the relationships of MetS with short-term HRV indices. The study found that MetS and obesity are common in persons with ID. ID subjects have significantly lower HRV than healthy adults, and persons with ID persons with MetS have significantly lower HRV than ID subjects without MetS. The individual components of MetS are differentially associated with HRV in ID men and women. Metabolic syndrome adversely affects autonomic cardiac control, and reduced autonomic cardiac control could contribute to an increased risk of subsequent cardiovascular events in individuals who exhibit metabolic syndrome. Sex differences in vagal activity and sympathovagal balance may partly explain the greater increase in cardiovascular risk associated with MetS in ID women compared with ID men.     

Overall management of patients with Dravet syndrome

Dravet syndrome, or as it was called in the past 'severe myoclonic epilepsy in infancy', is a drug-resistant epilepsy first described by Charlotte Dravet in 1978. Besides the well-known and well-described therapy resistance, Dravet syndrome dramatically impacts the development and behaviour of the affected children. As it is still not a curable disease, families need to be taught how to cope with the disorder and will require assistance from both clinical and non-clinical structures. At the onset of the disease, many questions arise regarding the diagnosis of Dravet syndrome, the severity of the illness and its deleterious effects, and the management of seizures, especially the long-lasting status epilepticus. Once the diagnosis has been established, severe convulsions, often unpredictable and long-lasting, are still a major worry, but developmental and behavioural problems also rapidly become a serious concern. Later on, nearly all parents will have a child who becomes an adult with special needs, requiring specialised attention from professionals.     

Blood pressure and heart rate variability in patients with essential hyperhidrosis

Introduction Essential hyperhidrosis (EH) is often considered to be related to an increased activity of sympathetic nervous system (SNS). However, there is a lack of studies comparing autonomic nervous system (ANS) activity in controls and in EH patients. The aim of the present study was to simultaneously investigate in patients with severe EH, blood pressure, heart rate variability and plasma catecholamine levels in comparison with controls.Methods 19 EH patients and 20 controls with normal ANS function assessed by clinical testing were included. Blood pressure (BP) and heart rate (HR) were measured using a Finapres beat-to-beat monitor. BP and HR variabilities (Fast Fourier transformation) and plasma catecholamine levels (HPLC) were obtained at rest and during a 15 min 70° head-up tilt test.Results At rest, a significantly higher relative energy of low frequency band (LF) of systolic BP was observed in EH in comparison with controls contrasting with the lack of difference in BP, HR, plasma catecholamine levels and in other spectral parameters. During tilt, all changes were comparable in EH and in control subjects excepting relative energy of LF of SBP which remained unchanged when compared to the resting condition in EH group.Conclusions In EH, SNS is not overreactive even if resting overactivity cannot be excluded.     

Differential pattern of heart rate variability in patients with schizophrenia

The cardiac autonomic dysfunction has been reported in patients with schizophrenia. Heart rate variability (HRV) provides non-invasive indices of cardiac autonomic modulation. This study examined whether patients with schizophrenia may show a distinctive pattern of HRV compared to healthy controls. Nine measures of time, frequency and complexity domains were extracted from 5-min resting evaluation of HRV in 30 unmedicated patients with schizophrenia and 30 age- and gender-matched controls. In addition to inferential statistics, a hierarchical clustering (HC) was used to examine difference in the interrelationships among HRV measures between the two groups. Multivariate analysis of variance revealed a significant group effect. Significantly lower sample entropy (SampEn) and a trend towards a higher ratio of low- to high frequency (LF/HF) were observed in the schizophrenia group. In the results of HC using Ward's method, SampEn co-clustered with LF/HF ratio in patients with schizophrenia compared to the separation of LF/HF ratio in healthy controls. In concert with decreased parasympathetic activity, low complexity of heart rate dynamics may reduce adaptability of cardiovascular system to changes in internal or external environment, thus increasing the risk of cardiovascular events. Diverse HRV measures combined in a multivariate fashion appear to be useful in understanding the pattern of neurocardiac modulation in patients with schizophrenia.     

The relationship between heart rate, heart rate variability and depression in patients with coronary artery disease

Seventy-seven patients undergoing elective cardiac catheterization were administered a diagnostic psychiatric interview and their mean heart rates and heart rate variability were determined from the results of a 24 hr ambulatory ECG. The mean heart rate for depressed patients with coronary artery disease (CAD) was significantly higher than for nondepressed CAD patients, independent of the patient's age, smoking status, and beta blocker therapy. Heart rate variability was lower in depressed patients but did not achieve significance. With the exception of smoking, which was more common in depressed patients, there were no significant differences between the depressed and nondepressed patients on any other medical or demographic variable assessed. It is concluded that elevated heart rate may represent increased sympathetic tone in depressed CAD patients, and may help to explain the increased morbidity and mortality reported in these patients.     

Lamotrigine can be beneficial in patients with Dravet syndrome

Dravet syndrome, a severe infantile epilepsy syndrome, is typically resistant to anti‐epileptic drugs (AED). Lamotrigine (LTG), an AED that is effective for both focal and generalized seizures, has been reported to aggravate seizures in Dravet syndrome. Therefore, LTG is usually avoided in Dravet syndrome. We describe two adults and a child with Dravet syndrome in whom LTG resulted in decreased seizure duration and frequency. This benefit was highlighted in each patient when LTG was withdrawn after 6 to 15 years, and resulted in an increased frequency of convulsive seizures together with longer seizure duration. A 25‐year‐old male required hospital admission for frequent seizures for the first time in 7 years, 6 weeks after ceasing LTG. Reintroduction of LTG improved seizure control, suggesting that in some patients with Dravet syndrome, LTG may be beneficial.     

Stiripentol open study in Japanese patients with Dravet syndrome

Purpose:   To survey the treatment situation of Dravet syndrome in Japan and to compare this result with effectiveness of stiripentol (STP) add-on therapy in an open-label multicenter study.
Methods:   Medical records of patients with Dravet syndrome who visited the study institutions during 2006 were surveyed to examine the effect of antiepileptic drugs (AEDs) on clonic or tonic–clonic seizures (GTCS). Patients older than 1 year of age treated with at least one conventional AED and more than four GTCS per month were invited to participate in the STP study. Seizure status and adverse effects during the first 4 weeks of STP (50 or 1,000 mg/day) add-on therapy (early period) and during long-term treatment were compared with baseline.
Results:   Only 15% of the treatment trials with 15 conventional AEDs in 112 patients succeeded in reducing seizures by more than 50%. With STP, GTCS were reduced more than 50% in 14 of 23 patients (61%), including 2 who became seizure-free, in the early period. Moreover, duration of seizures was shortened in 10 patients and status epilepticus decreased in 6. These effects continued in the long-term although to a lesser degree. Adverse effects (loss of appetite, sleep disturbance, ataxia, hyperactivity/irritability) disappeared after dose modification in most cases. STP was effective at a lower than initial dose in five patients. Some patients benefited from STP added on clobazam despite mutation in CYP2C19 .
Conclusion:   Our data suggest that an early introduction of STP into Japan will result in substantial patient benefit.     

Clinical prognostic significance of heart abnormality and heart rate variability in patients with stroke

Abstract

Objective: To investigate the difference of heart rate variability (HRV) and serum creatine kinase isoenzyme (CK-MB) activity between right-sided and left-sided stroke, and the relative impact of cardiac autonomic imbalance and heart abnormality on death by serum CK-MB activity and fractal dimension (FD) detection in patients with stroke.

Methods: Three hundred and twenty-seven patients (mean age: 61·12 ± 9.74 years) with an acute first-ever stroke underwent a comprehensive clinical investigation and laboratory tests, and were followed up for 1 month. Serum CK-MB activity and FD of heart rate variability were detected on the next day after admission.

Results: During the 1 month follow-up period, 42 out of 327 (12·84%) patients had died. Among all the variables analysed, FD decreased and serum CK-MB activity increased after stroke, and decreased FD was more common in the right-sided stroke. This study also demonstrated that acute phase increased serum CK-MB activity [odds ratio (OR)=0·226, 95% CI: 0·103–0·493, p= 0·000) and decreased FD (OR=0·276, 95% CI: 0·135–0.567, p=0·000) had been linked with the risk of death.

Conclusions: Right-sided stroke and left-sided stroke had different influences on cardiac autonomic nerve activity. Acute phase increased serum CK-MB activity and decreased FD are well-established prognostic factors of death in patients with stroke. Assessment of FD and serum CK-MB activity may provide additional information on the risk of death in stroke patients.     

Effects of hyperventilation on heart rate and QT variability in panic disorder pre- and post-treatment

Panic disorder is associated with an elevated risk of cardiovascular disease and sudden death. Individuals with panic disorder have been shown to have reduced variability in heart rate and increased variability in the QT interval on electrocardiogram (ECG), patterns predictive of sudden cardiac death in certain forms of cardiomyopathy. Given that panic disorder patients often hyperventilate during a panic attack, we assessed the effects of voluntary hyperventilation on the ECG utilizing linear analyses of heart rate and QT interval variability. Sixteen symptomatic, medication-free patients underwent hyperventilation challenge. A small subgroup of eight subjects underwent re-challenge after treatment. Pre-treatment, hyperventilation resulted in a decrease in a measure of heart rate variability and an increase in the QT variability index (QTVI; QT variance normalized for mean QT, divided by heart rate variance normalized for mean heart rate). In a remitted state, the QTVI was reduced both during rest and during hyperventilation compared with the respective pre-treatment levels. These findings suggest a possible mechanism explaining increased rates of cardiovascular morbidity and mortality in panic disorder. Moreover, the reduction in QTVI observed post-treatment raises the question of whether treatment might have cardioprotective effects, at least in panic disorder patients who have particular types of co-morbid cardiac disease. Yet these results must be interpreted cautiously; they are preliminary, exploratory and observed in a very small sample without a healthy comparison group.     

Impaired heart rate variability in euthymic bipolar patients

Background:  Power spectral analysis of heart rate variability (HRV) has recently been shown to be a reliable non-invasive test for quantitative assessment of the central sympathovagal interaction that modulates cardiovascular autonomic function.
Methods:  We studied 39 euthymic bipolar patients and 39 controls, matched for age and sex. A high-resolution electrocardiogram was obtained during complete rest. Spectral analysis of R–R intervals was performed by the fast Fourier transform algorithm.
Results:  Euthymic bipolar patients at rest are characterized by markedly low HRV, independent of specific drug treatments.
Conclusion:  While these results of autonomic stability in euthymic bipolar patients are counter-intuitive, the findings may be important in understanding pathophysiology of bipolar affective illness.     

Twenty-four-hour QT interval variability: increased QT variability during sleep in patients with panic disorder

BACKGROUND/AIM: There is now some evidence that autism may be accompanied by abnormalities in the inflammatory response system (IRS). Products of the IRS, such as proinflammatory cytokines, may induce some of the behavioral symptoms of autism, such as social withdrawal, resistance to novelty and sleep disturbances. The main aim of the present study was to examine whether autism is accompanied by an activation of the IRS. METHODS: We measured the production of interleukin (IL)-6, IL-10, the IL-1 receptor antagonist (IL-1RA), interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha by whole blood and the serum concentrations of IL-6, the IL-2 receptor (IL-2R) and IL-1RA. RESULTS: This study showed a significantly increased production of IFN-gamma and IL-1RA and a trend toward a significantly increased production of IL-6 and TNF-alpha by whole blood of autistic children. There were no significant differences in the serum concentrations of IL-6, IL-2R and IL-1RA between autistic and normal children. CONCLUSIONS: These results suggest that autism may be accompanied by an activation of the monocytic (increased IL-1RA) and Th-1-like (increased IFN-gamma) arm of the IRS. It is hypothesized that increased production of proinflammatory cytokines could play a role in the pathophysiology of autism.