Autonomic neuropathy and prolongation of QT interval in human immunodeficiency virus infection

Autonomic neuropathy has been reported in human immunodeficiency virus positive (HIV+) patients. Since alterations in cardiac innervation may determine QT interval prolongation, this interval was studied in a group of HIV+ subjects to evaluate if it is prolonged and to compare this measurement with other diagnostic tests for autonomic neuropathy. Fifty-seven HIV+ and 23 human immunodeficiency virus negative (HIV–) subjects were studied. Autonomic function was tested by noninvasive cardiovascular reflex tests, and the QT interval on the electrocardiogram was measured at rest, at maximum tachycardia during Valsalva manoeuvre, and afterwards at maximum bradycardia. QT intervals were corrected for heart rate according to Bazzett's formula (QTc). Autonomic neuropathy was found in 37 HIV+ subjects: 25 had moderate autonomic neuropathy (HIV+/mAN) and twelve had severe autonomic neuropathy (HIV+/sAN). The 23 HIV– and 20 HIV+ (HIV+/AN–) patients did not have autonomic neuropathy. QTc intervals were significantly longer in HIV+/sAN and HIV+/mAN than in HIV– at rest; in HIV+/sAN than in HIV– at maximum tachycardia; in HIV+/sAN and HIV+/mAN than in HIV+, in HIV+/sAN and HIV+/mAN than in HIV+/AN– and in HIV+/sAN than in HIV+/mAN at maximum bradycardia. QTc was 440 ms in 24 out of 37 (64.8%) patients with autonomic neuropathy and in five out of 20 (25%) HIV+/AN– patients (sensitivity 65%, specificity 75%). A significant correlation was observed between scores of autonomic involvement and QTc interval prolongation. This study confirms that the QTc measurement is a reliable parameter indicating the presence of autonomic neuropathy. Since QT prolongation may determine ventricular arrhythmias, such patients must be followed because they may be at increased risk of sudden death.     

QT interval and QT dispersion in multiple system atrophy (Shy-Drager syndrome)

To evaluate the influence of autonomic function on the QT interval and QT dispersion, 18 patients (10 males and 8 females; mean age 61±9 years) with multiple system atrophy (MSA, Shy-Drager syndrome) were studied. Cardiovascular tests were performed to assess the degree of autonomic dysfunction. The QT interval, corrected QT (QTc), QT dispersion (QTd), corrected and adjusted QTd were calculated from a standard 12-lead electrocardiogram. Fifteen healthy subjects matched for sex and age were studied as controls. Nine MSA patients showed severe autonomic dysfunction with orthostatic hypotension. In the remaining patients definite autonomic impairment was found. No statistically significant difference was found in QTd and only a trend towards higher values of maximal QTc was found in patients compared with controls. QTc prolongation, defined as greater than the mean±2 SD of the controls, was detected only in three out of the 18 MSA patients (17%). No correlation was found between the severity of autonomic impairment and repolarization parameters. Our data suggest that chronic autonomic impairment in patients with MSA does not significantly affect ventricular repolarization and ventricular dispersion.     

Autonomic neuropathy and QT interval in hemodialysed patients

Abstract. Background QT interval prolongation increases the risk of ventricular arrhythmias and sudden death in diabetic autonomic neuropathy and ischemic heart disease. In end–stage renal disease (ESRD), the effects of hemodialysis on QT interval are diverse and the influence of autonomic neuropathy has yet to be clearly defined. Methods Sixty–nine ERSD patients (age 64 ± 14) were studied. Prior to the dialysis session, patients underwent four standard autonomic cardiovascular tests; before and after the dialysis session, a 12–lead ECG was recorded. Corrected QT intervals (QTc) were measured and QT dispersion (QTd) was calculated. Twelve subjects (age 59 ± 6) with normal renal function served as control group. Results Compared to controls, ESRD patients showed a longer QTc (434 ± 26 vs 414 ± 28ms; p = 0.016) and a similar QTd (35 ± 13 vs 37 ± 14ms; p = 0.54).QTc was > 440ms in 33.3% of the patients. No difference in the prevalence or score of autonomic neuropathy was observed between the subgroups with and without a prolonged QTc. After the hemodialysis session, QTc increased in 56% and decreased in 43% of the patients, and QTd increased in 45 % and decreased in 55% of the patients. QTc and QTd changes were not related to the presence of autonomic neuropathy. Conclusions A large variability in QTc and QTd response was observed after hemodialysis. Autonomic neuropathy did not contribute to QTc and QTd length, nor to QTc and QTd change after dialysis.     

Seizure-related cardiac repolarization abnormalities are associated with ictal hypoxemia

Purpose: Cardiac arrhythmias and respiratory disturbances have been proposed as likely causes for sudden unexpected death in epilepsy. Oxygen desaturation occurs in one‐third of patients with localization‐related epilepsy (LRE) undergoing inpatient video–electroencephalography (EEG) telemetry (VET) as part of their presurgical workup. Ictal‐related oxygen desaturation is accompanied by hypercapnia. Both abnormal lengthening and shortening of the corrected QT interval (QTc) on electrocardiography (ECG) have been reported with seizures. QTc abnormalities are associated with increased risk of sudden cardiac death. We hypothesized that there may be an association between ictal hypoxemia and cardiac repolarization abnormalities. Methods: VET data from patients with refractory LRE were analyzed. Consecutive patients having at least one seizure with accompanying oxygen desaturation below 90% and artifact‐free ECG data were selected. ECG during the 1 min prior to seizure onset (PRE) and during the ictal/postictal period with accompanying oxygen desaturation below 90% (DESAT) was analyzed. Consecutive QT and RR intervals were measured. In the same patients, DESAT seizures were compared with seizures without accompanying oxygen desaturation below 90% (NODESAT). For NODESAT seizures, QT and RR intervals for 2 min after seizure onset were measured. Key Findings: Thirty‐seven DESAT seizures were analyzed in 17 patients with localization‐related epilepsy. A total of 2,448 QT and RR intervals were analyzed during PRE. During DESAT, 1,554 QT and RR intervals were analyzed. Twelve of the 17 patients had at least one NODESAT seizure. A total of 19 NODESAT seizures were analyzed, including 1,558 QT and RR intervals during PRE and 3,408 QT and RR intervals during NODESAT. The odds ratio for an abnormally prolonged (>457 ms) QTcH (Hodges correction method) during DESAT relative to PRE was 10.64 (p < 0.0001). The odds ratio for an abnormally shortened (<372 ms) QTcH during DESAT relative to PRE was 1.65 (p < 0.0001). Seizure‐related shortening and prolongation of QTc during DESAT were also observed when Fridericia correction of the QT was applied. During DESAT seizures, the mean range of QT values (QTr) (61.14 ms) was significantly different from that during PRE (44.43 ms) (p = 0.01). There was a significant association between DESAT QTr and oxygen saturation nadir (p = 0.025) and between DESAT QTr and duration of oxygen desaturation (p < 0.0001). Both QTcH prolongation and shortening also occurred with NODESAT seizures. A seizure‐associated prolonged QTcH was more likely during DESAT than NODESAT, with an odds ratio of 4.30 (p < 0.0001). A seizure‐associated shortened QTcH was more likely during DESAT than NODESAT with an odds ratio of 2.13 (p < 0.0001). Significance: We have shown that the likelihood of abnormal QTcH prolongation is increased 4.3‐fold with seizures that are associated with oxygen desaturation when compared with seizures that are not accompanied with oxygen desaturation. The likelihood of abnormally shortened QTcH increases with seizures that are accompanied by oxygen desaturation with an odds ratio of 2.13 compared with that in seizures without desaturations. There is a significant association between the depth and duration of oxygen desaturation and QTr increase. These findings may be related to the pathophysiology of SUDEP.     

Loss of nocturnal blood pressure fall in various extrapyramidal syndromes

Cardiovascular autonomic dysfunction has frequently been reported in some patients with extrapyramidal syndromes, especially multiple system atrophy (MSA) but also Parkinson's disease (PD). However, there are only few reports on the prevalence of cardiovascular autonomic dysfunction progressive in supranuclear palsy (PSP). Moreover, the relation of detailed cardiovascular testing and easy to assess 24‐hour ambulatory blood pressure (BP) is not known. Our study evaluates 24‐hour ambulatory BP monitoring in patients with PD, PSP, MSA, and corresponding controls (Con) and relates the findings to the results of comprehensive cardiovascular autonomic testing. Twenty‐three patients with PD, 25 patients with PSP, 25 patients with MSA, and 26 corresponding controls were studied by 24‐hour ambulatory BP monitoring (ABPM) in comparison to cardiovascular autonomic testing. Patients with PD, PSP, and MSA presented frequently with a pathological nocturnal BP regulation (no decrease or even an increase of nocturnal BP) in comparison to the control group (PD 48%, PSP 40%, MSA 68% vs. Con 8%). In MSA and PD patients, the frequent pathological BP increase during night was closely correlated to orthostatic hypotension. Since loss of nocturnal BP fall is frequent in patients with extrapyramidal syndromes, even if they are free of subjective autonomic dysfunction, we recommend 24‐hour ABPM as an easy to perform screening test, especially if detailed autonomic testing is not available. Pathological loss of nocturnal BP fall may account for increased cardiovascular mortality in extrapyramidal syndromes. © 2009 Movement Disorder Society     

Highly abnormal thermotests in familial dysautonomia suggest increased cardiac autonomic risk

OBJECTIVE—Patientswith familial dysautonomia have an increased risk of sudden death. Insome patients with familial dysautonomia, sympathetic cardiacdysfunction is indicated by prolongation of corrected QT (QTc)interval, especially during stress tests. As many patients do nottolerate physical stress, additional indices are needed to predictautonomic risk. In familial dysautonomia there is a reduction of bothsympathetic neurons and peripheral small nerve fibres which mediatetemperature perception. Consequently, quantitative thermal perceptiontest results might correlate with QTc values. If this assumption iscorrect, quantitative thermotesting could contribute to predictingincreased autonomic risk.
METHODS—To test thishypothesis, QTc intervals were determined in 12 male and eight femalepatients with familial dysautonomia, aged 10 to 41 years (mean 21.7 (SD10.1) years), in supine and erect positions and postexercise andcorrelated with warm and cold perception thresholds assessed at sixbody sites using a Thermotest.
RESULTS—Due toorthostatic presyncope, six patients were unable to undergo erect andpostexercise QTc interval assessment. The QTc interval was prolonged(>440 ms) in two patients when supine and in two additional patientswhen erect and postexercise. Supine QTc intervals correlatedsignificantly with thermal threshold values at the six body sites andwith the number of sites with abnormal thermal perception (Spearman'srank correlation p<0.05). Abnormal Thermotest results were morefrequent in the four patients with QTc prolongation and the sixpatients with intolerance to stress tests.
CONCLUSION—The resultssuggest that impaired thermal perception correlates with cardiacsympathetic dysfunction in patients with familial dysautonomia. Thusthermotesting may provide an alternative, albeit indirect, means ofassessing sympathetic dysfunction in autonomic disorders.

     

Menopause, hormone replacement and RR and QT modulation during sleep

BACKGROUND AND PURPOSE: Sleep affects the RR interval in electrocardiogram (ECG) recordings and ventricular repolarization differentially in men and women. Compared to men, pre-menopausal women have a more pronounced shortening of RR interval and prolongation of QT and QT corrected (QTc, by Bazett's formula) ECG waves during rapid eye movement (REM) sleep. The aim of the present study was to evaluate sleep-related RR and QT changes: (1) with the physiological decline in female hormones occurring with menopause, and (2) after hormone replacement therapy with estrogen and progesterone (HRT). PATIENTS AND METHODS: We analyzed ECG recordings from 14 post-menopausal women (48-61 years old) who underwent polysomnography before HRT (T1) and after 6 months of HRT (T2) with estrogen and progesterone. Eight of the post-menopausal women (48-54 years) were also compared to eight age-matched pre-menopausal women. In all subjects, mean RR interval, mean QT interval and QTc, were obtained from 1-min recordings selected from wakefulness, stage 2 and REM sleep. RESULTS: Pre-menopausal and post-menopausal women showed similar changes in RR, QT and QTc intervals from wakefulness through sleep. Specifically, in both pre-menopausal and post-menopausal women the RR interval was shorter during REM sleep compared to wakefulness (P=0.009) and stage 2 sleep (P=0.001); the QT interval was more prolonged during stage 2 (P=0.002) and REM (P=0.006); and the QTc interval was significantly prolonged during stage 2 (P=0.01) and REM (P=0.0003) sleep compared to wakefulness. Among post-menopausal women, both before and after HRT (T1 and T2), RR interval shortened significantly during REM compared to wakefulness (P=0.03) and to stage 2 (P=0.002); the absolute QT interval was longer during stage 2, compared to both wakefulness (P<0.001) and REM (P<0.001); the QTc interval was increased during REM sleep compared to wakefulness (P=0.003). CONCLUSIONS: Sleep-related RR and QT changes in women are not altered by menopausal status nor by post-menopausal hormonal replacement with estrogen and progesterone.     

Corrected QT intervals in newly admitted geriatric psychiatric patients: an examination of risk factors.

OBJECTIVES: The primary objective of this study was to determine the incidence of prolonged corrected QT (QTc) intervals in a population of geriatric psychiatry inpatients. Our secondary objective was to examine the associations between prolonged QTc intervals and risk factors identified as determinants in prolonging the QTc interval. METHODS: We identified all geriatric patients (aged 60 years and older) who were admitted to the geriatric program of our facility between May 1, 2003, and December 31, 2003. Those patients with a heart rate QTc interval calculated on the electrocardiogram (ECG) were eligible for the study. We used Bazett's formula to calculate the QTc interval. We defined a priori that a prolonged QTc interval would be 450 ms and 460 ms for men and women, respectively. We collected data on demographic variables such as weight, sex, age, and Axis I and III diagnoses, as well as on recognized risk factors for prolonged QTc interval. We used Student's t tests to conduct parametric analysis on continuous variables, and chi-square to test categorical variables for independence. RESULTS: During the study period, 88 patients were admitted to the geriatric division of Riverview Hospital. Of these patients, 34 men and 42 women had calculated QTc intervals on their ECG and therefore made up the study population. Our data show that 29.4% of men and 21.4% of women had prolonged QTc intervals. However, neither diagnostic nor medicinal risk factors were found to be associated with an increased incidence of prolonged QTc interval in this patient population. CONCLUSION: The preliminary findings of this study suggest that in this patient population the QTc interval may not be influenced by recognized risk factors to the same extent as observed in the adult population. These results warrant confirmation by a larger, prospectively designed study.     

Use of corrected QT interval in autonomic function testing: assessment of reproducibility

QT interval duration is influenced by the autonomic nervous system and has been proposed as an additional tool in the diagnosis of diabetic autonomic neuropathy. The study aimed to assess in normal subjects the reproducibility of QT interval duration compared with that of cardiovascular tests commonly used to explore the function of the autonomic nervous system. Fifty-nine healthy subjects (31 males, 28 females; mean age 35.1 ±17.7 years) performed five cardiovascular tests: deep breathing test (DBT), lying to standing test (LST), Valsalva manoeuvre (VM), postural blood pressure test (PBPT) and cough test (CT). QT interval duration was measured on an electrocardiogram (ECG) registered after a 15-min rest in the supine position. Corrected QT interval (QTc) was calculated according to Bazett's formula. The QTc interval duration for each subject was expressed as the mean of the QTc calculated by two observers. Each subject was submitted to the cardiovascular test battery and the ECG twice in 1 week. The coefficient of variation (CV) was calculated to assess the reproducibility. The observed CV values were as follows: DBT 15.8%, LST 8.0%, VM 9.5%, CT 7.2%, PBPT 176%, QTc 3.4%. Our data confirm the reproducibility of heart rate cardiovascular tests: the QTc interval is a reproducible, easily measurable parameter, which has the advantage of not requiring patient cooperation.     

Functional polymorphisms of the cytochrome P450 1A2 (CYP1A2) gene and prolonged QTc interval in schizophrenia

CYP1A2 is an important inducible enzyme involved in the metabolism of antipsychotics. This study examined two functional polymorphisms in the gene as potential markers in predicting prolongation of QTc interval in patients treated with antipsychotics. QT intervals were measured by 12-lead electrocardiography (ECG) for patients with a DSM-IV diagnosis of schizophrenia. Genomic DNA extracted from venous blood were genotyped for the two polymorphisms by PCR-RFLP. Statistically significant result for CYP1A2(*)1F was noted for all patients receiving chlorpromazine equivalent doses of above 300 mg and also for a further subgroup on antipsychotics known to be CYP1A2 substrates (p=0.007, mean QTc in ms for A/A: 395.5+/-15.1, A/C: 425.7+/-25.1, C/C: 427.3+/-20.7). For CYP1A2(*)1C, there was no statistically significant association between genotypes and mean QTc interval. Overall, there was a trend of those with the C allele of the CYP1A2(*)1F polymorphism having longer QTc intervals. The results of this study suggest that the CYP1A2(*)1F polymorphism may contribute to the risk of developing prolonged QT-interval in patients who are treated with higher doses of antipsychotics.     

A retrospective study of the safety of intramuscular ziprasidone in agitated elderly patients

OBJECTIVE: Authors evaluated the safety of intramuscular ziprasidone for use in acute agitation in an elderly population. METHOD: Medical records were reviewed retrospectively to identify consecutive patients who were admitted to our neuropsychiatry service with the presenting complaint of dementia (DSM-IV) with agitation and who were given intramuscular ziprasidone and then administered an electrocardiogram (ECG) (N = 23). Some patients also had a baseline ECG (N = 14). QTc intervals were recorded, and significance was defined as a QTc of > or =450 ms or a 10% prolongation from baseline. A paired-samples t test was performed to compare the baseline and postmedication QTc intervals. Confounding factors were examined, and cardiac events (torsades de pointes, cardiac arrest) were recorded. RESULTS: There was no significant difference in the QTc interval between the baseline and the post-ziprasidone values. One patient had a QTc greater than 500 ms and 25% over baseline, and therefore the medication was discontinued. The mean prolongation of the QTc interval was only 0.5 ms. There were no episodes of torsades de pointes. Other medications that the patients were taking did not appear to affect the QTc interval in an expected manner. CONCLUSION: Larger studies need to be done to evaluate the safety of intramuscular ziprasidone in agitated elderly patients, a population with an increased risk of QT prolongation and torsades de pointes because of their age, comorbid conditions, and concomitant use of multiple medications.     

Cardiac sympathetic dysfunction in Parkinson's disease--relationship between results of 123I-MIBG scintigraphy and autonomic nervous function evaluated by the Valsalva maneuver]

We examined whether the results of 123I-MIBG scintigraphy reflect cardiac sympathetic nerve function in patients with Parkinson's disease (PD). The subjects were 62 patients with Parkinson's disease (age, 65.4 +/- 6.3 years) and 53 controls (65.2 +/- 7.1 years). All subjects underwent 123I-MIBG scintigraphy and QTc interval measurement on ECG. Hemodynamic autonomic function was estimated by the Valsalva maneuver in 37 subjects (63.9 +/- 5.2 years) randomly selected from the patients with PD. As control, the Valsalva maneuver was also done in 20 randomly selected controls (64.1 +/- 5.0 years), and 123I-MIBG scintigraphy was performed in 21 controls (67.7 +/- 5.3 years old). The subjects rested in a supine position for 20 min and were given an intravenous injection of 111 MBq 123I-MIBG. Relative organ uptake was determined by the region of interest (ROI) in the anterior view and the ratio of average pixel count in the heart (H) to that in the mediastinum (M) was calculated (H/M ratio) for early (after 15 min) and delayed (after 3 hrs) periods. The Valsalva maneuver was done by having the subjects exhale into a mouthpiece at an expiratory pressure of 40 mmHg for 15 seconds. Blood pressure and RR intervals were measured during the Valsalva maneuver by tonometry, using a noninvasive blood pressure monitoring system (ANS 508, Nihon Colin Co., Ltd.). Baroreceptor reflex sensitivities (BRS) of the second phase (BRS II) and fourth phase (BRS IV) of the Valsalva maneuver were calculated, and blood pressure elevations during the late second phase (IIp) and fourth phase (IVp) were measured. QTc was greater in the patients with PD (417 ms) than in the control subjects (409 ms). The H/M ratios of the early and delayed images in the patients with PD (1.76, 1.61) were significantly lower than those in the control subjects (2.56, 2.45). The early and delayed H/M ratios significantly correlated with the severity of disease according to Hoehn-Yahr stage. QTc interval and IVp significantly correlated with early and delayed H/M ratios. No other significant correlations were detected. The early H/M ratio in the patients with PD who had IVp within the normal range was lower than the early H/M ratio in control subjects. Our results show that early and delayed H/M ratio correlates with cardiac autonomic function, evaluated on the basis of QTc interval and the Valsalva maneuver, but not with baroreceptor reflex sensitivity or vasomotor autonomic function. Our findings suggest that silent cardiac autonomic dysfunction may be evaluated by 123I-MIBG scintigraphy, because early and delayed H/M ratios were lower in the patients with PD who had normal IVp than in the control subjects.     

Insular cortex lesion and autonomic instability in a herpes simplex virus encephalitis patient

The cardiovascular system is regulated by a central autonomic network (CAN) consisting of the insular cortex, anterior cingulate gyrus, and amygdala. Because the insular cortex often tends to be damaged in patients with herpes simplex virus (HSV) encephalitis, the autonomic instability observed in these patients was suggested to be moderated by an insular cortex lesion. Here, we report the case of a 51-year-old Japanese male who was hospitalized following a collapse 5 days earlier; he was diagnosed as herpes encephalitis. Diffusion-weighted MRI revealed asymmetric right greater hyperintensity throughout his insular cortex and anterior cingulate gyrus. At 1 week after admission, transthoracic echo showed diffuse hypokinesis in the left ventricle (LV). Cardiac ¹²³I-meta-iodobenzylguanidine uptake (¹²³I-MIBG) scintigraphy revealed reduced uptake in the inferior and posterior wall. Electrocardiograhy at rest showed that the coefficient variation of RR intervals (CVR-R) was reduced, and the corrected QT (QTc) interval length was prolonged. In this HSV encephalitis patient, signs of a right insular cortex lesion and autonomic instability were observed: LV hypokinesis, regional reduced ¹²³I-MIBG uptake, decreased CVR-R, and QTc interval prolongation. Our patient’s autonomic instability may thus be derived from disrupted autonomic balance due to the right insular cortex lesion.     

精神分裂症患者QTc问期延长的影响因素

目的 调查精神分裂症患者心电图QTc间期延长及相关影响因素。方法 对服用稳定剂量抗精神病药的522例住院精神分裂症患者进行横断面调查,收集人口学资料,测定空腹血糖等生化指标,并进行心电图检查,以QTc≥440ms作为QTc间期延长标准,分析QTc间期延长状况及其相关因素。结果 QTc间期延长发生率12．8％,女性（22．7％）高于男性（7．8％）,差异有统计学意义（P〈0．01）,心电图窦性心动过速和传导阻滞患者QTc间期延长风险分别是心电图正常患者的2．6和3．1倍（P〈0．05）。结论 抗精神病药治疗期间QTc间期延长发生率存在性别差异,女性QTc间期延长的风险可能更高。     

Cardiovascular reflex testing contributes to clinical evaluation and differential diagnosis of Parkinsonian syndromes.

The differentiation between Parkinson's disease (PD), progressive supranuclear palsy (PSP), and multiple system atrophy (MSA) may be difficult but is important for prognostic and therapeutic purposes. Varying degrees of autonomic failure have been described in PD and MSA, whereas its involvement in PSP remains controversial. The aim of this study was to investigate autonomic function in patients fulfilling strict clinical diagnostic criteria for the disorders above, to evaluate the diagnostic capacity of laboratory autonomic tests. The study group was consecutively recruited among patients referred to a movement disorder unit. Thirty-four patients with PD, 15 patients with PSP, and 47 patients with MSA were compared with 18 healthy age-matched controls. Autonomic tests included analysis of heart rate variability (HRV) in temporal domain, at rest and during forced respiration, as well as blood pressure (BP) changes during 75 degrees head-up tilt. HRV did not differ between groups during quiet breathing but was significantly reduced during forced respiration in MSA (P < 0.01), while PD and PSP groups did not differ from controls. Hypotensive responses during orthostatic provocation were seen in PD (P < 0.01) and MSA (P < 0.001), whereas BP remained stable in most PSP patients, not differing from the healthy control group. On an individual basis, decreased HRV and severe hypotensive responses were seen in MSA patients regardless of age and disease duration, whereas PD patients showed this combination only at high age and long duration. In PSP, only a few cases with decreased HRV and limited hypotensive responses were found. We conclude that cardiovascular reflex tests can supplement the clinical differentiation of Parkinsonian syndromes.     

心电图QT间期与抗精神病药及代谢等的关系

目的：观察心电图叩间期与抗精神病药及代谢等的关系。方法：对390例应用抗精神病药至少6个月住院患者的代谢参数作评估，测量他们的校正QT间期（帆）。结果：25例（6．4％）出现QTc间期延长。联用与单一应用抗精神病药患者的QR间期差异无显著性（P=0．884）。服氯氮平患者的叽间期较其他药物明显延长。结论：QT间期延长并不多见，与三酰甘油相关，与其他代谢参数无显著相关。     

Valsalva manoeuvre in patients with different Parkinsonian disorders

The valsalva manoeuvre (VM), used as an autonomic function test, can detect sympathetic and/or parasympathetic autonomic dysfunction. This study investigated the value of VM in patients with different Parkinsonian syndromes (PS). We continuously recorded blood pressure, ECG and respiration among 38 patients with multiple system atrophy (MSA), 32 patients with progressive supranuclear palsy (PSP), 26 patients with idiopathic Parkinson’s disease (PD) and in 27 healthy subjects matched in age and sex (Con). VM was performed in addition to metronomic breathing and tilt-table testing. VM could not be analysed in 26% of the ES patients. Valsalva ratio (VR), as a parameter of cardiovagal function, was pathologically decreased in all patient groups. Valsalva ratio (VR) was not able to discriminate parasympathetic dysfunction between patients and controls as well as E/I ratio of metronomic breathing. As a parameter of sympathetic dysfunction during VM, the physiological increase of blood pressure was more often missing during phase IV than phase II especially in PD and MSA patients. Correlation with orthostatic hypotension during tilt-table testing was only moderate. Although VM can demonstrate sympathetic and parasympathetic autonomic dysfunction, we cannot recommend VM as a first line autonomic test in PS patients. Metronomic breathing and tilt-table test seem more capable as parasympathetic resp. and sympathetic function tests to identify cardiovascular abnormalities in PS patients.     

Comparison of corrected QT interval as measured on electroencephalography versus 12-lead electrocardiography in children with a history of syncope

Long QT syndrome can present with neurological manifestations, including syncope and seizure-like activity. These patients often receive an initial neurologic evaluation, including electroencephalography (EEG). Our previous retrospective study suggested an increased prevalence of prolonged corrected QT interval (QTc) measured during the EEG of patients with syncope. The aim of the current study is to assess the accuracy of the EEG QTc reading compared with the nonsimultaneous 12-lead electrocardiography (ECG) in children with syncope. Abnormal QTc was defined as ≥450 ms in boys, ≥460 ms in girls. Forty-two children were included. There was no significant correlation between QTc readings in the EEG and ECG. EEG failed to identify 2 children with prolonged QTc in the ECG and overestimated the QTc in 3 children with normal QTc in the ECG. This study suggests that interpretation of the QTc segment during an EEG is limited. Further studies with simultaneous EEG and 12-lead ECG are warranted.     

蛛网膜下腔出血患者并发长QT间期综合征的危险因素探讨

目的：分析哪些因素与蛛网膜下腔出血患者伴发长QT间期综合征有关。方法：对98例发病2小时内人住我院的蛛网膜下腔出血患者分别记录了年龄、性别以及是否有糖尿病史,测定了每一例的心电图QT间期,用Bazettformula方法计算了经心率校正后的QT间期即QTc,并测定了每一例患者的血钠、血钾、血钙、血镁浓度和血糖水平。用多元线性回归方法分析了蛛网膜下腔出血患者的校正后QT间期即QTc与年龄、性别、血钠、血钾、血钙、血镁浓度及血糖水平的关系。结果：平均QTc间期为469．80±24．19ms。多元线性回归分析表明女性、低血钾及血糖为QTc间期延长的独立危险因素。女性相对于男性的相对危险度为4．23,低血钾(＜3．5mmol/L)者与正常血钾者比较相对危险度为2．86,高血糖(＞7．4mmol/L)患者相对于非高血糖患者(≤7．4mmol/L)的相对危险度为1．10。结论：女性、低血钾浓度及高血糖水平是蛛网膜下腔出血患者QTc延长的独立危险因素。