QT间期离散度在冠心病诊治中的应用

<正> QT间期离散度(QTd)反映了心室肌复极的不均一性,QTd值越大反映心室肌复极的不均一程度愈高,反之则表示心室肌复极的不均一程度愈低。有学者提出QTd增大是冠心病患者心律失常性死亡的独立危险因子。本文旨在通过QTd在冠心病诊治中的意义,探讨其应用价值。1 QTd曾大的机理及计算方法     

扩张型心肌病并发心律失常临床特点及预后分析

目的 探讨扩张型心肌病(DCM)并发心律失常的临床特点及其对患者预后的影响.方法 42例DCM患者根据终点事件分为存活组(28例)和死亡组(14例).回顾性分析两组患者的12导联心电图、24h动态心电图及心脏超声等资料,比较两组患者心律失常类型、心律失常发生率及心脏超声相关参数的差异.结果 死亡组NYHA心功能分级Ⅳ级率为64.3％(9/14),显著高于存活组的14.3％(4/28)(P＜0.01).死亡组QT间期离散度、校正QT间期离散度显著高于存活组[(73.14±13.01) ms比(61.31±12.38)ms,(85.37±12.46) ms比(71.03±11.23) ms ](P＜ 0.01).死亡组恶性室性心律失常发生率显著高于存活组[64.3％(9/14)比7.1％(2/28),P＜0.01].死亡组左房内径、左室舒张末期内径显著高于存活组[(48.79±6.14) mm比(42.81±5.23) mm,(75.73±5.19) mm比( 63.29±5.62) mm ](P＜ 0.01),而左室射血分数、左室短轴缩短率显著低于存活组[(27.91±6.83)％比(36.45±11.03)％,(14.17±5.61)％比(21.06±6.14)％](P＜0.01).结论 DCM患者多伴有各种心律失常及心脏形态结构改变,直接影响患者预后,通过对心脏超声及心电图的监测,可进行早期干预.     

扩张型心肌病患者心室复极变异性的特点和临床意义

目的 探讨扩张型心肌病(DCM)患者心室复极变异性的特点和临床意义.方法 应用24 h动态心电图检测30例DCM患者(DCM组)与30例正常人(对照组)的QT间期、RR间期,分别计算并比较24 h标准化QT变异度(QTVnor)、24 h标准化心率变异度(HRVnor)的QT变异度指数(QTVI).结果 DCM组与对照组比较24 h QTVnor和QTVI增大,分别为1.31±1.02、0.67±0.66,P＜0.05和0.62±0.13、-0.68±0.41,P＜0.01.QTVnor和HRVnor呈中度正相关关系,其中DCM组r=0.44,P＜0.05;对照组r=0.57,P＜0.05.结论 QT变异度受心率变异度变化影响,消除心率变异度影响后,DCM患者心室自身复极变异性增大,可能与发生恶性心律失常有关.     

妊娠期高血压对心室复极的影响

目的分析妊娠期高血压疾病患者体表心电图的心室复极指标,探讨其对心室复极的影响。方法选择2009年4月—2011年4月收治的324例孕妇作为研究对象,根据是否患有妊娠期高血压疾病分为高血压组和正常组各162例。两组均于入院第1天接受心电图检查,分析和比较两组ST-T段、QT间期、QTc等心室复极指标。计量资料采用t检验,计数资料采用χ2检验,P0.05为差异有统计学意义。结果高血压组ST-T段异常63例,占38.89%;正常组32例,占19.75%,差异有统计学意义(P0.05)。高血压组QT间期为(323.8±17.1)ms,低于正常组的(355.5±15.7)ms,差异有统计学意义(P0.05)。高血压组QTc为(444.2±19.3)ms,高于正常组的(428.4±28.4)ms,差异有统计学意义(P0.05)。结论妊娠期高血压疾病影响心室正常复极,并使心室复极时间延长。     

QT间期离散度的临床应用及研究进展

QT间期离散度(QTD)是指体表12导联心电图不同导联之间最长QT间期和最短QT间期的差异程度，它反映了心室肌复极化的不均一性。从广义而言，凡是能够影响心室肌的局部复极都会有QTD的变化。因此，在临床上．对于急性心肌梗塞、冠心病、心肌肥厚、肺心病、心力衰竭等引起的心肌功能和形态变化或者室性心律失常疾病的诊断及预后具有重要意义，近年来其临床价值越来越受到重视。     

QT离散度的动态变化研究进展

QT离散度(QT dispersion,以下简称QTd)系指心电图各导联间QT时限变异的程度。最早由campbell等于1985年提出,1990年Day等首次证实QTd具有重要的临床价值。QTd增加为心室肌复极不均匀的表现,而最大QT值存在于病变区域,这种区域性复极化不均匀,极易产生多数性折返激动,它代表心室肌不稳定性。目前QTd研究领域已经不断深入,尤其临床上将QT离散度的动态变化观察运用于急性心肌梗死、心肌梗死溶栓治疗过程中、平板运动试验过程中、判断血管紧张转换酶抑制剂等治疗后左心室肥厚的逆转程度等方面取得了一些结果,本文就上述问题作一小结,供同道参考。 1 急性心肌梗死(AMI) 有关AMI时QTd的动态演变研究已有不少结论。如国内王兆禹等分析49例AMI患者QTd演变显示:急性期QTd(43.9±18.4)ms、恢复期(38.4±18.3)ms、陈旧期     

川崎病患儿心电图QT离散度检测

目的检测川崎病(KD)患儿心电图QT离散度(QTd),探讨其临床意义。方法回顾性分析19例川崎病患儿心电图QT离散度,测量12导联心电图最大QT间期(QTmax)、最小QT间期(QTmin)和心率,计算QTd和心率校正的QTd(QTcd),与健康小儿的QTd、QTcd值比较,P<0.05有统计学意义。结果 KD患儿QTd、QTcd值分别是(37.2±5.3)ms,(61.5±7.1)ms;而健康小儿是(26.2±2.7)ms和(37.2±6.2)ms,两组比较,t值分别是7.98和11.24,P均<0.001。结论 KD患儿心电图QTd值增大,预示心肌受损、易于发生室性心律失常。     

老年冠心病患者QT间期离散度临床分析

目的探讨分析老年冠心病患者QT间期离散度（QTd）的临床特点和意义。方法选择门诊120例老年冠心病患者与同期非冠心病老人的常规心电图进行QTd测定和对比分析。结果老年冠心病组的QTd均值为66．21±10．87ms;非冠心病组45．82±8．16ms。两组比较差异显著（P〈0．01）。结论分析认为,老年冠心病患者QTd异常增大可能与其冠脉病变程度及严重心血管事件的发生有密切关系。     

房性心律失常对自主神经功能的影响

目的 探讨房性心律失常对自主神经功能的影响.方法 选择47例(病例组)房性心律失常患者及60例(对照组)非房性心律失常患者,分别监测24h动态心电图,得出P波最大时限(Pmax)、P波离散度(Pd)、心率变异指数(HRVI)、24h内全部正常窦性R-R间期标准差(SDNN)及24h平均心室率,并进行对比分析.分别以Pmmax＞110 ms、Pd＞ 40 ms、HRVI＜ 25、SDNN≤100 ms作为判定房性心律失常的阳性预测指标,比较两组患者上述各项指标的阳性率.结果 病例组Pmax、Pd 及24h平均心室率显著高于对照组[(109.40±8.25) ms比(93.36±9.45) ms,(42.76±6.14) ms比(34.20±6.38) ms,(89.29±24.62)次/min比(73.86±14.60)次/min],HRVI、SDNN显著低于对照组[35.16±14.93比39.77±16.01,(98.79±26.87) ms比(123.37±22.14) ms],差异均有统计学意义(P＜0.0l).病例组Pmax＞ ll0ms、Pd ＞40ms、Pmax＞ 110 ms+ Pd ＞40 ms、HRVI＜ 25、SDNN≤l00ms的阳性率均高于对照组(P＜0.01).结论 房性心律失常患者心脏自主神经有明显的功能紊乱.     

心电图QT离散度在慢型克山病中的临床意义

QT间期离散度(QTd)代表心肌复极的离散程度,其测值增大,常表示某原因所致的心肌细胞复极时间不均,心肌细胞电活动不稳定,为探讨该指标的应用价值,我们观察了慢型克山病心功能不全患者心电图的QTd,并与无心脏疾患的健康人进行了对比分析。1 材料与方法1.1 观察对象 慢型克山病75例,均为经临床各项检查确诊的患者,临床心功能定为Ⅲ～Ⅳ级的患者。对照70例,男女各35例,系确诊的无心脏疾患的健康人。以上两组年龄大致在     

检定间隔期中辐射计量器具的受控分析

通过时检定间隔期内辐射计量器具量值超差失准原因及受控状态统计分析，提出检定间隔期中应按计量器具稳定性情况和分级加权法确定的动态检定周期实施计量器具动态检定校准，以保证计量器具状态受控，确保医疗质量。     

Perceptions of personal belief vaccine exemption policy: A survey of Arizona vaccine providers

Background

As exemptions to school-entry requirements rise, vaccination rates in Arizona school children are approaching levels that may threaten public health. Understanding the interactions physicians have with vaccine-hesitant parents, as well as the opinions physicians hold regarding vaccination, exemption, and exemption policies, are critical to our understanding of, and ability to affect, vaccination exemption rates among children.

Methods

Survey responses were elicited from practitioners listed in The Arizona Partnership for Immunization and the Arizona Medical Association databases using a multi-pronged recruitment approach. Respondents provided data regarding their practice, comfort with parental refusal of individual vaccines, opinions about the beliefs held by parents that seek exemptions, parent education strategies, issues regarding providing care to unvaccinated children, and potential changes to Arizona policy.

Results

A total of 152 practitioners providing care to a wide geographic and economic population of Arizona responded to the survey. Respondents were generally strong advocates of all immunizations but were more accepting of parents’ desires to refuse hepatitis B and rotavirus vaccines. Almost all providers indicated that they see patients whose parents request to refuse or delay from vaccinations at least occasionally (88% and 97%, respectively). Only 37% of respondents indicated that they would be supportive of a policy requiring them to sign off on a parent's decision to refuse vaccination.

Conclusions

Vaccination providers in Arizona are generally very supportive of childhood immunizations but have varying comfort with exemption from individual vaccines. Responding providers tended to not support a requirement for a physician's signature for vaccine exemptions due to varying concerns regarding the implementation of such a practice.     

Educational interventions to increase HPV vaccination acceptance: A systematic review

Background

The Human papillomavirus (HPV) vaccine has been available for protection against HPV-associated cervical cancer and genital warts since 2006. Nonetheless, uptake has varied among countries and populations within countries. Studies have found that individuals’ knowledge and attitudes toward the vaccine are associated with immunization uptake. The purpose of the current review is to summarize and evaluate the evidence for educational interventions to increase HPV vaccination acceptance.

Methods

We searched the databases of PubMed and Web of Science for English-language articles describing educational interventions designed to improve HPV vaccination uptake, intention or attitude.

Results

We identified 33 studies of HPV vaccination educational interventions: 7 tested the effectiveness of interventions with parents, 8 with adolescents or young adults, and 18 compared the effectiveness of different message frames in an educational intervention among adolescents, young adults or their parents. Most studies involved populations with higher educational attainment and most interventions required participants to be literate. The minority of studies used the outcome of HPV vaccine uptake. Well-designed studies adequately powered to detect change in vaccine uptake were rare and generally did not demonstrate effectiveness of the tested intervention.

Conclusions

There is not strong evidence to recommend any specific educational intervention for wide-spread implementation. Future studies are required to determine the effectiveness of culturally-competent interventions reaching diverse populations.     

Arsenic Exposure from Drinking Water and QT-Interval Prolongation: Results from the Health Effects of Arsenic Longitudinal Study

Background: Arsenic exposure from drinking water has been associated with heart disease; however, underlying mechanisms are uncertain.Objective: We evaluated the association between a history of arsenic exposure from drinking water and the prolongation of heart rate–corrected QT (QTc), PR, and QRS intervals.Method: We conducted a study of 1,715 participants enrolled at baseline from the Health Effects of Arsenic Longitudinal Study. We assessed the relationship of arsenic exposure in well water and urine samples at baseline with parameters of electrocardiogram (ECG) performed during 2005–2010, 5.9 years on average since baseline.Results: The adjusted odds ratio (OR) for QTc prolongation, defined as a QTc ≥ 450 msec in men and ≥ 460 msec in women, was 1.17 (95% CI: 1.01, 1.35) for a 1-SD increase in well-water arsenic (108.7 µg/L). The positive association appeared to be limited to women, with adjusted ORs of 1.24 (95% CI: 1.05, 1.47) and 1.24 (95% CI: 1.01, 1.53) for a 1-SD increase in baseline well-water and urinary arsenic, respectively, compared with 0.99 (95% CI: 0.73, 1.33) and 0.86 (95% CI: 0.49, 1.51) in men. There were no apparent associations of baseline well-water arsenic or urinary arsenic with PR or QRS prolongation in women or men.Conclusions: Long-term arsenic exposure from drinking water (average 95 µg/L; range, 0.1–790 µg/L) was associated with subsequent QT-interval prolongation in women. Future longitudinal studies with repeated ECG measurements would be valuable in assessing the influence of changes in exposure.     

Soy and isoflavone intake associated with reduced risk of ovarian cancer in southern Chinese women

Isoflavones, mainly found in soy, have been shown to inhibit ovarian cancer cell proliferation. We hypothesized that soy consumption and isoflavone intake are related to the risk of ovarian cancer. A case–control study was conducted in southern China to ascertain this hypothesis. Five hundred incident patients with histologically confirmed cancer of the ovary and 500 controls (mean age 59 years) were recruited from four public hospitals in Guangzhou. Information on habitual consumption of soy foods, including soybean, soy milk, fresh tofu, dried tofu, and soybean sprout, was obtained face-to-face from participants through a validated and reliable semi-quantitative food frequency questionnaire. Isoflavone intakes were then estimated using the USDA nutrient database. The ovarian cancer patients reported lower consumption levels of individual and total soy foods (75.3 ± 53.6 g/day) compared to the controls (110.7 ± 88.8 g/day). Logistic regression analyses showed that regular intake of soy foods could reduce the ovarian cancer risk, the adjusted odds ratio being 0.29 (95% confidence interval 0.20 to 0.42) for women who consumed at least 120 g/day relative to those less than 61 g/day. Similarly, isoflavone intakes were inversely associated with the ovarian cancer risk, with significant dose–response relationships (P < 0.001). We concluded that consumption of soy foods is associated with a reduced risk of ovarian cancer in southern Chinese women.     

Serum levels of zinc,calcium, and iron are associated with the risk of preeclampsia in pregnant women

Evidence indicates that various elements, including antioxidant minerals, might play an important role in preeclampsia (PE). This study was carried out to investigate the relationship between serum mineral levelsof zinc, calcium, iron, and selenium and the risk of preeclampsia in Korean women. Twenty-nine normal controls and 30 women with preeclampsia were recruited for the study. Preeclampsia was defined as having high blood pressure (≥140/90 mm Hg after 20 weeks gestation) and proteinuria (≥300 mg/24 hours). Serum mineral content was determined by instrumental neutron activation analysis. Serum zinc (P < .0001) and calcium (P = .0188) levels were lower in women with preeclampsia than those of normal women, while serum iron was significantly higher in women with preeclampsia (P = .0045). The odds ratio for preeclampsia was lower in women with higher serum zinc levels than those with lower levels after adjustment for age, height, and weight before delivery (P < .0001). The adjusted odds ratio for preeclampsia also decreased across tertiles of serum calcium concentration (P = .0452). However, there was an increased adjusted odds ratio for preeclampsia across tertiles of serum iron level (P = .0104). These results suggest that levels of serum minerals such as zinc, calcium, and iron may be associated with the risk of preeclampsia in Korean pregnant women.     

雷米芬太尼对全麻患者气管插管期平均动脉压、心率和QTc间期延长的影响

目的 观察和评价雷米芬太尼对全麻患者气管插管期平均动脉压(MAP)、心率和QTc间期的影响.方法 选取择期全麻手术患者75例,ASA分级Ⅰ～Ⅱ级,按随机数字表法分为三组:对照组(C组)、雷米芬太尼Ⅰ组(R1组)和雷米芬太尼Ⅱ组(R2组),每组25例.麻醉诱导:静脉注射芬太尼3μg/kg、普鲁泊福1.0～1.5 mg/kg和维库溴铵0.1 mg/kg后2 min,双盲法≥40 s给予雷米芬太尼0.50 μg/kg(R1组)或0.75μg/kg(R2组)后,两组分别连续输注雷米芬太尼0.10μg/(kg·min);C组患者给予相同容量的0.9%氯化钠.记录麻醉诱导前(T0)、诱导后2 min(T1)、首次给予雷米芬太尼或0.9%氯化钠后1 min(T2)、气管插管前即刻(T3)及气管插管后30 s(T4)、2 min(T5)和4 min(T6)的MAP和心率,并描记心电图.结果 与C组比较,R2组T4～T6时QTc间期明显缩短(P＜0.05或＜0.01＝;R,组T4和C组T4～T6时QTc间期较T0明显延长(P＜0.05或＜0.01).C组气管插管期OTc间期＞440ms 11例(44%,11/25),R2组3例(12%,3/25),两组比较差异有统计学意义(P＜0.05).结论 芬太尼和普鲁泊福麻醉诱导气管插管期间患者的QTc间期是延长的;插管前1 min静脉注射雷米芬太尼0.75μg/kg,继以0.10 μg/(kg·min)输注可有效抑制气管插管诱发QTc间期延长和血流动力学反应.

Abstract：

Objective To evaluate the effect of remifentanil on mean arterial pressure (MAP), heart rate (HR) and QTc interval during tracheal intubation of general anesthesia patients. Methods Seventy-five ASA Ⅰ -Ⅱ grade patients were selected and allocated to receive either saline (group C), remifentanil 0.50 μg/kg (group R1) or remifentanil 0.75 μg/kg(group R2) by random digits table with 25 cases in each, they were administrated as a bolus intravenous, followed by a continuous infusion at 0.10 μg/ (kg·min), 1 min before laryngoscopy. All patients received fentanyl 3 μg/kg,propofol 1.0 - 1.5 mg/kg and vecuronium 0.1 mg/kg. The ECG.MAP and HR were recorded prior to induction of anesthesia (T0), 2 min following the start of drug intravenous of fentanyl and propofol with vecuronium (T1), 1 min following remifentanil or saline (T2), before laryngoscopy(T3), 30 s (T4), 2 min (T5) and 4 min (T6) after intubation. Results The QTc interval was significantly prolonged immediately following intubation in group C and group R1, but it remained stable in group R2, compared with the QTc interval just before laryngoscopy. In group R2, QTc interval was significantly shorter at T4-T6 compared to group C(P＜ 0.05 or ＜ 0.01). QTc interval significantly increased from baseline at T4 in group R1 and T4-T6 in group C (P＜ 0.05 or ＜ 0.01). The number of patients with QTc interval ＞ 440 ms were significantly greater immediately following tracheal intubation in group C than that in group R2 [44% (11/25) vs. 12% (3/25)] (P ＜ 0.05). Conclusions QTc interval increases following tracheal intubation during induction of anesthesia using fentanyl and propofol. Intravenous of remifentanil attenuates the QTc interval prolongation associated with tracheal intubation. In addition, remifentanil decreases the hemodynamic responses to tracheal intubation.     

Association between urinary concentrations of bisphenol A and type 2 diabetes in Korean adults: A population-based cross-sectional study

Bisphenol A (BPA) is a synthetic phenolic compound to which the general public may be exposed via consumer products and environmental contamination. We assessed the association between urinary BPA concentration and the prevalence of type 2 diabetes. This cross-sectional study included Korean adult participants (n = 1210) aged 40–69 years and was based on the 2009 Korean National Human Biomonitoring Survey. Demographic characteristics and medical history of type 2 diabetes were collected from the participants by questionnaire, and BPA levels were determined by analysis of urine samples. The mean age of the participants was 53.4 years and 41.6% were men; the prevalence of type 2 diabetes differed according to demographic characteristics. The geometric mean urinary BPA levels of participants with and without type 2 diabetes were 2.03 and 2.40 ng/mL, respectively. Among BPA quartiles, no clear association was found between BPA levels and type 2 diabetes. Although the adjusted odds ratio of type 2 diabetes was slightly increased for participants in the upper BPA quartile, the association was not statistically significant. These findings suggest that a high body BPA burden may not be associated with an increased prevalence of type 2 diabetes in Korean adults.     

Confidence limits for the ratio of two rates based on likelihood scores: non-iterative method

This paper describes a method for creating a confidence interval for the ratio of rates using the score statistic. This non-iterative and easy to apply procedure produces confidence intervals that are suitable for use with Poisson data and simulation results indicate that it is close to the nominal level for a wide range of scenarios.     

Model based estimates of long-term persistence of inactivated hepatitis A vaccine-induced antibodies in adults

Background

In this paper, we review the results of existing statistical models of the long-term persistence of hepatitis A vaccine-induced antibodies in light of recently available immunogenicity data from 2 clinical trials (up to 17 years of follow-up).

Methods

Healthy adult volunteers monitored annually for 17 years after the administration of the first vaccine dose in 2 double-blind, randomized clinical trials were included in this analysis. Vaccination in these studies was administered according to a 2-dose vaccination schedule: 0, 12 months in study A and 0, 6 months in study B (NCT00289757/NCT00291876). Antibodies were measured using an in-house ELISA during the first 11 years of follow-up; a commercially available ELISA was then used up to Year 17 of follow-up. Long-term antibody persistence from studies A and B was estimated using statistical models for longitudinal data. Data from studies A and B were modeled separately.

Results

A total of 173 participants in study A and 108 participants in study B were included in the analysis. A linear mixed model with 2 changepoints allowed all available results to be accounted for. Predictions based on this model indicated that 98% (95%CI: 94–100%) of participants in study A and 97% (95%CI: 94–100%) of participants in study B will remain seropositive 25 years after receiving the first vaccine dose. Other models using part of the data provided consistent results: ≥95% of the participants was projected to remain seropositive for ≥25 years.

Conclusion

This analysis, using previously used and newly selected model structures, was consistent with former estimates of seropositivity rates ≥95% for at least 25 years.