血压盐敏感者一氧化氮系统与非对称性二甲基精氨酸和补钾的作用

目的 通过观察慢性盐负荷及补钾后血浆非对称性二甲基精氨酸(ADMA)和血、尿一氧化氮(NO)水平的变化及其与血压的关系,探讨血压正常盐敏感者(SS)的血管内皮功能损伤及补钾的保护作用.方法选60例年龄在20～60岁的血压正常者参与为期3周的慢性盐负荷及补钾试验,包括基线调查3 d,低盐(LS)饮食,高盐(HS)饮食,和高盐补钾(HS K)饮食各7 d的研究.每个阶段均测量血压,并收集血、尿标本.血、尿NO用Griess法测量,血浆ADMA用高效液相色谱法测量.结果 受试者60例中共检出SS 13例,检出率为21.6%.盐负荷后,SS血浆ADMA的浓度明显升高[(0.89±0.09 vs 0.51±0.07)μmol/L,P＜0.05],而血浆NO的水平则较LS饮食期显著降低[(41.8±7.6 vs 63.5±7.6)μmol/L,P＜0.01].在HS摄入的基础上大剂量口服补钾可以逆转单纯HS负荷对SS血浆ADMA浓度和血、尿NO水平的作用[(ADMA:0.52±0.09 vs 0.89±0.09)μmol/L;NO:(58.1±7.4 vs 41.8±7.6)μmol/L],血浆ADMA浓度和平均动脉压之间存在正相关关系.结论 血压正常SS于HS负荷后伴随血压升高,血浆ADMA显著升高、NO降低,同时补充钾盐可以逆转前述作用,提示补钾可能通过抑制ADMA的升高降低血压.     

慢性盐负荷及补钾对健康成人血压变异性的影响

目的:探讨慢性盐负荷及补钾对健康成人血压和血压变异性的影响。方法:选取100例年龄在28～60岁的血压正常者参与为期3周的慢性盐负荷及补钾试验,包括基线调查3 d,低盐饮食、高盐饮食和高盐补钾饮食各7 d的研究。在基线调查和各干预阶段的第5,6,7天采用英国产随机零点血压计连续测量3 d血压。测量血压前受试者静坐休息5 min,测量3次,求平均值,并计算3 d血压测量值的标准差和变异系数,作为长时血压变异性指标。结果:受试者血压在低盐期较基线期显著下降［SBP:(112±11)mmHg vs.(117±14)mmHg;DBP:(74±8)mmHg vs.(76±10)mmHg,P<0.01］;高盐期较低盐期明显升高［SBP:(119±14)mmHg vs.(112±11)mmHg;DBP:(77±9)mmHg vs.(74±8)mmHg,P<0.01］;补钾期较高盐期显著降低［SBP:(114±12)mmHg vs.(119±14)mmHg;DBP:(75±8)mmHg vs.(77±9)mmHg,P<0.01］。限盐后收缩压标准差、舒张压标准差均降低［SDSBP:(3.9±1.5)mmHg vs.(4.3±1.0)mmHg;SDDBP:(3.2±1.4)mmHg vs.(3.6±1.6)mmHg,P<0.01］;高盐期较低盐期升高［SDSBP:(4.4±1.6) vs.(3.9±1.5)mmHg;SDDBP:(3.7±1.2) vs.(3.2±1.4)mmHg,P<0.01］。结论:钠、钾摄入量与血压变化密切相关,其中低盐饮食后血压下降,高盐饮食后血压升高,而在高盐负荷基础上给予大剂量补钾使血压下降。高盐饮食可增大血压变异性,限盐可降低血压变异性。     

血压盐敏感者一氧化氮系统与非对称性二甲基精氨酸和补钾的作用

目的通过观察慢性盐负荷及补钾后血浆非对称性二甲基精氨酸(ADMA)和血、尿一氧化氮(NO)水平的变化及其与血压的关系,探讨血压正常盐敏感者(SS)的血管内皮功能损伤及补钾的保护作用。方法选60例年龄在20～60岁的血压正常者参与为期3周的慢性盐负荷及补钾试验,包括基线调查3d,低盐(LS)饮食,高盐(HS)饮食,和高盐补钾(HS K)饮食各7d的研究。每个阶段均测量血压,并收集血、尿标本。血、尿NO用Griess法测量,血浆ADMA用高效液相色谱法测量。结果受试者60例中共检出SS13例,检出率为21.6%。盐负荷后,SS血浆ADMA的浓度明显升高[(0.89±0.09vs0.51±0.07)μmol/L,P<0.05],而血浆NO的水平则较LS饮食期显著降低[(41.8±7.6vs63.5±7.6)μmol/L,P<0.01]。在HS摄入的基础上大剂量口服补钾可以逆转单纯HS负荷对SS血浆ADMA浓度和血、尿NO水平的作用[(ADMA:0.52±0.09vs0.89±0.09)μmol/L;NO:(58.1±7.4vs41.8±7.6)μmol/L],血浆ADMA浓度和平均动脉压之间存在正相关关系。结论血压正常SS于HS负荷后伴随血压升高,血浆ADMA显著升高、NO降低,同时补充钾盐可以逆转前述作用,提示补钾可能通过抑制ADMA的升高降低血压。     

钠钾对血压盐敏感者短时血压变异性的影响

目的观察血压盐敏感者在钠、钾饮食干预后短时血压变异性(BPV)的变化,探讨BPV与盐敏感的关系。方法 2004-04-10对陕西眉县农村正常血压成人93名进行低盐(氯化钠51.3mmol/d)饮食7d,高盐(氯化钠307.7mmol/d)饮食7d的慢性盐负荷试验,之后进行高盐补钾(307.7mmol/d氯化钠基础上口服60mmol/d氯化钾缓释胶囊)干预7d;每个阶段最后一天测3次血压,以血压标准差、变异系数为短时BPV指标。根据高盐饮食后平均动脉压升高幅度是否≥10%,分为血压盐敏感组(n=30)及盐不敏感组(n=63)。结果盐敏感性检出率为32.3%。基线期时,与盐不敏感组比较,盐敏感组收缩压标准差[(4.4±1.1)比(2.5±0.5)mmHg,P<0.01];舒张压标准差[(3.7±1.7)比(2.8±0.9)mmHg,P<0.01];收缩压变异系数[(3.78±1.01)比(2.35±0.55),均P<0.01];舒张压变异系数[(5.06±2.50)比(3.99±1.46),P<0.05]均较高。盐敏感组低盐期及高盐补钾期收缩压、舒张压标准差及变异系数均降低,与盐不敏感组比较,差异无统计学意义;予高盐饮食后,盐敏感组收缩压标准差较低盐期升高,与盐不敏感组比较,差异有统计学意义[(3.7±1.9)比(3.0±1.1)mmHg,P<0.05]。结论高盐摄入、盐敏感是短时BPV增大的重要原因,限盐及补钾具有降低短时BPV的保护作用。     

高血压左心室肥大患者T波峰-末间期的检测

目的:检测高血压左心室肥大患者的T波峰一末间期(Tp-Te间期)TL心率校正的Tp-Te/√R-R间期,并探讨其可能的临床意义.方法:依据超声心动图测定的左室重量指数(LVMI)分为正常组和左室肥大组.比较正常组与高血压左室肥大组Tp-Te间期及Tp-Te/√R-R间期的差异.结果:正常组男性Tp-Te间期及Tp-Te/√R-R间期长于女性(P＜0.05);左室肥大组男、女性Tp-Te间期及Tp-Te/√R-R间期均比正常组明显延长(P＜0.05,P＜0.01).结论:高血压左心室肥大患者的Tp-Te间期及Tp-Te/√R-R间期比正常人明显延长,可能成为预测此类患者发生心律失常事件的临床指标之一.     

心电图心室复极指标与冠脉狭窄程度的相关性

目的 分析12导联心电图T波峰末间期(Tp-Te)及QT间期离散程度(QTd)与冠心病严重程度的相关性及对冠心病的诊断价值.方法 回顾性分析50例健康体检者及50例冠心病患者的临床资料,以健康体检者为健康组,以冠心病患者为冠心病组,对比两组Tp-Te、QTd差异,分析Tp-Te、QTd与冠心病严重程度的相关性及对冠心病...     

心肌梗死患者QTd、Tp-Te和Tp-Te/QT的观察

目的观察心肌梗死后3~6个月患者心电图QTd、Tp-Te和Tp-Te/QT与对照组之间有无差异。方法选取自2011年1月至9月行心电图检查的心梗后3~6个月患者30例,男14例,女16例,平均年龄(51.2±11.94)岁;收集年龄、性别相匹配的对照组30例,男15例,女15例,平均年龄(50.4±9.45)岁,测量各组心电图QTd、Tp-Te间期并计算Tp-Te/QT值。结果心梗组Tp-Te和Tp-Te/QT比值均大于对照组,差异具有统计学意义(心梗组Tp-Te:101.9±14.5ms;Tp-Te/QT:0.287±0.04;对照组Tp-Te:75.7±12.4ms;Tp-Te/QT:0.193±0.03;p<0.05);QTd在两组之间无差异(心梗组:40.5±3.9ms;对照组:37.9±3.8ms;p>0.05)。结论心梗患者Tp-Te,Tp-Te/QT比值增高,可反映跨室壁复极离散度的变化,与心律失常的发生关系密切。     

血压盐敏感者内皮功能损伤及补钾的保护作用研究

目的通过观察血、尿-氧化氮（NO）水平的变化,探讨盐敏感者血管内皮功能损伤及补钾的保护作用。方法选39例年龄16～60岁、血压正常或血压轻度偏高者参与为期3周的慢性盐负荷及补钾试验,包括基线3天,低盐饮食、高盐饮食和高盐加补钾饮食各7天的研究。各个阶段测量体重、血压,并收集血、尿标本。结果盐敏感者血浆NO浓度和尿中NO水平在基线、低盐和高盐阶段均低于盐不敏感者;限盐后血、尿NO浓度增加,而高盐饮食后NO浓度显著减少;盐敏感者在高盐摄入的基础上大剂量口服补钾后血浆NO浓度、尿NO水平显著升高。结论盐敏感者尽管尚处在血压正常或血压轻度偏高阶段已存在一定程度的内皮功能损伤,且这种损伤与盐负荷相关联;大剂量补钾可能通过增加NO水平而改善盐敏感者的血管内皮功能。     

不同体质指数对盐负荷及补钾的血压反应研究

目的探讨不同体质指数(BMI)受试者对盐负荷及补钾的血压反应。方法在陕西眉县农村选择年龄在16-60岁的农民39例,血压正常或轻度偏高的自愿者进行为期三周的慢性盐负荷及补钾试验,包括基线3天、低盐、高盐、补钾各7天的研究。各个阶段测量身高、体重及血压。结果与BMI30kg/m2者相比,BMI≥30kg/m2者有较高的基线血压,限盐饮食后血压下降幅度更大,高盐饮食后血压升高幅度大,补钾后的血压下降幅度也大。结论体质指数不仅与高血压相关,可能也参与了盐敏感性的发生与发展。补钾对于高体质指数者降压效果更明显。     

老年人急性心肌梗死QT离散度变化的探讨

目的观察老年急性心肌梗死(AMI)病人溶栓前后QT离散度(QTd)的变化,分析其与室性心律失常的关系。方法测量40例老年AMI病人的QT间期,计算其QTd及校正后的QT离散度(QTdc)。结果QTd及QTdc>100ms病人中,室性心动过速、心室颤动发生率明显高于QTd、QTdc<100ms者(72.7%及6.9%,P<0.001)。溶栓再通组溶栓后QTd及QTdc分别为51.2ms±21.4ms及62.8ms±21.9ms,较溶栓前缩短(分别为77.4ms±21.1ms及90.0ms±30.6ms,P<0.05)。结论老年AMI病人QTd、QTdc延长者,室性心动过速及心室颤动发生率增高,溶栓后QTd及QTdc缩短提示溶栓后血管再通。     

QT intervals as an index of high serum calcium in hypercalcemia

The relationship between QT interval and serum calcium concentration (s-Ca) was examined in 9 hypercalcemic (s-Ca greater than 11 mg/dl) patients. Three QT intervals corrected by Bazett's formula were used for the analysis: the intervals from the beginning of the QRS to the onset (QoTc), the apex (QaTc), and the end of T wave (QeTc). The measurements of s-Ca and other electrolytes were made on the blood sample taken on the same day of the electrocardiogram (ECG) recordings. The normal range of s-Ca and three QTc intervals was determined in 50 outpatients with no cardiac disease. Three QT intervals in the hypercalcemic patients were significantly shortened with a diminution in the s-Ca. The QTc intervals showed significant negative correlation with s-Ca. Sensitivity of QoTc, QaTc, and QeTc in predicting high s-Ca was 83%, 57%, and 39%, respectively, and specificity was 100%, 100%, and 89%. The PQ interval tended to be prolonged in the case of hypercalcemia, but the change was statistically insignificant. These observations suggest that QT intervals can serve as an indicator of high s-Ca and that the QoTc seems to be a good indicator of the three QTc's.     

Reliability of QT intervals as indicators of clinical hypercalcemia

Reliability of corrected QT intervals (QoTc, QaTc, and QeTc) as indicators of clinical hypercalcemia was assessed in 14 hypercalcemic patients. Hypercalcemia was severe to extreme (serum calcium 14.9 to 22.8 mg/dl) in 11, moderate (13.4 mg/dl) in 1, and mild (12.2 and 11.8 mg/dl) in 2 patients. QT intervals during hypercalcemia were compared with those during normocalcemia either before or after development of hypercalcemia. QeTc interval showed neither significant correlation with serum calcium nor any consistent pattern of change with development of hypercalcemia or normalization of serum calcium. In contrast, QoTc and QaTc intervals shortened with development of hypercalcemia and returned toward normal with normalization of serum calcium in all the patients, and showed significant correlation with serum calcium (QoTc: r = -0.77, p less than 0.001, n = 35; QaTc: r = 0.82, p less than 0.001, n = 35). QaTc was short (less than 0.30 s) in all the ECGs in severe and moderate hypercalcemia and in 2 of the 5 ECGs in mild hypercalcemia. Combination of short QoTc (less than 0.18 s) and short QaTc was found to be highly specific for, and was present in 65% of ECGs, in moderate and severe hypercalcemia. Combination of normal QoTc (greater than 0.18 s) and normal QaTc (greater than 0.30 s) was not observed in moderate or severe hypercalcemia. We conclude that QoTc and QaTc intervals are reliable indicators of clinical hypercalcemia.     

右室心尖部和间隔部S1S2刺激电重构后对跨室壁复极离散的影响

目的通过观察右室不同部位S1S2刺激电重构后对室壁QRS间期、QRS波起始至T波顶点间期（QTp）、QT间期和T波峰末间期（Tp2e）影响,分析不同部位起搏对跨室壁复极离散的影响。方法选取因阵发性室上性心动过速拟行射频消融患者18例,随机分心尖部刺激组（RVA组,n=9）和间隔部刺激组（RVS组,n=9）,分别行S1S2刺激,测量每组体表起搏心电图V1导联S2刺激的QRS间期、QRS波起始至T波顶点间期（QTp）、QT间期和T波峰末间期（Tp2e）并进行统计分析。结果 RVS组较RVA组的QRS间期、QTp无差异、至S1S2500/260ms后QT间期及Tp2e明显减低;两组均随S1S2刺激间期缩短QT间期及Tp2e明显增大,而QRS间期及QTp无差异。结论电重构后RVS组比RVA组心室跨壁复极离散低、心脏同步性较好,是选择起搏的较好部位。     

心动过缓患者QT与RR间期的相关变化

分析33名病窦综合症和高度房室传导阻滞所致心动过缓患者的24小时动态心电图。用直线回归方程计算QT和RR间期回归直线的斜率(slode).分为RR间期≤1.4s(slopeL)和>1.4s(slope2)。发现所有患者的slope_2(0.0086±0.0039)明显小于sIope_1(0.0785±0.0057;P<0.001)。12名校正后QT间期(QT_c)≥0.44s患者(B组)的slope_1(0.0969±0.0083)和slope_2(0.0198±0.0049)均明显大于QT_c<0.44s患者(A组)的slope_1(0.063±0.0063;P<0.01)和slope_2(0.0022±0.0028;P<0.01)。slope_1和slope_2与QT_c呈正相关。表明心动过缓患者.随着心率的减慢,QT间期延长的量逐渐减少,与QT间期正常组相比,QT延长组当RR间期延长时.QT间期有较大的延长。     

Subject-specific heart rate dependency of electrocardiographic QT, PQ, and QRS intervals

Although heart rate dependency of QT interval is well known, the relationship of other electrocardiogram (ECG) parameters to heart rate has been researched less intensively. This study investigated the heart rate dependencies of QT interval, PQ interval, and QRS width in 40 healthy subjects (18 women; mean age, 30.4 +/- 8.1 years). In each subject, 3 long-term (approximately 13 hours) 12-lead ECGs were obtained for 3 day-time periods with gaps of 2 to 3 weeks between repeated recordings. In each recording, approximately 230 ECG measurements of QT interval, PQ interval, and QRS width were made, each preceded by stable heart rate. For each recording, linear regression slopes of QT/RR, PQ/RR, and QRS/RR relationships were obtained. Intrasubject SDs of individual values were compared with intersubject SDs of intrasubject means to test the individuality of the relationships. The intrasubject means of the slope values were also compared between sexes. The individual SDs of the QT/RR regression slopes were 0.0116 +/- 0.0065, whereas the population SD of intrasubject means was 0.0245 (P = 3.6 x 10(-15)). For the PQ/RR slopes and QRS/RR slopes, these values were 0.0085 +/- 0.0050 vs 0.0314 (P = 7.9 x 10(-28)) and 0.00189 +/- 0.00157 vs 0.00550 (P = 2.6 x 10(-17)), respectively. The QT/RR slopes were steeper in women than in men (0.194 +/- 0.019 vs 0.168 +/- 0.022, 0.0005), whereas the QRS/RR slopes were, on average, negative in women while positive in men (-0.00138 +/- 0.0045 vs 0.00335 +/- 0.0054, P = .005). There were no sex differences in the PQ/RR slopes (0.054 +/- 0.032 in women vs 0.055 +/- 0.031 in men, P = .95). Thus, not only the heart rate dependency of QT interval but also the rate dependencies of PQ interval and of QRS width show high intrasubject stability with substantial intersubject differences.     

不同部位起搏对体表心电图有关参数的影响

目的观察心脏不同部位起搏对体表心电图有关参数的影响。方法 10只健康猪,分别在右房(RA)起搏、右室心尖部心内膜起搏(RVEndo)及左室心外膜(LVEpi)起搏,记录并测量不同部位起搏后体表心电图12个导联的QRS波时限、QT间期、JT间期和T波峰-末间期(Tpe),计算Tpe平均值(TpeAVE)、Tpe最大值(TpeMAX)。结果 LVEpi起搏时QT间期、JT间期大于RA及RVEndo起搏时(P均<0.05);LVEpi起搏时TpeAVE,TpeMAX大于RA及RVEndo起搏时(P均<0.05),而RA与RVEndo起搏时此两指标无差异。结论 LVEpi起搏可能会增加健康心室整体复极离散。     

Beat‐to‐Beat QT Interval Variability Is Primarily Affected by the Autonomic Nervous System

Background : Beat‐to‐beat QT interval variability is associated with life‐threatening arrhythmias and sudden death, however, its precious mechanism and the autonomic modulation on it remains unclear. The purpose of this study was to determine the effect of drugs that modulate the autonomic nervous system on beat‐to‐beat QT interval. Method : RR and QT intervals were determined for 512 consecutive beats during fixed atrial pacing with and without propranolol and automatic blockade (propranolol plus atropine) in 11 patients without structural heart disease. Studied parameters included: RR, QTpeak (QRS onset to the peak of T wave), QTend (QRS onset to the end of T wave) interval, standard deviation (SD) of the RR, QTpeak, and QTend (RR‐SD, QTpeak‐SD, and QTend‐SD), coefficients of variation (RR‐ CV, QTpeak‐CV, and QTend‐CV) from time domain analysis, total power (TP; RR‐TP, QTpeak‐TP, and QTend‐TP), and power spectral density of the low‐frequency band (LF; RR‐LF, QTpeak‐LF, and QTend‐LF) and the high‐frequency band (HF; RR‐HF, QTpeak‐HF and QTend‐HF). Results : Administration of propranolol and infusion of atropine resulted in the reduction of SD, CV, TP, and HF of the QTend interval when compared to controlled atrial pacing (3.7 ± 0.6 and 3.5 ± 0.5 vs 4.8 ± 1.4 ms, 0.9 ± 0.1 and 0.9 ± 0.1 vs 1.2 ± 0.3%, 7.0 ± 2.2 and 7.0 ± 2.2 vs 13.4 ± 8.1 ms², 4.2 ± 1.4 and 4.2 ± 1.2 vs 8.4 ± 4.9 ms², respectively). Administration of propranolol and atropine did not affect RR interval or QTpeak interval indices during controlled atrial pacing. Conclusions : Beat‐to‐beat QT interval variability is affected by drugs that modulate the autonomic nervous system.     

Acute electrophysiologic effects of an HT2-serotonin antagonist,ketanserin, in humans

Summary The acute electrophysiologic effects of an intravenous bolus of ketanserin, a 5HT₂ serotonin blocker, were studied in ten patients (four females, six males) during invasive electrophysiology. Following baseline electrophysiologic measurements during sinus rhythm and fixed-rate atrial pacing at 600 ms, a bolus of 0.2 mg/kg ketanserin was given over a 3-minute period. After 30 minutes all measurements were repeated. Systemic blood pressure was measured at regular intervals throughout. During sinus rhythm, there was no significant change in the basic cycle length or in the PA, AH, HV, QRS, QT, and QTc intervals. During atrial pacing there was a nonsignificant increase in the QT interval, from 342±13 ms to 366±16 ms, and a significant increase in the QTc interval, from 422±27 ms to 449±29 ms (p<0.05). There was no reduction in blood pressure. Thus ketanserin produced a significant prolongation of the QTc interval, in the absence of hypokalemia, in humans.     

胺碘酮治疗室性心律失常对TpTe的影响

目的:观察胺碘酮治疗室性心律失常治疗时程对心电图T波顶点至T波终点的宽度(T-peak to T-end interval,TpTe)的影响。方法: 85例室性心律失常患者,胺碘酮150 mg静脉注射,继以1 mg/kg,持续6 h,后减量至0.5 mg/kg,持续48 h后停用,静脉胺碘酮24 h后,开始同时加用口服胺碘酮,每次0.2 g ,1日3次,1周;每次0.2 g,每日2次,1周; 0.2 g每日1次维持,观察用药后1、3、7、10、14、17、21 d心率、TpPe、QT、TpPe-c、QTc变化。结果: 心律失常控制率达92%（78/85）。治疗有效组自治疗后第1天心率明显减慢,QT间期明显延长（P≤0.01）,14 d时达最大值,后趋于平稳,但未见统计学意义差异。但整个治疗时程中胺碘酮对TpTe、TpTe-c及QTc未见有统计学意义的改变。结论: 胺碘酮治疗室性心律失常不影响TpTe,TpPe独立于心率,不需要心率校正。