1461名老年患者血压波动与颈动脉斑块形成关系的研究

目的：除了血压水平的高低以外,血压波动也是造成人体靶器官损伤的独立危险因素。本研究以老年男性人群为研究对象,观察血压波动（BPV）与颈动脉斑块形成的关联性。方法：本研究选用1461名患有动脉硬化的老年男性患者为研究对象,将入选对象分为：非颈动脉斑块组和颈动脉斑块组,根据24小时动态血压测定（ABPM）中收缩压（SBP）、舒张N（DBP）的数据,用”个体血压波动法”测定每个患者的血压波动,分析探讨血压波动与颈动脉斑块形成之间的关联性。结果：①颈动脉斑块的形成与24小时收缩期血压波动（SBPV）密切相关（8-3±2．1mmHgVS7．9士2．0mmHg;P〈0．001）,其中与白昼（6：00．22：00）SBPV有关（8．1±2．1mmHgVS7．7土2．1mmHg：P〈0．001）,而与夜间（22：00-6：00）SBPV关系不明显（8,9±3．8mmHgVS8,6±3．7mmHg;P〉0．05）。②与24小时舒张期血压波动（DBPV）有关（5．6±1．4mmHgVS5．4±1．4mmHg;P〈0．05）,其中与白昼（6：00．22：00）舒张期血压波动有关（5．4±1．4mmHgVS5．2士1．4mmHg;P〈0．05）,而与夜间舒张期血压波动无关（6．2±2．7mmHgVS5．9±2．5mmHg;P〉0．05）。结论：在老年男性人群中,颈动脉斑块的形成与收缩期和舒张期血压波动均有关系,主要表现在白昼血压波动。     

基于遥测技术对巴马小型猪部分生理指标的观测

目的：应用遥测技术观察巴马小型猪在清醒自由状态下心电、血压、呼吸、活动等指标昼夜波动变化。方法取雄性6月龄巴马小型猪6只,行浅表股动脉VAP血管通路植入手术,恢复7 d后,用EMAK遥测系统进行24 h连续清醒自由状态下心电、血压、呼吸、活动指标监测,并用EMAK分析软件对上述指标进行分析。结果6月龄巴马小型猪心电、血压、呼吸、活动都有昼夜节律变化,白昼心率显著高于黑夜心率（ P ＜0.01）,且白昼PR间期、QRS间期与QT间期均显著低于黑夜（P ＜0.05,P ＜0.01）,白昼平均心率为76.22次/分,黑夜平均心率为67.03次/分,白昼平均PR间期、QRS间期和QT间期分别为109.97 ms、42.72 ms、380.37 ms,黑夜平均PR间期、QRS间期和QT间期为112.32 ms、44.01 ms、389.24 ms。巴马小型猪白昼收缩压、舒张压、平均压都显著高于夜间（ P ＜0.01）,白昼平均收缩压、舒张压、平均压分别为129.57 mmHg、96.75 mmHg、111.73 mmHg,夜间平均收缩压、舒张压、平均压分别为122.81 mmHg、92.65 mmHg、106.19 mmHg,且黑夜收缩压、舒张压、平均压下降率分别为19.89％、19.05％、19.35％。另外,巴马小型猪在白昼的活动情况与呼吸频率都要显著高于夜间（ P ＜0.01）。结论利用遥测技术可以对清醒自由状态下巴马小型猪心电、血压、呼吸、活动等进行连续监测,能真实的反应小型猪在24 h内上述生理指标的变化规律,为巴马小型猪在药理毒理研究中的应用提供参考。     

硝酸甘油复合艾司洛尔应用对推管减压术控制性降压的临床观察

目的:比较椎管减压椎弓根钉内固定手术中硝酸甘油(NTG)-艾司洛尔控制性降压与单纯NTG控制性降压对血流动力学的影响。方法:40例在持续异丙酚 瑞芬太尼、异氟醚静吸复合麻醉下实施椎管减压椎弓根钉内固定手术患者,随机分为两组,Ⅰ组采用NTG艾司洛尔,Ⅱ组单纯采用NTG控制性降压至平均压65-70mmHg,持续30min。监测降压前后及降压期间血氧饱和度及心率、血压、动脉氧分压变化。结果:在静吸复合麻醉下Ⅱ组患者的降压消耗时间和复压所需时间均高于Ⅰ组患者,同时维持剂量也大于Ⅰ组患者,且Ⅰ组的血压、心率在降压前后各个时期较Ⅱ组稳定。但两种控制性降压方案时手术病人的血气变化影响情况是基本一致的。结论:NTG-艾司洛尔用于异丙酚 瑞芬太尼、异氟醚复合麻醉在椎管减压椎弓根钉内固定术中的控制性降压比单纯NTG降压对心率、血压的影响小,且更迅速,更平稳,用量少,可控性好。艾司洛尔50μg·kg-1·min-1,可减慢心率,防止硝酸甘油NTG停药后反跳性高血压。所以联合使用NTG、艾司洛尔,优于单纯使用NTG。     

小型猪生物可降解支架置入术中不同麻醉方法的研究

目的比较两种不同麻醉方法对小型猪的麻醉效果。方法将12头小型猪随机分成两组,每组6头,一组是戊巴比妥钠复合氯胺酮静脉麻醉（Ⅰ组）,另一组是丙泊酚复合氯胺酮静脉麻醉（Ⅱ组）。麻醉后对动物实施心脏生物可降解支架置入术,观察动物麻醉起效时间、苏醒时间、麻醉效果、呼吸频率（RR）、心率（HR）、血氧饱和度（SpO2）及术后苏醒情况。结果两种方法麻醉后,动物分别在7.6±2.4 min（Ⅰ组）、2.4±1.4 min（Ⅱ组）进入麻醉状态（P〈0.05）。术后苏醒时间分别为30.8±8.8 min（Ⅰ组）、16.5±2.8min（Ⅱ组）（P〈0.05）,Ⅱ组动物比Ⅰ组动物苏醒平稳（P〈0.05）。两组心率及呼吸频率变化无明显差别,而氧饱和度在第10 min（Ⅰ组87%,Ⅱ组92%）和30 min（Ⅰ组94%,Ⅱ组89%）由于追加麻醉药后,两组值差异较大,但很快恢复正常。Ⅱ组麻醉效果较Ⅰ组麻醉效果好。结论两种麻醉方法均能达到良好的麻醉效果,丙泊酚复合氯胺酮麻醉较戊巴比妥钠复合氯胺酮麻醉的效果强且术后苏醒快,是一种比较理想的麻醉方法。     

全身麻醉和硬膜外麻醉对老年骨科手术患者术后短期认知功能的影响

目的：探讨全身麻醉和硬膜外麻醉对老年骨科手术患者术后短期认知功能的影响。方法：按随机数字方式将2010年3月至2013年5月收治的全麻骨科手术老年患者64例分为两组,全身麻醉组（32例）给予全身麻醉进行手术,硬膜外麻醉组（32例）给予硬膜外麻醉进行手术,对比分析两组观察麻醉前后动脉血压与心率,睁眼、拔管及应答时间,术后6、12、24、72h的MMSE评分差异,并统计术后POCD的发生情况。结果：两组的年龄、体重、麻醉时间、受教育时间、出血量等一般临床资料均无明显差异（P〉0．05）;两组麻醉前、麻醉后术前、手术0．5h及手术结束时动脉血压和心率差异均不显著（P〉0．05）;全身麻醉组的睁眼、拔管及应答时间分别为（30．3±10．5）min、（30.3±7．8）min、（33．2±9．6）min;膜外麻醉组的睁眼、拔管及应答时间分别为（30．6±11．6）min、（30．1±6．6）min、（34.3±8．5）min,两组差异不显著（P〉0．05）;全身麻醉组麻醉前MMSE评分为29．2±1．5,而膜外麻醉组麻醉前MMSE评分为29．1±1．0,差异不显著（P〉0．05）;麻醉后,两组的MMSE评分均出现先减少后恢复的变化,膜外麻醉组麻醉后24h时的MMSE评分28．7±1．0明显高于全身麻醉组的27．3±0．8（t=-5．491,P=0．000〈0．05）;全身麻醉组麻醉后6h和12hPOCD的发生率均明显高于膜外麻醉组的（P〈0．05）,而两组在麻醉后24h开始POCD的发生率无明显差异（P〉0．05）。结论：全身麻醉对老年骨科手术患者术后短期认知功能的影响明显大于硬膜外麻醉。     

大鼠肺鳞癌模型两种麻醉方法的比较

目的探讨不同麻醉方法建立大鼠肺鳞癌模型的差异。方法体重180～220g Wistar大鼠,依不同麻醉方法分为2组：实验Ⅰ组（110只）用0．3％戊巴比妥钠麻醉;实验Ⅱ组（80只）基础麻醉用盐酸氯胺酮44mg／kg,然后乙醚吸入麻醉。两组均采用额镜直视法,灌注3-甲基胆蒽（MCA）、二乙基亚硝胺（DEN）与普通碘油混悬液于大鼠左下叶支气管。结果麻醉显效时间和维持时间分别为：Ⅰ组,（23．50±1．98）min,（246．56±15．46）min,Ⅱ组,（3．05±0．45）min,（12．47±1．35）min,两组间有显著性差异（P〈0．01）;灌注成功率、存活率、诱癌率分别为：Ⅰ组94．55％,48．08％,90．00％,Ⅱ组93．75％,90．67％,92．65％,两组成功率、诱癌率差异无显著性（P〉0．05）,存活率有显著差异（P〈0．01）。分别于不同时间处死大鼠,2组基本病理过程相同。结论戊巴比妥钠麻醉剂量易控制,以小剂量灌注雄性大鼠为佳;盐酸氯胺酮与乙醚复合麻醉较难控制,但速度快,实用性强。     

应用植入式遥测技术观察自发性高血压大鼠血压的昼夜波动

目的应用植入式遥测技术观察自发性高血压大鼠在清醒无束缚状态下血压昼夜波动变化。方法取8只SPF级3月龄雄性SHR大鼠,进行C50-PXT植入子植入手术,恢复7 d后,用遥测系统进行24 h连续清醒无束缚的血压监测,并用EMKA分析软件对动态血压心率均值、24 h血压心率趋势等指标进行分析。结果 3月龄的SHR大鼠血压和心律呈昼夜节律性变化,白昼阶段血压明显低于夜间阶段(P<0.01),血压在1∶30～2∶30和20∶30～21∶30时出现两个高峰期,14∶00～14∶30时出现一低谷期。其中夜间阶段平均收缩压为166.02 mmHg,两个收缩压峰值分别为172.13 mmHg和171.38 mmHg;白昼平均收缩压是162.73 mmHg,收缩压谷底值为155.73mmHg。而心率两个高峰期出现在1∶30～2∶00和20∶00～21∶00,高峰值分别为375.00次/分和373.26次/分;心率低谷出现在11∶00左右,谷底值为310.91次/分,白昼和夜间的平均心率分别为328.85次/分和346.05次/分。结论 3月龄的SHR大鼠血压和心律呈昼夜节律性变化,血压和心率在夜间出现两个高峰,白昼出现一个低谷,且夜间的平均血压和心率要高于白昼,SHR大鼠的血压和心率的节律变化与其活动有关。植入式遥测技术可准确反映SHR大鼠血压昼夜的节律性变化,有助于正确评价抗高血压药物的作用和高血压的生理机制研究。     

戊巴比妥钠联用速眠新Ⅱ对西藏小型猪麻醉效果观察

目的观察联合应用速眠新Ⅱ和戊巴比妥钠对西藏小型猪的麻醉效果。方法采用速眠新Ⅱ（0.1mL/kg）肌内注射和3%戊巴比妥钠生理盐水溶液（0.2 mL/kg）静脉注射联合麻醉方法对15头行胚胎移植术的西藏小型猪进行麻醉,观察动物麻醉维持时间、镇痛效果、呼吸频率和心率变化及术后苏醒情况。结果80%（12头/15头）西藏小型猪初始量麻醉状态维持45 min以上,20%（3头/15头）西藏小型猪手术过程中追加麻醉。麻醉期间肌肉松弛效果好,动物呼吸和心率平稳。手术过程中西藏小型猪呼吸频率为（12-22）次/min,心率为（63-85）次/min,麻醉过程中未出现麻醉死亡,术后苏醒时间为30-60 min。结论速眠新和戊巴比妥钠混合麻醉效果好,且麻醉剂量较以往大幅减少,术后苏醒快。戊巴比妥钠联用速眠新复合麻醉对西藏小型猪是一种较理想的麻醉方法,且动物麻醉安全性高。     

耳聋左慈丸对水杨酸耳鸣模型大鼠听中枢神经元放电的影响

目的：在慢性水杨酸（SA）耳鸣模型上,观察耳聋左慈丸对大鼠下丘外侧核（ICx）和次听皮层（AⅡ）放电的影响,探讨耳聋左慈丸防治耳鸣的神经机制。方法：健康SD大鼠30只,随机平均分成三组：正常对照组、慢性SA耳鸣模型组和耳聋左慈丸防治组。采用立体定位技术及细胞外记录方法,观察不同组别大鼠ICx和AⅡ自发放电活动,用平均自发放电率和放电间隔直方图为观察指标。结果：①慢性SA耳呜模型组与正常对照组大鼠相比,ICx神经单元平均自发放电率增高（4．57±0．54Hz vs 3．14±0．40Hz,P〈0．05）,进一步从放电间隔直方图来分析,短间隔自发放电脉冲数占总放电数比例较高（0-40ms为58％ vs 40％;0～4ms为9％vs5％）。慢性SA耳鸣模型组AⅡ神经单元平均自发放电率与正常对照组大鼠相比有增高趋势（3．844±0．36Hzvs3．17±0．34Hz）,短间隔自发放电脉冲数占总放电数比例较正常对照组增高（0-22ms：31％VS 16％;0—8ms：19％vs16％）。②耳聋左慈丸防治组大鼠与慢性SA耳鸣模型组相比,ICx和AⅡ神经单元平均自发放电率显著降低（ICx：2．41±0．21Hzvs4．57±0．54Hz,P〈0．01;AⅡ：2．24±0．24Hz vs 4．57±0．54Hz,P〈0．01）,短间隔自发放电脉冲数占总放电数比例较低（ICx 0～40 ms：50％vs58％;0-4ms：4％vs9％;AⅡ0～22ms：24％VS 31％;0—8 ms;11％ vs 19％）。结论：慢性SA耳鸣模型动物ICx和AⅡ神经元自发放电活动增加,短间隔放电脉冲数比例较正常对照组增加,耳聋左慈丸能减弱这种变化。     

两种用于小型猪胰肾联合移植实验麻醉方法的比较

目的比较静脉复合吸入全麻和静脉全麻两种方法用于小型猪胰肾联合移植实验中的麻醉效果,探讨简单、安全、易行的麻醉方法。方法A、B两组健康贵州小香猪,每组6只,基础麻醉后气管插管,A组：持续吸入异氟醚维持麻醉,根据手术要求间断注入万可松和芬太尼;B组：持续注入氯胺酮,间断静脉注射万可松和芬太尼维持麻醉。观察麻醉持续时间,镇痛和肌松药量,术后拔管和完全清醒时间,监测麻醉过程中血压、心率、脉搏氧的变化。结果A组术中麻醉效果好,血压、心率和脉搏氧稳定,与B组有显著差异（P〈0.05）;B组麻醉效果较差,肌松用药量明显增多,术后完全清醒时间长于A组（P〈0.05）。结论气管插管后静吸复合的麻醉方法是用于贵州小型猪实验安全、合适的麻醉方法。     

Cardiovascular regulation during long-duration spaceflights to the International Space Station

Early evidence from long-duration flights indicates general cardiovascular deconditioning, including reduced arterial baroreflex gain. The current study investigated the spontaneous baroreflex and markers of cardiovascular control in six male astronauts living for 2-6 mo on the International Space Station. Measurements were made from the finger arterial pressure waves during spontaneous breathing (SB) in the supine posture pre- and postflight and during SB and paced breathing (PB, 0.1 Hz) in a seated posture pre- and postflight, as well as early and late in the missions. There were no changes in preflight measurements of heart rate (HR), blood pressure (BP), or spontaneous baroreflex compared with in-flight measurements. There were, however, increases in the estimate of left ventricular ejection time index and a late in-flight increase in cardiac output (CO). The high-frequency component of RR interval spectral power, arterial pulse pressure, and stroke volume were reduced in-flight. Postflight there was a small increase compared with preflight in HR (60.0 ± 9.4 vs. 54.9 ± 9.6 beats/min in the seated posture, P < 0.05) and CO (5.6 ± 0.8 vs. 5.0 ± 1.0 l/min, P < 0.01). Arterial baroreflex response slope was not changed during spaceflight, while a 34% reduction from preflight in baroreflex slope during postflight PB was significant (7.1 ± 2.4 vs. 13.4 ± 6.8 ms/mmHg), but a smaller average reduction (25%) during SB (8.0 ± 2.1 vs. 13.6 ± 7.4 ms/mmHg) was not significant. Overall, these data show no change in markers of cardiovascular stability during long-duration spaceflight and only relatively small changes postflight at rest in the seated position. The current program routine of countermeasures on the International Space Station provided sufficient stimulus to maintain cardiovascular stability under resting conditions during long-duration spaceflight.     

小鼠经颈外静脉右心导管法测定心室压力的实验方法研究

目的：研究可行性高的测定小鼠右心室压力的实验方法。方法：通过自制PE导管,连接powerlab多通道生物信号记录系统,经颈外静脉插管,右心导管法测定小鼠右心室压力,并借以研究肺动脉压力变化。结果：用此方法对51只小鼠进行插管,46例成功进入心室并测压,成功率90．2％。其中33只正常小鼠中,成功30例,测得压力值：收缩压（23．4±5．7）mmHg,舒张压（3．7±2．6）mmHg,平均压（12．0±3．7）mmHg;18只肺动脉高压模型小鼠中,成功16例,测得压力值：收缩压：（32．2±2．8）mmng,舒张压（3．8±2．0）mmng,平均压（14．94±2．3）mmHg。共失败5例,经解剖发现2例进入下腔静脉,2例穿破心耳,1例穿破腋静脉进入胸壁。结论：使用自制的PE导管经颈外静脉插管,右心导管法测定右心室压具有成功率高、数据更准确、操作省时、方法易普及的优点。是一种较好的对小鼠进行右心室压力测定的方法。     

Subtotal nephrectomy plus coronary ligation leads to more pronounced damage in both organs than either nephrectomy or coronary ligation

Coexistence of chronic kidney disease (CKD) and heart failure (HF) in humans is associated with poor outcome. We hypothesized that preexistent CKD worsens cardiac outcome after myocardial infarction, and conversely that ensuing HF worsens progression of CKD. Subtotally nephrectomized (SNX) or sham-operated (CON) rats were subjected to coronary ligation (CL) or sham surgery in week 9 to realize four groups: CON, SNX, CON + CL, and SNX + CL. Blood pressure and renal function were measured in weeks 8, 11, 13, and 15. In week 16, cardiac hemodynamics and end-organ damage were assessed. Blood pressure was significantly lower in SNX + CL vs. SNX. Despite this, glomerulosclerosis was more severe in SNX + CL vs. SNX. Two weeks after CL, SNX + CL had more cardiac dilatation compared with CON + CL (end-diastolic volume index: 0.28 ± 0.04 vs. 0.19 ± 0.03 ml/100 g body wt; mean ± SD, P < 0.001), although infarct size was similar. During follow-up in SNX + CL, ejection fraction declined. Mortality was only observed in SNX + CL (2 out of 9). In SNX + CL, end-diastolic pressure (18 ± 4 mmHg) and tau (29 ± 9 ms), the time constant of active relaxation, were significantly higher compared with SNX (13 ± 3 mmHg, 20 ± 4 ms; P < 0.01) and CON + CL (11 ± 5 mmHg, 17 ± 2 ms; P < 0.01). The diameter of small arterioles in the myocardium was significantly decreased in SNX + CL vs. CON + CL (P < 0.01). Urinary excretion of NO metabolites was significantly lower in SNX + CL compared with both CL and SNX. This study demonstrates the existence of more heart and more kidney damage in a new model of combined CKD and HF than in the individual models. Such enhanced damage appears to be separate from systemic hemodynamic changes. Reduced nitric oxide availability may have played a role in both worsened glomerulosclerosis and cardiac diastolic function and appears to be a connector in the cardiorenal syndrome.     

Lower limb-localized vascular phenomena explain initial orthostatic hypotension upon standing from squat

The cause(s) of initial orthostatic hypotension (transient fall in blood pressure within 15 s upon active rising) have not been established. We tested the hypothesis that this hypotension is due to local vascular phenomena in contracting leg muscles from the brief effort of standing up. Seventeen young healthy subjects (2 male and 15 female, 22.5 ± 1.0 years) performed an active rise from resting squat after a 10-s squat, a 1-min squat, or a 5-min squat. Beat-by-beat arterial blood pressure, cardiac output, heart rate, and stroke volume (Finometer finger photoplethysmography) and right common femoral artery blood flow (Doppler and Echo ultrasound) were recorded. Data are means ± SE. Quiet standing before squat represented baseline. Peak increases in lower limb and total vascular conductance (ml·min(-1)·mmHg(-1)) upon standing were not different within squat conditions (10-s squat, 50.0 ± 12.4 vs. 44.3 ± 5.0; 1-min squat, 54.7 ± 9.2 vs. 50.5 ± 4.5; 5-min squat, 67.4 ± 13.7 vs. 58.8 ± 3.9; all P > 0.574). Mean arterial blood pressure (in mmHg) fell to a nadir well below standing baseline in all conditions despite increases in cardiac output. The hypotension predicted by the increase in leg vascular conductance accounted for this hypotension [observed vs. predicted (in mmHg): 10-s squat, -17.1 ± 2.1 vs. -18.3 ± 5.5; 1-min squat, -22.0 ± 3.8 vs. -25.3 ± 4.9; 5-min squat, -28.3 ± 4.0 vs. -29.2 ± 6.7]. We conclude that rapid contraction induced dilation in leg muscles with the effort of standing, along with a minor potential contribution of elevated lower limb arterio-venous pressure gradient, outstrips compensatory cardiac output responses and is the cause of initial orthostatic hypotension upon standing from squat.     

苯磺酸左旋氨氯地平在治疗老年轻中度高血压中的作用

目的：观察探讨苯磺酸左旋氨氯地平治疗老年轻中度高血压患者的临床疗效和安全性。方法：160例老年轻中度高血压患者随机分为研究组与对照组,研究组给予苯磺酸左旋氨氯地平;对照组给予苯磺酸氨氯地平,治疗过程中进行24h血压监测,总治疗8周为一疗程。结果：研究组4周末和8周末的总有效率分别为78.75%和96.25%,显著高于对照组的53.75%和86.25%,差异有统计学意义（P〈0.05）。治疗前后两组的舒张压和收缩压均有明显降低,其中研究组收缩压平均下降（29.0±3.2）mmHg,舒张压平均下降（15.3±2.3）mmHg,对照组则分别下降（18.5±2.8）mmHg和（9.0±2.5）mmHg,差异具有统计学意义（P〈0.05）。治疗8周末的24h、白昼和夜间的收缩压和舒张压均有明显降低,差异有统计学意义（P〈0.05）,但治疗组下降更明显,与对照组比较差异有统计学意义（P〈0.05）。治疗后两组的脉压均有明显降低,差异具有统计学意义（P〈0.05）,但研究组下降更明显。结论：苯磺酸左旋氨氯地平治疗老年轻中度高血压临床疗效好,不良反应少,且对心脏具有保护功能。     

Diastolic dysfunction and intraventricular dyssynchrony are restored by low intensity exercise training in obese men

The aim of this study was to evaluate the impact of a low-intensity training program on subclinical cardiac dysfunction and on dyssynchrony in moderately obese middle aged men. Ten obese and 14 age-matched normal-weight men (BMI: 33.6 ± 1.0 and 24.2 ± 0.5 kg/m(2)) were included. Obese men participated in an 8-week low-intensity training program without concomitant diet. Cardiac function and myocardial synchrony were assessed by echocardiography with tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE). At baseline, obese men showed diastolic dysfunction on standard echocardiography, lower strain values (systolic strain: 15.9 ± 0.9 vs. 18.8 ± 0.3%, diastolic strain rate: 0.81 ± 0.09 vs. 1.05 ± 0.06 s(-1)), and significant intraventricular dyssynchrony (systolic: 13.3 ± 2.1 vs. 5.4 ± 2.1 ms, diastolic: 17.4 ± 3.2 vs. 9.1 ± 2.1 ms) (P < 0.05 vs. controls for all variables). Training improved aerobic fitness, decreased systolic blood pressure and heart rate, and reduced fat mass without weight loss. Diastolic function, strain values (systolic strain: 17.4 ± 0.9%, diastolic strain rate: 0.96 ± 0.12 s(-1)) and intraventricular dyssynchrony (systolic: 3.3 ± 1.7 ms, diastolic: 5.5 ± 3.4 ms) improved significantly after training (P < 0.05 vs. baseline values for all variables), reaching levels similar to those of normal-weight men. In conclusion, in obese men, a short and easy-to-perform low intensity training program restored diastolic function and cardiac synchrony and improved body composition without weight loss.     

Can we detect the development of baroreflex sensitivity in humans between 11 and 20 years of age?

The aim of the study was to determine changes of baroreflex sensitivity in humans between 11 and 20 years of age. Continuous 5 min blood pressure recordings using a Finapres were taken in 415 healthy subjects while in a sitting, resting position (breathing at a frequency of 0.33 Hz). Beat-by-beat values of interbeat intervals (IBI) or heart rate, and systolic and diastolic blood pressures were measured. Baroreflex sensitivity in ms/mmHg (BRS) and in mHz/mmHg (BRSf) was determined at an average frequency of 0.1 Hz by spectral analysis. BRS did not correlate with age, but BRSf significantly decreased with age (p < 0.001). BRS correlated with mean IBI (p < 0.001) in all subjects and also in the particular subgroups, but BRSf was IBI-independent. Results of multiregression equations were BRS = 1.37 - 0.56 x age (years) + 0.02 x IBI (ms) (p < 0.001 for BRS vs. age and for BRS vs. IBI); BRSf = 34.74 - 0.97 x age (years) - 0.001 x IBI (ms) (p < 0.001 only for BRS vs. age), where age was measured in years and IBI was measured in ms. The limits of BRS were estimated for the total group: 5th percentile, 3.9; 50th percentile, 9.1; and 95th percentile, 18.7 ms/mmHg; and limits for BRSf were 5th percentile, 8.5; 50th percentile, 16.4; and 95th percentile, 33.6 mHz/mmHg. We conclude that IBI-dependent BRS was unchanged in the particular age groups, but the standardization of BRS on IBI decreased with age. BRSf was IBI-independent and better reflected the development of the BRS.     

Exercise training improves aortic depressor nerve sensitivity in rats with ischemia-induced heart failure

Exercise training improves arterial baroreflex control in heart failure (HF) rabbits. However, the mechanisms involved in the amelioration of baroreflex control are unknown. We tested the hypothesis that exercise training would increase the afferent aortic depressor nerve activity (AODN) sensitivity in ischemic-induced HF rats. Twenty ischemic-induced HF rats were divided into trained (n = 11) and untrained (n = 9) groups. Nine normal control rats were also studied. Power spectral analysis of pulse interval, systolic blood pressure, renal sympathetic nerve activity (RSNA), and AODN were analyzed by means of autoregressive parametric spectral and cross-spectral algorithms. Spontaneous baroreflex sensitivity of heart rate (HR) and RSNA were analyzed during spontaneous variation of systolic blood pressure. Left ventricular end-diastolic pressure was higher in HF rats compared with that in the normal control group (P = 0.0001). Trained HF rats had a peak oxygen uptake higher than untrained rats and similar to normal controls (P = 0.01). Trained HF rats had lower low-frequency [1.8 +/- 0.2 vs. 14.6 +/- 3 normalized units (nu), P = 0.0003] and higher high-frequency (97.9 +/- 0.2 vs. 85.0 +/- 3 nu, P = 0.0005) components of pulse interval than untrained rats. Trained HF rats had higher spontaneous baroreceptor sensitivity of HR (1.19 +/- 0.2 vs. 0.51 +/- 0.1 ms/mmHg, P = 0.003) and RSNA [2.69 +/- 0.4 vs. 1.29 +/- 0.3 arbitrary units (au)/mmHg, P = 0.04] than untrained rats. In HF rats, exercise training increased spontaneous AODN sensitivity toward normal levels (trained HF rats, 1,791 +/- 215; untrained HF rats, 1,150 +/- 158; and normal control rats, 2,064 +/- 327 au/mmHg, P = 0.05). In conclusion, exercise training improves AODN sensitivity in HF rats.