Heart rate dynamics during a treadmill cardiopulmonary exercise test in optimized beta-blocked heart failure patients

BACKGROUND: Calculating the maximum heart rate for age is one method to characterize the maximum effort of an individual. Although this method is commonly used, little is known about heart rate dynamics in optimized beta-blocked heart failure patients. AIM: The aim of this study was to evaluate heart rate dynamics (basal, peak and % heart rate increase) in optimized beta-blocked heart failure patients compared to sedentary, normal individuals (controls) during a treadmill cardiopulmonary exercise test. METHODS: Twenty-five heart failure patients (49+/-11 years, 76% male), with an average LVEF of 30+/-7%, and fourteen controls were included in the study. Patients with atrial fibrillation, a pacemaker or noncardiovascular functional limitations or whose drug therapy was not optimized were excluded. Optimization was considered to be 50 mg/day or more of carvedilol, with a basal heart rate between 50 to 60 bpm that was maintained for 3 months. RESULTS: Basal heart rate was lower in heart failure patients (57+/-3 bpm) compared to controls (89+/-14 bpm; p<0.0001). Similarly, the peak heart rate (% maximum predicted for age) was lower in HF patients (65.4+/-11.1%) compared to controls (98.6+/-2.2; p<0.0001). Maximum respiratory exchange ratio did not differ between the groups (1.2+/-0.5 for controls and 1.15+/-1 for heart failure patients; p=0.42). All controls reached the maximum heart rate for their age, while no patients in the heart failure group reached the maximum. Moreover, the % increase of heart rate from rest to peak exercise between heart failure (48+/-9%) and control (53+/-8%) was not different (p=0.157). CONCLUSION: No patient in the heart failure group reached the maximum heart rate for their age during a treadmill cardiopulmonary exercise test, despite the fact that the percentage increase of heart rate was similar to sedentary normal subjects. A heart rate increase in optimized beta-blocked heart failure patients during cardiopulmonary exercise test over 65% of the maximum age-adjusted value should be considered an effort near the maximum. This information may be useful in rehabilitation programs and ischemic tests, although further studies are required.     

卡维地洛对缺血性心脏病患者心肌收缩力的影响

目的研究卡维地洛对缺血性心脏病心肌收缩力及预后的临床疗效。方法选取缺血性心脏病CHF64例,随机分为倍他乐克组（A组,32例）和卡维地洛组（B组,32例）,A组和B组在常规药物治疗、病情稳定基础上分别加用倍他乐克和卡维地洛,调整剂量稳定,随访3个月后回医院检测各项指标。结果卡维地洛组和倍他乐克组均能有效降低心率,降低血压,减少左心室LVEDD、LVESD,但前者的LVESD较后者低（P〈0．05）,Dd值较后者高（P〈0．05）。倍他乐克组可以明显地减少CO和CI,而卡维地洛组CO和CI变化不明显,两组比较差异有统计学意义（P〈0．05）。两者均可提高每搏输出量和LYEF值,但与治疗后倍他乐克组比较,卡维地洛组有较高的每搏输出量（P〈0．05）和LVEF值（P〈0．01）.结论卡维地洛比倍他乐克的临床疗效好,是一种安全、有效的CHF新药。     

缬沙坦联合卡维地洛治疗原发性高血压左室肥厚

目的观察缬沙坦联合卡维地洛治疗原发性高血压左室肥厚的疗效。方法将86例高血压病患者随机分为两组：治疗组给予缬沙坦80 mg,1次/d;卡维地洛10 g,2次/d。对照组给予非洛地平5 mg,1次/d;卡维地洛10 g,2次/d。共12个月,观察两组用药后血压、左室结构的变化。结果用药后两组收缩压和舒张压均显著降低（P〈0.05）;治疗组室间隔厚度及左室后壁厚度均变薄（P〈0.05）;左室重量指标明显减少（P〈0.05）,对照组各项指标无明显变化（P〉0.05）。结论缬沙坦联合卡维地洛治疗原发性高血压左室肥厚患者可安全有效降压,并同时逆转左室肥厚,改善左室舒张功能。     

卡维地洛对2型糖尿病合并心肌梗死大鼠治疗影响分析

目的:通过血流动力学测定研究卡维地洛对2型糖尿病合并心肌梗死大鼠治疗影响。方法:36只建立2型糖尿病合并左冠状动脉建立急性心肌梗死模型平分为两组,治疗组予卡维地洛分二次灌胃,对照组大鼠则予等量蒸馏水,观察两组血流动力学情况。结果:治疗组的主动脉收缩压(SBP)、舒张压(DBP)和左心室收缩压(LVSP)都明显少于对照组(P<0.05),有统计学意义。结论:卡维地洛能有效抑制2型糖尿病合并心肌梗死大鼠左室舒张末压,改善血流动力学和左心功能,值得在临床上尝试使用。     

卡维地洛治疗充血性心力衰竭的临床疗效

目的 观察卡维地洛治疗充血性心力衰竭的疗效.方法 将124例充血性心力衰竭患者随机分为治疗组和对照组,在常规强心、利尿、扩血管药物治疗基础上,治疗组加用卡维地洛治疗24周,观察两组治疗效果.结果 卡维地洛对改善充血性心力衰竭患者临床症状、体征及心脏收缩功能、舒张功能均有显著效果.结论 在常规抗心力衰竭治疗的基础上加用卡维地洛能明显改善患者的心功能,提高患者的生存率.     

螺内酯联合卡维地洛治疗难治性高血压的疗效观察

目的观察螺内酯联合卡维地洛治疗难治性高血压的临床效果。方法62例难治性高血压患者,随机分成治疗组和对照组,各31例,治疗组给予卡维地洛12．5-25mg／d,螺内酯20～40mg／d,对照组给予卡维地洛25mg,1次／d。结果治疗组有效率为93．5％,对照组有效率为67．7％（P〈0．05）。结论卡维地洛联合螺内酯治疗难治性高血压疗效好,值得临床推广。     

卡维地洛对肾功能不全高血压患者的疗效观察

目的对卡维地洛(金络)治疗肾功能不全患者高血压的疗效及安全性进行临床评价。方法肾功能不全患者并有高血压患者76例,用卡维地洛治疗6周,观察治疗前后血压、心率的变化。结果治疗后血压(SBP、DBP)下降,与治疗前比较差异具有统计学意义(P<0.05)。心率(HR)治疗前后差异无统计学意义(P>0.05)。结论卡维地洛对肾功能不全患者高血压疗效确切,不影响心率,安全性良好。     

不同剂量卡维地洛对急性心肌梗死大鼠左室重构及血流动力学的影响

目的比较不同剂量卡维地洛对大鼠急性心肌梗死(AMI)后左室重构及血流动力学的影响。方法选取AMI术后存活的SD大鼠随机分为AMI组、卡维地洛大剂量组[30mg/(kg.d)]、卡维地洛小剂量组[2mg/(kg.d)]。给药6周后用导管法行血流动力学测定和心脏组织病理分析。另设正常对照组及假手术组。结果与假手术组比,AMI组左室舒张末压(LVEDP)、各心室重量均显著增加,左室内压最大收缩和舒张速率(±dp/dtmax)显著降低。与AMI组比,大、小剂量卡维地洛组的LVEDP、心室重量均显著降低,±dp/dtmax显著升高。与卡维地洛大剂量组比,小剂量组LVEDP及左心室重量下降更明显。结论卡维地洛疗能有效抑制大鼠AMI左室重构并改善血流动力学,且小剂量卡维地洛组疗效优于大剂量组。     

小剂量双氢克尿噻与卡维地洛联合治疗轻中度高血压病35例

目的　观察小剂量双氢克尿噻与卡维地洛联合治疗轻中度原发性高血压的疗效和安全性。方法　随机单盲平行对照试验 ,符合条件的 6 5例轻中度原发性高血压患者随机分为 2组 :小剂量双氢克尿噻与卡维地洛联合治疗组 35例 ,口服卡维地洛 10mg ,2次 /d ,同时加用双氢克尿噻 12 5mg/d。卡维地洛组 30例 ,口服卡维地洛 10mg ,2次 /d。疗程 8周。结果　 (1)治疗 8周末 ,联合组降压总有效率 94 2 8% ,卡维地洛组总有效率 70 0 % ,2组比较有统计学差异 ;(2 )不良反应的发生率相似 ,常见的不良反应为头晕、皮疹、丙氨酸转氨酶轻度升高 ,但较轻。结论　小剂量双氢克尿噻与卡维地洛联合治疗轻中度原发性高血压安全有效。     

卡维地洛的降压作用及对胰岛素抵抗的影响

目的　探讨卡维地洛的降压作用及对胰岛素抵抗的影响。方法　对 5 8例高血压病Ⅰ期或Ⅱ期患者服用卡维地洛 10mg ,2次 /d ,疗程为 6周 ;治疗前后观察血压及血糖、血脂和胰岛素敏感性的变化。结果　卡维地洛能有效控制高血压患者的收缩压及舒张压 (P <0 .0 5 ) ,治疗前后血糖、血脂无显著性改变 ,胰岛素敏感性增加 (P <0 .0 5 )。结论　卡维地洛能有效地降低收缩压和舒张压 ,能显著改善胰岛素抵抗。