Jorde Ulrich P, Vittorio Timothy J, Kasper Michael E, Arezzi Emma, Colombo Paolo C, Goldsmith Rochelle L, Ahuja Kartikya, Tseng Chi-Hong, Haas Francois, Hirsh David S
Division of Cardiology, New York Presbyterian Hospital, Columbia University College of Physicians and Surgeons, United States.
Eur J Heart Fail. 2008 Jan;10(1):96-101. doi: 10.1016/j.ejheart.2007.11.006. Epub 2007 Dec 21.
Chronotropic incompetence (CI) is often seen in subjects with chronic congestive heart failure (CHF). The prevalence of CI, its mechanisms and association with beta-blocker use as well as exercise capacity have not been clearly defined.
Cardiopulmonary exercise tolerance testing data for 278 consecutive patients with systolic CHF was analyzed. CI, defined as the inability to reach 80% of maximally predicted heart rate was present in 128 of 278 subjects (46%). The prevalence of CI was highest in those with most impaired exercise capacity (72, 48, and 24% for subjects with a VO(2) of <14.0, 14.0-20.0, and >20.0 ml/kg/min respectively; p=0.001). While subjects with CI had lower peak exercise heart rate (114 vs. 152 bpm), and lower peak VO(2) (15.4 vs. 19.9 ml/kg/min), they were equally likely to be on chronic beta-blocker therapy (74% vs. 71%; p=0.51). Heart rate and norepinephrine (NE) levels were measured during exercise in a separate cohort of 24 subjects with CHF. There was no difference in beta-blocker dose between subjects with and without CI, however, exercise induced NE release and Chronotropic Responsiveness Index, a measure of post-synaptic beta-receptor sensitivity to NE, were lower in subjects with CI (1687+/-911 vs. 2593+/-1451 pg/ml p=0.08; CRI 12.7+/-5.7 vs. 22.1+/-4.7, p=0.002).
CI occurs in >70% of subjects with advanced systolic CHF irrespective of beta-blocker use and is associated with a trend toward impaired NE release, post-synaptic beta-receptor desensitization and reduced exercise capacity.
变时性功能不全（CI）常见于慢性充血性心力衰竭（CHF）患者。CI的患病率、机制、与β受体阻滞剂使用的关联以及与运动能力的关系尚未明确。
分析了278例连续收缩性CHF患者的心肺运动耐力测试数据。CI定义为无法达到最大预测心率的80%，278例受试者中有128例（46%）存在CI。CI的患病率在运动能力受损最严重的患者中最高（VO₂<14.0、14.0 - 20.0和>20.0 ml/kg/min的受试者分别为72%、48%和24%；p = 0.001）。虽然CI患者的运动高峰心率较低（114对152次/分钟），峰值VO₂也较低（15.4对19.9 ml/kg/min），但他们接受慢性β受体阻滞剂治疗的可能性相同（74%对71%；p = 0.51）。在另一组24例CHF患者中，运动期间测量了心率和去甲肾上腺素（NE）水平。有CI和无CI的患者之间β受体阻滞剂剂量无差异，然而，运动诱导的NE释放和变时反应指数（一种衡量突触后β受体对NE敏感性的指标）在CI患者中较低（1687±911对2593±1451 pg/ml，p = 0.08；CRI 12.7±5.7对22.1±4.7，p = 0.002）。
CI发生在超过70%的晚期收缩性CHF患者中，与β受体阻滞剂的使用无关，且与NE释放受损、突触后β受体脱敏趋势以及运动能力降低有关。
