Grassi G, Seravalle G, Cattaneo B M, Lanfranchi A, Vailati S, Giannattasio C, Del Bo A, Sala C, Bolla G B, Pozzi M
Cattedra di Medicina Interna, Ospedale S. Gerardo, Monza, Milano, Italy.
Circulation. 1995 Dec 1;92(11):3206-11. doi: 10.1161/01.cir.92.11.3206.
Baroreflex control of sympathetic activity is impaired in severe congestive heart failure (CHF), probably causing the marked sympathetic activation typical of this condition. Little information exists, however, as to whether baroreflex impairment and related sympathetic activation also occur in mild CHF.
We studied 19 patients (age, 57.5 +/- 2.2 years, mean +/- SEM) with CHF in New York Heart Association (NYHA) class III or IV and with a marked reduction in left ventricular ejection fraction (LVEF, 30.1 +/- 1.5% from echocardiography) and 17 age-matched patients with CHF in NYHA class I or II and with an only slightly reduced LVEF (44.9 +/- 3.3%) that never was < 40%. Seventeen age-matched healthy subjects served as control subjects. Primary measurements included beat-to-beat arterial blood pressure (with the Finapres technique), heart rate (from ECG), and postganglionic muscle sympathetic nerve activity (MSNA, from microneurography at the peroneal nerve). Measurements were performed at baseline and during baroreceptor stimulation (intravenous phenylephrine infusion), baroreceptor deactivation (intravenous nitroprusside infusion), and cold-pressor test. Baseline blood pressure was similar in the three groups, whereas heart rate was progressively greater from control subjects to patients with mild and severe CHF, MSNA (bursts per 100 heart beats) increased significantly and markedly from control subjects to patients with mild and severe CHF (47.1 +/- 2.9 versus 64.4 +/- 6.2 and 82.1 +/- 3.4, P < .05 and P < .01, respectively). Heart rate and MSNA were progressively reduced by phenylephrine infusion and progressively increased by nitroprusside infusion. Compared with control subjects, the responses were strikingly impaired in severe CHF patients, but a marked impairment also was seen in mild CHF patients. On average, baroreflex sensitivity in mild CHF patients was reduced by 59.1 +/- 5.5% (MSNA) and 64.8 +/- 4.8% (heart rate). In contrast, reflex responses to the cold-pressor test were similar in the three groups.
These results demonstrate that in mild CHF patients the baroreceptor inhibitor influence on heart rate and MSNA is already markedly impaired. This impairment may be responsible for the early sympathetic activation that occurs in the course of CHF.
在严重充血性心力衰竭（CHF）中，压力反射对交感神经活动的控制受损，这可能是导致该疾病典型的明显交感神经激活的原因。然而，关于压力反射受损及相关交感神经激活是否也发生在轻度CHF中，目前知之甚少。
我们研究了19例纽约心脏协会（NYHA）心功能III或IV级的CHF患者（年龄57.5±2.2岁，均值±标准误），其左心室射血分数（LVEF，经超声心动图检查为30.1±1.5%）显著降低；以及17例年龄匹配的NYHA心功能I或II级的CHF患者，其LVEF仅轻度降低（44.9±3.3%）且从未低于40%。17例年龄匹配的健康受试者作为对照。主要测量指标包括逐搏动脉血压（采用Finapres技术）、心率（来自心电图）以及节后肌肉交感神经活动（MSNA，通过腓总神经的微神经ography记录）。测量在基线时以及压力感受器刺激（静脉注射去氧肾上腺素）、压力感受器失活（静脉注射硝普钠）和冷加压试验期间进行。三组的基线血压相似，而心率从对照组到轻度和重度CHF患者逐渐升高，MSNA（每100次心跳的爆发次数）从对照组到轻度和重度CHF患者显著且明显增加（47.1±2.9对64.4±6.2和82.1±3.4，P<0.05和P<0.01）。静脉注射去氧肾上腺素使心率和MSNA逐渐降低，静脉注射硝普钠使其逐渐升高。与对照组相比，重度CHF患者的反应明显受损，但轻度CHF患者也存在明显受损。平均而言，轻度CHF患者的压力反射敏感性MSNA降低了59.1±5.5%，心率降低了64.8±4.8%。相比之下，三组对冷加压试验的反射反应相似。
这些结果表明，在轻度CHF患者中，压力感受器对心率和MSNA的抑制作用已经明显受损。这种损害可能是CHF病程中早期交感神经激活的原因。
