Yamanaka Takashi, Onishi Katsuya, Tanabe Masaki, Dohi Kaoru, Funabiki-Yamanaka Kaoru, Fujimoto Naoki, Kurita Tairo, Tanigawa Takashi, Kitamura Tetsuya, Ito Masaaki, Nobori Tsutomu, Nakano Takeshi
The First Department of Internal Medicine, Mie University School of Medicine, Tsu, Japan.
Am Heart J. 2006 Nov;152(5):966.e1-7. doi: 10.1016/j.ahj.2006.06.023.
Chronotropic effects on myocardial contractility (the positive force-frequency relation) and relaxation (the positive relaxation-frequency relation) are impaired in patients with congestive heart failure and depressed left ventricular (LV) ejection fraction (systolic heart failure [SHF]). However, the force- and relaxation-frequency relation and LV-arterial coupling in patients with diastolic heart failure (DHF) has not been fully investigated.
To examine inotropic and lusitropic responsiveness to atrial pacing, LV pressure-volume relations were measured using a conductance catheter and microtip manometer in patients with DHF (n = 18) and SHF (n = 11). In patients with SHF, an increase in heart rate by 40 beat/min did not affect LV end-systolic elastance (Ees), which reflects LV contractility, or the time constant of LV relaxation. By contrast, in patients with DHF, an increase in heart rate by 40 beat/min significantly enhanced Ees (2.1 vs 2.9 mm Hg/mL, P < .05) but not the time constant. Furthermore, LV-arterial coupling, quantified as Ees/arterial elastance, was impaired during pacing in patients with DHF (1.1 vs 0.8, P < .05) as well as SHF.
In patients with DHF, the force-frequency relation was preserved, but the relaxation-frequency relation was impaired. Furthermore, LV-arterial coupling was impaired as heart rate increased, which may be related to the impaired LV function. These results suggest that the impaired relaxation-frequency relation and exacerbated LV-arterial coupling during tachycardia may be an important therapeutic target in patients with DHF.
充血性心力衰竭和左心室（LV）射血分数降低（收缩性心力衰竭[SHF]）的患者，变时性对心肌收缩力（正向力-频率关系）和舒张功能（正向舒张-频率关系）的影响受损。然而，舒张性心力衰竭（DHF）患者的力-频率关系、舒张-频率关系以及左心室-动脉耦合尚未得到充分研究。
为了研究心房起搏时的变力性和变时性反应，我们使用电导导管和微尖端压力计测量了DHF患者（n = 18）和SHF患者（n = 11）的左心室压力-容积关系。在SHF患者中，心率增加40次/分钟并不影响反映左心室收缩力的左心室收缩末期弹性（Ees），也不影响左心室舒张时间常数。相比之下，在DHF患者中，心率增加40次/分钟显著增强了Ees（2.1 vs 2.9 mmHg/mL，P < 0.05），但不影响时间常数。此外，以Ees/动脉弹性来量化的左心室-动脉耦合，在DHF患者（1.1 vs 0.8，P < 0.05）以及SHF患者起搏期间均受损。
在DHF患者中，力-频率关系得以保留，但舒张-频率关系受损。此外，随着心率增加，左心室-动脉耦合受损，这可能与左心室功能受损有关。这些结果表明，心动过速期间舒张-频率关系受损和左心室-动脉耦合加剧可能是DHF患者的一个重要治疗靶点。
