Inooka E, Umeda S, Kutsuwa Y, Takahashi T, Sagawa K, Takahashi T, Inooka H
Ohizumi Memorial Hospital, Miyagi Prefecture, Japan.
Clin Cardiol. 1998 Dec;21(12):893-8. doi: 10.1002/clc.4960211207.
Heart failure has been evaluated by several methods, the New York Heart Association (NYHA) classification of heart failure based on symptoms being used most frequently. However, the degree of heart failure assessed by these criteria does not always correlate with cardiac function in daily life.
The aim of the study was to evaluate cardiac function based on the walking pace/heart rate (HR) relationship to assess the effects of enalapril, an angiotensin-converting enzyme inhibitor, in patients with mild to moderate cardiac function.
To evaluate cardiac function objectively, we developed a method using a pedometer to count the steps walked while simultaneously recording HR using a Holter electrocardiograph (ECG). Step-count walk rate (WR) was recorded on the magnetic tape of the Holter apparatus, and both HR and walking pace were calculated automatically by the Holter ECG analysis system. Data were determined every hour, and mean pace and HR were plotted along the x and y axes, respectively. The slope of HR x WR was calculated using the least squares method. The slope and the total number of steps were regarded as indicators of cardiac function and quality of life, respectively. We analyzed 36 subjects, consisting of 8 normal volunteers, 8 patients in New York Heart Association (NYHA) class I. 11 in class II, and 9 in class III chronic mild heart failure, during maximal exercise work load by bicycle ergometer; furthermore, fractional shortening of the left ventricle on echocardiogram was determined in 14 patients with chronic mild heart failure and was compared with the slope of HR x WR. Enalapril was administered at a daily dose of 2.5-10 mg for 1-24 months (mean 6 months) in 60 patients to evaluate the effects of this drug on these parameters.
There was a significant inverse relationship between maximal work load and the HR x WR slope, and also between the fractional shortening and the slope, suggesting that the slope may reflect the severity of cardiac dysfunction. Furthermore, the slope decreased significantly from 1.8 +/- 1.26 before enalapril to 1.0 +/- 0.94 (mean +/- standard deviation) after drug administration, while the total number of steps increased significantly from 4842 +/- 3581 to 7804 +/- 4793.
The slope of the graph relating step count and HR proved to be a good, objective indicator of cardiac function, and enalapril therapy improved this parameter.
心力衰竭已通过多种方法进行评估，其中基于症状的纽约心脏协会（NYHA）心力衰竭分类最为常用。然而，通过这些标准评估的心力衰竭程度在日常生活中并不总是与心功能相关。
本研究的目的是基于步行速度/心率（HR）关系评估心功能，以评估血管紧张素转换酶抑制剂依那普利对轻至中度心功能患者的影响。
为了客观地评估心功能，我们开发了一种方法，使用计步器计算行走步数，同时使用动态心电图仪（ECG）记录心率。计步行走速度（WR）记录在动态心电图仪的磁带上，心率和步行速度均由动态心电图分析系统自动计算。每小时确定一次数据，平均步速和心率分别沿x轴和y轴绘制。使用最小二乘法计算心率×步速的斜率。斜率和总步数分别被视为心功能和生活质量的指标。我们分析了36名受试者，包括8名正常志愿者、8名纽约心脏协会（NYHA）I级患者、11名II级患者和9名III级慢性轻度心力衰竭患者，在自行车测力计最大运动负荷期间进行分析；此外，对14例慢性轻度心力衰竭患者进行超声心动图检查，测定左心室短轴缩短率，并与心率×步速的斜率进行比较。60例患者每天服用依那普利2.5 - 10mg，持续1 - 24个月（平均6个月），以评估该药物对这些参数的影响。
最大工作负荷与心率×步速斜率之间以及短轴缩短率与斜率之间存在显著的负相关，表明斜率可能反映心脏功能障碍的严重程度。此外，斜率从服用依那普利前的1.8±1.26显著下降至服药后的1.0±0.94（平均值±标准差），而总步数从4842±3581显著增加至7804±4793。
步数与心率关系图的斜率被证明是心功能的一个良好、客观的指标，依那普利治疗改善了这一参数。
