Azeem Hamdy Abd El, Khalek El Shazly Abd El, Akabawy Hazem El
Cardiology Department, Faculty of Medicine, Al Azhar University, Egypt.
J Saudi Heart Assoc. 2011 Apr;23(2):67-73. doi: 10.1016/j.jsha.2010.12.001. Epub 2011 Jan 1.
There is a strong correlation between heart rate and myocardial ischemia, cardiovascular diseases, and life expectancy in general; however, heart rate has been neglected as an important risk factor as well as a therapeutic opportunity.
To investigate the effect of aggressive heart rate reduction (50 ⩽ HR ⩽ 60 bpm) on anti-ischemic and anti-anginal efficacy, left ventricular function, exercise tolerance and quality of life in patients with stable coronary artery disease with or without left ventricular dysfunction during 4 months.
A total of 159 patients presented with stable CAD without clinical heart failure symptoms were included in a open-label, non-comparative, prospective clinical study between June 2009 to February 2010 in King Abdul Aziz Specialist Hospital, Taif, KSA, Al Hayah National Hospital, Khamis Mushyt, KSA and Critical care department, Cairo University, Egypt. All included patients were, in addition to the ant ischemic treatment, subjected to aggressive heart rate control starting by beta blocker titrated to the maximum dose as tolerated, then Ivabradine added if the target heart rate is not achieved or rate control started by Ivabradine if beta blockers are contraindicated. Exercise treadmill test (ETT) to assess exercise capacity using time to 1 mm ST-segment depression in milliseconds, ejection fraction (EF) assessed by transthoracic echocardiography and frequency of angina attacks and the use of sublingual nitroglycerin per week during the last week were evaluated during a follow-up for 4 months. The patients were divided into two groups, group-I (patients achieved a resting heart rate between 50 and 60 bpm with heart rate reduction treatment) and group-II (patients with resting HR >60 bpm in spite of maximum treatment for heart rate reduction).
The resting heart rate was significantly reduced from 77.98 ± 8.7 at baseline to 60.68 ± 4.34 bpm after 4 months of treatment, P < 0.001. The frequency of angina pectoris attacks had been significantly reduced from 2.14 ± 1.27 to 0.48 ± 0.58 attacks per week, P < 0.001 and the highest significant reduction was observed with group-I. Also, the frequency of use sublingual nitrate therapy was significantly reduced from 1.38 ± 1.1 tablet per week at the last week before the study to 0.12 ± 0.33 tablet per week during the last week after 4 months of treatment, P < 0.001 and the reduction was more significantly with group-I. Exercise treadmill test demonstrated statistically significant increase in the time to 1 mm ST-segment depression from 357.36 ± 66.73 at baseline to 387.96 ± 65.19 ms. after 4 months with P < 0.001. The degree of improvement was significantly higher for group-I (from 358.06 ± 68.81 at baseline to 391.71 ± 69.01 after 4 months with P < 0.001) than that of group-II (from 356.11 ± 64.8 at baseline to 381.27 ± 59.08 after 4 months with P < 0.001). Ejection fraction showed a statistically significant increase from 59.76 ± 6.86 at baseline to 61.04 ± 5.35 after 4 months with P < 0.001.
This study indicates that heart rate reduction has been associated with an improvement in quality of life in patients with stable coronary artery disease, presenting new opportunities for treatment.
一般而言，心率与心肌缺血、心血管疾病及预期寿命之间存在密切关联；然而，心率作为一个重要的风险因素以及治疗契机却一直被忽视。
探讨积极降低心率（50⩽心率⩽60次/分钟）对伴有或不伴有左心室功能障碍的稳定型冠状动脉疾病患者在4个月期间的抗缺血和抗心绞痛疗效、左心室功能、运动耐量及生活质量的影响。
2009年6月至2010年2月期间，在沙特阿拉伯塔伊夫的阿卜杜勒·阿齐兹专科医院、沙特阿拉伯哈米斯穆谢特的国家医院以及埃及开罗大学重症监护科开展了一项开放标签、非对照、前瞻性临床研究，共纳入159例无临床心力衰竭症状的稳定型冠心病患者。所有纳入患者除接受抗缺血治疗外，均接受积极的心率控制，起始使用β受体阻滞剂滴定至最大耐受剂量，若未达到目标心率则加用伊伐布雷定，若β受体阻滞剂禁忌则起始使用伊伐布雷定进行心率控制。在4个月的随访期间，评估运动平板试验（ETT）以使用ST段压低1毫米的时间（以毫秒计）评估运动能力、经胸超声心动图评估的射血分数（EF）、心绞痛发作频率以及最后一周每周使用舌下硝酸甘油的情况。患者被分为两组，第一组（接受心率降低治疗后静息心率在50至60次/分钟之间的患者）和第二组（尽管接受了最大程度的心率降低治疗但静息心率>60次/分钟的患者）。
治疗4个月后，静息心率从基线时的77.98±8.7显著降至60.68±4.34次/分钟，P<0.001。心绞痛发作频率从每周2.14±1.27次显著降至0.48±0.58次，P<0.001，且第一组降幅最大。此外，舌下硝酸酯类药物治疗的使用频率从研究前最后一周的每周1.38±1.1片显著降至治疗4个月后最后一周的每周0.12±0.33片，P<0.001，且第一组降幅更显著。运动平板试验显示，ST段压低1毫米的时间从基线时的357.36±66.73毫秒在4个月后统计学显著增加至387.96±65.19毫秒，P<0.001。第一组的改善程度（从基线时的358.06±68.81至4个月后的391.71±69.01，P<0.001）显著高于第二组（从基线时的356.11±64.8至4个月后的381.27±59.08，P<0.001）。射血分数从基线时的59.76±6.86在4个月后统计学显著增加至61.04±5.35，P<0.001。
本研究表明，降低心率与稳定型冠状动脉疾病患者的生活质量改善相关，为治疗带来了新的契机。
