Gowdak Luis Henrique W
Heart Institute (InCor-HCFMUSP), Av. Dr. Eneas de Carvalho Aguiar, 44, São Paulo, SP, 05403-000, Brazil.
Cardiol Ther. 2022 Mar;11(1):163-174. doi: 10.1007/s40119-021-00247-1. Epub 2021 Dec 3.
Angina is a significant contributor to disability and impairment in quality of life in patients with chronic coronary syndromes (CCS). An elevated heart rate (HR) may trigger myocardial ischemia by increasing oxygen consumption and decreasing the diastolic time, compromising the coronary flow. HR-lowering strategies offer symptom control and prevent cardiovascular events in subgroups of patients with CCS. However, the best therapeutic approach to achieve the desired HR in patients with CCS can be challenging based on efficacy and tolerability. Guidelines usually propose β-blockers and/or non-dihydropyridine calcium channel blockers (CCB) for angina patients with elevated HR. Nonetheless, there is no clear evidence of greater antianginal efficacy of this strategy versus an alternative HR-lowering agent. Ivabradine reduces the HR by blocking the I current in the sinoatrial node without affecting myocardial contractility or vascular tone. The magnitude of the HR reduction by ivabradine is proportional to the initial HR, which decreases the risk of significant bradycardia. Ivabradine increases the diastolic time and the coronary flow reserve to a greater extent than β-blockers and favors collateralization, improving the regional blood flow. We present two clinical cases of patients with symptomatic CCS in whom HR control with ivabradine was fundamental for symptom control and improvement in left ventricular (LV) function. An earlier combination of ivabradine plus β-blockers would have provided more rapid symptom control and improved LV function in the first case. In the second case, the primary mechanism responsible for angina was most likely a coronary vasomotor abnormality, in which the use of β-blockers aggravated the discomfort. The combination of a dihydropyridine CCB plus ivabradine was highly influential in symptom control. Due to its effects beyond HR reduction and good tolerability, ivabradine should be considered an essential ally in managing patients with angina and high HR with or without LV dysfunction.
心绞痛是慢性冠状动脉综合征（CCS）患者残疾和生活质量受损的重要因素。心率（HR）升高可通过增加氧消耗和缩短舒张期时间来触发心肌缺血，从而损害冠状动脉血流。降低心率的策略可控制症状并预防CCS患者亚组中的心血管事件。然而，基于疗效和耐受性，在CCS患者中实现理想心率的最佳治疗方法可能具有挑战性。指南通常建议对心率升高的心绞痛患者使用β受体阻滞剂和/或非二氢吡啶类钙通道阻滞剂（CCB）。尽管如此，尚无明确证据表明该策略比其他降低心率的药物具有更强的抗心绞痛疗效。伊伐布雷定通过阻断窦房结中的I电流来降低心率，而不影响心肌收缩力或血管张力。伊伐布雷定降低心率的幅度与初始心率成正比，从而降低了严重心动过缓的风险。与β受体阻滞剂相比，伊伐布雷定能更大程度地增加舒张期时间和冠状动脉血流储备，并有利于侧支循环形成，改善局部血流。我们介绍了两例有症状的CCS患者的临床病例，在这些病例中，使用伊伐布雷定控制心率对于控制症状和改善左心室（LV）功能至关重要。在第一个病例中，早期联合使用伊伐布雷定加β受体阻滞剂本可更快地控制症状并改善LV功能。在第二个病例中，心绞痛的主要机制很可能是冠状动脉血管舒缩异常，其中使用β受体阻滞剂加重了不适。二氢吡啶类CCB加伊伐布雷定的联合用药对症状控制有很大影响。由于伊伐布雷定除了降低心率外还有其他作用且耐受性良好，因此应将其视为治疗有心绞痛且心率高的患者（无论有无LV功能障碍）的重要辅助药物。
