高输出量性心力衰竭的诊断与治疗

有心衰的症状和体征、并伴有心输出量升高的心衰被称作“高输出量性心力衰竭”。伴有心衰的心输出量升高与多种疾病有关．包括：慢性贫血．全身性动-静脉瘘．脓毒症、高碳酸血症和甲状腺功能亢进症。发生这种病变的生理学基础是动-静脉分流或外周血管扩张所导致的全身血管阻力降低。这两方面原因都可以引起全身动脉压的下降和神经内分泌活动增强．进而导致心衰的临床表现。与低输出量性心力衰竭不同。关于高输出量性心力衰竭的临床试验比较缺乏。治疗心衰的常规疗法。如血管紧张素转化酶抑制剂、血管紧张素受体阻滞剂和一些能扩张血管的β受体阻断剂的应用．对于高输出量性心衰非但没效，反而会进一步降低全身血管阻力，使病情恶化。高输出量性心衰尽管少见，但常伴有一些可纠正的潜在病因。治疗方案比较局限：可以限制饮食中盐和水，并辅以利尿剂的适当应用。不建议使用血管扩张剂和β肾上腺素受体正性肌力药。

Diagnosis and Treatment of High Output Heart Failure

The symptoms and signs of heart failure can occur in the setting of an increased cardiac output and has been termed ＇high output heart failure＇. An elevated cardiac output with clinical heart failure is associated with several diseases including chronic anaemia, systemic arterio-venous fistulae, sepsis, hypercapnia and hyperthyroidism. The underlying primary physiological problem is of reduced systemic vascular resistance either due to arterio-venous shunting or peripheral vasodilatation. Both scenarios can lead to a fall in systemic arterial blood pressure and neurohormonal activation leading to overt clinical heart failure. In contrast to low output heart failure, clinical trial data in this area are lacking. The use of conventional therapies for heart failure, such as angiotensin converting enzyme inhibitors, angiotensin receptor blockers and certain b-blockers with vasodilatory properties, is likely to further reduce systemic vascular resistance resulting in deterioration. The condition, although uncommon, is often associated with a potentially correctable aetiology. In the absence of a remediable cause, therapeutic options are very limited but include dietary restriction of salt and water combined with judicious use of diuretics. Vasodilators and β-adrenoceptor positive inotropes are not recommended.