If the heart works too hard, it can develop a rapid heartbeat (tachycardia), and/or another serious condition known as left ventricular hypertrophy (LVH), an enlargement of the heart muscle that in turn can lead to heart failure.
重度贫血代偿功能失调，
出现心脏扩大、心脏杂音，
甚至出现充血性心力衰竭。
心电图ST段下降， T波低平或倒置。
（2）神经系统（Nervous System)
精神不振、嗜睡、烦躁不安、注意力不集中，神 经精神发育缓慢，智力减退，对周围反应力差， 年长儿可诉头痛、头晕、畏寒、耳鸣、眼前出现 黑点。
（3）消化系统(Digestive System)
消化功能减退，食欲不振。婴儿常有腹 泻。
（4）其他：溶贫有黄疸，地中海贫血有骨骼的改 变等。
Symptoms of Anemia: * exercise dyspnea, * fatigue, * heart palpitation, * pica (consumption of substances such as ice, starch or clay, frequently found in iron deficiency anemia), * syncope (particularly following exercise)
贫血
新生儿 < 145g/L
轻度 144-120g/L 中度 119-90g/L 重度 89-60g/L 极重度<60g/L
