Depending on the location and extent of the abnormal protein infiltration, initial symptoms and presentation may vary. In the early disease stage, patient may not have many symptoms. As protein accumulates in the heart muscle causing it to become stiff and thick, patients can gradually develop symptoms such as difficulty breathing (especially on walking or lying flat), leg or abdominal swelling, reduced stamina and fatigue. If the misshapen protein accumulates on the conduction system of the heart, irregular heart rhythm or excessively slow heartbeat may occur. This may cause the patient to feel giddy, faint or have palpitations.
