Transthyretin amyloid cardiomyopathy, also known as ATTR-CM, is a type of cardiomyopathy which is underdiagnosed and potentially fatal.In ATTR-CM, a protein called transthyretin, which circulates in the bloodstream becomes misshapen and builds up in the heart, nerves and other organs. When this protein builds up in the heart, the walls of the heart become thickened and stiff. The stiff heart is unable to relax properly to fill with blood and becomes inefficient in pumping blood to rest of the body. As the condition progresses, the heart pumping function weakens. This results in heart failure, where the heart is unable to pump sufficient blood to meet the needs of the body.
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.
In ATTR-CM, the normal protein transthyretin, which circulates in the blood, becomes deformed due to genetic mutation or ageing. While there is little one can do to reduce the risk of ATTR-CM, if you do develop the symptoms listed, it is recommended to check with your doctor on your concerns. Early diagnosis and treatment make a difference in the progression of this disease.
ATTR-CM is caused by a deposition of abnormal misshapen proteins on the heart muscles. This protein, called transthyretin, is normally produced by the liver. Its main function is to transport the thyroid hormone and vitamin A in our bloodstream. Due to either genetic mutation or the ageing process, this transport protein can become misshapen. The abnormal proteins can then be deposited in the heart and various organs, resulting in disease.There are two types of ATTR-CM:
Diagnosing ATTR-CM may be challenging, due to little awareness about the condition. The symptoms of ATTR-CM also overlap with those of many other common conditions. If this condition is suspected, your doctor may need to do various tests such as an electrocardiogram (heart tracing) to assess your heart rhythm. Specialised heart imaging tests will also be ordered. This will usually include an ultrasound of the heart (transthoracic echocardiogram) to assess the heart pumping function and thickness of the heart. Depending on the outcome of your clinical examination and test results, further dedicated heart scans such as the cardiac magnetic resonance imaging (a MRI scan of the heart) or the nuclear pyrophosphate scan (special scan to assess for possible abnormal proteins in the heart) may be performed. Blood tests will also be performed to assess various organ functions. In a small number of cases, a small sample of the affected organ, such as the heart muscle, nerve or kidney tissue, may have to be obtained to get an accurate diagnosis.
The treatment for ATTR-CM is aimed towards:
