Cardiac amyloidosis happens when abnormal proteins build up in the heart muscle. This buildup can disrupt the heart’s normal rhythm and lead to heart failure.
Since heart failure can be caused by many different things, diagnosing cardiac amyloidosis can be challenging and may take several years. The condition can lead to serious and potentially life-threatening complications.
To manage cardiac amyloidosis effectively, it is crucial to have regular check-ups and treatment from a cardiologist, a healthcare provider who specializes in heart conditions. They can help observe the condition and provide the best care to manage symptoms and prevent complications.
Types
Cardiac amyloidosis is categorized into two main kinds based on the type of misfolded protein involved. The following are given two types:
Light Chain Amyloidosis
Light Chain Amyloidosis, also known as AL Amyloidosis, happens when misfolded light chain proteins accumulate in various organs, including the heart. Light chains are a kind of antibody produced by plasma cells, which originate from the bone marrow. Although light chains play a crucial role in the immune system, problems arise when plasma cells malfunction, producing either too many light chains or abnormal ones. These misfolded proteins can then deposit in the heart and other parts, causing symptoms and organ dysfunction. Risk factors for AL Amyloidosis include a history of plasma cell disorders like multiple myeloma and monoclonal gammopathy of undetermined significance.
Transthyretin Amyloidosis
Transthyretin Amyloidosis, or ATTR Amyloidosis, involves the deposition of a misfolded protein called transthyretin in the muscle of the heart. Transthyretin is normally produced by the liver and is involved in transporting Vitamin A and thyroid hormones over the body. There are two subtypes of ATTR Amyloidosis: wild-type and hereditary.
In wild-type, ATTR, formerly known as senile amyloidosis, does not involve a genetic mutation. Rather, the transthyretin protein accumulates in the heart over several decades, and this form is commonly observed in individuals older than 70 years.
In contrast, hereditary ATTR, a genetic change makes the transthyretin protein more likely to misfold and build up in tissues, especially the nerves and heart. This type is inherited, meaning the genetic change is passed down through families.
Symptoms
Cardiac amyloidosis is frequently not diagnosed until several years after the onset of heart failure symptoms. Common signs include:
- Fatigue: Feeling unusually tired or weak.
- Shortness of Breath: Difficulty breathing, especially during physical activity.
- Exercise Intolerance: A reduced ability to perform physical activities.
- Swelling: Fluid buildup in the lower extremities and abdomen.
- Difficulty Lying Flat: Trouble breathing or discomfort when lying down.
- Nocturnal Dyspnea: Waking up at night short of breath.
- Heart Palpitations: Noticeable irregular or rapid heartbeats.
- Fainting: Loss of consciousness or feeling lightheaded.
- Gastrointestinal Symptoms: Feeling unusually full or experiencing nausea.
These symptoms are not unique to cardiac amyloidosis and can be caused by other kinds of heart failure, which can delay diagnosis. A cardiologist can evaluate these symptoms and help determine the basic cause. Additionally, individuals with cardiac amyloidosis might have trouble with common heart failure treatments, experiencing drops in blood pressure and worsening symptoms with these medicines.
Diagnosis
To diagnose cardiac amyloidosis, your cardiologist may use a variety of tests, including:
- Blood Tests: These can measure levels of N-terminal proB-type natriuretic peptide and troponin, which help assess heart function. They can also check liver and kidney function and detect light chains.
- Urine Tests: These tests can identify kidney involvement and the existence of light chains, which are indicators of amyloidosis.
- Electrocardiogram: This test records the electrical activity of the heart and can reveal abnormalities related to amyloidosis.
- Bone Marrow Biopsy: In cases of suspected AL amyloidosis, a bone marrow biopsy may be performed to check for abnormal plasma cells.
- Heart Imaging Tests: These include cardiac MRI, an echocardiogram, and nuclear imaging tests like a pyrophosphate scan. These tests provide detailed images of the heart and help identify protein deposits.
- Tissue Biopsy: A biopsy involves removing a small sample of tissue from the affected area, like the heart, for laboratory analysis to confirm the presence of amyloid proteins.
- Genetic Testing: This test checks for mutations associated with ATTR amyloidosis, helping to identify hereditary forms of the disease.
These diagnostic tests used together, can help confirm the presence and type of cardiac amyloidosis, guiding appropriate treatment and management.
Treatment
Treating cardiac amyloidosis involves managing heart failure and irregular heart rhythms, as well as addressing the root cause of the condition.
For heart failure, treatment often includes diuretics, which help the body remove excess fluid, and dietary salt restriction to prevent fluid buildup. However, common heart failure medications like ACE inhibitors, beta-blockers, ARBs, and aldosterone antagonists are usually not well-tolerated by individuals with amyloidosis and do not provide the same benefits as they do in other kinds of heart failure.
For irregular heart rhythms, treatments may include antiarrhythmic and beta-blocker medicines to help control the heart rate. In some cases, a pacemaker may be needed for slow cardiac rhythms. Heart specialists might also consider an implantable cardioverter defibrillator, a device that can prevent sudden cardiac arrest by delivering a shock to restore a normal heart rhythm.
These treatments aim to manage symptoms, improve quality of life, and slow the progression of the disease.
Complications
Cardiac amyloidosis often has a poor prediction because of the serious heart-related complications it can cause. These complications include the worsening of heart failure and dangerous arrhythmias like ventricular tachycardia or atrial fibrillation, which are irregular heartbeats that can lead to severe health issues. In some cases, patients may experience a heart block, a condition where the electrical signals in the heart are slowed or blocked, and in the most severe instances, sudden cardiac death can occur.
Additionally, if amyloidosis spreads beyond the heart, it can affect other organs, leading to complications such as kidney failure and nerve damage. These issues can further complicate the patient’s overall health and require specialized care and management.
Summary
Cardiac amyloidosis is a serious condition where abnormal proteins accumulate in the heart, leading to heart failure and arrhythmias. It has two main types: AL amyloidosis and ATTR amyloidosis, each requiring different treatments. Symptoms can include fatigue, shortness of breath, and swelling. Diagnosis involves various tests, including blood and urine tests, ECG, imaging, biopsies, and genetic testing. Treatment focuses on managing symptoms and the underlying cause, with options like diuretics, pacemakers, and specific medications like tafamidis. Complications can include worsening heart failure, dangerous arrhythmias, and potential spread to other organs, such as the kidneys and nerves.
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