- In healthy people the heart relaxes and contracts between 60 to 100 times a minute.
- When the heart muscles relax the inner chambers fill with blood. When the muscles contract the blood is squeezed out of these chambers into the blood vessels.
What happens when the amyloid protein deposits in the heart?
Cardiac amyloidosis is defined by the presence of extracellular deposition of amyloid with in the heart.
Amyloid deposited in the heart may cause the heart muscle to become stiff over time. If the heart muscle cannot relax enough to fill with blood this leads to accumulation of fluid in the lungs, legs and liver. With time the pumping function decreases, which results in reduced blood flow to the body organs and tissues and may lead to drop in blood pressure.
- The consequences of cardiac amyloidosis are similar in all types of amyloid. They belong to a group called infiltrative cardiomyopathy and result in progressive heart failure.
- Patients with cardiac amyloidosis typically exhibit heart failure with preserved ejection fraction (otherwise known as diastolic heart failure). This is a common form of heart failure in elderly patients and requires diuretic therapy.
- Cardiac amyloidosis may also affect the way electrical signals move through the heart (conduction system). This can lead to faulty heart signals, (heart block) and may require a pace maker. Abnormal heartbeats (arrhythmias) re also common.
Most types of amyloidosis disease are described as systemic meaning that more than one organ will be effected by the amyloid deposition.
Cardiac amyloidosis therefore is rarely seen alone. Damage in other organs can also impact on the working of the heart.
In AL amyloidosis heart failure may go hand in hand with:
- Peripheral and autonomic neuropathy
- Nephrotic syndrome
- Periorbital purpura
In ATTRv heart failure is often seen with peripheral and autonomic neuropathy.
In ATTRwt heart failure is the predominant problem. However, carpal tunnel syndrome, biceps tendon rupture and spinal stenosis may be experienced with atrial fibrillation experienced sometime occurring some time before heart failure.