Stanford Cardiac Arrhythmia Service

Arrhythmias in Patients with Amyloidosis and Sarcoidosis

Sarcoidosis is a disorder that usually affects a number of systems of the body and that may also affect the heart.  Some patients with sarcoidosis have problems lung abnormalities or may have on chest X-ray or CT scan evidence of lymph node enlargement in the chest.  A blood test called an Angiotensin Converting Enzyme level may be abnormal in patients with sarcoidosis. Sarcoidosis may affect the heart by producing abnormalities of the heart rhythm.  Patients may have evidence of slow heart rhythms, most commonly due to A-V block in which electrical impulses may be blocked from the upper to lower heart chambers or bundle branch block in which only some of the routes from the upper to the lower heart chambers are abnormal. Some patients with sarcoidosis and A-V block may need a permanent pacemaker implanted . Patients with sarcoidosis may also be at risk of having serious fast heart rhythms of the ventricles, the lower heart chambers. These rhythms called ventricular tachycardia may result in collapse or sudden cardiac death . 

Sarcoidosis involving the heart may be detected using noninvasive tests such as echocardiography and cardiac MRI.  Patients with A-V block requiring a pacemaker may undergo an echocardiogram to detect sarcoidosis and other potentially unsuspected abnormalities. In some cases, it may be difficult to distinguish other heart disorders such as Arrhythmogenic right ventricular dysplasia from sarcoidosis and a heart sample called a biopsy might be needed.  Patients with evidence of sarcoidosis involving the heart may be recommended to have a special implantable device called an Implantable Cardioverter Defibrillator (ICD).

Amyloidosis

Amylodosis is a disease that involves the  accumulation of protein deposits within many organs within the body, including the heart.  Amyloidosis may affect the kidneys and result in decreased heart function.

As the diseases progress the deposits replace the healthy heart tissue with non functioning tissue result in thickening of the heart tissue and making it harder for the heart to work properly. The specialized cells within the heart responsible for the conduction of the electrical signal from the top chamber (atrium) to the bottom chamber (ventricle) are gradually replaced. The heart may eventually become enlarged (cardiomyopathy) and may exhibit abnormalities in the  pathway of the electrical signals. Patients may have evidence of slow heart rhythms, most commonly due to A-V block in which electrical impulses may be blocked from the upper to lower heart chambers or bundle branch block in which only some of the routes from the upper to the lower heart chambers are abnormal.  Some patients with amyoloidosis and A-V block may need a permanent pacemaker implanted .  Patients with amyoloidosis may also be at risk of having serious fast heart rhythms of the ventricles, the lower heart chambers. These rhythms called ventricular tachycardia may result in collapse or sudden cardiac death. Some patients with evidence of amyloidosis involving the heart may be recommended to have a special implantable device called an Implantable Cardioverter Defibrillator (ICD). However, because ICDs have not been shown in some studies to increase overall survival this decision is made according to the individual patient’s risk and is not performed in some patients.

Amyoloidosis involving the heart may be detected using noninvasive tests such as echocardiography  and cardiac MRI . Most commonly amyloidosis may result in an increased thickness of the walls of the main pumping chamber of the heart, the left ventricle.

In some cases, it may be difficult to distinguish other heart disorders such as Hypertrophic cardiomyopathy from amyloidosis and a heart sample called a biopsy might be needed if there are no other evidence of amyloidosis in the body.  Blood tests to detect a common form of amyloidosis includes a kappa to lamda ratio of the light chain, a substance found in the blood stream.

 

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