Amyloid heart disease is an accumulation of fibrillar proteins in the extracellular sector of the heart.

Identified on echocardiography as Ventricular hypertrophy. The investigation of a Left Ventricular hypertrophy (LVH) is the most frequent discovery circumstance of amyloid heart disease.

Pathophysiological mechanisms poorly understood, resulting in late diagnosis. Transthyretin amyloid heart disease (CATTR) is the most common form of cardiac amyloidosis in the West Indies due to an abnormally high frequency of the Val122Ile and Val107Ile mutations of the transthyretin gene in this population. Val122Ile and Val107Ile mutated-transthyretin are the substitution of valine for isoleucine at codon 122 of the TTR gene ( V122I) and at codon 107 of the TTR gene (V107I).

Complications of CATTR are functional changes in heart cells or even death due to mechanical abnormalities (loss of contractility and increased wall stiffness cardiac arousal and conduction disturbances).

These disorders result from an electrical abnormality of the heart the reason why the cardiologist performs preventive performance of electrophysiological explorations with EnSite Precision™. It's a registration system used to detect foci of necrosis within the myocardium.

Amyloid deposits are areas devoid of electrical activity. Do they detectable by the EnSite Precision™ recording system ?

Transthyretin's amyloid heart disease (CATTR) is a rare disease whose frequency is high in the Caribbean's due to a high frequency of Val122Ile, an amyloidosis prone mutation in the Transthyretin gene. The Val122Ile variant might be present in 15 to 20 000 subjects in Martinique, placing them at high risk to develop the CATTR.

CATTR results from the accumulation of amyloid deposits between the intercellular spans, resulting in mechanical cardiac abnormalities, but also in latent excitation or conduction defects: atrial and ventricular hyperexcitability, bundle branch blocks, atrio-ventricular blocks. These abnormalities require systematic electrophysiological studies and if necessary, antiarrythmic medications or pacemaker placement.

Electro-mapping of the cardiac chambers offers high-resolution three-dimensional maps of cardiac electrical activity which has been used recently to detect focal myocardial infarction.

This anatomo-functional imaging, used only once in cardiac amyloidosis, showed a correlation between areas of low voltage of the left atrial myocardium and areas of late gadolinium enhancement, a marker of amyloidosis deposit, found in cardiac MRI.

Inclusion Criteria:

Controls:

• Aged 18 and more
• Have had an echocardiogram within 6 months prior to inclusion
• Have had a cardiac Holter in the 6 months prior to inclusion.
• Informed Consent given

Cases :

• Aged 18 and over
• Presence of cardiac amyloidosis with Transthyretin
• Have had an echocardiogram within 6 months prior to inclusion
• Have had a cardiac Holter monitoring in the 6 months prior to inclusion.
• Informed Consent given

Exclusion Criteria:

Controls

• Known case of amyloidosis in the immediate family
• Patient known to have amyloidosis
• Left ventricular wall thickness greater than or equal to 14 mm
• Hyperechogenicity of the left ventricular walls
• Cardiac disease which may affect electro-anatomic mapping: Right ventricular dysplasia, myocardial infarction, congenital heart disease.
• Contraindication such as pregnancy to radiological exams
• Presence of an anomaly of the vena cava
• Presence of intracavitary thrombus at cardiac echocardiography
• Patients with a pacemaker

Cases

• Cardiac disease which may affect electro-anatomic mapping: Right ventricular dysplasia, myocardial infarction, congenital heart disease.
• Contraindication such as pregnancy to radiological exams
• Presence of an anomaly of the vena cava
• Presence of intracavitary thrombus at cardiac echocardiography