Study of Hypertrophic Cardiomyopathy Under Stress Conditions. Concordance Between Two Complementary Tests: Stress MRI and Exercice Stress Echocardiography
Study of Hypertrophic Cardiomyopathy Under Stress Conditions. Concordance Between Two Complementary Tests: Stress MRI and Exercice Stress Echocardiography
Hypertrophic cardiomyopathy (HCM) is a primitive myocardic disease and the first of genetic
 cardiac diseases. The definition of HCM is an increase of the myocardial thickness of the
 left ventricle (LV) wall without any other causes of hypertrophy. It's characterized by an
 important heterogeneity of prognosis and clinical expression going from a asymptomatic state
 until the devastating sudden death occurring in a young person.The diagnosis of HCM is
 definite by a myocardial thickness greater or equal to 15mm (or 13mm if there is a familial
 history).This hypertrophy is often accompanied by other abnormalities detected by
 echocardiography: dynamic left ventricular outflow obstruction at rest or stress, mitral
 regurgitation …Now, the current challenge is to determine the prognosis factors of the
 disease that could help to identify the patients with high risk of sudden death. Some
 prognosis factors are knowed and used in the calculation of a new risk score. This risk score
 allows to estimate the risk of sudden death at 5 years and propose depending on the result,
 the implantation of a defibrillator for primary prevention.The physiopathological mechanism
 of HCM is very complex and still misunderstood. Myocardial fibrosis could be a major
 mechanism of the disease evolution. Indeed, fibrosis is responsible of scar areas where
 ventricular tachycardia may develop. Moreover, if the fibrosis is very extensive, it can be
 the responsible of a systolic or diastolic dysfunction of the left ventricle leading to heart
 failure.Myocardial ischemia caused by a microvascular dysfunction is now recognized as an
 important mechanism of the disease evolution. Acute ischemic events could be a trigger of
 malignant arrhythmia whereas chronic ischemia leads to fibrosis.Left ventricle function is
 long time preserved in HCM. Segmentary hypokinesia corresponding to extensive fibrosis
 appears at a very advanced stage of the disease. Exercice stress echocardiography permits to
 detect myocardial ischemia caused by microvascular dysfunction in the HCM before the fibrosis
 apparition. Moreover the investigators suggest to study the deformation parameters by speckle
 tracking or 2D strain witness of a contractile LV dysfunction before the apparition of
 segmentary hypokinesia.Magnetic resonance imaging (MRI) is now recognized as the more
 sensible technique to identify focal myocardial fibrosis resulting in areas of late
 gadolinium enhancement (LGE). LGE is frequent in HCM and his extension is correlated with the
 severity of the hypertrophy and the risk of sudden death. Myocardial ischemia is detected by
 hypoperfused defects in the perfusion sequences and as LGE, is correlated with the degree of
 hypertrophy. Some studies using stress MRI with vasodilatator agent show inductible
 hypoperfused areas correlated to the degree of hypertrophy. T1 mapping is a new hopeful
 sequence of MRI permitting to detect the diffuse and early myocardial fibrosis. Some studies
 show that T1 mapping values are reduced in the areas of LGE in HCM but also in areas without
 LGE which reflects the presence of new fibrosis.The objective of study is to compare these
 two imagery techniques in order to detect ischemia and fibrosis. These techniques are usually
 used in the diagnosis or the monitoring of the disease. The investigators propose to realize
 an exercise stress echocardiography to study: the segmentary kinetic of the left ventricle
 and the 2D strain and a stress MRI to study the LGE, the stress perfusion and the T1
 mapping.Actually the investigators consider that LGE is a risk factor of the disease
 (although not yet involved in the calculation of the risk of sudden death) and need to be
 study in each MRI realized for HCM. From the same way, the investigators suggest to follow
 patients to determine if the abnormalities detected by these two techniques and particularly
 2D strain abnormalities, stress myocardial ischemia and T1 mapping abnormalities are
 prognosis factors of the disease and appear more precociously than LGE.
Inclusion Criteria:

 -  The patient is adult (> or = 18 years) and informed.

 -  He's agree for a 24-month follow-up.

 -  The patient must be member or beneficiary of a health insurance system.

 -  He must have a clear diagnosis of HCM defined by a left ventricular hypertrophy in
 tranthoracic echocardiography (superior to 15mm or 13mm if there is a familial
 history) without other causes of hypertrophy (severe hypertension, aortic stenosis,
 amyloidosis or fabry disease, ..)

 Exclusion Criteria:

 -  The patient is under safeguarding justice, tutorship or curatorship.

 -  The patient formalizes his opposition.

 -  It's impossible to give enlightened information.

 -  The patient doesn't read French.

 -  The patient is pregnant or breastfeeding.

 -  Contraindication to the realization of a MRI (defibrillator, no-MRI compatible PMK,
 claustrophobia,..)

 -  Contraindication to the Persantine° injection (asthma, high degree block, ..)

 -  Contraindication or impossibility to realize a stress echocardiography.

 -  Comorbidity that can be responsible of the studied anomalies: coronaropathy,
 myomectomy, multicomplicated diabetes, …