Inclusion Criteria:

- Women over 18 years

- Free and informed consent signed

- Histologically confirmed adenocarcinoma of the breast, metastatic or non-metastatic

- LVEF> 50% angioscintigraphy before the start of treatment with Herceptin ®,

- Overexpression of HER2 in the invasive component of the primary tumor (3 + 2 +
according to ICH or with confirmation of positivity by FISH or CISH)

- Patient receiving treatment with Herceptin ®,

- Inclusion in the control group: patients treated with Herceptin ® episode without LV
dysfunction,

- For the inclusion in the Group LV dysfunction: the appearance of a decrease in LVEF
during treatment with Herceptin ®, angioscintigraphy identified.

Exclusion Criteria:

- Heart disease or serious medical conditions do not allow to administer Herceptin ®
(documented history of heart failure, angina requiring treatment, severe dyspnoea at
rest or oxygen dependency),

- History of ischemic heart disease or myocarditis

- Known allergy to trastuzumab, murine proteins or any of the excipients

- Patients with an indication against the MRI (claustrophobia, ferromagnetic foreign
body, pacemaker or implantable defibrillator, known allergy to gadolinium salts)

- Renal impairment (creatinine clearance <60 ml / min according to the MDRD formula)

- Arrhythmia atrial fibrillation,

- Contraindications to the administration of Dotarem ®,

- Patient unable to give informed consent,

- Adult Trust,

- Pregnant or lactating

- Patient unable to undergo a medical for geographical, social or psychological.