Brief Summary : Rhythm disorders are a frequent and potentially serious complication of critical patients in the ICU and postoperative cardiac surgery. In particular, atrial fibrillation (AF) is the most common rhythm disorder in patients admitted to the ICU and is associated with excess mortality during acute circulatory failure. In postoperative cardiac surgery, AF affects 15 to 45% of patients. In addition to hemodynamic effects, AF increases the risk of stroke, bleeding, respiratory or renal failure, and doubles mortality at 30 days and 6 months. In the longer term, the recurrence rate of AF within 1 year after hospital discharge is about 50%. Similarly, other rhythm disorders, supraventricular or ventricular, can be life-threatening in ICU patients.

While the incidence and complications of rhythm disorders are well documented during sepsis, cardiogenic shock or after cardiac surgery, there are to our knowledge no data on the frequency and complications of rhythm disorders in patients assisted by VA ECMO.

The primary objective is to describe the incidence of supraventricular rhythm disorders in patients assisted by VA ECMO.

This study is an observational study to describe the conditions of occurrence of arrhythmias, particularly atrial fibrillation, in patients supported by VA ECMO, as well as their short-term and long-term prognosis. Patients will be recruited from the intensive care units and CRFs will be completed by the investigators at each of the participating centers. Data will be collected directly from the medical records, except for vital status at 1 year, which may be collected by telephone from the patient by the investigator at the center in the absence of data in the medical record.

Atrial fibrillation episodes will be recorded on a 12-lead electrocardiogram and securely transmitted to the coordinating center. In addition, investigators will send weekly data to the principal investigator for incidence calculation. Patients or their relatives will be informed about the study by an information sheet presented and explained by the investigator or another person authorized to conduct the research. The investigator will record the patient's consent in the patient's medical record.

Inclusion Criteria:

• Patient 18 years of age or older
• Assistance with VA ECMO

Exclusion Criteria:

• Opposition to the use of data.
• Persons under legal protection (curators, guardianship), judicially safeguarded.
• VA ECMO for refractory cardiac arrest.

Major Patients Assisted by VA ECMO in Intensive care

Data are available upon reasonable request The procedures carried out with the French data privacy authority (CNIL, Commission nationale de l'informatique et des libertés) do not provide for the transmission of the database, nor do the information and consent documents signed by the patients.

Consultation by the editorial board or interested researchers of individual participant data that underlie the results reported in the article after deidentification may nevertheless be considered, subject to prior determination of the terms and conditions of such consultation and in respect for compliance with the applicable regulations.

Beginning 3 months and ending 3 years following article publication. Requests out of these time frame can also be submitted to the sponsor

Researchers who provide a methodologically sound proposal