Introduction: After electric cardioversion (EC), several cases of cardiac stunning with cardiogenic shock have been reported. Several hypotheses have been proposed, including stunning of the left ventricle (LV) and modifications in the LV conformation that could lead to severe mitral regurgitation (MR). We report 2 cases of cardiogenic shock with severe MR after EC for atrial fibrillation (AF).

Case 1: A 75-year-old man presented with AF. A transesophageal echocardiography before the EC showed moderate MR. Shortly after successful EC, the patient developed a cardiogenic shock. The transthoracic and a transesophageal echocardiography showed severe MR. Four days later, an echocardiography showed recovery of MR to a moderate grade.

Case 2: An 85-year-old woman with a history of percutaneous aortic valve replacement presented with AF. After EC, she developed a cardiogenic shock. The transthoracic echocardiography showed severe MR. After recovery, the echocardiography showed moderate MR.

Discussion: Cardiac stunning after EC is well known and could explain the development of severe MR due to restrictive movement of leaflets. The transient character of the MR favors a functional origin with an alteration in the geometry of the mitral apparatus. Some cases of so-called “eclipsed MR” are described in the literature, however, independently to electric shocks.

Conclusion: In some patients, flash pulmonary edema seems to be due to transient severe functional MR, although the exact underlying physiopathologic mechanism remains unclear. An ischemic origin with papillary muscle dysfunction due to transient low perfusion could also be advocated.