Mediastinitis is a rare complication but can occur after any form of cardiac surgery via midline sternotomy. Despite early diagnosis, management in intensive care and appropriate treatment, the prognosis remains severe. Progression towards a chest wall defect, exposing a sternal flap is not uncommon and requires reconstructive surgery because of the potential life-threatening risk. Among the techniques currently used, the authors emphasize the value of pectoralis major myoplasty centered on perforating vessels derived from the internal mammary artery according to the technique described by Nahai in 1982. They have performed this procedure in 7 patients with a high-risk context, always using a single muscle, and also assessed its technical simplicity, low morbidity, absence of obvious functional handicap associated with the aesthetic aspects by means of regular review with a mean follow-up of 18 months.