Morgagni hernias are very rare in adults accounting for 2-3% of all diaphragmatic hernias [1]. Although obstructive symptoms of the herniated viscera represent the most common clinical presentation there have been rare cases of severe compressive symptoms to the heart [2]. We present the case of a 75 year old male admitted to the hospital because of severe respiratory failure with cardiac tamponade due to a giant foramen of Morgagni hernia complicating an existing severe aortic valve stenosis. The patients underwent to emergency treatment of both problems under cardiopulmonary bypass. To the best of our knowledge this case is the only one reported with combined aortic valve replacement and Morgagni hernia repair.

Morgagni hernia is a rare malformation that constitutes 3% of all diaphragmatic hernias. It was first described by Giovanni Battista Morgagni in 1761. The foramen of Morgagni is a persistent developmental defect in the diaphragm anteriorly between septum transversum and the right and left costal origins of the diaphragm. A hernia through the foramen of Morgagni is invariably right sided and is presented as an anterior mediastinal mass. Though usually asymptomatic it may cause retrosternal pain, epigastric discomfort and dyspnoea. The content of the hernia is usually omental fat, while larger hernia may contain transverse colon, stomach or small intestine [3]. Echocardiography may show a right anterior pericardiophrenic mass. However in this case the hernia sac was on the left side and the location of the stomach in front of the heart made very difficult an accurate echo evaluation of the cardiac function. Further CT imaging diagnosed Morgagni's defect, defined its content as greater omentum and stomach and confirmed the severe compression of the right ventricle. In addition a severe aortic valvular stenosis complicated the diagnosis by worsening the clinical profile of the patient.

Up to now there has been no report on a combined management of aortic valve stenosis and a Morgagni hernia. In this scenario the treatment should in generally be a two stage procedure. The treatment of the severe aortic stenosis constitutes a priority towards any hernia defect since it threatens the patient's life and should be carried out immediately. In this case however the severity of the respiratory failure, due primarily to the compressive effects of the giant hernia, dictated the need for an urgent combined management of both conditions. The cornerstone of treatment was the rapid sternotomy and initiation of cardiopulmonary bypass so as to relief the obvious mechanical compression and cardiac tamponade provoked by the hernia.

Morgagni hernia is currently treated by laparoscopy, laparotomy or even thoracoscopy [4, 5]. However the transternal repair of the hernia is preferred in patients undergoing concomitant open heart surgery [6–8]. The repair should be carried out during the cardiopulmonary reperfusion period in patients presenting such severe cardiac compression and every effort should be directed to secure hemostasis.

Conclusively, Morgagni hernia can rarely accompany several cardiac surgical pathologies. Cardiac surgeons should be familiar with the transsternal hernia repair which is as effective as other popular surgical reconstructive procedures, unless gastric or bowel strangulation and necrosis are suspected.