Dynamic cardiomyoplasty in a growing organism

Background. Until now cardiomyoplasty has been a treatment option for adult s only. However, there may be a demand for cardiomyoplasty in children. The purpose of this study was to investigate the possibility of applying the m ethod of cardiomyoplasty before growth is completed. Methods. The latissimus dorsi muscle (LD) was wrapped around the heart of 2 0 Gottinger Minipigs (9.1 +/- 1.2 kg body weight). The LD was fixed to the pericardium in group 1 (n = 11) and to the epimyocardium in group 2 (n = 9) and stimulated with burst impulses. After 5.6 +/- 1.8 months hemodynamic a nd histologic follow-up-examinations were carried out in 13 surviving anima ls (weight 32.4 +/- 5.3 kg). Results. In group 1 (n = 6) only the left ventricle was covered by the LD. In 4 animals the LD contracted strongly; in 2 the outer border of the muscl e was atrophied. In group 2 (n = 7) both ventricles were covered by the LD in all animals and showed strong contractions. In 2 animals the outer borde r of the muscle was atrophied. In both groups the contracting parts of the LD showed an intact muscle structure, but compared with the contralateral L D, there was a higher percentage of interstitial fat and connective tissue. Hemodynamic measurements and the well-being of the animals suggest that re striction of cardiac chamber diameter did not occur. The electrical stimula tion of the LD caused a minimal increase of left ventricular pressure and a ortic peak now in group 2. Conclusions. Cardiomyoplasty can be applied in a growing organism. There is growth of the LD with the heart. The muscle structure remains intact. To p revent dislocation of the LD, it seems to be important to fix the LD direct ly onto the epimyocardium. (C) 2000 by The Society of Thoracic Surgeons.