Impairment of mitochondrial respiratory chain enzyme activities in tetralogy of Fallot.

BACKGROUND: During the last decade, disorders of the respiratory chain, so-called mitochondrial disorders, have emerged as a major clinical entity. Tetralogy of fallot (TOF) children>2 month of age are at risk for postoperative myocardial contractile failure. Myocardial ischemia is associated with a reduction in mitochondrial enzyme activity and have impaired metabolism resulting in decreased postoperative myocardial adenosine triphosphate (ATP) concentrations and increased lactate levels. With this in view, we measured the mitochondrial energy system (respiration and OXPHOS) and to study morphological changes from the right ventricular outflow tract (RVOT) muscle of patients with TOF. METHODS: 30 infants with TOF were studied with age-matched control group consisted of 12 normal patients who died due to extracardiac causes. Mitochondrial respiratory chain complexes, OXPHOS, cytochrome content and ATPase activity were measured by documented standard procedure. Morphological changes examined with a transmission electron microscope. RESULTS: In the presence of glutamate and succinate as substrates, the rate of mitochondrial oxygen consumption was significantly lower in RVOT muscles (p<0.001) by using with and without addition of ADP. The ADP/O ratio indices for glutamate and succinate were not significantly affected. The activities of rotenone-sensitive NADH cytochrome c reductase (complexes I+III), cytochrome c oxidase (complex IV) and the ratio of I and III to II and III complexes (complex I) were significantly lower in TOF (p<0.001). A significant reduction of total cytochrome content and ATPase activity (p<0.001) was noted in study group. Morphological changes were also seen in study group as compared with control. CONCLUSIONS: OXPHOS, mitochondrial respiratory chain complex I, I+III and IV, cytochrome content and ATPase activity are more impaired in RVOT muscles in patients with TOF.

Technique of lung retraction during internal mammary artery harvesting.

We describe a novel technique for lung retraction during dissection of the internal mammary artery for its use in coronary artery bypass grafting. The lung is retracted using the blades of the Octopus (Medtronic Inc, Minneapolis, MN) suction stabilizer, without the suction connected. This technique can be used when the internal mammary artery is harvested by widely opening the pleura or by the extrapleural approach. This technique makes mammary artery dissection easy, and it can be used for harvesting internal mammary arteries bilaterally. The method described is simple, causes no impairment in gas exchange, and offers no additional expense, because the same stabilizer would be used later for the off-pump coronary artery bypass surgery.

Unexplained systemic hypertension after closure of ductus arteriosus.

Immediately after surgical closure of a patent ductus arteriosus, a 12-year-old boy developed severe systemic arterial hypertension refractory to medication. The cause of hypertension could not be found, but it came under control 3 weeks postoperatively with a combination of angiotensin-converting enzyme inhibitor and chlorothiazide.