[Long QT syndrome and Brugada syndrome: 2 aspects of the same disease?]. / Sindrome del QT lungo e sindrome di Brugada: due aspetti della stessa malattia?

In clinical cardiology, resort has recently been made to molecular genetics in order to explain some mechanisms that underlie sudden cardiac death in young people with structurally normal hearts. It has become evident that genetic mutations regarding cardiac ion channels may disrupt the delicate balance of currents in the action potential, thus inducing malignant ventricular tachyarrhythmias. The cardiac sodium channel gene, SCN5A, is involved in two of such arrhythmogenic diseases, the Brugada syndrome and one form of the long QT syndrome (LQT3). It is believed that these syndromes result from opposite molecular effects: Brugada syndrome mutations cause a reduced sodium current, while LQT3 mutations are associated with a gain of function. The effects of class I antiarrhythmic drugs have been used to differentiate these diseases. Intravenous flecainide is used as a highly specific test to unmask the electrocardiographic phenotype of the Brugada syndrome. On the other hand, on the basis of experimental and clinical studies, the possibility that the same drugs act as a gene-specific therapy in this disorder by contrasting the effect of mutations in LQT3 has been explored. Recent evidence shows that phenotypic overlap may exist between the Brugada syndrome and LQT3. One large family with a SCN5A mutation and a "mixed" electrocardiographic pattern (prolonged QT interval and ST-segment elevation) has been reported. Moreover, our recent data showed that flecainide challenge may elicit ST-segment elevation in some LQT3 patients. The presence of "intermediate" phenotypes highlights a remarkable heterogeneity suggesting that clinical features may depend upon the single mutation. Only deepened understanding of the genotype-phenotype correlation will allow the definition of the individual patient's risk and the development of guidelines for clinical management.

Increased burn patient survival with once-a-day high dose teicoplanin and netilmicin. An Italian multicenter study.

This is the final report of a large, controlled, multicenter Italian study on immuno- and chemotherapy in adult patients with burns affecting 20 to 95% of total body surface area (mean 35%). The antibiotic treatment of burn patients consisted of topical silver sulfadiazine, short-term antimicrobial chemoprophylaxis with pefloxacin (800 mg i.v. qd) for the first 4 days and polychemotherapy with teicoplanin (800 mg i.v. qd) together with netilmicin (300 mg i.m. qd) in one or more cycles of 5-12 days. At random, half of the patients received thymostimulin, 70 mg i.m. qd for the first month and every other day thereafter. The analysis at completion of 634 valid cases showed that when the results are stratified by means of the Roi risk index, 396 of the 530 patients who contracted wound infection (84%) after chemoprophylaxis were in the first three categories and a mean of 95% survived. Of the remaining 134 patients (Roi index 4-5) only 50% survived. There was no difference in survival of the immunotherapy group in comparison with the parallel group without thymostimulin. The short-term antimicrobial prophylaxis prevented wound infection in only 104 of 634 patients (16%) and they were at low risk (84% Roi index 1). Of the bacterial pathogens involved in septic complications Staphylococcus aureus and Pseudomonas aeruginosa were prevalent (86%): eradication was achieved in 43% of patients and clinical cure or improvement were seen with combination chemotherapy in 64% of all patients, mainly with only one treatment cycle. This value increased to 79% for the 395 protocol-complying patients and went down to 20% in the 135 non-compliers. The total survival of complier and non-complier patients was 447 of the 530 valid patients (84%). The overall mortality of the 634 evaluable patients was 13.1%, ranging from less than 2% to 68%. Burn mortality was directly proportional to the percentage of burned body surface area, to increasing age and other variables of the Roi index, a 50% mortality being associated with a 72.5% total body surface area burned. Normoergic burn patients had a mortality rate of 9.1% versus 35.7% in anergic patients.