Ventricular tachycardia with an outflow tract septal origin after repair of double outlet right ventricle.

A 12-year-old boy born with double outlet right ventricle (RV) developed sustained ventricular tachycardia (VT) 6 years after the corrective surgery and underwent electrophysiologic testing and catheter ablation. Electroanatomic mapping of the right and left ventricles during the VT revealed a centrifugal activation from the outflow tract septum. Though an excellent pace map was obtained in the RV, successful ablation was achieved on the left side. These findings suggested that the VT origin might have been located in the intramural region of the ventricular outflow tract septum with a preferential breakout site in the RV outflow tract.

A study of pre-antibiotic bacteriology in 125 patients with necrotizing enterocolitis.

Over a five-year period, 125 newborns with necrotizing enterocolitis (NEC) were managed by us. Their mean birthweight was 1700 g and mean maturity was 32 weeks. Before commencement of antibiotics, routine septic work-up was done in order to define the bacterial spectrum and antibiotic sensitivity. The study includes aerobic and anaerobic cultures of gastric and pharyngeal aspirates, blood cultures, umbilical swabs and culture of umbilical catheter tips in relevant cases. Peritoneal swab results were also analyzed if laparatomy was performed. Positive cultures were present in 45 patients (36%) with 55 positive specimens. Fifteen types of organism were isolated: the commonest was Enterobacter (29%), followed by E. coli (14.5%) and Klebsiella (13%). They were resistant to ampicillin and first-generation cephalosporin. These organisms were usually opportunistic pathogens. Overgrowth of them may be the cause of NEC. Regular review of the antibiotic sensitivity of these organisms allows prompt and appropriate choice of antibiotics. At the same time, antibiotic sensitivity for these organisms was analyzed to guide us in the choice of antibiotic therapy.

Ceftazidime versus imipenem-cilastatin as initial monotherapy for febrile neutropenic patients.

One hundred febrile episodes in 89 neutropenic patients after cytotoxic chemotherapy were randomized to be treated with either ceftazidime or imipenem as initial monotherapy. The clinical characteristics of the two groups of patients were comparable. The response of the fever in patients who received imipenem was significantly better than that in those who received ceftazidime (77 versus 56%, respectively; P = 0.04), especially in those with microbiologically documented infection (81 versus 33%, respectively; P = 0.02). The in vitro susceptibilities and the clinical responses suggested that, with the possible exception of Pseudomonas spp., imipenem was more effective than ceftazidime in treating neutropenic infections caused by both gram-positive and -negative organisms. An additional 23 and 21% of the patients in the ceftazidime and imipenem groups, respectively, responded to the addition of cloxacillin and amikacin following failure of monotherapy. The majority of the treatment failures, relapses, and superinfections were related to resistant infective organisms such as methicillin-resistant Staphylococcus spp. and Pseudomonas spp. or disseminated fungal infections.

Ofloxacin versus co-trimoxazole for prevention of infection in neutropenic patients following cytotoxic chemotherapy.

The efficacy of ofloxacin in preventing infection in neutropenic patients following cytotoxic chemotherapy was evaluated and was compared with that of co-trimoxazole. A total of 102 patients with hematological malignancies were randomly selected to receive either co-trimoxazole or ofloxacin. All patients were monitored for compliance, occurrence of infection, and drug-related side effects. A surveillance culture of a rectal swab was performed regularly. A total of 25 of the 52 patients (48%) who received co-trimoxazole and 11 of the 50 patients (22%) who received ofloxacin developed fever during the study period (P less than 0.025). Gram-negative bacteremia occurred in nine patients in the co-trimoxazole group (17%) but in only one patient (2%) in the ofloxacin group (P less than 0.05). No patient in either group had documented gram-positive bacterial or Pneumocystis carinii infection. Poor performance status was the only identifiable factor associated with an increased incidence of bacteremia. The surveillance study showed that significantly fewer bacterial strains were resistant to ofloxacin than to co-trimoxazole and that acquisition of resistance to co-trimoxazole was more commonly observed than was acquisition of resistance to ofloxacin. Significantly more patients had skin rashes following co-trimoxazole than ofloxacin treatment (P less than 0.05). Ofloxacin was superior to co-trimoxazole in preventing infection in this population of neutropenic patients.

Imipenem/cilastatin as initial therapy for febrile neutropenic patients.

Imipenem 2 g daily was administered intravenously to 40 evaluable patients with neutropenia and fever. Twenty-three patients had acute leukaemia and 17 malignant lymphoma. The overall response rate was 70.0%. Of the 14 patients with documented infection, 9 (64.3%) responded. Poorer responses were observed in patients with pneumonia (40%) or pseudomonal infection (50%). The response rate was significantly higher among patients with increasing neutrophil counts during therapy (P less than 0.02). Fungal infection was a common cause of treatment failure. Gastrointestinal side effects and skin rashes were occasionally seen. No patient developed central nervous system toxicity. Imipenem is a practical alternative to antibiotic combinations for management of neutropenic infection. However, careful monitoring is essential in the subgroups of patients with pneumonia or pseudomonal infections, who may require modifications of therapy.