Exaggerated QT prolongation after cardioversion of atrial fibrillation

AbstractOBJECTIVESThe purpose of this study was to test the hypothesis that the extent of drug-induced QT prolongation by dofetilide is greater in sinus rhythm (SR) after cardioversion compared with during atrial fibrillation (AF).BACKGROUNDAnecdotes suggest that when action potential–prolonging antiarrhythmic drugs are used for AF, excessive QT prolongation and torsades de pointes (TdP) often occur shortly after sinus rhythm is restored.METHODSQT was measured in nine patients with AF who received two identical infusions of dofetilide: 1) before elective direct current cardioversion and 2) within 24 h of restoration of SR.RESULTSDuring AF, dofetilide did not prolong QT (baseline: 368 ± 48 ms vs. drug: 391 ± 60, p = NS) whereas during SR, QT was prolonged from 405 ± 55 to 470 ± 67 ms (p < 0.01). In four patients (group I), the SR dofetilide infusion was terminated early because QT prolonged to >500 ms, and one patient developed asymptomatic nonsustained TdP. The remaining five patients (group II) received the entire dose during SR. Although ΔQT was greater in group I during SR (91 ± 22 vs. 45 ± 25 ms, p < 0.05), plasma dofetilide concentrations during SR were similar in the two groups (2.72 ± 0.96 vs. 2.77 ± 0.25 ng/ml), and in AF (2.76 ± 1.22 ng/ml). ΔQT in SR correlated inversely with baseline SR heart rate (r = −0.69, p < 0.05), and QT dispersion developing during the infusion (r = 0.79, p < 0.01).CONCLUSIONSShortly after restoration of SR, there was increased sensitivity to QT prolongation by this IKr-specific blocker. Slower heart rates after cardioversion and QT dispersion during treatment appear to be important predictors of this response

Apgar score and perinatal death after one previous caesarean delivery

Objective To assess the impact of the indication for a previous caesarean section on the outcome of a subsequent delivery. Design Population-based cohort study. Setting Sweden. Population Women with two deliveries between 1987 and 2007 identified using the Swedish Medical Birth Registry. Methods The outcome of 69 133 pregnancies after one caesarean section was compared with the outcome of 487 610 pregnancies following one vaginal delivery. The indication for the first caesarean section was estimated using a new hierarcharchical system based on information from birth records. Main outcome measures Perinatal death, low Apgar score (less than seven at 5 minutes). Results Infants of women with one previous caesarean section were at increased risk of low Apgar score compared with infants of women with one previous vaginal delivery (OR, 2.0; 95% CI, 1.9-2.1). The risk estimate was reduced when adjustment for maternal and fetal/infant characteristics was made (OR, 1.6; 95% CI, 1.5-1.8). The corresponding crude and adjusted odds ratios for perinatal death were 1.6 (95% CI, 1.4-1.7) and 1.1 (95% CI, 1.0-1.2), respectively. The infant outcome of the delivery after one caesarean section was mainly dependent on the indication for the first-delivery caesarean section and, when no medical indication was present, no increase in risk was detected. Conclusions Infants of women with one previous caesarean section were at increased risk of low Apgar score and/or perinatal death compared with infants of women with one previous vaginal delivery. The results suggest that medical conditions, not the previous caesarean section per se, contributed to the increase in risk

Antimicrobial resistance in colonizing group B Streptococci before the implementation of a Swedish intrapartum antibiotic prophylaxis program

The prevalence of antibiotic resistance and their genetic determinants in colonizing group B streptococci (GBS) sampled in a Swedish nationwide survey was examined. In five GBS isolates (1.3%), kanamycin/amikacin resistance and the presence of the aphA-3 gene was identified. Three of these isolates carried the aad-6 gene and were streptomycin-resistant. Screening with kanamycin and streptomycin 1,000-mu g disks enabled a rapid and easy detection of these isolates. In all, 312/396 (79%) GBS were tetracycline-resistant and 95% of the examined isolates harbored the tetM gene. Among the 22 (5.5%) GBS resistant to erythromycin and/or clindamycin, the ermB gene was detected in nine isolates (41%) and erm(A/TR) in ten isolates (45%). A high level of erythromycin and clindamycin resistance with minimum inhibitory concentrations (MICs) > 256 mg/L was found in four serotype V isolates that harbored ermB. The erythromycin/clindamycin resistance was distributed among all of the common serotypes Ia, Ib, II, III, IV, and V, but was not present in any of the 44 serotype III isolates associated to clonal complex 17. Screening for penicillin resistance with 1-mu g oxacillin disks showed a homogenous population with a mean inhibition zone of 20 mm. A change in the present oxacillin breakpoints for GBS is suggested

A live video observatory reveals temporal processes at a shelf-depth whale-fall

There have been very few studies of temporal processes at chemosynthetic ecosystems, even at relatively more accessible shallow water sites. Here we report the development and deployment of a simple cabled video observatory at ≈ 30 m water depth in Gullmarsfjorden, Sweden. The camera provides a live video feed to the internet of faunal activity in the experiments, which to date have included 5 separate whale-fall deployments. Our data suggest that the time to decomposition of small cetacean carcasses at shelf-depth settings is considerably slower than at deep-sea sites. We have also provided a new methodology for the deployment of low-cost live video observatories at up to 30 m water depth, which can be used both for research and outreach activities