Regional left atrial voltage in patients with atrial fibrillation

BACKGROUND: Regional differences in fibrosis, particularly related to the posterior wall and septum, may be important in atrial fibrillation (AF). Using electroanatomic mapping, voltage can be used as a measure of fibrosis. OBJECTIVES: The purpose of this study was to determine if patients with AF have disproportionately lower voltage in the septal and posterior walls of the left atrium. METHODS: Sinus rhythm left atrial electroanatomic maps were used in serial patients presenting for left atrial ablation of AF (8-mm tip). Patients undergoing left atrial mapping for focal atrial tachycardia (AT) were used as a comparison group (4-mm tip). Animal experiments were performed to assess the influence of ablation catheter tip size on voltage amplitude. RESULTS: The posterior and septal walls exhibited the lowest voltages in both groups. Compared with the anterior wall, there was a 3.78-fold greater odds of finding a low-voltage point (<0.5 mV) in the septum (P <.001) and a 3.37-fold greater odds of finding a low-voltage point in the posterior wall (P <.001) in the AF patients; the proportion of low-voltage points by region were not significantly different in the AT group. In the animal model, the mean voltage obtained from an 8-mm ablation catheter was significantly higher (0.30 +/- 0.17 mV) than that obtained from the same points using a 4-mm catheter (0.22 +/- 0.17, P = .05). CONCLUSION: Regional differences in voltage are present in patients with atrial arrhythmias, with AF patients exhibiting significantly more low-voltage areas in the septum and posterior walls.     

Deep dermal burn injury results in scarless wound healing in the ovine fetus

Early to mid-term fetuses heal cutaneous incisional wounds without scars; however, fetal response to burn injury has not been ascertained. We present a fetal model of thermal injury and subsequent analysis of fetal and lamb response to burn injury. A reproducible deep dermal burn injury was created in the fetus by application of water at 66 degrees C for 7 seconds, and at 82 degrees C for 10 seconds to the lamb. Macroscopically, the area of fetal scald was undetectable from day 7 post injury, while all lamb scalds were readily identified and eventually healed with scarring. Using a five-point histopathology scoring system for alteration in tissue morphology, differences were detected between control and scalded skin at all stages in lamb postburn, but no difference was detected in the fetal model after day 7. There were also large differences in content of alpha-smooth muscle actin and transforming growth factor-beta1 between control and scalded lamb and these differences were statistically significant at day 14 (P < 0.01). This novel model of fetal and lamb response to deep dermal injury indicates that the fetus heals a deep burn injury in a scarless fashion. Further elucidation of this specific fetal process of burn injury repair may lead to improved outcome for patients with burn injury.     

Extracorporeal membrane oxygenation for postcardiotomy mechanical cardiovascular support in children with congenital heart disease

Extracorporeal membrane oxygenation (ECMO) is increasingly used to support postcardiotomy cardiorespiratory failure in children with congenital heart disease. We report on survival outcomes and factors associated with survival for postcardiotomy ECMO patients.     

Antibiotic prescribing for chronic skin wounds in primary care

The aim of this study was to describe and quantify systemic antibiotic prescribing for patients with chronic skin wounds presenting at the primary care, nonspecialist setting. Data for 1 year were extracted from a general practice morbidity database comprising approximately 185,000 patients attending family medical practitioners in Wales. Patients with chronic wounds (PCW) were identified using Read Codes and compared with nonwound patients who were randomly selected after matching for age-band, sex, and general practice. PCW received a significantly greater number of antibiotic courses than nonwound patients (p<0.001). This increased level of prescribing was evident for flucloxacillin, co-amoxiclav, cefaclor, cefalexin, erythromycin, trimethoprim, metronidazole, and ciprofloxacin (p<0.01 for all). While PCW also had a significantly higher prevalence of diabetes (16.5% compared with 6.6%, p<0.001), and attended at general practice significantly more frequently than nonwound patients (median (interquartile range) of 25 (17-40) visits per year compared with 12 (4-20), p<0.001), importantly, exclusion of diabetic patients and analysis of the proportion of visits on which patients received antibiotics did not affect the significance of the difference in antibiotic consumption. These data show a strong association between occurrence of chronic wounds and prescribing of antibiotics in primary health care, and wide variation in the type and duration of antibiotic therapy for chronic wounds. Further work is now indicated to rationalize this prescribing and determine the role that this exposure to antibiotics plays in the prevalence of antibiotic resistance in this at-risk elderly population.     

Lymphatic drainage from the skin of the back to retroperitoneal and paravertebral lymph nodes in melanoma patients

Background: Preoperative lymphoscintigraphy (LS) with^99mTc antimony sulphide colloid is now part of the routine management of patients with intermediate thickness melanoma at the Sydney Melanoma Unit. Over a 13-year period, 1375 patients have been examined using LS, and we have observed many unusual lymphatic drainage pathways, including direct drainage through the body wall to retroperitoneal and paravertebral lymph nodes from the skin of the back. The aim of this study was to determine the incidence of such drainage in the 542 patients who had primary melanoma sites on the posterior trunk. Methods: The lymphoscintigrams performed on these patients were examined for the presence of direct lymphatic drainage through the posterior body wall to sentinel nodes in the retroperitoneal and paravertebral regions. Results: Lymphatic drainage directly through the body wall to such lymph nodes occurred in 14 of these 542 patients. Conclusions: Preoperative knowledge of the presence of this lymph drainage pattern may influence surgical management, and follow-up investigations in these patients can be tailored to ensure that the relevant areas are examined with anatomic imaging or F18-FDG PET scans.