Pulmonary vein isolation as an end point for left atrial circumferential ablation of atrial fibrillation.

OBJECTIVES: We sought to determine whether elimination of pulmonary vein (PV) arrhythmogenicity is necessary for the efficacy of left atrial circumferential ablation (LACA) for atrial fibrillation (AF). BACKGROUND: The PVs often provide triggers or drivers of AF. It has been shown that LACA is more effective than PV isolation in eliminating paroxysmal AF. However, it is not clear whether complete PV isolation is necessary for the efficacy of LACA. METHODS: In 60 consecutive patients with paroxysmal (n = 39) or chronic (n = 21) AF (mean age 53 +/- 12 years), LACA to encircle the left- and right-sided PVs, with additional lines in the posterior left atrium and along the mitral isthmus, was performed under the guidance of an electroanatomic navigation system. The PVs were mapped with a decapolar ring catheter before and after LACA. If PV isolation was incomplete, no attempts at complete isolation were made. RESULTS: After LACA, there was incomplete electrical isolation of one or more PVs in 48 (80%) of the 60 patients. The prevalence of PV tachycardias was 82% before and 8% after LACA (p < 0.001). At 11 +/- 1 months of follow-up, 10 (83%) of the 12 patients with complete and 39 (81%) of 48 patients with incomplete PV isolation were free from recurrent AF without antiarrhythmic drug therapy (p = 1.0). A successful outcome was not related to the number of completely isolated PVs per patient (p = 0.6). CONCLUSIONS: Left atrial circumferential ablation modifies the arrhythmogenic substrate within the PVs. Complete electrical isolation of the PVs is not a requirement for a successful outcome after LACA.     

Childhood anaplastic large cell lymphoma has a high incidence of ALK gene rearrangement as determined by immunohistochemical staining and fluorescent in situ hybridisation: a genetic and pathological correlation

Anaplastic large cell lymphoma (ALCL) comprises 10-15% of childhood non-Hodgkin lymphomas (NHL). Systemic ALCL is highly associated with anaplastic lymphoma kinase (ALK) gene translocations with over-expression of ALK protein. We studied ALK rearrangements using fluorescence in situ hybridisation (FISH) and ALK immunohistochemical staining in 43 paediatric systemic ALCLs. FISH (performed on 35 cases) identified a translocation in 29 cases (83%). Immunohistochemistry identified ALK over-expression in 42/43 cases (97%) with the single ALK-negative case demonstrating an ALK rearrangement by FISH, indicating 100% incidence of ALK translocations.     

Osteoporosis and fractures in postmenopausal women using estrogen

BACKGROUND: Previous studies demonstrate that postmenopausal women who use estrogen are somewhat protected from bone loss and fractures compared with nonusers, but the extent to which estrogen users remain at risk for osteoporosis and fractures is uncertain. OBJECTIVE: To determine long-term probabilities for incident fractures among postmenopausal estrogen users. METHODS: We examined data from the Study of Osteoporotic Fractures, a prospective cohort study with 10 years of follow-up (1986-1999). This cohort includes 8816 women 65 years and older from community settings in 4 areas of the United States. MAIN OUTCOME MEASURES: Hip, wrist, vertebral, and nonvertebral fractures. RESULTS: At baseline, using criteria developed by the World Health Organization, 40% of continuous estrogen users were osteopenic and 13% were osteoporotic at the hip or spine. Although women currently using estrogen lost less bone density than past users or those who never used estrogen, all user groups on average lost bone from the hip and calcaneus. During 10 years of observation, the adjusted probability of nonvertebral fractures was 19.6% for continuous estrogen users, similar to current partial users and lower than past users and those who never used estrogen (P<.05). These comparisons were similar for hip, wrist, and vertebral fractures. CONCLUSIONS: Although estrogen use is associated with reduced prevalence of low bone density, less bone loss, and lower probabilities for fractures, osteoporosis and fractures are common in older women who used estrogen continuously since menopause. Estrogen users should be considered in strategies designed to detect, prevent, and treat osteoporosis.     

Neoadjuvant chemoradiotherapy for adenocarcinoma of the pancreas: analysis of histopathology and outcome

To examine the histopathologic effect of neoadjuvant therapy and its impact on survival in patients with carcinoma of the pancreas, we retrospectively reviewed the records of 116 patients who underwent resections for pancreatic cancer from 1987 to 2000. Median follow-up of surviving patients was 19 mo(range 4-150 mo). Preoperative chemotherapy was administered in 61 patients (53%) and consisted of 5-fluorouracil/mitomycin C in 35 patients and gemcitabine in 26 patients, given concurrently with external beam radiation (5040 cGy). All resections were performed with curative intent (98 Whipples, 11 total, 6 distal, and 1 central pancreatectomy). Histopathologic examination included an estimation of the amount of fibrosis present in the tumor specimen (expressed as the percentage of fibrosis identified relative to the amount of neoplastic cells present). The mean fibrosis level for the series was 56% (range 5% to 100%). The administration of neoadjuvant therapy resulted in greater fibrosis (73%) than no preoperative treatment (38%) (p = 0.0001). Higher mean fibrosis levels were observed in patients with negative lymph nodes (p = 0.0006) and negative margins (p = 0.05). Factors associated with improved survival(log rank test) included: negative margins (p = 0.001), negative lymph nodes (p = 0.03), and use of neoadjuvant therapy (p = 0.03). Median survival in the neoadjuvant group was 23 mo vs 16 mo without preoperative therapy (p = 0.03). In conclusion, the use of neoadjuvant therapy resulted in a greater degree of fibrosis in the specimen. Patients with negative margins and negative lymph nodes had a greater amount of fibrosis present, and these were significant predictors of improved outcome. Although retrospective,this series suggests an improvement in survival in patients treated with neoadjuvant therapy.     

Noninvasive assessment of coronary vasodilation using magnetic resonance angiography

OBJECTIVES: The purpose of this study was to investigate the use of coronary magnetic resonance angiography (MRA) for assessing human epicardial coronary artery vasodilation. BACKGROUND: Coronary vasodilation plays a vital role in the human coronary circulation. Previous studies of epicardial coronary vasodilation have used invasive coronary angiography. Coronary MRA may provide an alternative noninvasive method to directly assess changes in coronary size. METHODS: Thirty-two subjects were studied: 12 patients (age 55 +/- 18 years) and 20 healthy subjects (age 34 +/- 4 years). High-resolution multi-slice spiral coronary MRA (in-plane resolution of 0.52 to 0.75 mm) was performed before and after sublingual nitroglycerin (NTG). Quantitative analysis of coronary vasodilation was performed on cross-sectional images of the right coronary artery (RCA). A time-course analysis of coronary vasodilation was performed in a subset of eight subjects for 30 min after NTG. Signal-to-noise ratio was also measured on the in-plane RCA images. RESULTS: Coronary MRA demonstrated a 23% increase in cross-sectional area after NTG (16.9 +/- 7.8 mm2 to 20.8 +/- 8.9 mm2, p <0.0001), with significant vasodilation between 3 and 15 min after NTG on time-course analysis. The MRA measurements had low interobserver variability (< or =5%) and good correlation with X-ray angiography (r=0.98). The magnitude of vasodilation correlated with baseline cross-sectional area (r=0.52, p=0.03) and age (r=0.40, p=0.019). Post-NTG images also demonstrated a 31% improvement in coronary signal-to-noise ratio (p = 0.002). CONCLUSIONS: Nitroglycerin-enhanced coronary MRA can noninvasively measure coronary artery vasodilation and is a promising noninvasive technique to study coronary vasomotor function.     

Rapid diagnosis of spontaneous bacterial peritonitis with leukocyte esterase reagent strips in a European and in an American center

BACKGROUND: Timely diagnosis and treatment of spontaneous bacterial peritonitis (SBP) are essential to survival. The purpose of the present paper was to evaluate leukocyte esterase reagent strips (Nephur-Test and MultistixSG10) in the bedside diagnosis of SBP. METHODS: Patients with cirrhotic ascites were prospectively included in France (center 1) and in the USA (center 2). Paracenteses were performed on admission and repeated as indicated. Bedside reagent strip testing was performed on the ascitic fluid and compared to manual cell count with differential and ascitic fluid culture. In center 1, the Nephur-Test was tested in all cases, with dual testing with MultistixSG10 in a subgroup. In center 2, all cases had dual testing. Spontaneous bacterial peritonitis was defined as a polymorphonuclear ascites count > or =250/microL. RESULTS: A total of 184 samples was obtained in 76 patients. Center 1 included 151 samples from 53 patients. Seven samples had SBP, obtained in six patients. Center 2 included 33 samples from 23 patients. Six samples had SBP, obtained in five patients. The sensitivity, specificity, positive and negative predictive value of the reagent strips were as follows. Center 1/Nephur-Test: 86%, 100%, 100%, 99%; center 1/MultistixSG10: 100%, 100%, 100%, 100%; center 2/Nephur-Test: 100%, 92.5%, 75%, 100%; center 2/MultistixSG10: 83%, 96%, 83%, 96%. CONCLUSION: Leukocyte esterase reagent strips may provide a rapid bedside diagnosis of SBP.     

Feedback and the mini clinical evaluation exercise

We studied the nature of feedback given after a miniCEX. We investigated whether the feedback was interactive; specifically, did the faculty allow the trainee to react to the feedback, enable self-assessment, and help trainees to develop an action plan for improvement. Finally, we investigated the number of types of recommendations given by faculty. One hundred and seven miniCEX feedback sessions were audiotaped. The faculty provided at least 1 recommendation for improvement in 80% of the feedback sessions. The majority of the sessions (61%) involved learner reaction, but in only 34% of the sessions did faculty ask for self-assessment from the intern and only 8% involved an action plan from the faculty member. Faculty are using the miniCEX to provide recommendations and often encourage learner reaction, but are underutilizing other interactive feedback methods of self-assessment and action plans. Programs should consider both specific training in feedback and changes to the miniCEX form to facilitate interactive feedback.     

Ice cores record significant 1940s Antarctic warmth related to tropical climate variability

Although the 20th Century warming of global climate is well known, climate change in the high-latitude Southern Hemisphere (SH), especially in the first half of the century, remains poorly documented. We present a composite of water stable isotope data from high-resolution ice cores from the West Antarctic Ice Sheet. This record, representative of West Antarctic surface temperature, shows extreme positive anomalies in the 1936–45 decade that are significant in the context of the background 20th Century warming trend. We interpret these anomalies—previously undocumented in the high-latitude SH—as indicative of strong teleconnections in part driven by the major 1939–42 El Niño. These anomalies are coherent with tropical sea-surface temperature, mean SH air temperature, and North Pacific sea-level pressure, underscoring the sensitivity of West Antarctica's climate, and potentially its ice sheet, to large-scale changes in the global climate.     

Mechanism of recurrence after radiofrequency catheter ablation of atrial fibrillation guided by complex fractionated atrial electrograms

Background A better understanding of the mechanisms of recurrent atrial fibrillation (AF) after radiofrequency ablation of complex, fractionated atrial electrograms (CFAEs) may be helpful for refining AF ablation strategies. Methods and results Electrogram-guided ablation (EGA) was repeated in 30 consecutive patients (mean age = 59 ± 8 years) for recurrent paroxysmal AF, 10 ± 4 months after the first ablation. During the first procedure, CFAEs were targeted without isolating all pulmonary veins (PVs). During repeat ablation, all PVs and the superior vena cava (SVC) were mapped with a circular catheter and the left atrium was mapped for CFAEs. EGA was performed until AF was rendered noninducible or all identified CFAEs were eliminated. During repeat ablation, ≥1 PV tachycardia was found in 83 PVs in 29 of the 30 patients (97%). Among these 83 PVs, 63 (76%) had not been completely isolated previously. During repeat ablation, drivers originating in a PV or PV antrum were identified only after infusion of isoproterenol (20 μg/min) in 12 patients (40%). At 9 ± 4 months of follow-up after the repeat ablation procedure, 21 of the 30 patients (70%) were free from recurrent AF and flutter without antiarrhythmic drugs. Conclusions Recurrence of AF after EGA is usually due to PV tachycardias. Therefore, it may be preferable to systematically map and isolate all PVs during the first procedure. High-dose isoproterenol may be helpful to identify AF drivers.