Long-term follow-up after the mini-maze procedure

BACKGROUND: Atrial fibrillation (AF) is associated with significant morbidity and mortality. The standard to treat AF surgically is the Cox maze III procedure but owing to its complexity it is not performed on a regular basis. Meanwhile several maze variants have been developed but their long-term results are still not well known. METHODS: From November 1995 until May 2002 a mini-maze procedure was performed upon 77 patients aged 64 +/- 8.7 years with chronic symptomatic AF. Electrophysiological evaluation, magnetic resonance imaging, echocardiography and electrocardiographic evaluations were performed after 3 and 12 months. After a mean follow-up of 50 +/- 2.6 months a standard questionnaire was sent to all patients. RESULTS: Early and late mortality was 1.2% and 9.3% respectively. Actuarial survival was 91%, 90%, and 87% after 1, 3, and 5 years respectively. Left bundle branch block was an independent risk factor for late death (p = 0.02). Patients who were in sinus rhythm at follow-up had significantly better survival rate as compared with the patients still in AF. Seventy-one percent of patients were in sinus rhythm or paced by an atrial pacemaker. Predictors for restoration of sinus rhythm were absence of preoperative mitral insufficiency (p = 0.03) and larger left atrium (p = 0.04). The presence of preoperative tricuspid insufficiency (p = 0.03) and larger right atrium (p = 0.017) were predictors for postoperative pacemaker implantation. CONCLUSIONS: The mini-maze procedure can be carried out with satisfactory early and long-term results regarding mortality and restoration of sinus rhythm. Prophylactic implantation of biventricular pacemakers in patients with left bundle branch block may decrease late mortality. Every effort should be done to cure AF as it affects long-term survival.     

Structure Elucidation and Toxicity Analysis of the Byproducts Formed after Biodegradation of Aflatoxins B1 and B2 Using Extracts of Mentha arvensis

The aqueous extracts of leaves and shoots of Mentha arvensis were checked for their potential to biodegrade aflatoxin B1 and B2 (AFB1; 100 µg/L and AFB2; 50 µg/L) through in vitro assays. Overall, the results showed that leaf extract degrades aflatoxins more efficiently than the shoot extract. First, the pH, temperature and incubation time were optimized for maximum degradation by observing this activity at different temperatures between 25 and 60 °C, pH between 2 and 10 and incubation time from 3 to 72 h. In general, an increase in all these parameters significantly increased the percentage of biodegradation. In vitro trials on mature maize stock were performed under optimized conditions, i.e., pH 8, temperature 30 °C and an incubation period of 72 h. The leaf extract resulted in 75% and 80% biodegradation of AFB1 and AFB2, respectively. Whereas the shoot extract degraded both toxins up to 40–48%. The structural elucidation of degraded toxin products by LCMS/MS analysis showed seven degraded products of AFB1 and three of AFB2. MS/MS spectra showed that most of the products were formed by the loss of the methoxy group from the side chain of the benzene ring, the removal of the double bond in the terminal furan ring and the modification of the lactone group, indicating less toxicity compared to the parent compounds. The degraded products showed low toxicity against brine shrimps, confirming that M. arvensis leaf extract has significant potential to biodegrade aflatoxins.     

Holter monitoring in the diagnosis of stroke mechanism

BACKGROUND: Atrial fibrillation (AF), an important and treatable cause of ischaemic stroke, can occur as a sustained or a paroxysmal arrhythmia. Continuous cardiac rhythm monitoring (Holter monitoring) is often performed in stroke patients to identify paroxysmal AF, which is an indication for warfarin anti-coagulation in this patient population. AIM: The aim of this study was to assess the clinical utility of Holter monitoring in detecting occult AF in patients with possible cardioembolic stroke. METHODS: The medical records of ischaemic stroke patients consecutively hospitalized at a single academic centre during a one-year period were reviewed. Data regarding patient demographics, stroke characteristics, electrocardiography and echocardiography results and duration and findings of Holter monitoring were abstracted. The primary outcome was yield of newly diagnosed AF on Holter monitoring. RESULTS: Of 465 consecutive patients admitted with a diagnosis of new ischaemic stroke, 210 underwent Holter monitoring. The mean duration of monitoring was 22.8 +/- 4.0 h. Previously undiscovered AF was -identified in five cases (2.4%), all of which represented non-rheumatic AF. In three cases, the Holter test was negative despite AF documented on an admission electro-cardiogram. CONCLUSIONS: Holter monitoring can identify occult paroxysmal AF, assisting targeted secondary prevention in patients with new ischaemic stroke. However, the standard 24-h duration of monitoring probably under-estimates the prevalence of paroxysmal AF in this population. Prospective studies are indicated to evaluate the value of longer monitoring periods in stroke populations.