84 research outputs found
Novel non-invasive algorithm to identify the origins of re-entry and ectopic foci in the atria from 64-lead ECGs: A computational study.
Atrial tachy-arrhytmias, such as atrial fibrillation (AF), are characterised by irregular electrical activity in the atria, generally associated with erratic excitation underlain by re-entrant scroll waves, fibrillatory conduction of multiple wavelets or rapid focal activity. Epidemiological studies have shown an increase in AF prevalence in the developed world associated with an ageing society, highlighting the need for effective treatment options. Catheter ablation therapy, commonly used in the treatment of AF, requires spatial information on atrial electrical excitation. The standard 12-lead electrocardiogram (ECG) provides a method for non-invasive identification of the presence of arrhythmia, due to irregularity in the ECG signal associated with atrial activation compared to sinus rhythm, but has limitations in providing specific spatial information. There is therefore a pressing need to develop novel methods to identify and locate the origin of arrhythmic excitation. Invasive methods provide direct information on atrial activity, but may induce clinical complications. Non-invasive methods avoid such complications, but their development presents a greater challenge due to the non-direct nature of monitoring. Algorithms based on the ECG signals in multiple leads (e.g. a 64-lead vest) may provide a viable approach. In this study, we used a biophysically detailed model of the human atria and torso to investigate the correlation between the morphology of the ECG signals from a 64-lead vest and the location of the origin of rapid atrial excitation arising from rapid focal activity and/or re-entrant scroll waves. A focus-location algorithm was then constructed from this correlation. The algorithm had success rates of 93% and 76% for correctly identifying the origin of focal and re-entrant excitation with a spatial resolution of 40 mm, respectively. The general approach allows its application to any multi-lead ECG system. This represents a significant extension to our previously developed algorithms to predict the AF origins in association with focal activities
Dietary intake of fish, omega-3, omega-6 polyunsaturated fatty acids and vitamin D and the prevalence of psychotic-like symptoms in a cohort of 33 000 women from the general population
<p>Abstract</p> <p>Background</p> <p>Low intake of fish, polyunsaturated fatty acids (PUFA) and vitamin D deficiency has been suggested to play a role in the development of schizophrenia. Our aim was to evaluate the association between the intake of different fish species, PUFA and vitamin D and the prevalence of psychotic-like symptoms in a population-based study among Swedish women.</p> <p>Methods</p> <p>Dietary intake was estimated using a food frequency questionnaire among 33 623 women aged 30-49 years at enrolment (1991/92). Information on psychotic-like symptoms was derived from a follow-up questionnaire in the years 2002/03. Participants were classified into three predefined levels: low, middle and high frequency of symptoms. The association between diet and psychotic-like symptoms was summarized in terms of relative risks (RR) and corresponding 95% confidence intervals and was evaluated by energy-adjusted multinomial logistic regression.</p> <p>Results</p> <p>18 411 women were classified as having a low level of psychotic-like symptoms, 14 395 as middle and 817 as having a high level. The risk of high level symptoms was 53% (95% CI, 30-69%) lower among women who ate fish 3-4 times per week compared to women who never ate fish. The risk was also lower for women with a high intake of omega-3 and omega-6 PUFA compared to women with a lower intake of these fatty acids. The effect was most pronounced for omega-6 PUFAs. The RR comparing the highest to the lowest quartile of omega-6 PUFAs intake was 0.78 (95% CI, 0.64-0.97). The associations were J-shaped with the strongest reduced risk for an intermediate intake of fish or PUFA. For fatty fish (herring/mackerel, salmon-type fish), the strongest inverse association was found for an intermediate intake (RR: 0.81, 95% CI, 0.66-0.98), whereas a high intake of fatty fish was associated with an increased risk of psychotic-like symptoms (RR: 1.90, 95% CI, 1.34-2.70). Women in the highest compared with the lowest quartile of vitamin D consumption experienced a 37% (95% CI, 22-50%) lower risk of psychotic-like symptoms.</p> <p>Conclusion</p> <p>Our findings raise a possibility that adult women with a high intake of fish, omega-3 or omega-6 PUFA and vitamin D have a lower rate of psychotic-like symptoms.</p
Protocol for Project FACT: a randomised controlled trial on the effect of a walking program and vitamin B supplementation on the rate of cognitive decline and psychosocial wellbeing in older adults with mild cognitive impairment [ISRCTN19227688]
BACKGROUND: the prevalence of individuals with cognitive decline is increasing since the number of elderly adults is growing considerably. The literature provides promising results on the beneficial effect of exercise and vitamin supplementation on cognitive function both in cognitively healthy as well as in the demented elderly. METHODS/DESIGN: the design is a two-by-two factorial randomised controlled trial. The study population consists of independently living elderly, between 70 and 80 years old, with mild cognitive impairment (MCI). In the RCT the effect of two interventions, a walking program and vitamin supplementation, is examined. The walking program (WP) is a group-based program aimed at improving cardiovascular endurance; frequency two lessons a week; lesson duration one hour; program duration one year. Non-walking groups receive a placebo activity program (PAP) (i.e. low intensive non-aerobic group exercises, like stretching) with the same frequency, lesson and program duration. Vitamin supplementation consists of a single daily vitamin supplement containing 50 mg B6, 5 mg folic acid and 0,4 mg B12 for one year. Subjects not receiving vitamin supplements are daily taking an identically looking placebo pill, also for a year. Participants are randomised to four groups 1) WP and vitamin supplements; 2) WP and placebo supplements; 3) PAP and vitamin supplements; 4) PAP and placebo supplements. Primary outcome measures are measures of cognitive function. Secondary outcomes include psychosocial wellbeing, physical activity, cardiovascular endurance and blood vitamin levels. DISCUSSION: no large intervention study has been conducted yet on the effect of physical activity and vitamin supplementation in a population-based sample of adults with MCI. The objective of the present article is to describe the design of a randomised controlled trial examining the effect of a walking program and vitamin B supplementation on the rate of cognitive decline in older adults with MCI
Nutrition and cancer: A review of the evidence for an anti-cancer diet
It has been estimated that 30–40 percent of all cancers can be prevented by lifestyle and dietary measures alone. Obesity, nutrient sparse foods such as concentrated sugars and refined flour products that contribute to impaired glucose metabolism (which leads to diabetes), low fiber intake, consumption of red meat, and imbalance of omega 3 and omega 6 fats all contribute to excess cancer risk. Intake of flax seed, especially its lignan fraction, and abundant portions of fruits and vegetables will lower cancer risk. Allium and cruciferous vegetables are especially beneficial, with broccoli sprouts being the densest source of sulforophane. Protective elements in a cancer prevention diet include selenium, folic acid, vitamin B-12, vitamin D, chlorophyll, and antioxidants such as the carotenoids (α-carotene, β-carotene, lycopene, lutein, cryptoxanthin). Ascorbic acid has limited benefits orally, but could be very beneficial intravenously. Supplementary use of oral digestive enzymes and probiotics also has merit as anticancer dietary measures. When a diet is compiled according to the guidelines here it is likely that there would be at least a 60–70 percent decrease in breast, colorectal, and prostate cancers, and even a 40–50 percent decrease in lung cancer, along with similar reductions in cancers at other sites. Such a diet would be conducive to preventing cancer and would favor recovery from cancer as well
Wave similarity mapping shows the spatiotemporal distribution of fibrillatory wave complexity in the human right atrium during paroxysmal and chronic atrial fibrillation
Introduction: The complexity of waveforms during atrial fibrillation may reflect critical activation patterns for the arrhythmia perpetuation. In this study, we introduce a novel concept of map, based on the analysis of the wave morphology, which gives a direct evidence in the human right atrium on the spatiotemporal distribution of fibrillatory wave complexity in paroxysmal (PAF) and chronic (CAF) atrial fibrillation. Methods and Results: Electrograms were recorded from a 64-electrode catheter in the right atrium of 15 patients during PAF (n = 8) and CAF (n = 7). Wave similarity maps were constructed by calculating the degree of morphological similarity of activation waves (S) at each atrial site and by following its temporal evolution. During PAF the spatiotemporal distribution of the waveforms was highly consistent across the subjects and was determined by the anatomic location. Wave similarity maps showed the existence of an extended area with low similarity index, which covered the low posteroseptal atrium (S = 0.28 \uc2\ub1 0.09) and the septal region (S = 0.22 \uc2\ub1 0.04), and the presence of a large tongue with high similarity index, which penetrated the lateral wall (S = 0.55 \uc2\ub1 0.08) starting from the high anterolateral atrium (S = 0.54 \uc2\ub1 0.06). A completely different spatiotemporal pattern was seen during CAF. No distinct regions with different similarity indexes were recognized, but a uniformly distributed low similarity index (S = 0.27 \uc2\ub1 0.07) was found. The spatial pattern was highly stable in time with fluctuations of S < 0.04. Conclusion: Quantification of the spatiotemporal distribution of fibrillatory wave complexity is feasible in humans by wave similarity mapping. Anatomic anchoring of waveforms during PAF and pattern destruction during CAF was determined
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