Effects of enriched-potassium diet on cardiorespiratory outcomes in experimental non-ischemic chronic heart failure

Background Chronic heart failure (CHF) is a global health problem. Increased sympathetic outflow, cardiac arrhythmogenesis and irregular breathing patterns have all been associated with poor outcomes in CHF. Several studies showed that activation of the renin-angiotensin system (RAS) play a key role in CHF pathophysiology. Interestingly, potassium (K+) supplemented diets showed promising results in normalizing RAS axis and autonomic dysfunction in vascular diseases, lowering cardiovascular risk. Whether subtle increases in dietary K+ consumption may exert similar effects in CHF has not been previously tested. Accordingly, we aimed to evaluate the effects of dietary K+ supplementation on cardiorespiratory alterations in rats with CHF. Methods Adult male Sprague–Dawley rats underwent volume overload to induce non-ischemic CHF. Animals were randomly allocated to normal chow diet (CHF group) or supplemented K+ diet (CHF+K+ group) for 6 weeks. Cardiac arrhythmogenesis, sympathetic outflow, baroreflex sensitivity, breathing disorders, chemoreflex function, respiratory–cardiovascular coupling and cardiac function were evaluated. Results Compared to normal chow diet, K+ supplemented diet in CHF significantly reduced arrhythmia incidence (67.8 ± 15.1 vs. 31.0 ± 3.7 events/hour, CHF vs. CHF+K+), decreased cardiac sympathetic tone (ΔHR to propranolol: − 97.4 ± 9.4 vs. − 60.8 ± 8.3 bpm, CHF vs. CHF+K+), restored baroreflex function and attenuated irregular breathing patterns. Additionally, supplementation of the diet with K+ restores normal central respiratory chemoreflex drive and abrogates pathological cardio-respiratory coupling in CHF rats being the outcome an improved cardiac function. Conclusion Our findings support that dietary K+ supplementation in non-ischemic CHF alleviate cardiorespiratory dysfunction.

Evaluating differences in respiratory motion estimates during radiotherapy: a single planning 4DMRI versus daily 4DMRI

Background In radiotherapy, respiratory-induced tumor motion is typically measured using a single four-dimensional computed tomography acquisition (4DCT). Irregular breathing leads to inaccurate motion estimates, potentially resulting in undertreatment of the tumor and unnecessary dose to healthy tissue. The aim of the research was to determine if a daily pre-treatment 4DMRI-strategy led to a significantly improved motion estimate compared to single planning 4DMRI (with or without outlier rejection). Methods 4DMRI data sets from 10 healthy volunteers were acquired. The first acquisition simulated a planning MRI, the respiratory motion estimate (constructed from the respiratory signal, i.e. the 1D navigator) was compared to the respiratory signal in the subsequent scans (simulating 5–29 treatment fractions). The same procedure was performed using the first acquisition of each day as an estimate for the subsequent acquisitions that day (2 per day, 4–20 per volunteer), simulating a daily MRI strategy. This was done for three outlier strategies: no outlier rejection (NoOR); excluding 5% of the respiratory signal whilst minimizing the range (Min95) and excluding the datapoints outside the mean end-inhalation and end-exhalation positions (MeanIE). Results The planning MRI median motion estimates were 27 mm for NoOR, 18 mm for Min95, and 13 mm for MeanIE. The daily MRI median motion estimates were 29 mm for NoOR, 19 mm for Min95 and 15 mm for MeanIE. The percentage of time outside the motion estimate were for the planning MRI: 2%, 10% and 32% for NoOR, Min95 and MeanIE respectively. These values were reduced with the daily MRI strategy: 0%, 6% and 17%. Applying Min95 accounted for a 30% decrease in motion estimate compared to NoOR. Conclusion A daily MRI improved the estimation of respiratory motion as compared to a single 4D (planning) MRI significantly. Combining the Min95 technique with a daily 4DMRI resulted in a decrease of inclusion time of 6% with a 30% decrease of motion. Outlier rejection alone on a planning MRI often led to underestimation of the movement and could potentially lead to an underdosage. Trial registration: protocol W15_373#16.007

Technical Advances in Respiratory Rate using Fusion Methods: A Review

Respiratory rate (BR) is a basic biological variable that is employed in a range of therapeutic applications. Yet, clinicians manually measure breaths while diagnostically ignoring RR's value. An irregular breathing rate is typically the first indication of a debilitating condition. In healthcare settings, a reliable estimate of respiratory rate is crucial. Traditional methods estimate RR using either ECG or PPG. However, there is a lack of consensus among existing algorithms in order to improve RR detection performance. One easy method is to fuse the best performing algorithms, which may easily improve the RR estimation. In this review, we will look at how modulation may be used to identify breathing rates using ECG or PPG.

The Prevalence of Symptoms of Life-Threatening Events in Infants of the First Year of Life: a Cross-Sectional Population Study

Background.The prevalence of symptoms of life-threatening events in infants was previously studied using hospital data. However, not all parents in the event of such symptoms seek medical help in the hospital.Objective.Our aim was to identify the prevalence and risk factors of life-threatening events in infants in the first year of life.Methods.In the period from November 2017 to February 2018, we interviewed mothers who have children in their second year of life who are registered at children's outpatient clinics in Syktyvkar. Respondents noted episodes of absent, infrequent or irregular breathing, blanching or cyanosis of the skin, changes in muscle tone (hypo- or hypertonia), changes in the level of responses that occurred in infancy. The prevalence of symptoms of life-threatening events was estimated based on the total number of infants in the first year of life (n = 3088) who lived in Syktyvkar as of January 1, 2018.Results.At least one symptom of life-threatening events in infancy was reported by 43 (4.3%) of the 1001 mothers surveyed. The prevalence of symptoms was 429.5 [95% confidence interval (CI) 321–574] per 10,000 children of the corresponding age. Independent predictors of life-threatening events in children of the first year of life were sudden deaths of relatives under the age of 50 years [odds ratio (OR) 2.4; 95% CI 1.1–5.3], cases of pre-syncope or syncope in relatives (OR 4.4, 95% CI 2.1–9.0), artificial feeding of infants (OR 4.0, 95% CI 1.5–11.2). The sensitivity of the model, which took into account the presence of at least one of the three predictors, was 19% (8/43), specificity — 99% (2/958).Conclusion.The issue of the occurrence of life-threatening events in an infant can impact every 25th family. In every fifth infant, the occurrence of symptoms of life-threatening events can be predicted based on risk factors.