Baseline characteristics of participants according to the time of data collection and in total; figures are presented as N (%) unless otherwise stated.

Baseline characteristics of participants according to the time of data collection and in total; figures are presented as N (%) unless otherwise stated.</p

Possible pathways of care for atrial fibrillation (AF) in Brazil.

* In Butantan, secondary care includes the specialised cardiology unit (Peri-Peri) and the outpatient clinic at the Hospital Universitario from the Universidade de Sao Paulo. ** There are no tertiary hospitals in Butantan. Solid line refers to a pathway that is always or nearly always available in Butantan; dotted line refers to a pathway that is not always or rarely available.</p

Study flow chart.

BackgroundAtrial fibrillation (AF) is a major risk factor for stroke. To enable improvements to AF diagnosis and follow-up care, understanding current patient pathways and barriers to optimal care are essential. We investigated the patient care pathways and their drivers, and the impact of the COVID-19 pandemic on patient pathways in a middle-income country setting, Brazil.MethodsThis mixed-methods study in São Paulo, included adults (≥18y) with AF from 13 primary/secondary healthcare facilities. Surveys using baseline, follow-up (administered ≥two months after baseline) and COVID-19 questionnaires (quantitative), and three focus group discussions (FGDs) were conducted. Minimum sample size for the quantitative component was 236 and we aimed to reach saturation with at least three FGDs for the qualitative component. Descriptive statistics were used for quantitative data and a content analysis was used for qualitative data to identify themes related to AF diagnosis and follow-up care.Results267 participants completed the baseline questionnaire: 25% were diagnosed in primary care, 65% in an emergency or inpatient department. At follow-up (n = 259), 31% visited more than one facility for AF care, and 7% had no follow-up. Intervals between international normalised ratio (INR) tests were increased during the pandemic, and the number of healthcare visits and availability of medication were reduced. Seventeen patients participated in three FGDs and revealed that AF diagnosis often occurred following a medical emergency and patients often delay care-seeking due to misconceptions about AF symptoms. Long waiting times, doctor/patient interactions and health system factors, such as doctor availability and the referral system, influence where participants visited for follow-up care.ConclusionsLack of public awareness and underdeveloped primary healthcare lead to delayed diagnosis, which impacts clinical outcomes and excess patient and healthcare system costs. Health system, care-provider, and pandemic factors disrupt timely and effective continuity of care.</div

Impacts from the COVID-19 pandemic on AF follow-up care, as mentioned by participants.

Impacts from the COVID-19 pandemic on AF follow-up care, as mentioned by participants.</p

Coding tree from qualitative analysis.

BackgroundAtrial fibrillation (AF) is a major risk factor for stroke. To enable improvements to AF diagnosis and follow-up care, understanding current patient pathways and barriers to optimal care are essential. We investigated the patient care pathways and their drivers, and the impact of the COVID-19 pandemic on patient pathways in a middle-income country setting, Brazil.MethodsThis mixed-methods study in São Paulo, included adults (≥18y) with AF from 13 primary/secondary healthcare facilities. Surveys using baseline, follow-up (administered ≥two months after baseline) and COVID-19 questionnaires (quantitative), and three focus group discussions (FGDs) were conducted. Minimum sample size for the quantitative component was 236 and we aimed to reach saturation with at least three FGDs for the qualitative component. Descriptive statistics were used for quantitative data and a content analysis was used for qualitative data to identify themes related to AF diagnosis and follow-up care.Results267 participants completed the baseline questionnaire: 25% were diagnosed in primary care, 65% in an emergency or inpatient department. At follow-up (n = 259), 31% visited more than one facility for AF care, and 7% had no follow-up. Intervals between international normalised ratio (INR) tests were increased during the pandemic, and the number of healthcare visits and availability of medication were reduced. Seventeen patients participated in three FGDs and revealed that AF diagnosis often occurred following a medical emergency and patients often delay care-seeking due to misconceptions about AF symptoms. Long waiting times, doctor/patient interactions and health system factors, such as doctor availability and the referral system, influence where participants visited for follow-up care.ConclusionsLack of public awareness and underdeveloped primary healthcare lead to delayed diagnosis, which impacts clinical outcomes and excess patient and healthcare system costs. Health system, care-provider, and pandemic factors disrupt timely and effective continuity of care.</div

STROBE statement—Checklist of items that should be included in reports of <i>cross-sectional studies</i>.

STROBE statement—Checklist of items that should be included in reports of cross-sectional studies.</p

Effects of calcium, magnesium, and potassium concentrations on ventricular repolarization in unselected individuals.

Background: Subclinical changes on the electrocardiogram are risk factors for cardiovascular mortality. Recognition and knowledge of electrolyte associations in cardiac electrophysiology are based on only in vitro models and observations in patients with severe medical conditions.Objectives: This study sought to investigate associations between serum electrolyte concentrations and changes in cardiac electrophysiology in the general population.Methods: Summary results collected from 153,014 individuals (54.4% women; mean age 55.1 ± 12.1 years) from 33 studies (of 5 ancestries) were meta-analyzed. Linear regression analyses examining associations between electrolyte concentrations (mmol/l of calcium, potassium, sodium, and magnesium), and electrocardiographic intervals (RR, QT, QRS, JT, and PR intervals) were performed. The study adjusted for potential confounders and also stratified by ancestry, sex, and use of antihypertensive drugs.Results: Lower calcium was associated with longer QT intervals (-11.5 ms; 99.75% confidence interval [CI]: -13.7 to -9.3) and JT duration, with sex-specific effects. In contrast, higher magnesium was associated with longer QT intervals (7.2 ms; 99.75% CI: 1.3 to 13.1) and JT. Lower potassium was associated with longer QT intervals (-2.8 ms; 99.75% CI: -3.5 to -2.0), JT, QRS, and PR durations, but all potassium associations were driven by use of antihypertensive drugs. No physiologically relevant associations were observed for sodium or RR intervals.Conclusions: The study identified physiologically relevant associations between electrolytes and electrocardiographic intervals in a large-scale analysis combining cohorts from different settings. The results provide insights for further cardiac electrophysiology research and could potentially influence clinical practice, especially the association between calcium and QT duration, by which calcium levels at the bottom 2% of the population distribution led to clinically relevant QT prolongation by >5 ms.</p