Left atrial (LA) strain parameters have been demonstrated to be valuable predictors of atrial fibrillation (AF) in several patient cohorts. The purpose of this study was to investigate whether LA strain, assessed by two-dimensional speckle-tracking echocardiography, can be used to predict the development of AF in the general population. This prospective longitudinal study included 4466 participants from the fifth Copenhagen City Heart Study. All participants underwent a health examination, including echocardiographic measurements of LA strain. Participants with prevalent AF at baseline were excluded. The primary endpoint was incident AF. During a median follow-up period of 5.3 years, 154 (4.3%) participants developed AF. In univariable analysis, peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and LA strain during the conduit phase were significantly associated with the development of AF. PALS [hazard ratio (HR) 1.05, 95% confidence interval (CI) (1.03–1.07), P < 0.001, per 1% decrease] and PACS (HR 1.08, 95% CI (1.05–1.12), P < 0.001, per 1% decrease] remained independent predictors of AF in multivariable analysis. In addition, PALS and PACS remained significantly associated with AF development even in participants with normal-sized atria and normal left ventricular (LV) systolic function. In the general population, PALS and PACS independently predict incident AF. These findings remained consistent even in participants with normal-sized LA and normal LV systolic function.

Aims : Left atrial (LA) function assessed by two-dimensional speckle-tracking echocardiography has shown increasing clinical and prognostic significance. We sought to establish age- and sex-based normative values of LA strain in the general population and to assess the prognostic yield of lower limits of normality of LA strain in relation to future atrial fibrillation (AF). Methods and results : We determined normative values of peak atrial longitudinal strain (PALS), peak atrial contraction strain (PACS), and LA strain during the conduit phase (LACS) in 1641 healthy participants included in the fifth Copenhagen City Heart Study. In a secondary analysis, a validation cohort of 2016 participants, regardless of health status, were included to assess the prognostic value of the established reference values. In the healthy cohort, median age was 46 years (interquartile range 32–57), 62% were female. Median PALS, PACS, and LACS and corresponding limits of normality in the healthy participants were 39.4% (23.0–67.6%), 15.5% (6.4–28.0%), and 23.7% (8.8–44.8%), respectively. There was a tendency of lower values of PALS and LACS in males and older participants, while PACS tended to increase with advancing age. The established lower limits of normality showed high specificity (range 93–94%) regarding future AF, implying a low risk of developing AF in participants with LA strain above the lower limits of normality in their respective sex and age group. Conclusion : We report normal values for LA strain stratified by sex and age. The lower limits of normality showed high specificity regarding future AF.

High-dose inactivated influenza vaccine has been shown to provide protection against influenza that is superior to that with the standard dose. However, data from individually randomized trials on the effectiveness of the high-dose vaccine against severe outcomes are limited. In this pragmatic, open-label, randomized, controlled trial conducted in Denmark during the 2022-2023, 2023-2024, and 2024-2025 influenza seasons, we assigned older adults (≥65 years of age) to receive the high dose of the inactivated influenza vaccine or the standard dose. Data collection relied on nationwide administrative health registries. The primary end point was hospitalization for influenza or pneumonia that occurred from 14 days after vaccination through May 31 of the following year. Of the 332,438 participants who underwent randomization, 166,218 were assigned to receive the high-dose vaccine and 166,220 to receive the standard-dose vaccine. The mean (±SD) age of the participants was 73.7±5.8 years, and 161,538 participants (48.6%) were women. A primary end-point event occurred in 1138 participants (0.68%) in the high-dose group and in 1210 (0.73%) in the standard-dose group (relative vaccine effectiveness, 5.9%; 95.2% confidence interval [CI], -2.1 to 13.4; P = 0.14). Hospitalization for influenza occurred in 0.06% of the participants in the high-dose group and in 0.11% of those in the standard-dose group (relative vaccine effectiveness, 43.6%; 95.2% CI, 27.5 to 56.3); hospitalization for pneumonia occurred in 0.63% and 0.63%, respectively (relative effectiveness, 0.5%; 95.2% CI, -8.6 to 8.8); hospitalization for cardiorespiratory disease in 2.25% and 2.38% (relative effectiveness, 5.7%; 95.2% CI, 1.4 to 9.9); hospitalization for any cause in 9.38% and 9.58% (relative effectiveness, 2.1%; 95.2% CI, -0.1 to 4.3), and death from any cause in 0.67% and 0.66% (relative effectiveness, -2.5%; 95.2% CI, -11.6 to 5.9). The incidence of serious adverse events was similar in the two groups. In this trial, a high-dose inactivated influenza vaccine did not result in a significantly lower incidence of hospitalization for influenza or pneumonia than a standard dose among older adults. (Funded by Sanofi; DANFLU-2 ClinicalTrials.gov number, NCT05517174; EU Clinical Trials Register number, 2022-500657-17-00.).

Background: Pressure-strain loop analyses is a noninvasive technique capable of evaluating myocardial work. Reference values are needed to benchmark these myocardial work indices for clinical practice. Methods: Healthy participants from a general population study were used to establish reference values for global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE) measured by pressure-strain loop analyses. The relation to age and sex was examined. We furthermore examined the proportion of abnormal work indices according to low, intermediate, and high cardiovascular risk by the Framingham risk score. Results: The healthy sample consisted of 1827 participants (median age, 45 years; 39% men). Lower reference values were GWI, 1576 mm Hg%; GCW, 1708 mm Hg%; and GWE, 93.0% and upper reference value for GWW was 159 mm Hg%. Women exhibited significantly higher GWI, GCW, and GWW and lower GWE. Sex significantly modified the association between all indices and age ( P for interaction: 0.001 for GWI, 0.009 for GCW, 0.003 for GWW, and 0.009 for GWE). For men, only GCW increased with age, whereas the other indices did not change with age. For women, GCW increased linearly with increasing age, whereas GWI, GWW, and GWE changed in a curvilinear fashion with age such that GWI increased in younger participants, GWW increased in elderly, and GWE declined concordantly. Abnormalities in myocardial work indices became more frequent with increasing Framingham risk score category (abnormal GWI: 2% versus 4% versus 5%, P =0.001; abnormal GCW: 2% versus 3% versus 4%, P =0.006; abnormal GWW: 3% versus 6% versus 11%, P <0.001; abnormal GWE: 3% versus 4% versus 11%, P <0.001). Conclusions: Myocardial work indices differ between sexes and change with age in a sex-dependent manner. Accordingly, we established age- and sex-specific reference values from a general population sample. Abnormal work indices become more frequent with higher clinical risk. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02993172.

Superior protection against laboratory-confirmed influenza has been proved for high-dose inactivated influenza vaccine, as compared with the standard dose, among adults 65 years of age or older. However, data on the relative effectiveness of the high-dose vaccine against severe clinical outcomes, including hospitalizations, are limited. We conducted a pragmatic, registry-based, open-label, randomized, active-controlled trial to evaluate the relative effectiveness of high-dose inactivated influenza vaccine, as compared with the standard dose, against severe clinical outcomes among community-dwelling adults 65 to 79 years of age. The trial was performed during two influenza seasons (2023-2024 and 2024-2025) with regional health registry data in Galicia, Spain. In each influenza season, the participants were randomly assigned in a 1:1 ratio to receive high-dose inactivated influenza vaccine or the standard dose. The primary end point was a composite of hospitalization for influenza or pneumonia from 14 days after vaccination to May 31 of the following year. A total of 103,169 unique participants underwent randomization; 31,307 participants were enrolled in both seasons and were counted for each. During the 2023-2024 and 2024-2025 seasons, 59,490 and 74,986 participants, respectively, underwent randomization. Among the participants, the mean (±SD) age was 72.3±4.3 years, and 53.6% were men. A primary end-point event occurred in 174 of 67,093 participants (absolute risk, 0.26%) in the high-dose group and in 227 of 66,789 (absolute risk, 0.34%) in the standard-dose group (relative vaccine effectiveness, 23.7%; 95% confidence interval [CI], 6.6 to 37.7). Hospitalization for influenza occurred in 63 of 67,093 participants (absolute risk, 0.09%) in the high-dose group and in 92 of 66,789 (absolute risk, 0.14%) in the standard-dose group (relative vaccine effectiveness, 31.8%; 95% CI, 5.0 to 51.3). The incidence of serious adverse events appeared to be similar in the two trial groups. Among community-dwelling adults 65 to 79 years of age, there appeared to be fewer hospitalizations for influenza or pneumonia with high-dose inactivated influenza vaccine than with the standard dose. (Funded by Sanofi; GALFLU ClinicalTrials.gov number NCT06141655; EudraCT number, 2023-506977-36-00.).