Inflammation and Cardiac Dysfunction in Hospitalized Patients With Influenza: The FluHeart Study

Figures

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  FIGURE 1. Participant flow. Flow diagram showing participant inclusion across three influenza seasons. A total of 49, 173, and 189 hospitalized patients with laboratory‐confirmed influenza were screened during the 2021/2022, 2022/2023, and 2023/2024 seasons, respectively. Of these, 36, 96, and 109 were included in the study, resulting in 241 participants overall.

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  FIGURE 2. Distribution of cardiac function abnormalities among hospitalized influenza patients. UpSet plot illustrating the frequency and overlap of cardiac function abnormalities in hospitalized patients with influenza. Abnormalities included LV systolic dysfunction (GLS < 16% or LVEF < 50%), LV diastolic dysfunction (E/e′ > 14), RV systolic dysfunction (RVLS < 20% or TAPSE < 1.7 cm), and pulmonary hypertension (RVSP ≥ 40 mmHg). Each column indicates the number of patients with the combination of abnormalities marked by the connected dots below the x‐axis. The horizontal bars illustrate the total number of patients with each abnormality, independent of overlap. Abbreviations: E/e′, ratio of early diastolic mitral inflow velocity to early diastolic tissue velocity; GLS, global longitudinal strain; LV, left ventricular; LVEF, left ventricular ejection fraction; RV, right ventricular; RVLS, right ventricular longitudinal strain; RVSP, right ventricular systolic pressure; TAPSE, tricuspid annular plane systolic excursion.

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  FIGURE 3. Relationship between CRP and cardiac function. Restricted cubic spline curves illustrating the relationships between CRP, as a marker of influenza‐related inflammation, and echocardiographic measurements of myocardial function. p‐values for nonlinearity are obtained from regression models including spline terms for CRP, and p‐values for the linear association are from linear regression models with CRP. Abbreviations: CRP, C‐reactive protein; E/e′, ratio of early diastolic mitral inflow velocity to early diastolic mitral annular velocity; GLS, global longitudinal strain; LVEF, left ventricular ejection fraction; RVLS, right ventricular longitudinal strain; RVSP, right ventricular systolic pressure; TAPSE, tricuspid annular plane systolic excursion.

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  FIGURE 4. Echocardiographic values according to CRP. Echocardiographic values according to CRP. Coefficients and p‐values from multivariable linear regression models are displayed. Whether CRP was log‐transformed depended on the significance of the linear association or nonlinearity observed in the data. Abbreviations: CI, confidence interval; CRP, C‐reactive protein; E/e′, ratio of early diastolic mitral inflow velocity to early diastolic tissue velocity; TAPSE, tricuspid annular plane systolic excursion.