Flu Infection Raises Risk of New Onset Atrial fibrillation

MedicalResearch.com Interview with:
Tze-Fan Chao MD PhD
Division of Cardiology, Department of Medicine
Taipei Veterans General Hospital
Institute of Clinical Medicine, and Cardiovascular Research Center
National Yang-Ming University, Taipei, Taiwan
Su-Jung Chen MD
Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital,
Institute of Public Health and School of Medicine, National Yang-Ming University
Taipei, Taiwan

MedicalResearch: What is the background for this study? What are the main findings?

Response: Atrial fibrillation (AF) is the most common cardiac arrhythmia in clinical practice, accounting for frequent hospitalizations, hemodynamic abnormalities, and thromboembolic events. Although the detailed mechanism of the occurrence of Atrial fibrillation remains unclear, systemic inflammation and sympathetic nervous system have been demonstrated to play an important role in the pathogenesis of AF. Flu (influenza infection) is a common disease which could happen to everyone in the daily life. It could cause significant morbidity and mortality, and is a serious human health concern worldwide. Previous studies have shown that influenza infection not only results in the productions of pro-inflammatory cytokines, but also activates the sympathetic nervous system, which are all related to the occurrence of  Atrial fibrillation. Therefore, we hypothesized that influenza infection could be a risk factor of new-onset AF. We also tested the hypothesis that influenza vaccination, a useful way to reduce the risk of influenza infection, could decrease the risk of AF.

In this large scale nationwide case-control study, a total of 11,374 patients with newly diagnosed  Atrial fibrillation were identified from the Taiwan National Health Insurance Research Database. On the same date of enrollment, 4 control patients (without AF) with matched age and sex were selected to be the control group for each study patient. The relationship between AF and influenza infection/vaccination 1 year before the enrollment was analyzed. The results showed that influenza infection was associated with an 18% increased risk of AF, and the risk could be easily reduced through influenza vaccination.

MedicalResearch: What should clinicians and patients take away from your report?

Response: According to the findings of our study, the possibility of Atrial fibrillation should be kept in mind when patients with influenza infection complained of palpitation or experienced ischemic stroke. In addition, influenza vaccination may be a useful way to reduce the  Atrial fibrillation burden associated with influenza infection, and high-risk patients should be encouraged to receive influenza vaccination annually.

MedicalResearch: What recommendations do you have for future research as a result of this study?

Response: While we reported the significant association between AF and influenza infection, these results were derived from an observational database. Therefore, we were not able to conclude whether influenza infection was the direct cause of the increased risk of  Atrial fibrillation . It is possible that patients who got influenza infection were sicker than those without influenza infection, and therefore had a higher risk of AF. A prospective study is necessary to confirm the findings of our study.

MedicalResearch: Is there anything else you would like to add?

Response: Influenza infection should not be regarded as solely an infectious disease. It may also cause  Atrial fibrillation which could result in devastating complications, such as disable stroke. Physicians should be highly alert about the relationship between influenza infection and AF. Influenza vaccination should be encouraged for patients, especially those who have a high risk of AF, to try to prevent the occurrence of AF and subsequent stroke.


The Association between Influenza Infection, Vaccination and Atrial Fibrillation: A Nationwide Case-Control Study
Chang, Ting-Yung et al. Heart Rhythm , Volume 0 , Issue 0 ,
DOI: http://dx.doi.org/10.1016/j.hrthm.2016.01.026

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Dr. Tze-Fan Chao MD PhD and Su-Jung Chen MD (2016). Flu Infection Raises Risk of New Onset Atrial fibrillation MedicalResearch.com