Mapping and Ablation of Multiple Atrial Arrhythmias in a Patient with Persistent Atrial Standstill after Remote Viral Myocarditis

Permanent Complete Heart Block: A Rare Complication of Influenza Infection

The cardiovascular complications of viral illnesses are often underestimated in clinical practice. The influenza virus, one of the most prevalent viral infections, has been associated with a wide spectrum of arrhythmias that are typically transient and self-resolving. We present the case of a 60-year-old female with no prior cardiac comorbidities who developed a complete heart block after an influenza infection. She presented to the clinic with flu-like symptoms and was found to have a complete heart block with a junctional escape rhythm. Polymerase chain reaction testing subsequently confirmed an influenza A infection. She was initially placed on a temporary pacemaker. However, a permanent dual-chamber pacemaker was implanted as bradycardia persisted. Later follow-ups in the cardiology clinic showed that the patient remained dependent on the pacemaker. While there are a few descriptions of influenza-induced transient atrioventricular block, cases of influenza-induced permanent complete heart block are extremely rare, particularly in the absence of severe myocardial inflammation.

Influenza vaccination is associated with a decreased risk of atrial fibrillation: A systematic review and meta-analysis

Background

Evidence from longitudinal studies has shown that influenza infection is linked to an increased risk of arrhythmia. Therefore, we aimed to assess the role of influenza vaccination in arrhythmia prevention.

Materials and methods

The PubMed, Embase, and Cochrane Library databases were searched to identify studies that investigated the potential effects of the influenza vaccine on arrhythmia risk published until October 25th, 2021. The study was registered with PROSPERO (CRD42022300815).

Results

One RCT with 2,532 patients and six observational studies with 3,167,445 patients were included. One RCT demonstrated a non-significant benefit of the influenza vaccine against arrhythmias [odds ratio (OR) = 0.43, 95% confidence interval (CI): 0.11–1.64; P = 0.20] in patients after myocardial infarction or those with high-risk stable coronary heart disease. A meta-analysis based on observational studies showed that vaccination was associated with a significantly lower risk of arrhythmia (OR: 0.82, 95% CI: 0.70–0.97; P = 0.02; I² = 76%). Additionally, subgroup analysis showed a decreased risk of atrial fibrillation (AF) (OR: 0.94, 95% CI: 0.90–0.98; P = 0.006; I² = 0%) and a non-significant but positive trend concerning ventricular arrhythmias (VAs) (OR: 0.68, 95% CI: 0.42–1.11; P = 0.12; I² = 85%) after influenza vaccination.

Conclusion

Based on the current evidence, influenza vaccination may be associated with a reduced risk of arrhythmia, especially AF. Influenza vaccination may be an effective tool for the prevention of arrhythmias. The effect of influenza vaccination on the risk of VAs and arrhythmias in patients at low risk for cardiovascular diseases should be further studied.

Systematic review registration

[https://www.crd.york.ac.uk/PROSPERO/], identifier [CRD42022300815].

The association between influenza infection, vaccination, and atrial fibrillation: A nationwide case-control study

BACKGROUND

Influenza infection could activate systemic inflammatory responses and increase the sympathetic tone that plays an important role in the pathogenesis of atrial fibrillation (AF).

OBJECTIVES

The goal of the present study was to investigate whether influenza infection was a risk factor for AF. We also aimed to study whether influenza vaccination could decrease the risk of AF.

METHODS

From 2000 to 2010, a total of 11,374 patients with newly diagnosed AF 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 or vaccination 1 year before the enrollment was analyzed.

RESULTS

Compared with patients without influenza infection or vaccination (reference group; n = 38,353), patients with influenza infection without vaccination (n = 1369) were associated with a significantly higher risk of AF with an odds ratio of 1.182 (P = .032) after adjustment for baseline differences. The risk of AF was lower in patients receiving influenza vaccination without influenza infection (n = 16,452) with an odds ratio of 0.881 (P < .001). In patients who have received influenza vaccination and experienced influenza infection (n = 696), the risk of AF was similar to that in the reference group (odds ratio 1.136; P = .214). The lower risk of AF with vaccination was consistently observed in subgroup analyses.

CONCLUSION

Influenza infection was significantly associated with the development of AF, with an 18% increase in the risk, which could be reduced through influenza vaccination.