Background: Influenza has been shown to exacerbate heart failure (HF). Importantly, no study to date has examined the relationship between HF hospitalizations (HFH) with laboratory confirmed influenza infections. This study evaluated the association between laboratory confirmed influenza infection and HFH in the two largest hospitals in Saskatchewan, Canada. Methods: We used a retrospective self-controlled case series design to evaluate the association between laboratory-confirmed influenza infection and HFH. We compared the incidence ratio for HFH during the influenza risk interval with the control interval. We defined the influenza risk interval as the seven days after a laboratory confirmed influenza result and the control interval as one year before and after the risk interval. Results: We identified 114 HFH that occurred within one year before and after a positive test result for influenza between April 1, 2010, and April 30, 2018. Of these, 28 (28 admissions per week) occurred during the risk interval and 86 (0.853 admissions per week) occurred during the control interval. The incidence ratio of a HFH during the risk interval as compared with the control interval was 33.53 (95% confidence interval [CI], 21.89 to 51.36). A decline in incidence was observed after day seven; between days 8 to 14 and 14 to 28 incidence ratios was 0.91 (95% CI, 0.13 to 6.52) and 0.91 (95% CI, 0.22 to 3.68) respectively. Conclusion: We have observed a significant association between acute influenza infection and HFH. However, further research with a larger sample size and involving a multicenter setting is warranted. Highlights Influenza may contribute and exacerbate heart failure events especially during annual influenza season. Early identification of influenza among patients with heart failure, could lead to earlier treatment with antiviral medication, reduce unnecessary antibiotic use, and tail off the morbidity and mortality. In this study, despite our efficient study design, our sample size was limited to only the two largest hospitals in the province, possibly excluding a significant population in remote areas.

A 72-year-old woman presented with a late-presenting inferior ST-segment elevation myocardial infarction (Fig. 1A ). Coronary angiography demonstrated a culprit lesion of the distal right coronary artery treated with 2 drug-eluting stents (Fig. 1B; Video 1 , view video online). A left ventriculogram demonstrated inferior wall hypokinesis and a sliver of contrast within the pericardium along the inferior wall with no obvious ventricular septal defect. Repeated injections into the coronary circulation revealed no evidence of contrast-dye extravasation. An urgent point-of-care ultrasound revealed a trivial pericardial effusion. An electrocardiogram-gated computed tomography (CT) scan of the heart within 30 minutes of the primary percutaneous coronary intervention confirmed that the pericardial effusion progressed to a moderate-sized hemopericardium with extravasation of contrast from the inferolateral wall of the left ventricle (Fig. 1C). Transthoracic echocardiography with left ventricular opacification following administration of Definity (Perflutren lipid microsphere [Lantheus, Billerica, MA]) demonstrated microbubbles within the pericardial space, confirming the free-wall rupture (Fig. 1D; Video 2 , view video online). The patient underwent emergency cardiac surgery; intraoperatively, a punctate inferolateral free-wall tear of the left ventricle was identified and repaired with a bovine pericardial patch (Fig. 1E; Video 3 , view video online). Mechanical complications following an acute myocardial infarction are exceedingly rare in the era of primary percutaneous coronary intervention, occurring in less than 1% of acute coronary syndrome presentations.1French J.K. Hellkamp A.S. Armstrong P.W. et al.Mechanical complications after percutaneous coronary intervention in ST-elevation myocardial infarction.Am J Cardiol. 2010; 105: 59-63Abstract Full Text Full Text PDF PubMed Scopus (124) Google Scholar,2Elbadawi A. Elgendy I.Y. Mahmoud K. et al.Temporal trends and outcomes of mechanical complications in patients with acute myocardial infarction.JACC Cardiovasc Interv. 2019; 12: 1825-1836Crossref PubMed Scopus (65) Google Scholar However, ventricular free-wall rupture is the most common complication with late-presenting ST-segment elevation myocardial infarction, with the right coronary artery being the least likely culprit vessel, accounting for only 23% of cases.3Massad M.G. Geha A.S. Surgical repair of mechanical complications of myocardial infarction.World J Surg. 2004; 28: 847-856Crossref PubMed Scopus (5) Google Scholar Although there are few case reports of survival following a conservative approach, surgical repair is the treatment of choice.3Massad M.G. Geha A.S. Surgical repair of mechanical complications of myocardial infarction.World J Surg. 2004; 28: 847-856Crossref PubMed Scopus (5) Google Scholar,4Reardon M. Carr C. Diamond A. et al.Ischemic left ventricular free wall rupture: prediction, diagnosis, and treatment.Ann Thorac Surg. 1997; 64: 1509-1513Abstract Full Text Full Text PDF PubMed Scopus (74) Google Scholar Surgical intervention alleviates the life-threatening pericardial tamponade and closes the ventricular free-wall tear. When a new pericardial effusion is identified in the acute coronary syndrome setting, prompt diagnosis of a ventricular free-wall rupture with multimodality cardiovascular imaging using CT and contrast echocardiography should be pursued.Novel Teaching Point•When a new pericardial effusion is identified in the post–myocardial infarction setting, prompt diagnosis of a ventricular free-wall rupture with multimodality cardiovascular imaging using CT and contrast echocardiography should be pursued. •When a new pericardial effusion is identified in the post–myocardial infarction setting, prompt diagnosis of a ventricular free-wall rupture with multimodality cardiovascular imaging using CT and contrast echocardiography should be pursued. The authors have no funding sources to declare.

Heart failure increases in prevalence with age and is usually associated with various cardiac and non-cardiac comorbidities. For common coexisting conditions such as renal dysfunction, anemia and type 2 diabetes mellitus, important pathophysiologic links have been implicated between cardiac dysfunction and the underlying condition. Indeed, the number and severity of comorbidities in the setting of heart failure is an important driver of prognosis. By targeting the management of coexisting diseases, it may be possible to improve functional capacity, quality of life and perhaps even overall mortality in heart failure patients. Recent clinical trial data has provided insights into cardio-renal interactions in acute heart failure, the impact of iron replacement therapy in iron deficient heart failure patients, and the role of pharmacologic therapies to prevent heart failure related events in high risk patients with type 2 diabetes.