Takotsubo syndrome in patients with influenza infection or anti-influenza (Flu) vaccination

Recent reports proposing a potential association of influenza virus infection with cardiovascular diseases like Takotsubo syndrome (TTS) warrant a literature review to elucidate the demographics, clinical presentation, and outcomes in these cases. A thorough literature search was performed until March 2020. We systematically discussed TTS cases reported following influenza infection or flu vaccination and related outcomes. Ten patients (7 women/3 men) were identified who displayed diagnostic and clinical signs of TTS after influenza infection or flu-like illness and influenza (flu) vaccination. Of 10 cases reviewed (mean age 77.0 ± 11.7 years), 7 (70%) were females, of whom 71.4% (n = 5) were above 60 years of age. Seven patients had influenza A, one patient had influenza B, and two patients had received a flu vaccination. Total 70% of cases reported the flu-like event as a triggering event for TTS and, all of them occurred within 5 days of symptoms onset or vaccination. The classical apical ballooning pattern, elevated cardiac enzymes, ST-segment/T-wave changes on electrocardiogram, and reduced left ventricular ejection fraction were present in a majority of the cases. Only one patient died during the course due to cardiac arrest whereas 6 cases (60%) reported at least one cardiopulmonary complication. Physicians should remain vigilant about an infrequent association of TTS and consequent cardiopulmonary complications in influenza virus infection especially in aged patients with prevalent cardiovascular risk factors. The overall prognosis of influenza-associated TTS while looks promising, there is a need for larger studies to find more conclusive evidence.