Discussion:
Myocardial dysfunction and heart failure secondary to cancer therapy (cardiotoxicity) is an important cause of patient morbidity and mortality in cancer survivors.5 Anthracycline-induced cardiotoxicity has a cumulative, dose dependant, and non-reversible presentation with cellular apoptosis. Myocardial dysfunction and/ or heart failure can be delayed for a number of years due to compensatory mechanisms.5 The highly effective treatment of monoclonal antibody Trastuzumab for HER2 positive breast cancer demonstrates partially reversible acute myocardial dysfunction with immediate improvements in left ventricular ejection fraction (LVEF) following Trastuzumab cessation, however with an ongoing subclinical reduction of LV GLS.5, 6
Prevention and management of cancer therapy induced cardiotoxicity is important for long term patient outcomes and requires screening, risk stratification, and ongoing monitoring as strategies.7Baseline cardiac assessment should include medical history, electrocardiography, cardiac imaging with determination of systolic, diastolic, and subclinical dysfunction with strain analysis, and/ or troponin assessment.5 Cardiac imaging is typically performed with TTE with evaluation of LVEF and GLS, where a reduction in LVEF by >10% to below 55% or a GLS relative reduction of 11-15% from baseline are indicative of cardiotoxicity.7 Follow-up cardiac imaging is recommended at the completion of anthracycline therapy, and then every 3 months during Trastuzumab treatment.5 Minimising risk of cardiotoxicity includes anthracycline dose modification and sequential administration of anthracyclines and Trastuzumab.7
Acute myocardial dysfunction has also been described in patients following infection with COVID-19, with reduction in GLS an independent indicator of COVID-19 related death.4, 8 Impairment has been demonstrated in both LVEF and GLS in an apical sparing pattern typical of a reverse-stress/ Takotsubo cardiomyopathy.9 The prevalence of myocardial dysfunction following COVID-19 infection in the wider population remains unknown, however there is 20 – 30% reported myocardial involvement in hospitalised patients.10 Conflicting reports have been presented regarding improvement of LVEF and GLS following COVID-19 recovery, which may indicate a need for ongoing monitoring and/or administration of cardioprotective agents.8, 9
Myocardial dysfunction is a recognised sequela of both cancer therapy related cardiac dysfunction and COVID-19 infection. In this case our patient demonstrated myocardial dysfunction during Trastuzamab therapy, albeit following a COVID-19 infection. Recovery was observed in the course of ongoing Trastuzamab treatment without administration of cardioprotective agents, indicating a probable subclinical myocarditis following COVID-19 infection. This indicates the importance of taking a history of prior COVID-19 infection, or indeed other significant viral infections that may alter LV function, in patients undergoing chemotherapy, with ongoing TTE surveillance.
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