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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