As a Cardiology Fellow working in the Medical Intensive Care Unit (MICU) during the COVID crisis, I am frequently called upon to diagnose and manage patients with high levels of troponin, a cardiac enzyme. It is often not immediately clear whether the high troponin is caused by an acute heart attack, increased demand on the heart from systemic infection, or potentially inflammation of the heart muscle (myocarditis) from the novel coronavirus itself.
Our diagnosis and management decisions are heavily influenced by images obtained by a transthoracic echocardiogram (TTE), the most common non-invasive ultrasound exam of the heart. TTE images may be enhanced with the use of an ultrasound contrast agent (UCA) to improve the quality of the image. In fact, a UCA can improve image quality so profoundly that an incorrect diagnosis may be prevented and patient management changed.
For example, we recently used a UCA to enhance the TTE image of a 57 year old COVID-positive woman in our MICU. She was rapidly decompensating after admission, and had a history of Crohn’s Disease (treated by Stelara), anemia, chronic obstructive pulmonary disease (COPD), and Type 2 Diabetes. She suffered from fevers and a sore throat for five days before appearing in our Emergency Department, where COVID-19 was confirmed. She quickly developed severe hypoxic respiratory failure requiring intubation as well as hypotension requiring several vasopressor agents.
Initially, TTE was performed without contrast and the images demonstrated severely reduced right ventricular and left ventricular ejection fraction, and troponin level increased to 10 ng/mL. In addition, the non-contrast images demonstrated severe mid-apical infero-septal and apical hypokinesis which, without more, may suggest the possibility of an acute left anterior descending myocardial infarct (heart attack). (Video 1.)
In order to improve our confidence in this diagnosis, we administered a UCA during the echocardiogram. The contrast images produced a significantly clearer delineation of the mid-apical anterolateral wall, demonstrating global severe mid-apical hypokinesis with intact basal segments. (Video 2.) These findings were most consistent with takotsubo cardiomyopathy, a sudden and acute form of heart failure induced by stress and sometimes referred to as “broken heart syndrome.”
Rather than rushing the patient to catheterization, this patient was managed conservatively and her ventricular function was fully restored at the time of discharge. (Video 3.)
Dr. Swearingen is a cardiology fellow at Rush University Medical Center in Chicago.