A Firefighter with Abnormal Cardiac Imaging
A 54-year-old male, highly active firefighter with a medical history significant for prostate cancer and subsequent radical prostatectomy presented to our Sports Cardiology Clinic with acute onset shortness of breath disproportionate to his perceived level of exertion. The patient is a multisport athlete, running 20-25 miles per week and rowing on his home ergometer two sessions per week dating back to his 20s. His training consisted of a mix of high intensity interval training and aerobic work during this time. Due to COVID-19 pandemic, the patient was initially evaluated via telehealth. He underwent a radical prostatectomy 6 weeks prior to presentation at another institution with an uncomplicated course. His symptoms began upon returning to activity once safe to do so per his urologist. He described activity-limiting shortness of breath after running one mile that progressed to shortness of breath and near syncope while mowing his lawn over the course of one week. He denied chest pain, palpitations, orthopnea, paroxysmal nocturnal dyspnea or leg edema. He denied any preceding fevers, chills or sick contacts and denied any known exposure to COVID-19. He did describe a significant amount of dust and fire exposure during his tenure as a firefighter (31 years) but stated that he always wore his protective equipment. His only medication is tadalafil prescribed by his urologist postoperatively. He does not smoke or drink alcohol and uses no illicit or performance enhancing drugs. He has no family history of heart disease or sudden death. His blood pressure was 118/64, pulse 59 bpm and he had a normal cardiac exam. Laboratory tests showed dyslipidemia with cholesterol 232 mg/dL and LDL 194 mg/dL. Otherwise, complete blood counts, renal function, hepatic function, thyroid function, and electrolytes were all within normal range.
Given his symptoms, we elected to proceed with a stress echocardiogram for further evaluation. His baseline electrocardiogram (ECG) (Figure 1) showed sinus bradycardia with a first degree atrioventricular (AV) block, right bundle branch block with inferior and anterior T wave abnormalities. No prior ECG was available for comparison. His baseline, resting echocardiogram disclosed asymmetric septal hypertrophy (basal anteroseptum 1.6 cm, posterolateral wall 1.2 cm). His left ventricular systolic function was mildly reduced, with a left ventricular ejection fraction measuring 50% by Simpson's method. Regional wall motion abnormalities were well visualized, specifically basal inferior, mid inferior and apical inferior wall hypokinesis. There were no other significant structural or functional abnormalities.
Due to the abnormal baseline echocardiographic findings, the stress portion of his study was cancelled, and a cardiac magnetic resonance imaging (MRI) was ordered. Findings were notable for the following:
- Left ventricle was normal in size with mildly reduced systolic function, ejection fraction (44%). The thickest segments were the basal anterior and basal anteroseptal walls measuring 1.6 cm.
- Right ventricle was mildly dilated with severely reduced systolic function (27%).
- On delayed gadolinium imaging, there is patchy subepicardial to transmural enhancement involving both left and right ventricles. Enhancement in the left ventricle is seen in the basal to mid septum, basal anterior wall, mid to apical inferoseptal-inferior wall and apical lateral wall. Enhancement is also seen in the right ventricular free wall. (Figure 2)
Based on the data above, what is the next best diagnostic step?