A Case Report and 31-Case Study: Does Takotsubo Cardiomyopathy in Myasthenia Gravis Patients Have a High Mortality Rate?

Abstract

Myasthenia gravis is an autoimmune disorder in which antibodies are formed against post-synaptic nicotinic acetylcholine receptors that lead to impeded muscle contraction and commonly affects the oculomotor muscles. Takotsubo cardiomyopathy (TTC) is a dilated cardiomyopathy that can mimic a myocardial infarction and causes reversible systolic dysfunction. This is a case of a 66-year-old Caucasian male with a known history of ocular myasthenia gravis that presented to the emergency room with worsening dyspnea secondary to a myasthenic crisis. One day, following admission, his shortness of breath failed to improve and was found to meet the diagnostic criteria for takotsubo cardiomyopathy. A brief review of 31 previous cases summarizes the current case reports, patterns, and mortality associated with the myasthenic crisis associated with TTC.

Keywords: broken-heart syndrome; myasthenia gravis; myasthenic crisis; stress-induced cardiomyopathy; takotsubo cardiomyopathy.

Figure 1. Echocardiography findings depicting the left ventricle

A: Pre-treatment systole displaying apical and mid-ventricular hypokinesis, B: Pre-treatment diastole, C: Post-treatment systole displaying appropriate left ventricle (LV) contraction, D: Post-treatment diastole

Figure 2. Approximately 24 hours after admission, the patient was found to have an elevated troponin despite an initially negative troponin and ECG. The repeat ECG, shown here, displays sinus rhythm with T wave inversion (red arrows) in the anterolateral leads (leads I, aVR, aVL, V1-V6) and prolonged QTc interval.