Case 2. On March 11, a woman aged 52 years was vaccinated; 22 days after vaccination,
she had a slight cough, malaise, weakness, and palpitations, and vomited twice.
She had no other abdominal symptoms and reported no chest pain, shortness
of breath, or diaphoresis. Medical history was positive for hypertension and
hyperlipidemia controlled with amlodipine, hydrochlorothiazide, and pravastatin.
On examination in the ED, her pulse was 120 beats per minute and irregular;
other vital signs and the physical examination were normal. An ECG indicated
atrial fibrillation and nonspecific ST-segment and T-wave changes; the patient's
rhythm converted spontaneously to normal sinus rhythm while in the ED. Routine
blood count and blood chemistries, including thyroid-stimulating hormone,
were within normal limits; cholesterol level was slightly elevated. Total
creatine kinase and troponin levels were normal; however, CK-MB fraction was
elevated on three occasions. ECG indicated normal sinus rhythm and an echocardiogram
showed normal left-ventricular chamber size and function with mild left-ventricular
hypertrophy. No wall-motion abnormalities or effusion were noted; heart valves
were normal, and the ejection fraction was 55%-60%. The patient had a diagnosis
of new-onset atrial fibrillation and suspected myocarditis. After 3 weeks,
the patient returned to work, complaining of persistent fatigue but without
recurrence of palpitations.