Myocarditis Mimicking Acute Coronary Syndrome With a Myriad of Arrhythmias

Dec 04, 2015   |  Dhanan Umadevan, MD; Azhari Rosman, MD, DM, FACC; Razali Omar, MD, FACC; Shamruz Khan
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Editor's Note: This case took place at the National Heart Institute of Malaysia. Treatments are based on the resources available to physicians at this facility at the time of the case.

A 28-year-old female patient with no previous history of present illness and two days of fever presented to the emergency department with a syncopal attack. An electrocardiogram (ECG) was taken, which showed left bundle branch block. She was diagnosed to have an acute myocardial infarction. Subsequently, she developed right bundle branch block with left posterior hemiblock. Later, she developed complete heart block with ventricular standstill requiring a temporary pacemaker (Figure 1).

Figure 1

Figure 1

She was referred to the National Heart Institute of Malaysia for further management. She subsequently developed first-degree AV block. Her echocardiogram showed good left ventricular function with an ejection fraction of 55% with no regional wall motion abnormality. Her right ventricular function was depressed (tricuspid annular plane systolic excursion = 1.2). There were no valvular abnormalities and the myocardium appeared normal. Initial laboratory data are included in Table 1. She was planned for an elective coronary angiogram on day two. However on the same day, she developed ventricular fibrillation. She required CPR, intubation, and defibrillation once at 360J. A coronary angiogram revealed normal vessels. She was started on IV lignocaine infusion.

Table 1

Troponin T

 

0.344g/l(0.003-0.100g/l)

LFT

ALT

68 U/L (10-32)

CBC

WBC

11 X109/L

 

Neutrophil

74%

 

Lymphocytes

15%

 

Monocytes

11%

CRP

 

18.8 mg/l(<10)

ESR

 

49 mm/h

CXR

 

Minimal congestion and upper lobe diversion of pulmonary vessels

At this point in her treatment, acute viral myocarditis was highly suspected. She was started on IV Methylprednisolone 30mg/kg 6 hourly for 2 days. On day three, she developed pulseless ventricular tachycardia, which required CPR and reverted to sinus rhythm with cardioversion at 200J. She developed another episode of ventricular fibrillation that same day requiring defibrillation at 200J (Figure 2). She was also covered with antibiotic therapy (IV piperacillin/tazobactam 4.5g TDS) as her repeat white cell count was raised. Viral and autoimmune studies were sent (Table 2).

Figure 2

Figure 2

Table 2

INVESTIGATIONS

 

RESULTS

VIRAL STUDIES

Cytomegalovirus

Negative

 

Influenza type A

Negative

 

Influenza type B

Negative

 

Parainfluenza type 1,2,3 and 4

Negative

 

Human enterovirus

Negative

 

Human rhinovirus

Negative

 

Human adenovirus

Negative

 

Human bocavirus

Negative

 

Human metapneumovirus

Negative

 

Respiratory syncytial virus, groups A and B

Negative

 

Coronavirus type (229E, NL63,OC43)

Negative

 

Herpes virus

Negative

 

Parvovirus

Negative

 

Coxsackie A&B

Negative

 

Dengue serology

Negative

Autoimmune Studies

ANA, dsDNA, complement factors (C3,C4) and rheumatoid factor, rheumatoid factor

Positive for ANA antibodies (SSA pattern) but she was negative for anti dsDNA antibodies

Complement Factor

C3,C4

Normal

She responded well to pulsed IV methylprednisolone, which was given to her for two days, and then transitioned to oral prednisolone, which was tapered off over two months. Her blood culture was negative for any growth. She subsequently underwent cardiac magnetic resonance imaging (MRI), which showed features suggestive of myocarditis. There was normal indexed left ventricular volumes and systolic function. Right ventricular indexed volumes and function were within normal limits. Short-tau inversion recovery (STIR) positive changes were found in the mid-cavity septal wall suggestive of myocardial inflammation (Figure 3). A follow-up echocardiogram performed after two weeks showed good left ventricular function.

Figure 3

Figure 3
Cardiac MRI STIR image showing inflammation of the mid-septal wall.

Which of the following statements describes the role for steroid therapy in patients with acute myocarditis?

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