History of presentation

Patient is a 29-year-old man who presented with chest pain, dyspnea, and an EKG with sinus tachycardia without a pattern for ischemic injury. Initial laboratory studies were notable for a troponin I of 0.38 ng/mL, anion gap of 36.0 mmol/L, lactic acid of 10.85 mmol/L, and WBC count of 22.3 × 10⁹/L. The ethanol level was 417 mg/dL and negative urine toxicology. Patient developed 30 s of self-terminating ventricular tachycardia. Initial echocardiogram revealed normal biventricular function without valvular or pericardial disease.

Past medical history

Past medical history includes poor dentition, active substance abuse (history of more than five years) with ethanol, kratom, and intermittent marijuana. Remote history of methamphetamine use. The use of these substances can lower the threshold for arrhythmia formation and end-organ damage.

Differential cardiac diagnosis

Acute myocarditis, left ventricular noncompaction, sarcoidosis, acute coronary syndrome, and pericarditis.

Investigations

Transthoracic echocardiogram (TTE) revealed a normal biventricular function with apical trabeculation and hyperdynamic left ventricular ejection fraction (LVEF). The following evening, he developed sustained pulseless ventricular tachycardia (Figure 1) treated with advanced cardiovascular life support (ACLS), including intubation and cardioversion to sinus tachycardia; however, he progressed to multi-organ system failure. A chest x-ray revealed bilateral pulmonary infiltrates (Figure 2). He was placed on amiodarone and lidocaine drips for rhythm control and laboratory findings revealed troponin > 440.00 ng/mL.

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Figure 1. EKG upon presentation. EKG revealing pulseless ventricular tachycardia with a rate of 150 bpm prior to reversion to normal sinus rhythm

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Figure 2. Chest x-ray obtained post-myocardial biopsy. Multifocal dense bilateral pulmonary opacities with small bilateral pleural effusions

Management

A repeat TTE revealed an ejection fraction of 10–15% and an emergent right and left heart cardiac catheterization revealed normal epicardial coronary vessels and elevated left ventricular end diastolic pressure (LVEDP) at 40 mmHg. A right ventricle (RV) endomyocardial biopsy was performed, and he was empirically treated for presumed giant cell myocarditis with high dose corticosteroids. Endomyocardial biopsy results were negative for giant cell myocarditis, lymphocytic or eosinophilic myocarditis, and sarcoid associated cardiomyopathy, but did reveal scattered CD3 lymphocytes and changes consistent with early ischemia. The presence of ischemia is unique because in arrhythmogenic cardiomyopathy, often there is a nonischemic etiology that presents with ventricular arrhythmia. The propensity for electrical instability often precedes heart failure or ventricular dilation [1]. A subsequent cardiac magnetic resonance (CMR) was obtained, which revealed severely hypokinetic basal and mid segments, with a LVEF of 16%. T2-weighted imaging findings were consistent with a large area of myocardial edema. There was diffuse late gadolinium enhancement in all basal segments, findings suggestive of acute fulminant myocarditis associated cardiomyopathy (Figure 3). Rapid viral serologies were all negative and intravenous immunoglobulin was administered. He was eventually discharged on a steroid taper, colchicine, and a LifeVest.

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Figure 3. Cardiac MRI findings. A. Delayed gadolinium enhancement noted by the arrows. B. CMR showing mid myocardial diffuse late gadolinium enhancement in all basal segments, mid cavity segments, and upper distal cavity segments, suggestive of diffuse myocardial edema. CMR: cardiac magnetic resonance

Four days later, the patient re-presented after being found nonresponsive and treated with bystander cardiopulmonary resuscitation (CPR). The initial rhythm was rapid ventricular tachycardia and the Emergency Medical Service (EMS) defibrillated the patient to sinus rhythm with spontaneous return of circulation. Persistent depressed LVEF and cardiogenic shock required surgical implantation of an Impella 5.5, during which a left ventricular endomyocardial biopsy was performed due to concerns for sampling error on the original RV septal endomyocardial biopsy. Left ventricular endomyocardial biopsy did not reveal features of myocarditis or infiltrative disease. After 7 days of support, the Impella device was removed, and a dual-chamber implantable cardioverter defibrillator (ICD) was placed. Despite multiple antiarrhythmic agents (amiodarone, lidocaine, procainamide, propranolol, and phenytoin), ventricular tachycardia episodes continued. He underwent thoracoscopic bilateral sympathectomy and one week later, an endocardial ventricular tachycardia ablation procedure. He was transferred to a high-volume heart transplantation center and was declined for urgent heart transplantation by a multidisciplinary team due to substance use, unstable psychosocial support, and malnutrition. Prolonged substance abuse can further exacerbate arrhythmogenic cardiomyopathy generation due to alterations in ion channel function. After returning to Mission Hospital (HCA North Carolina), the patient underwent high-risk implantation of a HeartMate 3 left ventricular assist device (LVAD), epicardial ablation of ventricular tachycardia, and left atrial appendage ligation. He was discharged from the hospital 16 days later. An Invitae cardiomyopathy panel returned with findings consistent with a heterozygous DSP mutation leading to a premature stop signal: c268C>T (p.Gln90).

Outcome and follow-up

After demonstrating abstinence from substance use, he has been listed for heart transplantation. His follow-up EKG also demonstrated resolution of his ventricular arrhythmia (Figure 4).

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Figure 4. EKG upon stabilization of the ventricular tachycardia rhythm. Comparison EKG revealing normal sinus rhythm with no signs of depolarization or repolarization abnormalities (e.g., prolonged QRS interval, prolonged QT interval, T wave inversion)