What are the management guidelines for a patient with infiltrative cardiomyopathy, recurrent nonsustained ventricular tachycardia (NSVT), elevated troponin levels, and abnormal electrocardiogram (ECG) findings, but with a normal coronary angiogram and a left ventricular ejection fraction (LVEF) of 50-55%?

Management of Infiltrative Cardiomyopathy with Recurrent NSVT

For a patient with infiltrative cardiomyopathy, recurrent nonsustained ventricular tachycardia (NSVT), elevated troponin, and abnormal ECG but normal coronary angiogram and preserved LVEF (50-55%), a wearable cardioverter-defibrillator (life vest) is reasonable as a bridge to definitive risk assessment and treatment.

Risk Assessment

The patient presents with several concerning features that require careful evaluation:

• Infiltrative cardiomyopathy (structural heart disease)
• Recurrent episodes of NSVT
• Elevated troponin (indicating myocardial injury)
• Abnormal ECG
• Preserved LVEF (50-55%)
• Normal coronary angiogram

Risk Stratification Considerations

• The presence of NSVT in patients with structural heart disease significantly increases the risk of sudden cardiac death (SCD) 1
• Infiltrative cardiomyopathies (such as cardiac sarcoidosis, amyloidosis) are associated with higher arrhythmic risk even with preserved LVEF 2
• Elevated troponin suggests ongoing myocardial injury, which may increase arrhythmic risk
• The European Society of Cardiology guidelines note that recurrent VT/VF may require specialized treatment including catheter ablation followed by ICD implantation 2

Management Recommendations

Immediate Management

1. Wearable cardioverter-defibrillator (life vest):

   • Reasonable as a temporary protective measure while completing risk assessment 2
   • The 2025 ACC/AHA guidelines state: "In patients early after MI, usefulness of a temporary wearable cardioverter-defibrillator is uncertain in patients with an LVEF ≤35% to improve survival" (Class IIb) 2
   • While this recommendation specifically addresses post-MI patients, the principle applies to our patient with infiltrative cardiomyopathy and recurrent NSVT

2. Medical therapy:

   • Initiate beta-blocker therapy to reduce arrhythmic burden 2
   • Consider amiodarone for suppression of recurrent NSVT if beta-blockers are insufficient 3

Further Evaluation

1. Identify specific infiltrative cardiomyopathy type:

   • Cardiac MRI with late gadolinium enhancement to assess for scar burden
   • Consider endomyocardial biopsy if etiology remains unclear

2. Electrophysiologic evaluation:

   • Consider electrophysiologic study to assess inducibility of sustained ventricular arrhythmias
   • Note: The 2017 AHA/ACC/HRS guidelines state that for hypertrophic cardiomyopathy, "An invasive electrophysiological study with programmed ventricular stimulation should not be performed for risk stratification" (Class III: No Benefit) 2
   • However, this may be considered for other infiltrative cardiomyopathies

Definitive Management

1. ICD consideration:

   • ICD implantation is reasonable for patients with cardiac sarcoidosis and evidence of myocardial scar, even with preserved LVEF (>35%) 2
   • The 2008 ACC/AHA/HRS guidelines state: "ICD implantation is reasonable for patients with cardiac sarcoidosis, giant cell myocarditis, or Chagas disease" (Class IIa) 2
   • For other infiltrative cardiomyopathies, ICD decisions should be based on specific etiology and risk factors

2. Specialized referral:

   • Referral to centers with expertise in managing complex arrhythmias and infiltrative cardiomyopathies 2

Important Considerations

• The preserved LVEF (50-55%) would typically not qualify for primary prevention ICD based on ejection fraction criteria alone
• However, the specific etiology of infiltrative cardiomyopathy may warrant ICD regardless of LVEF
• Wearable cardioverter-defibrillator provides temporary protection during evaluation period
• The combination of structural heart disease, recurrent NSVT, elevated troponin, and abnormal ECG suggests increased arrhythmic risk despite preserved LVEF

Pitfalls to Avoid

• Do not dismiss arrhythmic risk based solely on preserved LVEF
• Do not delay temporary protection while completing diagnostic workup
• Avoid relying solely on antiarrhythmic drugs for long-term management of high-risk patients
• Remember that some infiltrative cardiomyopathies (particularly cardiac sarcoidosis) can have high arrhythmic risk despite relatively preserved systolic function

In summary, a wearable cardioverter-defibrillator is reasonable as a bridge to definitive therapy while completing the diagnostic evaluation and risk stratification for this patient with infiltrative cardiomyopathy and recurrent NSVT.