Skill Checkup: An Electrical Conundrum

Xiaoxiao Qian, MD; Raghav Gattani, MD; Chirag M. Sandesara, MD

Disclosures

June 11, 2021

Starting intravenous amiodarone for recurrent VT is a reasonable next step to suppress recurrence.[3] Another potential option is sotalol, but owing to this patient's renal failure, this is contraindicated. Class Ic sodium channel blockers should be avoided in the presence of structural heart disease.

According to 2017 AHA/ACC/HRS Guideline for Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death,[4] the class I indications for ICD implantation for secondary prevention are patients who have survived cardiac arrest from VT or ventricular fibrillation and have a meaningful survival > 1 year. The guidelines emphasize "meaningful survival > 1 year" as a precondition for ICD consideration.

The prognosis of AL amyloidosis is based on the number, nature, and extent of organ involvement. Studies have demonstrated that patients with cardiac AL amyloidosis without disease-specific treatment had an overall median survival of only 6 months.[5] The Revised Mayo Staging for light chain amyloidosis is most commonly used for disease prognostication. This staging system integrates NT-proBNP, troponin T, and serum free light chain levels

  • Stage I: all three markers are below the cutoff; median overall survival, 94.1 months

  • Stage II: one marker is above the cutoff; median overall survival, 40.3 months

  • Stage III: two markers are above the cutoff; median overall survival, 14 months

  • Stage IV: all markers are above the cutoff; median overall survival, 5.8 months

This patient had elevated NT-proBNP, troponin, and free light chain levels, placing him in stage IV AL amyloidosis with a median survival time of 6 months. Although this patient meets the ICD implantation criteria given the cardiac arrest, he has an estimated life expectancy of 6 months; therefore, ICD implantation for secondary prevention is not indicated.

Catheter ablation can be the first-line therapy in idiopathic VT depending on patient preference and shared decision-making. In the presence of structural heart disease, as in this patient, catheter ablation is generally performed if refractory to antiarrhythmic medications in patients with frequent ICD therapies. Catheter ablation of VT in patients with AL amyloidosis has not been studied in large-scale randomized trials, and thus its efficacy in long-term arrhythmia suppression remains unclear. Therefore, initiation of antiarrhythmic medication is the first step in treatment in this patient. Of note, antiarrhythmic drugs can help reduce ventricular arrhythmia episodes but have not been shown to decrease mortality in any patient population.

Most patients with cardiac amyloidosis have concurrent noncardiac involvement of amyloidosis that precludes them from heart transplantation. Patients with isolated cardiac amyloidosis can potentially be accepted for heart transplant after a thorough evaluation. However, heart transplantation does not address the underlying etiology of AL amyloidosis, and if the disease recurs, it can re-infiltrate the transplanted heart. Therefore, heart transplantation for AL amyloidosis in this patient population is usually followed by high-dose chemotherapy and autologous hematopoietic stem cell transplantation for at least 12 months. Long-term follow-up data in these patients are not yet available, but several patients appear to have had excellent cardiac results and durable hematologic response. The patient in this case is not a candidate for a heart transplant owing to advanced age and extra cardiac involvement (renal, carpal tunnel, gastrointestinal).

This patient was started on intravenous amiodarone and was transferred out of the intensive care unit a few days later. He had a recurrence of nonsustained ventricular arrhythmia and had another arrest.

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