Prophylactic implantation of cardioverter-defibrillator in patients with advanced light-chain amyloidosis-A pilot study

Abstract

Background: Ventricular arrhythmias (VAs) and electromechanical dissociation have been observed as the most common causes of sudden cardiac death (SCD) in patients with light chain (AL) amyloidosis. However, an implantable cardioverter-defibrillator (ICD) has rarely been implanted in patients with advanced AL amyloidosis due to very poor prognosis.

Methods: Between July 2021 and December 2022, 10 patients with advanced cardiac AL amyloidosis referred to our institute who received prophylactic ICD implantation were prospectively recruited. The primary endpoint was the prevalence of VAs and appropriate ICD therapies determined by ICD interrogation. The secondary endpoint was all-cause mortality during the follow-up period.

Results: During a mean follow-up of 12.1 ± 4.4 months, sustained ventricular tachycardia (VT)/ventricular fibrillation (VF) occurred in 4 of 10 (40%) patients. One patient had spontaneous termination of VT before the delivery of ICD therapy, and the remaining 3 patients had ICD therapies used, either ATP or shock. Inappropriate shock was not recorded in any patients. Patients with sustained VT/VF had wider QRS duration (143 ± 41 vs. 99 ± 10 ms, p = 0.03) and a higher incidence of bundle branch block (BBB)/interventricular conduction delay (IVCD) (75% vs. 0%, p = 0.01) compared to those without.

Conclusion: VAs are commonly observed among patients with advanced AL amyloidosis, and ICD therapy can be effective in successfully treating sustained VA in these patients. On the basis of our preliminary data, prophylactic ICD implantation may be proposed to the advanced AL amyloidosis to improve the survival rate in selected patients with advanced AL amyloidosis, especially for the patients with wider QRS duration and BBB/IVCD.

Keywords: amyloidosis; implantable cardioverter‐defibrillator; survival; ventricular arrhythmia.

FIGURE 1

Flowchart of consecutive patients with advanced light chain cardiac amyloidosis enrolled in this study. AL, light chain; ICD, implantable cardioverter‐defibrillator; VA, ventricular arrhythmia. ICD treatment was successful in the majority of patients. Patients with wider QRS duration and RBBB/IVCD were more likely to experience sustained VAs. A higher level of hs‐cTnT and wider QRS duration were significantly associated with mortality in patients with advanced AL amyloidosis. Hs‐cTnT, high‐sensitivity cardiac Troponin T; ICD, implantable cardioverter‐defibrillator; IVCD, interventricular conduction delay; RBBB, right bundle branch block; VA, ventricular arrhythmia.