Key result
Appropriate ICD shock rates do not differ between AL and TTR cardiac amyloidosis.
Why the study?
Data on the benefits of implantable cardioverter defibrillators (ICD) in patients with cardiac amyloidosis remain conflicting.
Does ICD therapy yield different outcomes in AL versus TTR cardiac amyloidosis patients?
Cohort (n=62)
Yes
Does ICD therapy yield different outcomes in AL versus TTR cardiac amyloidosis patients?
Absolute Event Rate: 60% vs 54.5%
p-value: p=0.28
Captured external expert commentary on this paper, strongest first. Original sources are linked where available.
“Our findings show high rates of cardiac-related mortality in patients with cardiac amyloidosis without differences in survival between cardiac amyloidosis types”
In patients with cardiac amyloidosis, ICD therapy is associated with high mortality and frequent inappropriate shocks, with no significant difference in outcomes between AL and TTR subtypes.
Cardiac amyloidosis (CA) is associated with symptomatic heart failure and high morbidity and mortality. There is conflicting data on the benefits of implantable cardioverter defibrillators (ICD) in patients with CA. To characterize CA patients undergoing ICD therapy and assess long term outcomes and ICD shocks as both a cohort of CA stratified subtype of amyloid light chain (AL) versus transthyretin (TTR). We studied all patients undergoing ICD implantation for a diagnosis of CA as either primary or secondary prevention between 1997 and 2019 in our health system. Baseline characteristics and outcomes were reviewed. There were 62 patients with CA that underwent ICD implantation. Baseline characteristics included diabetes (30.6%), hypertension (72.6%), chronic obstructive pulmonary disease (12.9%), and New York Heart Association (NYHA) class III/IV (54.8%). Over a mean follow-up of 4.9 years (SD 4.0 years), the mortality rate was 62.1% in AL as compared to 69.7% in TTR CA patients ( p = 0.53). First appropriate ICD shock occurred in 60% of AL patients compared to 54.5% of TTR patients, with no statistically significant difference observed between the two cohorts ( p = 0.78). Inappropriate second ICD shock occurred in 71.4% of AL amyloid patients compared to 80% of TTR patients, with no significant difference observed between the two cohorts ( p = 0.74). Competing risk analysis for the occurrence of ICD shock demonstrated a non-significantly higher incidence of shock for AL CA patients as compared to TTR CA patients ( p = 0.20). Finally, multivariate cox regression demonstrated that TTR amyloid, advanced age, male sex, LVEF, andNYHA class III/IV were not independent predictors for the combined outcome of ICD shock, death, or heart failure hospitalization post-ICD placement. Patients with CA undergoing ICD therapy have high rates of mortality, with similar outcomes irrespective of amyloid subtype. The high rates of inappropriate shocks for both AL and TTR CA patients are relevant factors to consider during ICD counseling.
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Seby et al. (2026) conducted a cohort in Cardiac amyloidosis (n=62). AL amyloidosis vs. TTR amyloidosis was evaluated on Time to first appropriate ICD shock (p=0.28). In patients with cardiac amyloidosis undergoing ICD therapy, there was no significant difference in the rate of first appropriate ICD shock between the AL (60%) and TTR (54.5%) subtypes.
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