Prognostic Significance of Holter Monitor Findings in Patients With Light Chain Amyloidosis

Objective: To evaluate the prognostic impact of Holter findings in patients with light chain amyloidosis. Patients and Methods: We evaluated 239 patients in whom light chain amyloidosis was diagnosed from January 1, 2010, through December 31, 2015, who underwent 24-hour Holter monitoring. Results: Holter testing was done before stem cell transplant evaluation in 183 of the 239 patients (76.6%) and at diagnosis in 50 (20.9%). Holter findings were nonsustained ventricular tachycardia (NSVT) in 60 patients (25.1%), ventricular couplets in 103 (43.1)%, accelerated idioventricular rhythm in 32 (13.4%), and atrial fibrillation (AF) in 18 (7.5%). Overall survival (OS) at 3 and 6 months after Holter monitoring in patients with AF vs without AF was 78% (95% CI, 54%-91%) vs 96% (95% CI, 92%-98%) (P=.002) and 61% (95% CI, 38%-80%) vs 92% (95% CI, 87%-95%), (P<.001), respectively. In patients with and without NSVT, 3- and 6-month OS after Holter testing was 90% (95% CI, 80%-94%) vs 96% (95% CI, 91%-98%) (P=.12) and 77% (95% CI, 64%-85%) vs 94% (95% CI, 89%-97%) (P<.001), respectively. For patients with and without ventricular couplets, 3- and 6-month OS was 94% (95% CI, 88%-97%) vs 94% (95% CI, 89%-97%) (P=.98) and 84% (95% CI, 75%-89%) vs 94% (95% CI, 89%-97%) (P=.01), respectively. Atrial fibrillation (hazard ratio, 2.5; 95% CI, 1.2-5.0; P=.02) and NSVT (hazard ratio, 2.0; 95% CI, 1.1-3.5; P=.02) were independent predictors for OS after accounting for age and Mayo stage. For patients undergoing routine testing before stem cell transplant, AF (P=.002) and NSVT (P=.02) were associated with inferior OS at 6 months but did not retain statistical significance after adjusting for Mayo stage (P=.10 and P=.54, respectively). Conclusion: Atrial fibrillation and NSVT on 24-hour Holter monitoring are associated with inferior short-term OS outcomes but do not impact peritransplant mortality.