Signal-averaged electrocardiography in patients with AL (primary) amyloidosis

One hundred thirty-three patients with biopsy-proven AL amyloidosis were studied with echocardiography, Holter recording, 12-lead electrocardiography, and signal-averaged electrocordiograms. Features from these tests were analyzed in relation to their effect on mortality. Late potentials were more frequent in patients with echocardiographic evidence of cardiac amyloidosis (31%) compared with patients with normal echocardiograms (9%, p < 0.003), One hundred six of the 133 patients died during Follow-vp, of which 34 were nonsudden cardiac deaths and 33 were sudden deaths. Abnormal echocardiograms and signal-averaged electrocardiograms were each predictive of all-cause cardiac death (p < 0.0001) and sudden cardiac death (p < 0.0001). Abnormal signal-averaged electrocardiograms were also independently predictive of sudden death in the subgroup of patients with an abnormal echocardiogram (p < 0.05), Thus late potentials are predictive of sudden death in patients with AL amyloidosis and provide independent prognostic information in patients with echocardiographic evidence of amyloid involvement.