SIGNAL-AVERAGED ELECTROCARDIOGRAPHY IN PATIENTS WITH AL (PRIMARY) AMYLOIDOSIS

One hundred thirty-three patients with biopsy-proven AL amyloidosis we re studied with echocardiography, Holter recording, 12-lead electrocar diography, and signal-averaged electrocordiograms. Features from these tests were analyzed in relation to their effect on mortality. Late po tentials were more frequent in patients with echocardiographic evidenc e of cardiac amyloidosis (31%) compared with patients with normal echo cardiograms (9%, p < 0.003), One hundred six of the 133 patients died during Follow-vp, of which 34 were nonsudden cardiac deaths and 33 wer e sudden deaths. Abnormal echocardiograms and signal-averaged electroc ardiograms were each predictive of all-cause cardiac death (p < 0.0001 ) and sudden cardiac death (p < 0.0001). Abnormal signal-averaged elec trocardiograms were also independently predictive of sudden death in t he subgroup of patients with an abnormal echocardiogram (p < 0.05), Th us 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.