Most of the patients in this study with spinal muscular atrophy were f
ound to have tremors of the isoelectric line in the electrocardiogram
(EGG) tracings. There were a total of 47 cases of SMA (mean age 40.8 m
onths). All three types of SMA had a similar incidence (about 80%) of
tremors in the tracings (P = 0.885). In 7 cases the ECG tremors had an
intermittent pattern. ECG tremors were commonly found in the majority
of SMA patients and this finding, though non-specific, may suggest a
possible SMA diagnosis.