Autonomic dysfunction in cases of spinal muscular atrophy type 1 with long survival

In Japan, quite a few patients with spinal muscular atrophy type 1 (SMA type 1) survive with mechanical ventilation. Since a patient with SMA type I and continuous artificial ventilation exhibited excessive perspiration and tachycardia, we examined the autonomic functions in three cases of SMA type 1, undergoing mechanical ventilation. Two cases exhibited the common sympathetic-vagal imbalance on R-R interval analysis involving 24-h Holler ECG recordings in addition to an abnormality in finger cold-induced vasodilatation. Furthermore, one case showed blood pressure and heart rate fluctuation with the paroxysmal elevation, and a high plasma concentration of norepinephrine during tachycardia. These findings suggest that autonomic dysfunction should be examined in SMA type I patients with long survival, although the pathogenesis remains to be clarified. (c) 2005 Elsevier B.V. All rights reserved.