[Autonomic cardiovascular dysfunction in multiple sclerosis not caused solely by brain stem lesions]

Multiple sclerosis (MS) can cause alterations in autonomic cardiovascular functioning. Some authors attribute these anomalies detected in MS patients to brain stem lesions, due to the fact that important autonomic nuclei are located in this region of the brain. Other studies, however, have been unable to prove such a relation. AIMS. The purpose of this study was to analyse whether these alterations had an exclusive relation with the brain stem lesions that usually appear in the course of this disease.

We compared the spectral analysis of the heart rate variability (SAHRV) in the frequency domain between a group of 34 patients with MS and another group of 14 patients with isolated brain stem lesions (IBSL) of a non inflammatory origin, which were measured using a 24 hour Holter recording.

Heart rate, very low rates, low rates and the low rate/high rate quotient are significantly higher in the MS group than in the IBSL group, even when the former present brain stem lesions. Results in the high rate component, however, depend on the presence of brain stem lesions in the MS group.

These findings suggest that autonomic cardiovascular dysfunction in MS is only related with brain stem lesions, although we obtained results that confirm the importance of this area in cardiovascular innervation.