Heart Rate Variability (HRV) Modifications in adult hemiplegic patients after botulinum toxin type A (NT-201) injection

Background. The most important adverse effect of BoNT-A is the systemic diffusion of the toxin. There is some evidence that the administration of high doses can increase the risk of systemic diffusion and the development of clinically evident adverse effects, however an international consensus does not exist about its maximum dose. Aim. The aim of this study was to evaluate changes in autonomic heart drive induced by high doses (higher than 600 units) of incobotulinumtoxinA injection in spastic stroke patients. Moreover, the treatment safety by monitoring adverse events occurrence was assessed. Design. Case control study. Population. Eleven stroke survivors with spastic hemiplegia. Methods. Patients were treated with intramuscular focal injections of IncobotulinumtoxinA (NT 201; Xeomin((R)), Merz Pharmaceuticals GmbH, Frankfurt, Germany). Doses were below 12 units/Kg. Each patient underwent an ECG recording before injection and 10 days after treatment. Linear and non-linear Heart Rate variability (HRV) measures were derived from ECGs with a dedicated software. Results. None of the variable considered showed statistically significant changes after BoNT-A injection. Conclusion. The use of incobotulinumtoxinA in adult patients at doses up to 12 units/kg seems to be safe regarding autonomic heart drive. Clinical Rehabilitation Impact. The use of IncobotulinumtoxinA up to 600 units could be a safe therapeutic option in spastic hemiplegic stroke survivors.