Monitoring kardialer autonomer Funktionsstörungen mittels Messung der Herzfrequenzvariabilität bei Botulismus durch Nahrungsmittelvergiftung

Abstract

Botulism toxin blocks the presynaptic release of acetylcholine in motor and autonomic nerves. Therefore, autonomic cardiac dysfunction can be diagnosed in botulism. After eating half-raw, home-made smoked ham, two men developed typical clinical symptoms of botulism within three days. We wanted to know, whether early and repeated heart rate variability (HRV) monitoring using a computerized analysis System (ProSciCard®, Me-diSyst Comp., Linden, Germany) is necessary in order to detect autonomic cardiac disorders despite of specific antitoxin therapy. Analysis of HRV at rest, during deep breathing after active rising (Ewing manoeuvre), after Valsalva's manoeuvre, as well as spectral analysis of low-frequency (0.01 - 0.05 Hz), mid-frequency (0.05 - 0.15 Hz), and high-frequency (0.15 - 0.50 Hz) bands were used for diagnosis. In the beginning, tests were performed every fourth day, then after every second week. HRV analysis initially showed pathological findings in all tests indicating a lesion of both, the parasympathetic and sympathetic cardiac system. In the course of the disease, continual improvement of the HRV parameters could be demonstrated in both patients, however, pathological HRV values persisted up to the 42th, respectively the 75th, day. In contrast to fast clinical improvement of ocular, bulbar and peripheral motor impairment due to early specific antitoxin therapy, autonomic cardiac disturbances persisted up to 10 weeks unnoticed by both patients. We concluded that HRV analysis is a useful tool for cardiac monitoring of patients with botulism outside the intensive-care unit. Our cases also demonstrated that long-term HRV monitoring was obligatory for assessing the increased cardiac risk of these patients since autonomic dysfunction tended to show a later recovery than the other neurological symptoms.