[High purity ryanodine for in vitro diagnosis of malignant hyperthermia].

OBJECTIVE AND STUDY DESIGN

The identification of disposition for malignant hyperthermia (MH) is performed by the halothane-caffeine contracture test in skeletal muscle. However, testing currently renders about 14% of the patients MH equivocal (MHE). To reduce this number the "ryanodine contracture test" has been proposed in addition to the established procedure. As all ryanodine preparations used until now are combinations of ryanodine and dehydroryanodine, we investigate in this study the effects of the now available high-purity ryanodine (HPR) in concentrations of 2,5 and 10 mumol/l.

RESULTS

With all concentrations contractures appeared significantly earlier in MHS (malignant hyperthermia susceptible) than in MHN (malignant hyperthermia non-susceptible). However, only at 2 mumol/l a time overlap between both groups was not observed. By defining a time interval for MHS and MHN, three of the MHE patients could be assigned to MHS and three to MHN following their ryanodine-induced contractures.

CONCLUSION

The ryanodine contracture test should be added to the current diagnostics of malignant hyperthermia.