A patient is presented with hyperkalemic periodic paralysis (HyperPP) and a cardiac dysrhythmia. An amino acid substitution (Val783Ile) in the adult skeletal muscle sodium channel gene was detected. Although lack of available family members precluded rigorous genetic tests, the sodium channel change may be responsible for HyperPP in this patient and could also be responsible for the associated cardiac dysrhythmia.

Few patients have been reported with familial periodic paralysis and ventricular tachycardia. The natural history of these cases was unfavorable, with most dying because of a presumed cardiac dysrhythmia. We report for the first time the results of an electrophysiologic study of a similar case and the successful use of calcium channel blockers, shedding light on the possible mechanism and management of these patients.

Few patients have been reported with familial periodic paralysis and ventricular tachycardia. The natural history of these cases was unfavorable, with most dying because of a presumed cardiac dysrhythmia. We report for the first time the results of an electrophysiologic study of a similar case and the successful use of calcium channel blockers, shedding light on the possible mechanism and management of these patients.