[Cardiac arrhythmia associated with malignant neuroleptic syndrome: description of 2 clinical cases]

Malignant neuroleptic syndrome (alteration of consciousness, muscle rigidity and hyperthermia) is a potentially lethal condition, due also to its life-threatening complications. In particular, hypokinetic and hyperkinetic arrhythmias can be rare and severe early manifestations of this illness, and they deserve a careful approach because of their drug-refractoriness. Arrhythmias associated with the malignant neuroleptic syndrome depend on various mechanisms: neurotransmitter receptor blockades typical of neuroleptic drugs, clustered lipid droplets among the cardiac myofibrils and possible electrolytic disorder due to diaphoresis. The two cases described here presented hypokinetic and hyperkinetic (supraventricular and ventricular) arrhythmias. The arrhythmias, which failed to respond to antiarrhythmic drugs, were temporarily suppressed by DC shock, over-drive pacing and correction of electrolytic imbalance. In case 1, prolonged bromocriptine treatment was required. Complete wash-out of the causative agents resulted in lasting regression of arrhythmias. In conclusion, a correct treatment and a favourable outcome of this syndrome can be achieved only through early diagnosis.