Cardiac involvement in malignant syndrome in Parkinson's disease

Little is known about cardiac abnormalities in neuroleptic malignant syndrome (NMS) in Parkinson's disease (PD), although high levels of serum creatine kinase (CK) suggest the presence of cardiac involvement. We have also been aware of elevated serum myosin light chain I (MLCI) in these patients with no clear evidence of an acute coronary syndrome. To evaluate cardiac involvement in NMS in PD, we recorded the electrocardiogram (ECG) and measured serum MLCI and CK-MB levels. Plasma levels of noradrenaline and adrenaline were also determined. The patients were classified based on the in-hospital outcome into 55 survivors and 5 nonsurvivors. Age- and gender-matched PD patients without NMS served as controls (n = 51). All patients had high serum concentrations of CK-MB and MLCI. The mean values of CK, CK-MB, MLCI, adrenaline and noradrenaline were higher in both patient groups as compared to control subjects, and the values in nonsurvivors were significantly higher than those in survivors. A positive correlation was observed between serum MLCI and CK levels (p < 0.01), and between serum MLCI levels and plasma noradrenaline concentrations (p < 0.01). ECG abnormalities such as prolonged QTc interval, abnormal Q wave, ST elevation and T wave inversion were observed in all nonsurvivors and 32 (58.2%) survivors. We conclude that myocardial involvement is common in patients with NMS even when they have no symptoms suggestive of myocardial injury, and MLCI and CK-MB as well as ECG are useful indicators of mortality.