Identifying delirious states and autonomic cardiovascular dysfunction associated with amitriptyline treatment by standardized analysis of heart rate.

Ninety-one patients treated with amitriptyline and 60 normal control subjects underwent a standardized heart rate analysis in supine posture. Tests included the determination of time- and frequency-derived measurements of heart rate variability. The patients differed significantly from the control subjects in all parameters investigated. Two-thirds of the patients treated with a tricyclic antidepressant (TCA) reached values that met the criteria for cardiovascular autonomic neuropathy. Our results provide evidence that heart rate analysis might be a more sensitive tool in diagnosing amitriptyline-associated anticholinergic delirium than determination of TCA plasma levels. Further research is needed to elucidate what implications the TCA-associated alteration of autonomic cardiovascular function might have for patients.