Effects of desipramine on autonomic input to the heart

Objective: To examine the impact of age on the effects of desipramine (DMI) on autonomic input to the heart. Method: Twenty-four-hour electrocardiogra ms were obtained from 42 subjects, aged 7 to 66 years, while off and on DMI . To obtain measures of autonomic input to the heart, heart rate variabilit y was assessed via spectral analysis of RR interval variability. Results: D MI treatment was associated with a significant increase in 24-hour mean hea rt rate and significant decreases in RR interval variability in all spectra l bands, including in the high-frequency band, which provides a measure of parasympathetic input to the heart. RR interval variability was greater in younger individuals both off and on DMI. Conclusions: DMI treatment was ass ociated with a marked decline in RR interval variability, indicating that D MI affects autonomic input to the heart. Specifically, DMI reduced parasymp athetic input, which, in theory, may increase vulnerability to arrhythmias. However, the magnitude of DMI's impact on RR interval variability did not vary with age.