Effect of methamphetamine dependence on heart rate variability

Abstract

Methamphetamine (METH) is an increasing popular and highly addictive stimulant associated with autonomic nervous system (ANS) dysfunction, cardiovascular pathology and neurotoxicity. Heart rate variability (HRV) has been used to assess autonomic function and predict mortality in cardiac disorders and drug intoxication, but has not been characterized in METH use. We recorded HRV in a sample of currently abstinent individuals with a history of METH dependence compared to age- and gender-matched drug-free comparison subjects. HRV was assessed using time domain, frequency domain, and non-linear entropic analyses in 17 previously METH-dependent and 21 drug-free comparison individuals during a 5 minute rest period. The METH-dependent group demonstrated significant reduction in HRV, reduced parasympathetic activity, and diminished heartbeat complexity relative to comparison participants. More recent METH use was associated with increased sympathetic tone. Chronic METH exposure may be associated with decreased HRV, impaired vagal function, and reduction in heart rate complexity as assessed by multiple methods of analysis. We discuss and review evidence that impaired HRV may be related to the cardiotoxic or neurotoxic effects of prolonged METH use.

Figure 1

These plots illustrate the distribution of the data for lifetime quantity of METH use (A), length of abstinence (B), and number of days of METH use in the past year (C) in participants with a history of METH dependence. To examine the relationship between METH use and HRV, participants were divided into two groups as indicated by the horizontal bar in each plot. Participants with high METH use (greater than 4000 grams), longer abstinence (greater than 1 year), and greater METH use in the past year are designated by solid circles; lower values are indicated by open circles. Group comparison data are shown in Table 4.