Heart Rate Recovery and Selective Serotonin Reuptake InhibitorsReply.

To the Editor,

I have read, with great interest, the article entitled "Influence of Smoking Consumption and Nicotine Dependence Degree in Cardiac Autonomic Modulation" by Santos et al.,[1] recently published in Arquivos Brasileiros de Cardiologia 2016; 106: 510-8. The reseearchers reported that only the intensity of smoking consumption had influences over cardiac autonomic modulation of the evaluated smokers. Smokers with severe smoking consumption intensity presented worse autonomic modulation than moderate ones.[1]

Antidepressant medications are a first-line treatment option for moderate to severe mood and anxiety disorders; however, some studies suggest that long-term use may be associated with an increased risk for cardiovascular disease.[2-4]

Kemp et al.[5] reported that all users of selective serotonin reuptake inhibitor - except fluoxetine - display alterations in heart rate or heart rate variability (HRV) in comparison to non users. Similarly, users of paroxetine also display small to moderate reductions in HRV relative to users of citalopram, fluoxetine, and sertraline, but not escitalopram.

In this context, it might be beneficial to give more details about medications due to their effect on cardiac autonomic activity.

Firstly, I would like to thank you for your interest in our manuscript entitled "Influence of Smoking Consumption and Nicotine Dependence Degree in Cardiac Autonomic Modulation" by Santos APS et al., recently published in this magazine.

As described in the Methods section of the study, individuals on medications that influence cardiac autonomic modulation were not included. Antidepressants, which are among said medications, are commonly used by smokers, sometimes as a part of a drug therapy to aid in the cessation of the smoking habit.

Even though participants of the study were part of an Antismoking Awareness and Orientation Program, which consists of the association of cognitive behavioral and drug therapy, they had not yet started the offered treatment, and the cardiac autonomic modulation evaluation was done with smokers who were not abstinent or on specific cessation medication.

Given the above, we can state that, in our study, there was no influence of medications that could alter cardiac autonomic modulation.