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Association between depression severity and cardiac autonomic modulation

https://doi.org/10.1016/j.jpsychores.2016.03.125Get rights and content

Highlights

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    QT dispersion (QTd) measurements reflect cardiac autonomic modulation.

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    Increased QTd indicates decreased vagal tone and/or increased sympathetic tone.

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    QTd and heart rate-corrected QTd were significantly higher in depressive patients.

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    Increased QT dispersion was found in mild and moderate depression.

Abstract

Objective

Changes in autonomic modulation are found in depressive patients. QT dispersion is a convenient measure of cardiac autonomic modulation (CAM). As both QT dispersion and depression are related to changes in CAM, this study aimed to examine if there was an association between depression severity and QT dispersion.

Methods

The selected sample (n = 60) derived from 236 women who were recruited via a campaign for breast cancer prevention. The women selected to participate were all non-smokers and were not taking any drug that could interfere with the results. After applying inclusion and exclusion criteria, 60 women were selected. QT dispersion (QTd) and rate-corrected QTd (QTcD) were calculated in 37 physically and mentally healthy women and 23 nontreated depressive women. Univariate ANOVA(s) were used to test group differences. The 17-item Hamilton Depression Rating Scale (HDRS17) was scored to measure depression severity. The relationship between depression severity and cardiac autonomic modulation was analyzed by the best curve that fit the raw data of the HDRS17 scores and the QT dispersion variables.

Results

The QTd and QTcD were significantly smaller in non-depressed in relation to the depressed women. The best curve that fit the raw data of depression severity (HDRS17) and the two measurements of cardiac autonomic modulation (QTd and QTcD) was a cubic equation for both QTd and QTcD. An increase in QTd and QTcD were observed until the HDRS17 score reached 20 points.

Conclusion

There is a significant positive relationship between depression severity and cardiac autonomic modulation in mild and moderate depression.

Introduction

Depression is linked to physiological changes that can contribute not only to an unfavorable outcome in cardiac patients [1], [2], but also cardiovascular disease (CVD) in healthy individuals [2]. Dysregulation of the modulation of the autonomic nervous system (ANS) is considered one of the mechanisms linking depression to CVD [3].

Serotonin is reduced in unipolar depression (MDD) and could result in overexpression of sympathetic neural discharge [4]. Heart rate variability (HRV) and QT dispersion (QTd) reflect ANS modulation [5], [6], [7]. As HRV is found to be correlated with QTd, the cardiac autonomic modulation was evaluated solely with the aid of QTd in the present study.

QTd is an indirect electrocardiography measure of heterogeneity of ventricular repolarization [8], [9]. QTd is defined as the maximal interlead difference in QT interval on a 12-lead electrocardiogram (ECG) [8]. It is influenced by the ANS [6], [7]. Increased QTd is related to mortality [10] and indicates decreased vagal tone and/or increased sympathetic tone [5], [6], [7].

Both QT dispersion and depression are linked to ANS. The association between increased QTd and depression was investigated in a few studies [11], [12]. However, in one study the sample included patients taking antidepressants [11]. In another study, individuals with hypertension, and diabetes, along with those who smoke were not excluded [12]. Moreover, these studies focused only on the presence or absence of depression, but they did not take into account depression severity. The current study aimed to examine the relationship between QT dispersion and depression severity in non-smoking, healthy women who were not taking antidepressants at the time they were tested.

Section snippets

Participants

The participants were selected from a campaign for breast cancer prevention. The initial sample consisted of 236 women, and 22% (n = 52) were found to be depressed. Fifty-two non-depressed subjects matched by age and cognitive status were initially selected to participate in the extensive cardiovascular screening. All patients had fulfilled the inclusion criteria as follows: with normal findings upon physical examination, 12-lead ECG, and echocardiography; non-smokers in the previous six months;

Results

The intrarater reliability for QTd and QTcD were r = 0.86 (p < 0.001) and r = 0.88 (p < 0.001), respectively. These data indicate significant intrarater reliability.

With the aid of the DSM-5, the women were stratified into two groups: non-depressed (n = 37) and depressed (n = 23). There were no significant differences regarding age, EL, SES, BMI, MS, MMSE, and HR between depressed and non-depressed groups (Table 1).

Univariate ANOVA(s) indicated that average values of the QTd and QTcD (Table 2) were

Discussion

The total prevalence of depression (22%) and its prevalence among non-smokers (9.7%) are in agreement with previous studies [21], [22].

Previous studies have investigated the relationship between psychiatric disorders and QTd. Individuals with higher anxiety levels had higher QTd [23], [24]. A similar result was found in conversion patients [25]. QTd was also found to be altered in anorexia nervosa [26].

The first study that analyzed QTd in depressed individuals without cardiovascular disease

Conflict of interest statement

The authors have no conflicts of interest to declare. There was no direct financial support for the study.

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