Major depressive disorders (MDD) are among the most common psychiatric disorders affecting people worldwide. The steady increase in cases of depressive disorders has been mainly attributed to enhanced life stress. The association of this clinical condition with other systemic disorders, especially cardiac conditions, raises concerns about increased morbidity and mortality related to this disorder. Investigating neuro-cardiac regulation using heart rate variability (HRV) and cortical excitability using transcranial magnetic stimulation (TMS) in patients with depression can provide crucial insights to understand systemic involvement and possible therapeutic interventions. We recruited 60 patients suffering from moderate depression based on International Classification of Diseases ICD-10 criteria on treatment with Escitalopram for more than 2 months. The HRV measures and TMS techniques using cortical excitability measures with single and paired-pulse TMS measures were performed on all the patients and compared with age- and gender-matched healthy controls. Patients with depression showed significantly lesser standard deviation of normal-to-normal interval (SDNN), root mean square of successive differences (RMSSD), total power (TP), high frequency (HF) power, and increased low frequency (LF) power and LF/HF ratio which together indicate reduced HRV. Reduced short-interval intracortical inhibition (SICI), intracortical facilitation (ICF), and cortical silent period (CSP) (assessed by TMS) were also observed in patients with depression compared to healthy controls. Patients with depression showed decreased HRV, glutamatergic activity, gamma amino butyric acid-B (GABA-B) activity, and increased GABA-A activity. These findings suggest aberrant neuro-cardiac regulation and cortical excitability in this enigmatic disorder.

重度抑郁症 (MDD) 是影响全世界人民的最常见精神疾病之一。抑郁症病例的稳步增加主要归因于生活压力的增加。这种临床病症与其他全身性疾病（尤其是心脏疾病）的关联引起了人们对与这种疾病相关的发病率和死亡率增加的担忧。利用心率变异性 (HRV) 和经颅磁刺激 (TMS) 的皮层兴奋性来研究抑郁症患者的神经心脏调节，可以为了解全身参与和可能的治疗干预措施提供重要的见解。我们招募了60名根据国际疾病分类ICD-10标准患有中度抑郁症的患者，接受艾司西酞普兰治疗超过2个月。对所有患者进行 HRV 测量和 TMS 技术，使用皮质兴奋性测量和单脉冲 TMS 测量和配对脉冲 TMS 测量，并与年龄和性别匹配的健康对照进行比较。抑郁症患者的正常与正常区间 (SDNN)、连续差异均方根 (RMSSD)、总功率 (TP)、高频 (HF) 功率和低频 (LF) 功率增加的标准差显着降低和 LF/HF 比一起表明 HRV 降低。与健康对照相比，抑郁症患者的短间隔皮质内抑制 (SICI)、皮质内促进 (ICF) 和皮质静默期 (CSP)（通过 TMS 评估）也有所减少。抑郁症患者的 HRV、谷氨酸能活性、γ-氨基丁酸-B (GABA-B) 活性降低，GABA-A 活性升高。这些发现表明这种神秘疾病存在异常的神经心脏调节和皮质兴奋性。