Insomnia, or rather the sleep deprivation secondary to it, produces autonomic control changes (decrease in vagal tone and/or increase in sympathetic tone), among other neurohumoral mechanisms, modyfing heart rate variability.

 In the scientific database PubMed (http://www.pubmed.gov/), there are more than 2,400 reviews on this topic.  These results are consistent with the hypothesis that autonomic hyper-arousal is a major pathogenic mechanism in primary insomnia, and confirm that this condition is associated with an increased cardiovascular risk.

In study 2016 (788 participants with information on all relevant covariates of insomnia symptoms were included) were calculated the least square mean of indices of left ventricular function, including systolic mitral annular excursion, peak velocities of systolic and diastolic motion of the mitral annulus and systolic deformation of the left ventricle. As result was found no clear evidence that increasing number of insomnia symptoms is associated with any of the left ventricular function indices.The methods that were used are sensitive to detect preclinical HF, and therefore, these findings do not support a causal relation between insomnia symptoms and HF (PMID: 26924518)

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https://universaltcm.com/insomnia-causes/