Reduced Heart Rate Variability in Patients with Medically Unexplained Physical Symptoms A Meta-Analysis of HF-HRV and RMSSD, 2020, Vreijling et al

[Andy]

Objectives
Medically unexplained physical symptoms (MUPS) and related syndromes are common and place a substantial burden on both patients and society. Chronic psychological distress and dysregulation of the autonomic nervous system may be common factors associated with MUPS, although previous studies have reported mixed results. The aim of this meta-analysis is to provide an updated synthesis of studies investigating heart rate variability (HRV) indices associated with autonomic nervous system functioning in three common MUPS-syndromes and to explain inconsistencies in previous study findings.

Method
Literature search yielded 58 studies comparing HRV indices of reduced parasympathetic activity of healthy individuals to patients with chronic fatigue syndrome (Npatients = 271), irritable bowel syndrome (Npatients = 1005), and fibromyalgia (Npatients = 534). Separate random-effects meta-analyses were conducted on studies measuring root mean square of successive differences (RMSSD) and high frequency HRV (HF-HRV).

Results
Regardless of syndrome type, patients had significantly lower RMSSD (k = 22, Hedges’ g = - 0.37 [-0.53; -0.21], p < .001) and HF-HRV (k = 52, Hedges’ g = -0.69 [-1.03; -0.36], p < .001) than healthy individuals. Sample age and publication year explained substantial variation in RMSSD, whereas controlling for confounders in statistical analyses explained variation in HF-HRV.

Conclusions
Lower RMSSD and HF-HRV in patients with MUPS versus healthy controls indicates that autonomic nervous system dysregulation, particularly lower parasympathetic activity, may play a role in patients with these conditions. This conclusion may have important implications for the underlying mechanisms and treatment of MUPS and related syndromes.

Paywall, https://journals.lww.com/psychosoma..._Rate_Variability_in_Patients_with.98490.aspx
Sci hub unable to access at time of posting.

 

[Mithriel]

These sort of studies worry me. They find something that is also found in psychological distress and then assume it must be caused by psychological distress when there is no evidence of causality.

Since the beginning ME has been seen as a disease which has dysautonomia as part of it though the term is much more recent. In ME the nervous system does not work properly because of damage to the brain not the other way round.

It does not matter if anxiety and stress also lead to hear rate problems, we have them because the signal to the heart is not normal because of the brain disease and because our hearts can be damaged because of the disease as well.

If we are stressed and anxious it will only add to the problem but they are not the cause the dysfunction caused by the disease ME is the cause.

This is not a problem in other heart diseases because the psychologists are not allowed near them and they are understood to have a physical cause for the underlying damage.

 

[rvallee]

Congratulations on "discovering" dysautonomia after having incompetently dismissed it as anxiety for decades. You guys are so amazing if you keep working at this you may even catch up to the 1960's one day. Well, probably not, gotta make it to the 20th century first.

 

[Snow Leopard]

Congratulations on "discovering" dysautonomia after having incompetently dismissed it as anxiety for decades. You guys are so amazing if you keep working at this you may even catch up to the 1960's one day. Well, probably not, gotta make it to the 20th century first.

You, like the authors are also forming a non sequitur conclusion.

Heart rate variability is a non-specific measurement and there is no reason to conclude that these differences suggest abnormal physiology (or psychology for that matter).

The strongest predictor of reduced heart rate variability is lower cardiovascular fitness. Hence the entirety of the aforementioned studies results could be due to poor case-control matching.