Cardiac Autonomic Neuropathy in Obesity, the Metabolic Syndrome and Prediabetes: A Narrative Review

Abstract

Cardiac autonomic neuropathy (CAN) is a major complication of type 1 and type 2 diabetes mellitus (T1DM and T2DM). The increased morbidity, cardiovascular and allcause mortality associated with CAN is established from numerous epidemiological studies. However, CAN is increasingly recognised in people with prediabetes (pre-DM) and the metabolic syndrome (MetS) with a reported prevalence up to 11% and 24% respectively. CAN is associated with components of MetS including hypertension and obesity, predating hyperglycaemia. The aetiology of CAN is multifactorial and there is a reciprocal relationship with insulin resistance and MetS. Obstructive sleep apnoea (OSA) is also associated with CAN possibly through MetS and an independent mechanism. An estimated global prevalence of the impaired glucose tolerance (IGT) form of pre-DM of 587 million people by 2045 means CAN will become a major clinical problem. CAN is independently associated with silent myocardial ischaemia, major cardiovascular events, myocardial dysfunction and cardiovascular mortality. Screening for CAN in pre-DM using risk scores with analysis of heart rate variability (HRV) or Sudoscan is important to allow earlier treatment at a reversible stage. The link between obesity and CAN highlights the therapeutic potential of lifestyle interventions including diet and physical activity to reverse MetS and prevent CAN. Weight loss achieved using these dietary and exercise lifestyle interventions improves the sympathetic and Enhanced Digital Features To view enhanced digital features for this article go to https://doi.org/10.6084/ m9.figshare.9824660.

Assessment of baroreceptor reflex sensitivity in young obese Saudi males at rest and in response to physiological challenges

“…In contrast to their study, all of our subjects were young and it is documented that BRS declines with advancing age (Kardos et al, 2001). Autonomic depression, characterized by a reduction in both sympathetic as well as parasympathetic activity is also dependent upon the duration of obesity (Nagai et al, 2003;Williams et al, 2019). On a similar note, the inverse relationship between spontaneous BRS and BMI as seen in our study has also been described in normal weight and overweight/obese subjects in earlier studies (Beske et al, 2002;Kardos et al, 2001).…”

Effects of empagliflozin versus placebo on cardiac sympathetic activity in acute myocardial infarction patients with type 2 diabetes mellitus: the EMBODY trial

“…Glycemic variability is associated with cardiovascular autonomic neuropathy [41,42], and hyperglycemia results in ventricular tachycardia in patients hospitalized with AMI [43]. Moreover, the presence of T2DM without AMI is independently associated with an increase of all-cause mortality in patients presenting with ventricular tachyarrhythmias on admission [44].…”

Effects of empagliflozin versus placebo on cardiac sympathetic activity in acute myocardial infarction patients with type 2 diabetes mellitus: the EMBODY trial

“…Glycemic variability is associated with cardiovascular autonomic neuropathy [41,42], and hyperglycemia results in ventricular tachycardia in patients hospitalized with AMI [43]. Moreover, the presence of T2DM…”