The following is a summary of “Cardiac Autonomic Dysfunction and Risk of Silent Myocardial Infarction Among Adults With Type 2 Diabetes,” published in the October 2023 issue of Cardiology by Kaze et al.

The connection between cardiac autonomic neuropathy (CAN) and the risk of silent myocardial infarction (SMI) in individuals with type 2 diabetes remains relatively unexplored in large-scale epidemiological studies. In this research, the study group sought to assess the association between CAN and the likelihood of SMI among a substantial sample of adults diagnosed with type 2 diabetes.

The study incorporated participants with type 2 diabetes from the ACCORD (Action to Control Cardiovascular Risk in Diabetes) study, excluding those with atherosclerotic cardiovascular disease at the study’s outset. CAN was identified using heart rate variability indices derived from 10-second resting electrocardiograms, particularly focusing on the standard deviation of all normal-to-normal R-R intervals and the root mean square of successive differences between normal-to-normal R-R intervals. CAN was defined as values falling below the general population’s fifth percentile of these parameters. Utilizing Cox proportional hazards regression, the researchers calculated hazard ratios (HRs) to evaluate the relationship between incident SMI and CAN indicators. 

Among 4842 participants (mean age, 62.5 years; 46.6% women; 60.2% White), 73 experienced incident SMI during a median follow-up of 4.9 years, corresponding to an incidence rate of 3.1 per 1000 person-years (95% CI, 2.5–3.9). Upon adjusting for various confounding factors, reduced heart rate variability demonstrated a heightened risk of SMI (HR, 1.67 [95% CI, 1.02–2.72] and HR, 1.56 [95% CI, 0.94–2.58] for the low standard deviation of all normal-to-normal R-R intervals and root mean square of successive differences between normal-to-normal R-R intervals, respectively). Moreover, individuals with CAN exhibited a 1.9-fold increased risk of experiencing SMI (HR, 1.91 [95% CI, 1.14–3.20]).

Conclusively, within this extensive cohort of adults diagnosed with type 2 diabetes, the presence of CAN was markedly associated with a higher risk of incident SMI, highlighting the potential clinical significance of this relationship.

Source: ahajournals.org/doi/10.1161/JAHA.123.029814