New York Heart Association functional class influences the impact of diabetes on cardiac autonomic function

Area of Science:

• Cardiology
• Endocrinology
• Autonomic Neuroscience

Background:

• Diabetes Mellitus (D) and Heart Failure (HF) are independently linked to abnormal heart rate variability (HRV).
• The combined impact of D and HF on HRV and autonomic function is not well understood.
• Investigating cumulative effects is crucial for understanding disease progression and treatment.

Purpose of the Study:

• To compare HRV parameters in patients with systolic heart failure (HF) with and without diabetes (D).
• To assess the influence of HF severity (New York Heart Association class II vs. III) on HRV in diabetic and non-diabetic patients.
• To determine if the effects of D and HF on autonomic function are cumulative.

Main Methods:

• Compared pretreatment HRV (traditional, nonlinear, and heart rate turbulence) in 80 D and 74 non-diabetic (ND) HF patients.
• Stratified analysis by New York Heart Association (NYHA) class II versus III.
• Utilized data from patients enrolled in a drug evaluation study for HF.

Main Results:

• Age-adjusted heart rate (HR) was lower in NYHA class II D patients compared to class III patients.
• Most HRV measures, including HR turbulence, were better in NYHA class II ND patients than in all other groups.
• Few significant differences in HRV were observed between class II D and class III ND/D patients.

Conclusions:

• Autonomic dysfunction in HF may be cumulatively worsened by diabetes in NYHA class II patients.
• Diabetes appears to have a limited additional impact on most HRV measures in NYHA class III HF patients.
• Further research is needed to explore the prognostic value of various HRV measures in diabetic versus non-diabetic HF patients.