Cardiac Autonomic Neuropathy: Comparative performance of Phase-Rectified Signal Averaging methods with Cardiac...

Area of Science:

• Cardiology
• Autonomic Neuroscience
• Biomedical Engineering

Background:

• Cardiac autonomic function (CAN) assessment traditionally uses Time Domain Heart Rate Variability (TD-HRV) and Cardiac Autonomic Reflex Tests (CARTs).
• Phase-Rectified Signal Averaging (PRSA) methods, specifically Deceleration Capacity (DC) and Acceleration Capacity (AC), offer a comprehensive approach to evaluating CAN.
• No prior studies have compared PRSA methods with conventional techniques or established diagnostic cut-off values for AC and DC in identifying CAN.

Purpose of the Study:

• To compare the efficacy of PRSA methods (AC and DC) against conventional methods (TD-HRV and CARTs) for diagnosing CAN.
• To establish specific cut-off values for AC and DC that accurately distinguish between patients with and without CAN.
• To validate these cut-off values in independent patient cohorts.

Main Methods:

• Two cohorts were studied: a derivation cohort (126 individuals with normal ventricular function) and a validation cohort (143 individuals with Left Ventricular Dysfunction).
• Patients underwent CARTs and short-duration (2-3 min) resting ECG recordings.
• CAN status (+Ve/-Ve) was determined using TD-HRV and CART criteria (AIIMS-AFT and Toronto Consensus). ROC curve analysis was employed to derive and validate AC and DC cut-off values.

Main Results:

• A reduction in DC values and an increase in AC values correlated with a higher likelihood of CAN.
• The optimal cut-off values identified were AC ≥ -7 and DC ≤ 7, achieving an Area Under the Curve (AUC) of approximately 0.9.
• Reclassification of patients using these cut-offs showed good agreement (kappa values 0.5–0.7) with conventional diagnostic methods.

Conclusions:

• Decreased DC and increased AC values are significant indicators of CAN.
• The established cut-off values (AC ≥ -7, DC ≤ 7) demonstrate high accuracy in diagnosing CAN.
• PRSA methods, with these defined cut-offs, provide a reliable and accurate tool for CAN assessment.