Five-minute heart rate variability can predict obstructive angiographic coronary disease.

Area of Science:

• Cardiology
• Autonomic Nervous System Function
• Non-invasive Cardiac Diagnostics

Background:

• Obstructive coronary artery disease (CAD) is diagnosed in only half of patients referred for angiography.
• Five-minute heart rate variability (HRV) serves as a non-invasive marker for autonomic control of the vasculature.
• HRV may help risk-stratify cardiac patients and decrease unnecessary angiograms.

Purpose of the Study:

• To investigate the hypothesis that five-minute heart rate variability (HRV) can risk-stratify cardiac patients.
• To determine if HRV can reduce the number of unnecessary coronary angiograms performed.
• To assess the predictive value of HRV for obstructive coronary artery disease.

Main Methods:

• Prospective observational study (Alternative Risk Markers in Coronary Artery Disease (ARM-CAD) study).
• 470 consecutive patients with predominantly normal cardiac rhythm undergoing elective angiography across three Australian cardiac centres.
• Obstructive CAD defined as ≥50% stenosis on angiography.

Main Results:

• Patients with obstructive CAD exhibited significantly reduced HRV, particularly in the low frequency (LF) range (median 180 vs 267 ms²; p<0.001).
• A linear trend was observed between decreasing LF power and increasing CAD severity (p=0.003).
• Reduced LF power was independent of stenosis location, and HRV added to risk prediction irrespective of Framingham risk score (p<0.0001).

Conclusions:

• Low HRV is a strong predictor of angiographic coronary artery disease.
• HRV is clinically useful for risk prediction in patients with sinus rhythm.
• HRV can aid in identifying patients with obstructive CAD, potentially reducing the need for invasive procedures.