The Ratio of Low-Frequency to High-Frequency in Ambulatory Electrocardiographic Monitoring Immediately Before Coronary Angiography as a Predictor of the Presence of Coronary Artery Disease

BACKGROUND: There is considerable evidence that impaired autonomic control may be associated with the etiology of coronary artery disease (CAD). We hypothesized that the autonomic imbalance as assessed by measuring heart rate variability (HRV) and biological parameters before and after coronary angiography (CAG) may predict the presence of CAD. METHODS: Ambulatory electrocardiographic (ECG) examination using eHEART(®) (Parama-Tec) is a novel, rapid, and simple method with which we can measure HRV within 5 min. We selected patients (n = 78, 68 ± 10 y) who underwent CAG and analyzed their ambulatory ECGs and blood levels of neuropeptides at both 1 day and immediately before and after CAG. The patients were divided into the presence (n = 64, CAD group) and absence of CAD (n = 14, non-CAD group). RESULTS: Although the CAD group showed an increase in blood pressure immediately before CAG, the ratio of low-frequency to high-frequency (LF/HF) was significantly decreased in the CAD group, but not in the non-CAD group. On the other hand, there was no difference in a coefficient of variation of the R-R interval or pulse rate between the two groups. CAD was independently associated with hypertension (P = 0.011), dyslipidemia (P = 0.009), and LF/HF immediately before CAG (P = 0.046) by a logistic regression analysis. CONCLUSIONS: These findings suggest that LF/HF immediately before CAG in addition to hypertension and dyslipidemia might predict the presence of CAD.