High N-terminal pro-B-type natriuretic peptide levels are associated with reduced heart rate variability in acute myocardial infarction

Abstract

Aim: We investigated the relationships between the autonomic nervous system, as assessed by heart rate variability (HRV) and levels of N-terminal Pro-B-type Natriuretic Peptide (Nt-proBNP) in patients with acute myocardial infarction (MI).

Methods and results: The mean of standard deviation of RR intervals (SDNN), the percentage of RR intervals with >50 ms variation (pNN50), square root of mean squared differences of successive RR intervals (rMSSD), and frequency domain parameters (total power (TP), high frequency and low frequency power ratio (LF/HF)) were assessed by 24 h Holter ECG monitoring. 1018 consecutive patients admitted <24 h for an acute MI were included. Plasma Nt-proBNP (Elecsys, Roche) was measured from blood samples taken on admission. The median (IQR) Nt-proBNP level was 681(159-2432) pmol/L. Patients with the highest quartile of Nt-proBNP were older, with higher rate of risk factors and lower ejection fraction. The highest Nt-proBNP quartile group had the lowest SDNN, LF/HF and total power but similar pNN50 and rMSSD levels. Nt-proBNP levels correlated negatively with SDNN (r = -0.19, p<0.001), LF/HF (r = -0.37, p<0.001), and LF (r = -0.29, p<0.001) but not HF (r = -0.043, p = 0.172). Multiple regression analysis showed that plasma propeptide levels remained predictive of LF/HF (B(SE) = -0.065(0.015), p<0.001)), even after adjustment for confounders.

Conclusions: In conclusion, our population-based study highlights the importance of Nt-proBNP levels to predict decreased HRV after acute MI.

Figure 1. Heart rate variability parameters in spectral analysis according to of Nt-proBNP quartiles: Low Frequency (LF), High Frequency (HF) and Low frequency/High Frequency (LF/HF) ratio.

P values correspond to one-way ANOVA.

Figure 2. Correlation analysis between Nt-proBNP circulating levels and heart rate variability parameters on 24 h holter ECG ; A: SDNN: Standard Deviation of the NN interval (SDNN); B: Low frequency (LF); C: High frequency (HF = ; D: Low frequency/high frequency (LF/HF) ratio.

P values correspond to one-way ANOVA. LF and HF are log-transformed values.