Thrombolytic therapy affects the time course of spectral components of heart period variability in anterior wall myocardial infarction

The authors evaluated the influence of thrombolytic therapy over the in-hospital time course of total power (PSD) and individual spectral components of heart period variability (HRV) in 26 patients with a first transmural anterior wall myocardial infarction (AMI). A fast Fourier transform method was used to detect the spectral components. Two major peaks were identified: low-frequency (LF), centered at 0.04-0.15 Hz, and high-frequency (HF), synchronous with the respiratory rate. Thrombolized patients had a small enzymatically estimated infarct size, lower Killip class, and higher 2-D echo ejection fraction than conventionally treated ones. No differences in total PSD, HF and LF peaks, and LF/HF ratio were detected between the two groups during the early phase of AMI. Instead, in the subacute phase thrombolized patients showed an increase in total PSD, mainly due to an increase in the HF peak and, to a lesser extent, in the LF peak. After an early ischemic stunning, thrombolytic therapy favorably affects the time course of HRV during the hospital phase of a first transmural anterior wall AMI, allowing an improvement of global autonomic activity through the recovery of vagal tone