Early and late changes in myocardial function and heart rate variability in patients after myocardial...

The purpose of the study was to evaluate the effect of myocardial revascularisation and associated improvement of left ventricular systolic function on heart rate variability in patients after myocardial infarction.

The study population consisted of 35 patients, who within the previous 6 months had suffered from myocardial infarction and in whom low dose dobutamine ventriculography revealed hibernating myocardium, whereas coronary angiography provided indications to revascularisation. CABG was performed in 22 patients, PTCA of the infarct-related artery in 13 patients. At baseline, 3 months and 3 years after the procedure radionuclide ventriculography, myocardial perfusion scintigraphy and 24hr continuous ECG recording were performed.

After initial improvement of systolic function in ventriculography (EF = 48.63 +/- 11.6 v. 52.37 +/- 11.27 at p < 0.001) it slightly but not significantly decreased at long-term follow-up (EF = 51.8 +/- 10.77). The remaining parameters of systolic function function behaved in a similar way in radionuclide ventriculography. Diastolic function parameters did not change significantly at early and long-term follow-up. HRV measures did not change at 3 months but at 3 years both sympathetic- and parasympathetic- related parameters and global autonomic activity were diminished. At 3 years global autonomic activity and parasympathetic activity were diminished with their values similar in both groups.

It seems that HRV measures diminish at long- -term follow-up. The type of revascularisation procedure is only of short-range value with the parameters stabilising on a similar level at long-term follow-up.