Niemelä M J, Airaksinen K E, Ikäheimo M J, Groundstroem K, Linnaluoto M K, Takkunen J T
Department of Medicine, Oulu University Central Hospital, Finland.
Int J Cardiol. 1989 Sep;24(3):305-9. doi: 10.1016/0167-5273(89)90009-0.
We measured the variation in heart rate during deep breathing, a sensitive non-invasive measure of cardiac parasympathetic activity, in 95 patients 3 weeks after myocardial infarction and in 40 asymptomatic healthy controls. The variation in rate was significantly lower (11.6 +/- 6.1 vs 17.6 +/- 7.3 beats/min, P less than 0.001) in patients with myocardial infarction than in controls. Forty-nine patients (52%) and 5 controls (13%) were considered to have diminished (less than or equal to 10 beats/min) variation of rate. The diminution in this variation was not related to the type or location of myocardial infarction, to maximum release of CK-MB or to cardiovascular medication. Our results suggest that impairment of vagal control of heart rate is common after myocardial infarction. The impairment cannot be predicted by any specific feature of the disease.
