[The effect of early appearing extrasystoles on systemic and coronary circulation]

In 10 anaesthesized dwarf pigs with an open thorax the effects of extrasystoles on systemic and coronary circulation were investigated. The actual effect of an extrasystole depends on the time of its onset. Early extrasystoles hamper the cardiac blood perfusion, with decreases in the stroke volume, mean arterial pressure, coronary blood flow, and elevation of coronary resistance. Extrasystoles setting on later are of minor haemodynamic and coronarodynamic importance. The effects of bigeminy and 2:1 extrasystolia are more adverse than the consequences of extrasystoles with later onset. With cumulation of several consecutive extrasystoles also adverse the haemodynamic coronarodynamic sequelae increase, in dependence on the magnitude of the quotient coupling time /extrasystolic excitation period [ greater than 1.1], or of the quotient: duration of pre- and postextrasystolic intervals/ normal interval of heart action [ greater than 1.5]. The authors point out the importance of haemodynamic findings during early extrasystoles in ischaemic heart disease.