[Reduction of cardiac ejection fraction as a problem of pacemaker treatment].

Ventricular pacing often is associated with a decrease of left ventricular output leading to symptoms of diminished cerebral perfusion. This is caused by a loss of properly timed atrial systole. The contribution of the atrial contribution of the atrial contraction to left ventricular output can reach 40% especially in patients with myocardial failure. A particular diminution of cardiac performance can be observed when ventriculoatrial conduction follows ventricular pacing. AV-sequential pacing, however, with a coordinated atrial systole leads to an obvious increase of cardiac output.