[A heart rate adaptable "physiologic" pacemaker. Is the effort worthwhile?]

The dual-chamber pacemaker provides an approximately physiologic cardiac action in patient with 3rd degree AV-block and preserved sinoatrial function. Newly developed so-called rate-responsive systems are now available. Initial clinical experience has been reported with pacemakers controlled via respiration rate, activity, central venous blood temperature, or intracardially measured QT-interval. The sensitivity and specificity of rate regulation like the effort of implantation and setting is not completely satisfactory and adequate until now. At the present time, such systems are being implanted mainly according to individual indications. Before a general use can be recommended, several problems still remain to be solved, in particular the question as to what therapeutic advantage is to be expected with respect to the underlying disease, arrhythmia and patient group.