The combined use of hysteresis and Holter functions improves diagnosis and therapy in patients with sick sinus syndrome.

We used the Holter functions of an implantable pacemaker in 12 patients with sino-atrial disease suffering from Adam-Stokes attacks to analyze the effects of hysteresis programming. The basic pacing rate of 50 ppm combined with a programmed hysteresis value of 10 to 20 ppm led to a drastic reduction in competition between paced and spontaneous beats: the percentage of paced beats decreased from 20.1% without hysteresis to 1.4% using 10 ppm hysteresis and the switches from sense to pace decreased from 2.0% to 0.06%. On the other hand, with hysteresis, no decrease in either the exercise tolerance or general well-being of the patients was observed.

A new pacemaker for monitoring asystole and prevention of Adams-Stokes syndrome and sudden cardiac death.

Patients with suspected Adams-Stokes syndrome are examined by Holter monitoring. During the monitoring, there is the danger of syncopes occurring and there are even reports of sudden cardiac death. We therefore developed a pacemaker for cardiac arrest monitoring and the prevention of Adams-Stokes syndrome and sudden cardiac death, which has the following functions: (1) the longest escape interval of the pacemaker not exceeding the value at which syncope is induced is determined by the decline of the mean heart rate including the asystole to a certain threshold rate; (2) once the pacemaker escapes from the interval it continues pacing for a while at a physiological rate to allow recover from ischemias in organs or tissues; and (3) to prevent overdrive suppression to the heart, the pacing rate gradually declines and stops pacing until the next asystole. This pacemaker is useful not only in the diagnosis of Adams-Stokes syndrome but also in pharmacological and pathophysiological studies and in determining when pacing should cease.

[Indications for pacemaker therapy of the heart (author's transl)]. / Indikationen zur Schrittmacher-Therapie des Herzens

During the last few years the indications for pacemaker therapy could be extended in step with the lowering of the frequency of complications and the effort required of doctors and departments. Now one does not only aim at prevention of dangerous Adams-Stokes attacks but increasingly at improvement of the range of cardiac function. If there is no pharmacologic alternative there are no absolute contraindications. Pacemaker therapy is indicated also, if only temporary symptomatic improvement can be expected.

[Electric stimulation as a means for the diagnosis of atrioventricular conduction disorders]. / Die Elektrostimulation als Hilfsmittel zur Diagnostik von atrioventrikulären Leitungsstörungen

A patient with 2 : 1-block and right-bundle-branch block is described, who developed a high-degree-AV block distal to the bundle of His during electrophysiological investigations. Rapid atrial pacing caused total AV block distal to the His bundle. Rapid pacing from the right ventricle also caused total AV block after sudden discontinuation of pacing. The duration of total AV block was 25 to 60 seconds and the preautomatic time 2300-4750 msec according to rate and duration of stimulation. These methods are considered as good tools to evaluate patients with severely diseased conduction system, who might develop total AV block or Adams-Stokes seizures.