14th International Congress
THE "NEW FRONTIERS"
OF ARRHYTHMIAS 2000

Jan. 29 - Feb. 5, 2000
Marilleva, Trento, Italy

RT-77

Electrical therapy for the prevention of the malignant vasovagal syncope: the DDD Closed Loop Stimulation

Eraldo Occhetta, Michele Maltese*, Corrado Vassanelli on behalf of the INVASY Preliminary Study Group.
Divisione Clinicizzata di Cardiologia, Facolta di Medicina e Chirurgia di Novara, Universita degli Studi del Piemonte Orientale, Novara, *Biotronik-Seda, Trezzano sul Naviglio, Italy

Introduction

The ideal method to obtain a physiologic pacemaker system would be the integration of the pacing device into the native cardio-circulatory system. This concept has been realized in the Closed Loop Stimulation (CLS) system, which converts information arising from the circulatory centres in pacing rate^1,2. Even under pathophysiologic conditions, the force developed by the myocardial reflects the information from the circulatory centres³. The inotropic regulation affects the myocardial contractility, which consequently reflect information about the haemodynamic state and requirements⁴.

Previous studies have shown that vasovagal syncopes are insufficiently prevented by standard pacing^5,6. More sophisticated pacemaker algorithms for treatment of vasovagal syncope aim to detect an initial drop in heart rate, which marks the onset of the cardioinhibitory reaction⁷. In patients suffering from malignant vasovagal syncopes, changes in contraction dynamics of the ventricular myocardium have been observed usually before any drop in heart rate^8-10.

The INOS² CLS pacemaker (Biotronik, Germany) detects changes in myocardial contraction dynamics via intracardiac impedance measurement and transfers them into individual pacing rates¹¹. Therefore, we started a preliminary study to investigate whether the DDD-CLS stimulation of the INOS² CLS pacemaker could provide pacing rates adequate to the patient’s circulatory demand and could react with a dominant pacing rate increase, especially during an incipient vasovagal syncope. Such a therapeutic effect should result in a marked reduction of the incidence of syncopes during daily life.