Patient-Activated Implantable Drug Pump for Treatment of Vasovagal Syncope: Is It Time for Clinical Use?

摘要

An implantable drug delivery system theoretically has a use in many arrhythmic situations, such as paroxysmal atrial fibrillation/atrial flutter, other supraventricular tachyarrhythmias, ventricular tachycardia, and vasovagal syncope. In this chapter the potential role of an implantable drug delivery system for treatment of vasovagal syncope is discussed.The rationale for development of such a device is the following [1], Vasovagal events, like many other autonomic nervous system disturbances, have a cyclic and unpredictable course with usually brief periods of symptom recrudescence (so-called clusters) alternating with sometimes very long periods of quiescence and asymptomatic status [2]. Thus, chronic therapy with drugs does not appear useful in the majority of cases and is often associated with significant or intolerable side effects as well as poor patient compliance, at least in young people [3]. Moreover, prevention of vasovagal reaction usually requires high drug plasma levels at the time of event occurrence that are difficult to reach with chronic oral administration [4]. As a matter of fact, drugs have only occasionally proved to be effective when evaluated in double-blind, randomized, placebo-controlled trials [5-9]. It is also noteworthy that electrical treatment with a pacemaker, even when effective, only rarely leads to complete elimination of symptoms [10-16], because of the hypotensive effects of the vasodepressor reflex that is present in practically all patients, generally precedes cardioinhibition, and is not amenable to correction or reversion by cardiac pacing [17-20].