Case presentationĪn 87 year old Bangladeshi lady who underwent a single chamber ventricular pacemaker (VVI mode: i.e.
A PACED WITH FAILURE TO CAPTURE GENERATOR
Treatment involves repositioning of the dislodged leads and suture fixation of the lead and pulse generator within its pocket. More commonly reported among elderly females with impaired cognition, the phenomenon usually occurs in the first year following pacemaker implantation. This causes coiling of the lead and its dislodgement, resulting in failure of ventricular pacing.
A PACED WITH FAILURE TO CAPTURE SKIN
It occurs due to unintentional or deliberate manipulation of the pacemaker pulse generator within its skin pocket by the patient. Our experience has shown that the variable nature of this type of pacing can even cause a different chamber to be stimulated by the bipolar electrode in the atrium (Figure 3).The pacemaker-twiddler’s syndrome is an uncommon cause of pacemaker malfunction. Asynchronous stimulation can also be produced by other types of pacing. Such arrhythmias can result in episodes of sustained intranodal tachycardia despite the underlying deterioration in atrioventricular conduction. However, pacemaker syndrome or pacemaker-mediated tachycardia can occur.ĭuring single-lead DDD pacing, failures in signal detection or atrial capture can lead to asynchronous stimulation, which can induce arrhythmias under certain conditions, as were observed in the patient described above. 5ĭuring VDD pacing, these variations in position and orientation can modify the amplitude of the atrial signal detected such that, in some cases, there is an intermittent loss of atrioventricular synchronization, which is usually of no clinical significance. Initially at least, this "floating" state means that the relative position and orientation of the two poles will change in response to numerous factors, including postural alterations, breathing, physical exercise and heart failure. These enable the atrial depolarization signal to be detected without the need for contact with the atrial wall. The electrode sensors designed for use with single-lead VDD pacing comprise two poles that "float" within the atrium.
P' indicates P wave A, atrial activity V, ventricular activity. a: external lead b: atrial electrocardiogram c: ventricular electrocardiogram during intranodal tachycardia.
This resulted in reproducibly induced sustained episodes of intranodal tachycardia (Figures 1 and 2).įig. During the follow-up period, and in accordance with the standard procedure for evaluating this type of pacemaker, atrial stimulation using OLBIs was started.ĭuring a subsequent routine check-up, intermittent failure of atrial capture was observed during atrial stimulation using AAI pacing at a near-threshold voltage. The pacemaker was programmed to function in a VDD mode just after implantation and performed without problems. Use of a Holter monitor prior to pacemaker implantation confirmed the existence of severe paroxysmal atrioventricular block but there was no evidence of concomitant sinus node dysfunction. In 1997, a permanent VDD pacemaker (Eikos SLD, Biotronik, with an Intermedics UniPass electrode) was implanted. Our patient was an 85-year-old ex-smoker with a history of trifascicular block and episodic syncope of cardiogenic origin. This mode of stimulation involves the generation of two broad large-amplitude unipolar impulses of opposite polarity. 2,3 During 19, at the Hospital Clínico in Zaragoza, Spain, we implanted a number of VDD pacemakers that were also able to provide atrial stimulation by means of overlapping biphasic impulses (OLBIs) from "floating" electrodes. 1įor a number of years, there has been an interest in developing single-lead DDD pacing.
The principal advantages of these pacemakers are the simplified implantation procedure and reduced overload of the venous system. The use of single-lead VDD pacemakers enables atrioventricular synchrony to be maintained in patients who have impaired atrioventricular conduction with preserved sinus node function.
0 kommentar(er)
