Atrial detection and timing for atrioventricular synchronous pacing
Year: 2013
Type: dissertation
Abstract: Dual chamber pacing can be employed to restore atrioventricular synchrony in patients with heart block; and chronotropic incompetence and sinus bradycardia in those with sinus node dysfunction (SND). The focus of this thesis is the feasibility and consequences of proper atrial sensing and pacing to atrioventricular (AV) synchrony in dual chamber pacing. With isolated AV block showed that single lead VDD pacing (single pass ventricular lead with a dual chamber electrode system) can be an alternative to standard dual chamber pacing systems. Adequate sinus-driven atrial rate and no history of paroxysmal atrial fibrillation or cardiac enlargement predict reasonably good long-term maintenance of the VDD pacing mode in elderly patients treated for heart block. Retrograde atrial waves can be discriminated from sinus waves in many patients by using a high sampling rate and algorithms for digital signal processing with data collected by a pacemaker (PM). This approach could enhance the capability of future devices to adapt their stimulation to the spontaneous heart rhythm and improve the collection of diagnostic information on arrhythmias. Atrial tachyarrhythmia (AT) sensing algorithms incorporated in a state-of-the art DDDR (dual lead atrioventricular pacing) pacemaker can accurately identify patients who develop ATs. However transient undersensing of continuous atrial fibrillation (AF) and failure to detect very short episodes ATs can occur frequently, despite the use of refined detection algorithms. With a fixed long AV delay in DDDR pacing as in this study, temporal disruption of AV synchrony and inappropriate mode switch (MS) due to repetitive non-reentrant ventriculo-atrial synchronous rhythm (RNRVAS) is relatively common with SND patients (in 25%) in the presence of retrograde VA conduction. An advanced atrio ventricular search hysteresis (AVSH) algorithm reduced incidence of unnecessary ventricular pacing in the majority of SND patients with both intact and impaired AV conduction and in patients with intermittent AV block, regardless of the lead positions in the right atrium and the ventricle. The avoidance of possible harmful right ventricular (RV) pacing with used state of art AVSH algorithm was not associated with unphysiological over-long AV delays. In conclusion, proper atrial detection and timing for atrioventricular pacing is also feasible in the long-term with contemporary clinical pacing. With appropriate programming, these devices may contribute to the avoidance of possible adverse consequences like congestive heart failure, atrial fibrillation and unwanted harmful symptoms. In future devices with digital signal processing the detection of atrial signals can be further improved.
Source: Työväentutkimus Vuosikirja
Author: Sami Pakarinen
Language: English
Subfield: Cardiology and Cardiovascular Medicine
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2285824891