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Clinical experience with Thera DR rate-drop response pacing algorithm in carotid sinus syndrome and vasovagal
D G Benditt1, R Sutton, M D Gammage
1Department of Medicine, University of Minnesota Medical School, Minneapolis 55455, USA.
Insights
Cardiac pacing with the Thera DR rate-drop response algorithm effectively reduced recurrent syncope and presyncope symptoms in patients with carotid sinus syndrome or vasovagal syncope.
Area of Science:
- Cardiology
- Neurology
- Medical Devices
Background:
- Recurrent syncope, particularly from carotid sinus syndrome (CSS) or vasovagal syncope, significantly impacts quality of life.
- Current management strategies for these conditions can be limited in effectiveness for highly symptomatic individuals.
Purpose of the Study:
- To evaluate the efficacy of the Thera DR rate-drop response algorithm for cardiac pacing in preventing recurrent syncope and presyncope.
- To assess the algorithm's dual diagnostic and therapeutic capabilities in managing neurally mediated syncopal episodes.
Main Methods:
- A cohort of 43 patients with CSS and/or vasovagal syncope experiencing recurrent syncope or presyncope were enrolled.
- The Thera DR algorithm was implemented, featuring a diagnostic window for identifying heart rate changes and a treatment arm for high-rate pacing.
- Outcomes were assessed based on symptom frequency, severity, and asyncope/presyncope status during post-pacing follow-up.
Main Results:
- Among 39 patients with available follow-up, 31 (80%) reported diminished symptom frequency or severity.
- Twenty-three patients (59%) became asymptomatic, while 16 experienced symptom recurrence (7 syncope, 9 presyncope).
- Recurrences were more common in patients with a history of vasovagal syncope, but overall symptoms were less frequent and severe.
Conclusions:
- The Thera DR rate-drop response algorithm, through transient high-rate pacing, demonstrated benefit in a significant proportion of highly symptomatic patients.
- This pacing strategy offers a promising therapeutic option for managing recurrent CSS and vasovagal syncope.
- Further investigation into specific patient subgroups, particularly those with vasovagal syncope, may refine treatment efficacy.
Abstract:
This study examined the effectiveness of cardiac pacing using the Thera DR rate-drop response algorithm for prevention of recurrent symptoms in patients with carotid sinus syndrome (CSS) or vasovagal syncope. The algorithm comprises both diagnostic and treatment elements. The diagnostic element consists of a programmable "window" used to identify heart rate changes compatible with an evolving neurally mediated syncopal episode. The treatment arm consists of pacing at a selectable rate and for a programmable duration. Forty-three patients (mean age 53 +/- 20.4 years) with CSS alone (n = 8), CSS in conjunction with vasovagal syncope (n = 4), or vasovagal syncope alone (n = 31) were included. Thirty-nine had recurrent syncope, while the remaining four reported multiple presyncopal events. Prior to pacing, 40 +/- 152 syncopal episodes (range from 1 to approximately 1,000 syncopal events) over the preceding 56 +/- 84.5 months. Postpacing follow-up duration was 204 +/- 172 days. Three patients have been lost to follow-up and in one patient the algorithm was disabled. Among the remaining 39 individuals, 31 (80%) indicated absence or diminished frequency of symptoms, or less severe symptoms. Twenty-three patients (23/29, or 59%) were asymptomatic with respect to syncope or presyncope. Sixteen patients had symptom recurrences. Of these, seven experienced syncope (7/39, or 18%) and 9 (29%) had presyncope: the majority of patients with recurrences (6/7 syncope and 7/9 presyncope) were individuals with a history of vasovagal syncope. Consequently, although symptoms were observed during postpacing follow-up, they appeared to be of reduced frequency and severity. Thus, our findings suggest that a transient period of high rate pacing triggered by the Thera DR rate-drop response algorithm was beneficial in a large proportion of highly symptomatic patients with CSS or vasovagal syncope.