Head-up Tilt Test in Patients With Reflex Syncope and Asystolic Response Who Received a Dual-chamber Pacemaker With the Closed Loop Stimulation (CLS) and Participated in the BIOSync Trial

Completed

Conditions: Syncope
Syncope, Vasovagal

Registration Number: NCT06038708

Lead Sponsor: Biotronik SE & Co. KG

Brief Summary: The purpose of this study is to explore changes in patients' hemodynamic parameters during the Head-Up Tilt Test ("HUTT") and their timing with respect to onset of the Closed Loop Stimulation (CLS) pacing. This study aims to add knowledge to better understand the mechanisms underlying recurrent syncopal events and optimal pacing programming.

Detailed Description: The 2021 European Society of Cardiology guidelines recommend cardiac pacing in patients aged \>40 years with tilt-induced asystolic reflex syncope (class I, level of evidence A). The recommendation relies on recent results from the multicentre, randomised, double-blinded, parallel-design BIOSync trial (NCT02324920). The BIOSync study provided evidence of benefit of dual chamber pacing in patients with tilt-induced reflex syncope and confirmed the role of Head-up Tilt Table (HUTT) test as a diagnostic method for cardiac pacing in reflex syncope. The Closed Loop Stimulation (CLS) is able to measure changes in intracardiac impedance during the systolic phase of each cardiac cycle which are strictly correlated to the increased heart rate and right ventricular contraction speed which are usually present during the pre-syncope phase of the reflex. It was hypothesized that an early onset of CLS pacing may be triggered by the compensatory increase in heart rate to counteract vasodilation and pressure drop during the pre-syncope phase of the reflex. The BIOSync study showed a 77% reduced risk of syncope in the DDD-CLS group as compared to pacing off. The design of the BIOSync study did not allow to assess the specific effect that CLS adds to dual-chamber pacing. Despite DDD-CLS pacing, 22% of patients had syncopal recurrence in 2 years. Further investigations are therefore needed in order to reduce this failure rate. Indeed, it is still unclear whether syncopal recurrences should be ascribed to dominant vasodilation or if the CLS programming/functioning needs optimization to more adequately sustain cardiac output during reflex in these specific cases.

Recruitment & Eligibility

Status: COMPLETED

Sex: All

Target Recruitment: 20

Inclusion Criteria

Not provided

Exclusion Criteria

Not provided

Study & Design

Study Type: OBSERVATIONAL

Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
Heart Rate [Bpm] at Specific Time-points During Head-up Tilt Test (HUTT) Examination	From the start to the end of the HUTT examination, assessed up to 45 minutes	Instantaneous measurement of heart rate value at specific time-points/stages during HUTT examination. Changes in Heart rate were investigated across four stages of the HUTT: baseline (Stage 1), pre-syncopal phase (Stage 2), maximum heart rate/pacing rate (Stage 3), and syncope or lowest Systolic Blood Pressure (Stage 4).
Systolic Blood Pressure at Specific Time-points During Head-up Tilt Test (HUTT) Examination	From the start to the end of the HUTT examination, assessed up to 45 minutes	Instantaneous measurement of blood pressure at specific time-points during HUTT examination. Changes in Systolic blood pressure were investigated across four stages of the HUTT: baseline (Stage 1), pre-syncopal phase (Stage 2), maximum heart rate/pacing rate (Stage 3), and syncope or lowest Systolic Blood Pressure (Stage 4).
Stroke Volume [ml] at Specific Time-points During Head-up Tilt Test (HUTT)	From the start to the end of the HUTT examination, assessed up to 45 minutes	Instantaneous measurement of stroke volume at specific time-points during HUTT examination
Peripheral Resistance [Dyn·s/cm5] at Specific Time-points During Head-up Tilt Test (HUTT)	From the start to the end of the HUTT examination, assessed up to 45 minutes	Instantaneous measurement of peripheral resistance at specific time-points during HUTT examination
Time of Maximum Spontaneous Heart Rate	From the start to the end of the HUTT examination, assessed up to 45 minutes	Recording of a specific time-point during HUTT examination. This time was collected as hours:minutes:seconds (e.g. 00:35:34).
Time of Pacing Onset	From the start to the end of the HUTT examination, assessed up to 45 minutes	Recording of a specific time-point during HUTT examination. This time was collected as hours:minutes:seconds (e.g. 00:35:34).
Time of Recovery of Spontaneous Rhythm After Pacing	From the start to the end of the HUTT examination, assessed up to 45 minutes	Recording of a specific time-point during HUTT examination. This time was collected as hours:minutes:seconds (e.g. 00:35:34).
Time of Syncope	From the start to the end of the HUTT examination, assessed up to 45 minutes	Recording of a specific time-point during HUTT examination. This time was collected as hours:minutes:seconds (e.g. 00:35:34).
Time of Tilt-down	From the start to the end of the HUTT examination, assessed up to 45 minutes	Recording of a specific time-point during HUTT examination. This time was collected as hours:minutes:seconds (e.g. 00:35:34).
Duration of the Recovery Phase [Minutes]	From the start to the end of the HUTT examination, assessed up to 45 minutes	Interval from maximum pacing rate to basic rate or spontaneous rhythm
Slope in Heart Rate [Bpm/Minute] During the Recovery Phase	From the start to the end of the HUTT examination, assessed up to 45 minutes	Calculation of the rate of change of heart rate from the time of maximum pacing rate to the time of basic rate or spontaneous rhythm recovery
Slope in Systolic Blood Pressure (mmHg Per Minute) During the Recovery Phase	From the start to the end of the HUTT examination, assessed up to 45 minutes	Calculation of the rate of change of systolic blood pressure from the time of maximum pacing rate to the time of basic rate or spontaneous rhythm recovery

Secondary Outcome Measures

Name	Time	Method

Trial Locations

Locations (2): Ospedale di Bolzano - Azienda Sanitaria dell'Alto Adige
🇮🇹
Bolzano, Italy
Monaldi - AORN dei Colli - Università della Campania "Luigi Vanvitelli"
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Napoli, Italy