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

BIO|Sync-HUTT: 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

Status

Completed

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT06038708

Acronym

BIO|Sync-HUTT

Enrollment

Registered

2023-09-15

Start date

2022-09-29

Completion date

2023-05-12

Last updated

2025-02-03

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Syncope, Syncope, Vasovagal

Keywords

Syncope, Head-up Tilt Test, Closed Loop Stimulation, CLS

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.

Interventions

None listed

Study design

Observational model

COHORT

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

40 Years to No maximum

Healthy volunteers

Inclusion criteria

* Ability to understand the nature of the study. * Willingness to provide written informed consent. * Patients undergoing HUTT for monitoring of syncope, therapy adjustment, training or other medical reasons during ordinary follow-up, irrespective of study participation * Patients who participated in the BIOSync study\*. * Patients with a dual-chamber pacing system equipped with the CLS algorithm. \* If needed, inclusion of other patients who did not participate in the BIOSync study will be considered to complete study cohort, provided that they have already a CLS pacemaker system and fulfill the same inclusion/

Exclusion criteria

of the BIOSync study.

Design outcomes

Primary

Measure	Time frame	Description
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

Countries

Italy

Participant flow

Participants by arm

Arm	Count
DDD-CLS Patients Patients with reflex syncope and positive cardioinhibitory response to Head-Up Tilt Test (HUTT) with a dual-chamber pacing system equipped with the CLS algorithm.	20
Total	20

Baseline characteristics

Characteristic	DDD-CLS Patients	—
Age, Continuous	68.3 years STANDARD_DEVIATION 11.9	—
Race and Ethnicity Not Collected	—	— Participants
Region of Enrollment Italy	20 Participants	—
Sex: Female, Male Female	4 Participants	—
Sex: Female, Male Male	16 Participants	—

Adverse events

Event type	EG000 affected / at risk
deaths Total, all-cause mortality	0 / 20
other Total, other adverse events	0 / 20
serious Total, serious adverse events	0 / 20