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NCT Number: NCT06038708

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

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.

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Key information

Conditions

Syncope Autonomic Nervous System Diseases Consciousness Disorders Nervous System Diseases Neurobehavioral Manifestations Neurologic Manifestations Orthostatic Intolerance Pathological Conditions, Signs and Symptoms Primary Dysautonomias Signs and Symptoms Syncope, Vasovagal Unconsciousness

Age range

40 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Ospedale di Bolzano - Azienda Sanitaria dell'Alto Adige, Bolzano, Italy

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About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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.

Exclusion criteria

  • Pregnant or breast feeding women.
  • Age less than 40 years.
  • Patients who after the BIOSync study participation have developed the following:
  • Any indication to pacemaker different from reflex syncope with positive HUTT response; or
  • Any classified indication to implantable defibrillator, cardiac resynchronization therapy according to current guidelines; or
  • Any cardiac dysfunctions likely leading to loss of consciousness (overt heart failure, ejection fraction <40%, myocardial infarction, diagnosis of hypertrophic or dilated cardiomyopathy, clinically significant valvular disease, sinus bradycardia <50 bpm or sinoatrial block, Mobitz I second degree atrioventricular block, Mobitz II second or third degree atrioventricular block, complete bundle-branch block).

Treatment and study plan

Primary outcomes

  1. Heart Rate [Bpm] at Specific Time-points During Head-up Tilt Test (HUTT) Examination

    Time frame: 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).

  2. Systolic Blood Pressure at Specific Time-points During Head-up Tilt Test (HUTT) Examination

    Time frame: 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).

  3. Stroke Volume [ml] at Specific Time-points During Head-up Tilt Test (HUTT)

    Time frame: 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

  4. Peripheral Resistance [Dyn·s/cm5] at Specific Time-points During Head-up Tilt Test (HUTT)

    Time frame: 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

  5. Time of Maximum Spontaneous Heart Rate

    Time frame: 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).

  6. Time of Pacing Onset

    Time frame: 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).

  7. Time of Recovery of Spontaneous Rhythm After Pacing

    Time frame: 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).

  8. Time of Syncope

    Time frame: 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).

  9. Time of Tilt-down

    Time frame: 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).

  10. Duration of the Recovery Phase [Minutes]

    Time frame: 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

  11. Slope in Heart Rate [Bpm/Minute] During the Recovery Phase

    Time frame: 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

  12. Slope in Systolic Blood Pressure (mmHg Per Minute) During the Recovery Phase

    Time frame: 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

Sponsors and collaborators

Lead sponsor

Biotronik SE & Co. KG

Industry

Registry information

Official study title

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

Acronym: BIO|Sync-HUTT

Important dates

Study start
2022
Primary completion
2023
Study completion
2023
First posted
Sep 15, 2023
Registry last updated
Feb 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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