Recruiting

Observational Study

Sponsor:

University of Calgary

Code:

NCT04391465

Conditions

Cerebrovascular Circulation

Physiology

Eligibility Criteria

Sex: All

Age: 18 - 70

Healthy Volunteers: Not accepted

Interventions

Electrophysiological Pacing

Study Details

Brief summary:

The investigators will seek to determine the relationship between heart rate and middle cerebral artery (MCA) cerebral blood flow (CBF), as well as better understand the hemodynamic determinants of MCA CBF velocity. In order to manipulate heart rate, the investigators will recruit patients already scheduled for clinically indicated elective electrophysiological studies, where temporary pacing catheters placed in the right atrium can be used to artificially pace the heart at controlled rates. MCA CBF will be measured by transcranial Doppler ultrasound.

Conditions

Cerebrovascular Circulation

Physiology

Study ID

NCT04391465

Start date

Aug 11, 2021

Status verified date

Apr, 2026

Completion date

Dec, 2027

Anticipated

Primary completion date

Dec, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 70

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Male or female
  • Age 18-70 years, inclusive
  • Scheduled for clinically indicated elective electrophysiological studies where temporary pacing catheters are being placed in the right atrium
  • Left ventricular ejection fraction ≥50%
  • Able and willing to provide informed consent
  • Able to travel to the Cardiac Electrophysiology Laboratory at the Foothills Medical Centre, Calgary, Alberta, Canada

Exclusion Criteria:

  • Unable or unwilling to provide informed consent
  • Other factors which in the investigator's opinion would prevent the participant from completing the protocol

Study Design

Enrollment

20 participants

Anticipated

Intervention Model

Single group

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Patients Scheduled for Elective Electrophysiological Study

High right atrial pacing will occur at the following rates for 60 seconds each, with a rest period of at least 60 seconds between pacing runs:

  • 600 msec (100 bpm)
  • 500 msec (120 bpm)
  • 400 msec (150 bpm)
  • 350 msec (171 bpm)

Interventions

Electrophysiological Pacing

Assess the MCA CBF velocity response at different paced heart rates.

Primary outcome measure

  • Change in MCA CBF velocity in response to high right atrial pacing at 400 ms (150 bpm) relative to baseline while in the supine position [ Time Frame: After 1 minute of pacing at 400 ms (150 bpm) ]

Central Contacts and Locations

Central contacts

Satish R Raj, MD MSCI

403-210-6152satish.raj@ucalgary.ca

Locations

Foothills Medical Center

Recruiting

Calgary, Alberta, Canada, T2N 4Z6

Contacts

Satish Raj, MD MSCI

4032106152autonomic.research@ucalgary.ca

More Information

Sponsor

University of Calgary

Last update posted

May 7, 2026

Last verified

Apr, 2026

Keywords

  • Cerebral Blood Flow

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of Calgary on 2026-05-07.