Syncope | Syncope: Pacing or Recording in the Later Years

Syncope research study

What is the primary objective of this study?

Syncope affects about 50% of Canadians, is the cause of 1 - 2% of all emergency room visits, and probably is responsible for CDN $250 million in health care spending each year. It is associated with decreased quality of life, trauma, loss of employment, and limitations in daily activities. It is a particular problem for older people, partly because of increased frailty, and partly because of a difficult differential diagnosis. One of the causes in older adults is intermittent complete heart block in the setting of bifascicular heart block, but they may also faint due to a variety of tachyarrhythmias, sick sinus syndrome, and several neurally mediated syncopes. Often treatment decisions should be made before the true cause is apparent.

Who is eligible to participate?

Inclusion Criteria: -Patients are eligible if they have: - >1 syncopal spell within 1 year preceding enrollment, and - bifascicular block on a 12-lead ECG, and - Age > 50 years and - written informed consent. Syncope will be defined based on history using a standardized form. Exclusion Criteria: -Patients will be excluded if they have criteria related to study strategies, including: 1. previous pacemaker, ICD, or Implantable Loop Recorder in situ, 2. ACC/AHA/HRS Class I indication for permanent pacing or ICD implantation, 3. left ventricular ejection fraction < 35% mandating ICD therapy, 4. contra-indication to a transvenous pacemaker such as artificial tricuspid valve or active sepsis. -Patients will also be excluded if a potential competing cause of syncope poses a threat to life, such as: 5. hypertrophic cardiomyopathy, 6. documented sustained ventricular tachycardia or 7. inducible, sustained monomorphic ventricular tachycardia on EP study. -They will be excluded if they have: 8. a history of myocardial infarction within 3 months prior to enrollment, and 9. a major chronic co-morbid medical condition that would preclude 24 months of follow-up.

Which medical condition, disease, disorder, syndrome, illness, or injury is researched?


Heart Block

Conduction Disorder of the Heart

Study Interventions

Interventions can include giving participants drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available or noninvasive approaches such as surveys, education, and interviews.

Procedure:pacemakerA single or dual chamber pacemaker will be implanted according to the manufacturer's instructions for use with standard techniques. Either a single or dual chamber pacemaker will be permitted according to local practice unless the patient is in chronic or persistent atrial fibrillation, in which case a single chamber pacemaker will be used. The pacemaker configuration will be at the discretion of the investigator. Single chamber ventricular pacemakers will be programmed to activity responsiveness off in VVI mode, rates 50-120 bpm. Dual chamber pacemaker programming will be to DDD mode (50-120) with mode switch on.

Procedure:implantable loop recorderThe implantable loop recorder will be programmed for automatic detection using settings of Low Heart Rate <50 bpm, High Heart Rate >165 bpm, and Pause > 3 seconds.

Study Arms

Research studies and clinical trials typically have two or more research arms. An arm is a group of people who receive the same treatment in the study.

implantable loop recorder


Study Status


Start Date: August 2011

Completed Date: November 1, 2017

Phase: Phase 4

Type: Interventional


Primary Outcome: The primary outcome measure will be a composite of Major Adverse Study-Related Events (MASRE) in a 2-year observation period.

Secondary Outcome: Secondary outcome measures will include total number of syncopal spells.

Study sponsors, principal investigator, and references

Principal Investigator: Robert S Sheldon, MD, PhD

Lead Sponsor: Canadian Institutes of Health Research (CIHR)

Collaborator: Vanderbilt University

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