Assessment of Proper Physiologic Response with Rate Adaptive Pacing Driven by Minute Ventilation or Accelerometer (APPROPRIATE)

Status: Currently enrolling patients

This study will evaluate Boston Scientific’s Minute Ventilation (MV) sensor compared to the accelerometer (XL) sensor for superiority in providing appropriate heart rate response in pacemaker patients that are chronotropically incompetent. 


APPROPRIATE is an ongoing trial and has not yet published results.


Patient Population

Eligible study participants are those who meet or met current pacemaker implantation indications and will be receiving a dual-chamber pacemaker or previously received a dual-chamber ALTRUA® 60 pacemaker with active atrial and ventricular leads.

Some of the exclusion criteria were:

  • Patient who is in Mobitz II second-degree or third-degree heart block
  • Patient with chronic atrial fibrillation or uncontrolled atrial arrhythmias within the past 90 days prior to consent
  • Patient who has neuromuscular, orthopedic, or vascular disability that prevents normal walking or weight carrying (e.g., intermittent claudication, arthritis, residual stroke weakness, need for a wheelchair or walker)
  • Patient in whom a symptom-limited exercise protocol is thought to be dangerous or contraindicated, including but not limited to changing pattern of chest discomfort or uncontrolled arrhythmias
  • Patient with pulmonary disease as defined by any one of the following:
    • Forced Vital Capacity (FVC) or Forced Expiratory Volume in one second (FEV1) < 60% of predicted values
    • Use of two or more pulmonary inhalers
    • Use of supplemental oxygen.
    • Chronic use of oral steroids for pulmonary disease treatment
  • Patient who has or who is indicated for an implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRT-D)

Clinical Relevance

  • Primary objective of this study is to determine whether an improvement in peak VO2 is greater using the MV sensor compared to XL in CI patients. (Peak VO2 will be calculated as the highest value recorded before volitional fatigue is reached.) 
  • Testing methods were chosen that are representative of the exercise (stair climbing) and activities of daily living (carrying groceries) that this population typically undergoes.