The Danish Multicenter Randomised Study on AAI Versus DDD Pacing in Sick Sinus Syndrome

This study has been terminated.
(Not able to recruit the estimated number of patients)
Information provided by:
The DANPACE Investigator Group Identifier:
First received: October 10, 2005
Last updated: February 20, 2009
Last verified: February 2009

Hypothesis Treatment with rate adaptive single chamber atrial pacing (AAIR) reduces the risk of death compared with rate adaptive dual chamber pacing (DDDR) in patients with sick sinus syndrome (SSS).

Primary purpose The primary purpose of this randomised trial is to compare AAIR and DDDR pacing in patients with SSS and normal atrioventricular (AV) conduction with respect to the primary end point overall mortality.

Condition Intervention Phase
Sick Sinus Syndrome
Device: AAIR/DDDR pacemaker
Phase 2
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Open Label
Primary Purpose: Treatment
Official Title: The Danish Multicenter Randomised Study on AAI Versus DDD Pacing in Sick Sinus Syndrome

Resource links provided by NLM:

Further study details as provided by The DANPACE Investigator Group:

Primary Outcome Measures:
  • All cause mortality after a mean follow-up of 5.5 year. [ Time Frame: 5,5 years ] [ Designated as safety issue: Yes ]

Secondary Outcome Measures:
  • Cardiovascular death [ Time Frame: 5,5 years ] [ Designated as safety issue: Yes ]
  • Chronic atrial fibrillation [ Time Frame: 5,5 years ] [ Designated as safety issue: No ]
  • Paroxysmal atrial fibrillation [ Time Frame: 5,5 years ] [ Designated as safety issue: No ]
  • Arterial thromboembolism [ Time Frame: 5,5 years ] [ Designated as safety issue: No ]
  • Congestive heart failure [ Time Frame: 5,5 years ] [ Designated as safety issue: No ]
  • Need for pacemaker re-operations [ Time Frame: 5,5 years ] [ Designated as safety issue: No ]
  • Quality of life [ Time Frame: 5,5 years ] [ Designated as safety issue: No ]
  • Health economics [ Time Frame: 5,5 years ] [ Designated as safety issue: No ]

Enrollment: 1415
Study Start Date: March 1999
Estimated Study Completion Date: July 2010
Estimated Primary Completion Date: July 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
AAIR Device: AAIR/DDDR pacemaker
Pacemaker with single lead or dual lead
DDDR Device: AAIR/DDDR pacemaker
Pacemaker with single lead or dual lead

Detailed Description:

Background In patients with isolated SSS, who need pacemaker treatment, any pacemaker can be used to treat the symptomatic bradycardia: a single chamber atrial (AAI) pacemaker, a single chamber ventricular (VVI) pacemaker, or a dual chamber (DDD) pacemaker. In the USA and in most European countries, DDD pacing is used in most cases. It is now known from the Danish AAI/VVI trial, that AAI pacing is superior to VVI pacing, since VVI pacing is associated with a higher mortality and a higher incidence of atrial fibrillation, thromboembolic complications and heart failure. This confirms previous findings in observational studies. Therefore, VVI pacing should no longer be used in patients with SSS.

The main argument for using DDD pacing is the concern, that the patients will develop symptomatic atrioventricular (AV) block. In the Danish AAI/VVI trial, the risk of AV block was approximately 0.6% per year, which is equivalent to the risk found in a larger meta analysis. This is only a little higher that the risk of atrioventricular block in the age-matched non-paced population. Implantation of a DDD pacemaker in all patients will effectively prevent development of symptomatic bradycardia in the minority of patients who develops AV block. However, the most important disadvantage during DDD pacing is the stimulation (pacing) of the ventricles by the pacemaker a large part of the time, also in patients without AV block. Pacing the right ventricle causes an asynchronous electrical activation and mechanical contraction of the ventricles as compared with the normal physiological contraction.

At present time, a randomised comparison of AAI and DDD pacing in patients with SSS has never been conducted, and to our knowledge, such a trial is not planned anywhere else.

Since several of the patients with SSS suffer from chronotropic incompetence, pacemakers with rate adaptive function are chosen for all patients included in the present trial.

All patients, that fulfils the inclusion criteria and none of the exclusion criteria and who give written informed consent, are included into the study. For all other patients undergoing primary pacemaker implantation in the study period, an exclusion data sheet is filled in stating the reason for exclusion. A total of 1,900 patients are included into the study.

Prior to the pacemaker implantation patients are randomised by lot (envelope) to either AAIR or DDDR pacing. The randomisation is performed after written informed consent has been obtained from the patient. Randomisation will ensure that all centres will randomise an equal number of patients into each treatment group.

Patients randomised to AAIR pacing will have a bipolar lead implanted in their right atrium connected to a single chamber pacemaker with rate adaptive function. Patients randomised to DDDR pacing will have two leads (one bipolar lead in their right atrium and a uni- or bipolar lead in their right ventricle) connected to a DDDR pacemaker.

Out of hospital follow-up The patients must attend for out of hospital follow-up after 3 months and 12 months and then once every year.

Criteria for closing the study

The DANPACE study is stopped and results are analysed when all of the following three criteria are fulfilled:

  1. 1,900 patients have been randomised.
  2. The last randomised patient has been followed for at least 1 year.
  3. The mean follow-up for the whole study population is at least 5.5 years.

Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:


A. Undergoing primary pacemaker implantation B. Able to appear for outpatient follow-up C. Age > 18 years


D. Syncope or E. Dizzy spells or F. Congestive heart failure


G. Sinus bradycardia <40/minute for at least 1 minute in a conscious awake state or H. Sinus arrest/sinoatrial block >2 seconds or I. Bradycardia/tachycardia with sinus-pauses >2 seconds

Exclusion Criteria:


A. Malignant disease. B. Severe psychogenic disease including severe decrepitude and dementia. C. Impending larger operation expected to influence the major end point. D. Cardiac disorder expected to need cardiac surgery during the follow-up period.

E. Need for other device implantation: ICD (implantable cardioverter defibrillator) or implantable DC converter (for atrial fibrillation).

F. Carotid sinus syndrome (positive carotid sinus massage with pauses >3 seconds).


G. Atrioventricular block. H. Bundle-branch block (complete RBBB, LBBB, bifascicular bundle-branch block or non-specific intraventricular block with QRS >0.12 seconds).

I. Chronic atrial fibrillation. J. Atrial fibrillation/atrial flutter with QRS pauses >3 seconds during atrial fibrillation.

K. Atrial fibrillation/atrial flutter with QRS frequency <40/minute for 1 minute.

  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT00236158

Department of Cardiology, Skejby Sygehus, Aarhus University Hospital
Aarhus, Denmark, DK-8200
Sponsors and Collaborators
The DANPACE Investigator Group
Principal Investigator: Henning R Andersen, MD, DMSc Skejby Sygehus, Aarhus University Hospital
  More Information

No publications provided by The DANPACE Investigator Group

Additional publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Henning Rud Andersen, Aarhus University Hospital Skejby, Departm. of Cardiology Identifier: NCT00236158     History of Changes
Other Study ID Numbers: 25100
Study First Received: October 10, 2005
Last Updated: February 20, 2009
Health Authority: Denmark: National Board of Health

Additional relevant MeSH terms:
Sick Sinus Syndrome
Pathologic Processes
Arrhythmia, Sinus
Arrhythmias, Cardiac
Heart Diseases
Cardiovascular Diseases
Heart Block processed this record on September 16, 2014