AV Delay Optimization vs. Intrinsic Conduction in Pacemaker Patients With Long PR Intervals

Cardiac Arrhythmia Clinical Trial

— AV Delay  

Official title:

Evaluation of AV Delay Optimization vs. Intrinsic Conduction in Patients With Long PR Intervals Receiving Dual Chamber Pacemakers for Symptomatic Bradycardia

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT02154750
• Other study ID #: 130663
• Status: Completed
• Phase: N/A
• Start date: June 1, 2013
• Est. completion date: December 31, 2021

Study information

• Verified date: May 2022
• Source: University of California, San Diego
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

This is a randomized, prospective clinical trial to determine the effects of two different pacemaker atrioventricular delay (AV delay) settings on heart function in patients with dual chamber pacemakers implanted for symptomatic bradycardia with long PR intervals (delayed conduction between upper and lower chambers of the heart). The study will compare a long, fixed AV delay (standard) with an optimized AV delay for each individual using echocardiography (experimental).

Description:

Cardiac pacing is the only effective treatment for symptomatic sinus node dysfunction. Most patients with preserved left ventricular function receive dual chamber pacemakers; however, right ventricular pacing can have detrimental effects on left ventricular function due to the abnormal electrical and mechanical activation pattern of the ventricles.

Many patients receiving dual chamber pacemakers for symptomatic bradycardia have prolonged intrinsic AV conduction (first degree AV block), and as a result, will receive a significant amount of ventricular pacing if programmed at physiologic AV intervals. As an alternative, many pacemakers can be programmed to minimize ventricular pacing at the expense of allowing longer AV delays. However, these long AV delays may not be physiologic and may also lead to reduced cardiac output. At present the standard of care is either to program the pacemaker at an physiologic "natural" AV delay of about 160 msec or to program the pacemaker with a long AV delay to minimize ventricular pacing.

The main scientific questions being addressed in this study are to evaluate the acute and chronic effects on cardiac output, functional status, sense of well-being, and cardiac remodeling of a long AV delay allowing for intrinsic conduction as compared to an echocardiographically optimized AV delay during dual chamber pacing.

Patients enrolled in the trial will complete a run-in period of two weeks prior to randomization in which pacemakers will be programmed with a long-fixed AV delay to allow intrinsic conduction and minimize ventricular pacing (standard). At two weeks, patients will receive a baseline echocardiogram. To determine optimal AV delay, all patients will undergo echocardiographic analysis at varying AV delays. Optimal AV delay will be defined as the AV delay associated with the largest average aortic Doppler velocity time integral (VTI). Then, patients will be randomized to either the short, optimized (experimental) or long, fixed (standard) AV delay groups. To assess functional status and sense of well-being, patients will complete a six minute walk test and Short Form-36 Medical Outcomes Study Questionnaire. Patients return to clinic for another study visit at 6 months and repeat research procedures, including baseline echocardiogram, questionnaire, and 6 minute walk test.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 23
• Est. completion date: December 31, 2021
• Est. primary completion date: December 31, 2021
• Accepts healthy volunteers: No
• Gender: All
• Age group: 18 Years and older

Eligibility

Patient population: Individuals with 1st degree atrioventricular (AV) block who have received a dual chamber pacemaker for symptomatic bradycardia.

Inclusion Criteria:

1. Patients greater than 18 years of age

2. Patients with symptomatic sinus bradycardia

3. Patients who meet standard indications for dual chamber pacemaker implantation

4. Patients who have 1st degree AV block determined by PR interval > 200ms

Exclusion Criteria:

1. Patients with complete or high grade AV block

2. Patients who are unable to complete dual chamber pacemaker implantation for any reason

3. Patients with congestive heart failure determined by a Left Ventricular Ejection Fraction < 45%

4. Patients with persistent atrial fibrillation

5. Sustained premature ventricular contractions (PVCs), premature atrial contractions (PACs), atrial flutter, or other heart conditions that may interfere with echocardiography measurements

6. Patients who are pregnant

7. Patients with Paroxysmal Atrial Fibrillation that have had an episode(s) within 30 days of consent

Related Conditions & MeSH terms

• Arrhythmias, Cardiac
• Atrioventricular Block
• Bradycardia
• Cardiac Arrhythmia
• Sick Sinus Syndrome
• Symptomatic Bradycardia

Intervention

Device:
• Long, fixed AV delay
Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing
• Short, optimized AV delay
Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.

Locations

Country	Name	City	State
United States	UCSD Sulpizio Cardiovascular Center	La Jolla	California

Sponsors (1)

Lead Sponsor	Collaborator
University of California, San Diego

Country where clinical trial is conducted

United States, 

References & Publications (4)

Iliev II, Yamachika S, Muta K, Hayano M, Ishimatsu T, Nakao K, Komiya N, Hirata T, Ueyama C, Yano K. Preserving normal ventricular activation versus atrioventricular delay optimization during pacing: the role of intrinsic atrioventricular conduction and pacing rate. Pacing Clin Electrophysiol. 2000 Jan;23(1):74-83. — View Citation

Sawhney NS, Waggoner AD, Garhwal S, Chawla MK, Osborn J, Faddis MN. Randomized prospective trial of atrioventricular delay programming for cardiac resynchronization therapy. Heart Rhythm. 2004 Nov;1(5):562-7. — View Citation

Sweeney MO, Ellenbogen KA, Tang AS, Whellan D, Mortensen PT, Giraldi F, Sandler DA, Sherfesee L, Sheldon T; Managed Ventricular Pacing Versus VVI 40 Pacing Trial Investigators. Atrial pacing or ventricular backup-only pacing in implantable cardioverter-defibrillator patients. Heart Rhythm. 2010 Nov;7(11):1552-60. doi: 10.1016/j.hrthm.2010.05.038. Epub 2010 Jun 4. — View Citation

Tops LF, Schalij MJ, Bax JJ. The effects of right ventricular apical pacing on ventricular function and dyssynchrony implications for therapy. J Am Coll Cardiol. 2009 Aug 25;54(9):764-76. doi: 10.1016/j.jacc.2009.06.006. Review. — View Citation

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Change in cardiac output determined by echocardiography		6 months
Secondary	Changes in functional status determined by 6 minute walk.	Measure distance walked in 6 minutes in meters.	6 months
Secondary	Changes in sense of well being as determined by Short Form - 36 Medical Outcomes Study Questionnaire	Sense of well being score determined by answers to questions on Short Form - 36 questionnaire.	6 months