Trial Outcomes & Findings for AV Delay Optimization vs. Intrinsic Conduction in Pacemaker Patients With Long PR Intervals (NCT NCT02154750)

Results Overview

Comparison (∆) of change in echocardiographic parameters left ventricular (LV) dimension at end-diastole, left ventricular (LV) dimension at end-systole, and tricuspid annular plane systolic excursion (cm) from baseline to followup, in Optimized AV delay versus Long-fixed AV delay groups. A reduction LV dimension indicates improvement in function, and an increase in tricuspid annular plane excursion represents an improvement in function.

Recruitment status

COMPLETED

Study phase

NA

Target enrollment

23 participants

Primary outcome timeframe

6 months

Results posted on

2025-07-24

Participant Flow

Participant milestones

Participant milestones
Measure	Long Fixed AV Delay 12 subjects were enrolled in the long-fixed AV delay group.	Optimized AV Delay 11 subjects were enrolled in optimized AV delay group
Overall Study STARTED	12	11
Overall Study COMPLETED	12	11
Overall Study NOT COMPLETED	0	0

Reasons for withdrawal

Withdrawal data not reported

Baseline Characteristics

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

Baseline characteristics by cohort

Baseline characteristics by cohort
Measure	Long, Fixed AV Delay n=12 Participants Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing Long, fixed AV delay: Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing	Short, Optimized AV Delay n=11 Participants Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled Short, optimized AV delay: Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.	Total n=23 Participants Total of all reporting groups
Age, Categorical <=18 years	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Age, Categorical Between 18 and 65 years	12 Participants n=5 Participants	11 Participants n=7 Participants	23 Participants n=5 Participants
Age, Categorical >=65 years	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Age, Continuous	67.8 years STANDARD_DEVIATION 6.6 • n=5 Participants	78.0 years STANDARD_DEVIATION 5.7 • n=7 Participants	72.7 years STANDARD_DEVIATION 6.2 • n=5 Participants
Sex: Female, Male Female	3 Participants n=5 Participants	3 Participants n=7 Participants	6 Participants n=5 Participants
Sex: Female, Male Male	9 Participants n=5 Participants	8 Participants n=7 Participants	17 Participants n=5 Participants
Race (NIH/OMB) American Indian or Alaska Native	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Asian	1 Participants n=5 Participants	1 Participants n=7 Participants	2 Participants n=5 Participants
Race (NIH/OMB) Native Hawaiian or Other Pacific Islander	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Black or African American	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) White	11 Participants n=5 Participants	10 Participants n=7 Participants	21 Participants n=5 Participants
Race (NIH/OMB) More than one race	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Race (NIH/OMB) Unknown or Not Reported	0 Participants n=5 Participants	0 Participants n=7 Participants	0 Participants n=5 Participants
Region of Enrollment United States	12 participants n=5 Participants	11 participants n=7 Participants	23 participants n=5 Participants

PRIMARY outcome

Timeframe: 6 months

Comparison (∆) of change in echocardiographic parameters left ventricular (LV) dimension at end-diastole, left ventricular (LV) dimension at end-systole, and tricuspid annular plane systolic excursion (cm) from baseline to followup, in Optimized AV delay versus Long-fixed AV delay groups. A reduction LV dimension indicates improvement in function, and an increase in tricuspid annular plane excursion represents an improvement in function.

Outcome measures

Outcome measures
Measure	Optimized AV Delay n=11 Participants Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled Short, optimized AV delay: Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.	Long Fixed AV Delay n=12 Participants Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing Long, fixed AV delay: Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing
Comparison of Change in Echocardiographic Parameters LV Dimension at End-diastole, LV Dimension at End-systole, and Tricuspid Annular Plane Systolic Excursion (cm) From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Left Ventricular Dimension at End-Diastole (LVDd)	-3.1 cm Standard Deviation 6.2	0.1 cm Standard Deviation 4.8
Comparison of Change in Echocardiographic Parameters LV Dimension at End-diastole, LV Dimension at End-systole, and Tricuspid Annular Plane Systolic Excursion (cm) From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Left Ventricular Dimension as End-Systole (LVDs)	-4.2 cm Standard Deviation 18.6	-1.9 cm Standard Deviation 14
Comparison of Change in Echocardiographic Parameters LV Dimension at End-diastole, LV Dimension at End-systole, and Tricuspid Annular Plane Systolic Excursion (cm) From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Tricuspid annular plane systolic excursion	2.4 cm Standard Deviation 0.5	2.3 cm Standard Deviation 0.4

PRIMARY outcome

Timeframe: 6 months

Comparison (∆) of echocardiographic parameters mitral E wave velocity (cm/s) and mitral A wave velocity (cm/s) at baseline and followup, in Optimized AV delay versus Long-fixed AV delay group. An increase in mitral E wave velocity and a decrease in mitral A velocity represent an improvement in function.

Outcome measures

Outcome measures
Measure	Optimized AV Delay n=11 Participants Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled Short, optimized AV delay: Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.	Long Fixed AV Delay n=12 Participants Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing Long, fixed AV delay: Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing
Comparison of Echocardiographic Parameters Mitral E Wave Velocity (cm/s) and Mitral A Wave Velocity (cm/s) at Baseline and Followup, in Optimized AV Delay Versus Long-fixed AV Delay Group. ∆ Mitral E wave velocity	-5.5 cm/s Standard Deviation 16.4	0.8 cm/s Standard Deviation 21.9
Comparison of Echocardiographic Parameters Mitral E Wave Velocity (cm/s) and Mitral A Wave Velocity (cm/s) at Baseline and Followup, in Optimized AV Delay Versus Long-fixed AV Delay Group. ∆ Mitral A wave velocity	3.5 cm/s Standard Deviation 12.3	0.0 cm/s Standard Deviation 26

PRIMARY outcome

Timeframe: 6 months

Comparison (Δ) of change in echocardiographic parameter ΔE/A and Mean E/e' ratio (unitless) from baseline to followup, in Optimized AV delay versus Long-fixed AV delay groups. An higher delta E/A and mean E/e' ratio represent improvement in function,

Outcome measures

Outcome measures
Measure	Optimized AV Delay n=11 Participants Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled Short, optimized AV delay: Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.	Long Fixed AV Delay n=12 Participants Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing Long, fixed AV delay: Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing
Comparison of Change in Echocardiographic Parameter ΔE/A and Mean E/e' Ratio (Unitless) From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Δ E/A Ratio	5.8 Ratio (unitless) Standard Deviation 32	-15.9 Ratio (unitless) Standard Deviation 31.1
Comparison of Change in Echocardiographic Parameter ΔE/A and Mean E/e' Ratio (Unitless) From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Δ Mean E/e'	-1.1 Ratio (unitless) Standard Deviation 29.2	-5.6 Ratio (unitless) Standard Deviation 14.4

PRIMARY outcome

Timeframe: 6 months

Comparison (∆) of Echocardiographic Parameter Deceleration time (msec) at Baseline and Followup, in Optimized AV Delay Versus Long-fixed AV Delay Group. A reduction in deceleration time represents an improvement in function.

Outcome measures

Outcome measures
Measure	Optimized AV Delay n=11 Participants Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled Short, optimized AV delay: Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.	Long Fixed AV Delay n=12 Participants Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing Long, fixed AV delay: Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing
Comparison of Echocardiographic Parameter Deceleration Time (Msec) at Baseline and Followup, in Optimized AV Delay Versus Long-fixed AV Delay Group.	14.6 msec Standard Deviation 15.7	2.1 msec Standard Deviation 20.2

PRIMARY outcome

Timeframe: 6 months

Comparison of change in echocardiographic parameters left ventricular end diastolic (LVED) volume index, left ventricular end systolic (LVES) volume index, maximum left atrial (LA) volume index, and minimum left atrial (LA) volume index (ml/m2) from baseline to follow-up, in Optimized AV delay versus Long-fixed AV delay groups. A reduction in volume indexes represents an improvement in function.

Outcome measures

Outcome measures
Measure	Optimized AV Delay n=11 Participants Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled Short, optimized AV delay: Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.	Long Fixed AV Delay n=12 Participants Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing Long, fixed AV delay: Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing
Comparison of Change in Echocardiographic Parameters LVED End Diastolic Volume Index, LVES Volume Index, Maximum LA Volume Index, and Minimum LA Volume Index (ml/m2) From Baseline to Follow-up, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Left ventricular end diastolic volume index	-13.2 ml/m2 Standard Deviation 11	5.8 ml/m2 Standard Deviation 18.7
Comparison of Change in Echocardiographic Parameters LVED End Diastolic Volume Index, LVES Volume Index, Maximum LA Volume Index, and Minimum LA Volume Index (ml/m2) From Baseline to Follow-up, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Left ventricular end systolic volume index	-16.4 ml/m2 Standard Deviation 13.6	6.7 ml/m2 Standard Deviation 22.9
Comparison of Change in Echocardiographic Parameters LVED End Diastolic Volume Index, LVES Volume Index, Maximum LA Volume Index, and Minimum LA Volume Index (ml/m2) From Baseline to Follow-up, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Maximum left atrial volume index	-9.7 ml/m2 Standard Deviation 40.9	0.6 ml/m2 Standard Deviation 25.4
Comparison of Change in Echocardiographic Parameters LVED End Diastolic Volume Index, LVES Volume Index, Maximum LA Volume Index, and Minimum LA Volume Index (ml/m2) From Baseline to Follow-up, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Minimum left atrial volume index	-9.1 ml/m2 Standard Deviation 42.1	1.8 ml/m2 Standard Deviation 28.6

PRIMARY outcome

Timeframe: 6 months

Comparison (∆) of Change in Echocardiographic Parameters Left Ventricular Ejection Fraction and Global Longitudinal Strain (%) From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups. An increase in left ventricular ejection time represents an improvement in function. A more negative global longitudinal strain % represents an improvement in function.

Outcome measures

Outcome measures
Measure	Optimized AV Delay n=11 Participants Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled Short, optimized AV delay: Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.	Long Fixed AV Delay n=12 Participants Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing Long, fixed AV delay: Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing
Comparison of Change in Echocardiographic Parameters Left Ventricular Ejection Fraction and Global Longitudinal Strain (%) From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Left Ventricular Ejection Fraction	4.4 percentage Standard Deviation 13.1	-0.7 percentage Standard Deviation 8.7
Comparison of Change in Echocardiographic Parameters Left Ventricular Ejection Fraction and Global Longitudinal Strain (%) From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups. Global Longitudinal Strain	5.5 percentage Standard Deviation 16.1	-11.8 percentage Standard Deviation 17.8

PRIMARY outcome

Timeframe: 6 months

Comparison (∆) of Change in Echocardiographic Parameters Tricuspid Regurgitation (TR) velocity m/s From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups. An reduction in tricuspid regurgitation velocity represents an improvement in function.

Outcome measures

Outcome measures
Measure	Optimized AV Delay n=11 Participants Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled Short, optimized AV delay: Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.	Long Fixed AV Delay n=12 Participants Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing Long, fixed AV delay: Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing
Comparison of Change in Echocardiographic Parameters Tricuspid Regurgitation (TR) Velocity m/s From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups.	2.2 m/sec Standard Deviation 0.3	2.2 m/sec Standard Deviation 0.5

PRIMARY outcome

Timeframe: 6 months

Comparison (∆) of Change in Echocardiographic Parameters left ventricular mass (gm) From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups. A reduction in left ventricular mass represents an improvement in function.

Outcome measures

Outcome measures
Measure	Optimized AV Delay n=11 Participants Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled Short, optimized AV delay: Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.	Long Fixed AV Delay n=12 Participants Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing Long, fixed AV delay: Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing
Comparison of Change in Echocardiographic Parameters Left Ventricular Mass (gm) From Baseline to Followup, in Optimized AV Delay Versus Long-fixed AV Delay Groups.	142.8 gm Standard Deviation 21	148.4 gm Standard Deviation 23.2

SECONDARY outcome

Timeframe: 6 months

Comparison (∆) of measured distance walked in 6 minutes in meters from baseline and followup, in Optimized AV delay group versus Long-fixed AV delay group. An increase in distance walked during the 6 minute walk test represents an improvement in function.

Outcome measures

Outcome measures
Measure	Optimized AV Delay n=11 Participants Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled Short, optimized AV delay: Pacemaker will be set to the AV delay that produces the greatest cardiac output in echocardiography for each patient enrolled.	Long Fixed AV Delay n=12 Participants Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing Long, fixed AV delay: Pacemaker will be set to a long, fixed AV delay to minimize ventricular pacing
Comparison of Measured Distance Walked in 6 Minutes in Meters From Baseline and Followup, in Optimized AV Delay Group Versus Long-fixed AV Delay Group.	368.7 meters Standard Deviation 71.8	473.8 meters Standard Deviation 83.2

Adverse Events

Intervention - Long Fixed AV Delay

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Intervention - Optimized AV Delay

Serious events: 0 serious events

Other events: 0 other events

Deaths: 0 deaths

Serious adverse events

Adverse event data not reported

Other adverse events

Adverse event data not reported

Additional Information

Gregory Feld, MD

UC San Diego Health

Phone: (858) 246-2972

Email: [email protected]

Results disclosure agreements

Principal investigator is a sponsor employee
Publication restrictions are in place