Conduction System Pacing vs Biventricular Resynchronization Therapy in Systolic Dysfunction and Wide QRS: CONSYST-CRT.

Not Applicable

Active, not recruiting

• Conditions: Resynchronization Therapy; Conduction System Pacing
• Interventions: Device: Conduction system pacing; Device: Biventricular pacing

• Registration Number: NCT05187611
• Lead Sponsor: Hospital Clinic of Barcelona

Brief Summary

Conduction system pacing vs biventricular resynchronization therapy in systolic dysfunction and wide QRS (CONSYST-CRT randomized clinical trial) is a non-inferiority trial that aims to study the composite endpoint consisting of all-cause mortality, cardiac transplant, heart failure hospitalizations, and left ventricular ejection fraction (LVEF) improvement \<5 points.

Detailed Description

To date, studies have shown that conduction system pacing could get similar clinical and echocardiographic responses to those obtained with biventricular therapy.

This study will randomize 130 patients to a strategy of biventricular pacing versus conduction system pacing.

CONSYST-CRT study will analyze the following parameters in the 2 groups: left ventricular ejection fraction, ventricular volumes, echocardiographic response (\>=15% decrease in left ventricular end-systolic volume), NYHA functional class, heart failure hospitalization, all-cause mortality, cardiac transplant, QRS shortening, echocardiographic asynchrony (septal flash).

Clinical, electrocardiographic, echocardiographic follow-up will be performed for 1 year.

The first 70 patients have been recruited in the context of the LEVELAT study (ClinicalTrials.gov Identifier: NCT04054895)

Study Timeline

• Study First Submitted: 2021-12-19
• Study First Submitted QC: 2022-01-07
• Study First Posted: 2022-01-12
• Study Start: 2022-01-17
• Primary Completion: 2024-07-15
• Status Verified: 2025-03
• Last Update Submitted: 2025-03-14
• Last Update Posted: 2025-03-17
• Study Completion: 2025-04

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 130

Inclusion Criteria

• The patient must indicate their acceptance to participate in the study by signing an informed consent document.
• The patient must be ≥ 18 years of age.
• Left bundle branch block, QRS ≥130 and LVEF <=35%. No indication of stimulation for AV block.
• Non-left bundle branch block, QRS ≥150 and LVEF <=35%.
• Patients with indication of resynchronization therapy for ventricular dysfunction (LVEF <40%) and indication of cardiac pacing for AV block.
• LVEF <=35% in NYHA class III or IV if they are in atrial fibrillation and have intrinsic QRS >=130 ms, provided a strategy to ensure biventricular capture is in place.

Exclusion Criteria

• Myocardial infarction, unstable angina or cardiac revascularization during the previous 3 months.
• Pregnancy.
• Participating currently in a clinical investigation that includes an active treatment.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
Conduction system pacing	Conduction system pacing	Pacing the His-Purkinje system. Crossover to biventricular pacing was allowed in case of failed conduction system pacing: failed His bundle pacing and failed Left bundle branch pacing (high thresholds (\>3.5V / 1ms); no left bundle branch pacing criteria; no left bundle branch correction). Electrocardiographic optimization allowed in order to obtain the narrowest QRS.
Biventricular pacing	Biventricular pacing	Pacing from the right ventricular and coronary sinus leads. Electrocardiographic optimization with fusion-optimized intervals. Crossover from biventricular pacing to conduction system pacing will be allowed in the following situations: coronary sinus cannot be cannulated; no lateral or posterolateral branches; or phrenic stimulation.

Primary Outcome Measures

Name	Time	Method
Composite end-point: all-cause mortality, cardiac transplant, heart failure hospitalization, and left ventricular ejection fraction (LVEF) improvement <5 points.	12 months	Non inferiority margin 10%.

Secondary Outcome Measures

Name	Time	Method
Change in left ventricular ejection fraction.	6 months; 12 months	Non inferiority margin 2.5%
Change in left ventricular end-systolic volume.	6 months; 12 months	Non inferiority margin 3%
QRS shortening	Post-implantation (Electrophysiology Lab)	Non inferiority margin 12ms
Echocardiographic response (>=15% decrease in left ventricular end-systolic volume).	6 months; 12 months	Non inferiority margin 10%
Hospitalization due to heart failure, mortality or cardiac transplant (combined endpoint)	6 months; 12 months	Non inferiority margin 10%
Change in NYHA functional class	6 months; 12 months	NYHA functional class I, II, III, IV.
Correction of septal flash	15 days; 6 months; 12 months	Non inferiority margin 0.5mm

Trial Locations

Locations (1)

Lluís Mont; 🇪🇸 Barcelona, Spain