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

NCT ID: NCT05187611

Last Updated: 2025-07-10

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 130 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2022-01-17
• Study Completion Date: 2025-04-01

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)

Conditions

Resynchronization Therapy; Conduction System Pacing

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

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.

Group Type: EXPERIMENTAL

Conduction system pacing

Intervention Type: DEVICE

Lead placed in the His-Purkinje system in order to achieve QRS shortening.

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.

Group Type: ACTIVE_COMPARATOR

Biventricular pacing

Intervention Type: DEVICE

Lead is placed in a tributary of the coronary sinus.

Interventions

Conduction system pacing

Lead placed in the His-Purkinje system in order to achieve QRS shortening.

Intervention Type: DEVICE

Biventricular pacing

Lead is placed in a tributary of the coronary sinus.

Intervention Type: DEVICE

Eligibility Criteria

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.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Hospital Clinic of Barcelona

OTHER

Sponsor Role: lead

Responsible Party

Josep Lluis Mont Girbau

Principal Investigator

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Lluís Mont, MD, PhD

Role: STUDY_DIRECTOR

Hospital Clinic of Barcelona

Jose M Tolosana, MD, PhD

Role: PRINCIPAL_INVESTIGATOR

Hospital Clinic of Barcelona

Margarida Pujol Lopez, MD

Role: PRINCIPAL_INVESTIGATOR

Hospital Clinic of Barcelona

Locations

Lluís Mont

Barcelona, , Spain

Countries

Spain

References

Pujol-Lopez M, Graterol FR, Borras R, Garcia-Ribas C, Guichard JB, Regany-Closa M, Jimenez-Arjona R, Niebla M, Poza M, Carro E, Castel MA, Arbelo E, Porta-Sanchez A, Sitges M, Roca-Luque I, Doltra A, Guasch E, Tolosana JM, Mont L. Clinical Response to Resynchronization Therapy: Conduction System Pacing vs Biventricular Pacing: The CONSYST-CRT Trial. JACC Clin Electrophysiol. 2025 Aug;11(8):1820-1831. doi: 10.1016/j.jacep.2025.03.024. Epub 2025 May 14.

Reference Type: DERIVED

PMID: 40372330 (View on PubMed)

Other Identifiers

CONSYST-CRT.

Identifier Type: -

Identifier Source: org_study_id