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

NCT05187611 | Completed FDA Device

• 1 other identifier: CONSYST-CRT.
• Study Type: interventional
• Target: 130
• Locations: 1 country
• Sites: 1

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.

Conditions

Resynchronization Therapy; Conduction System Pacing

Keywords

Resynchronization Therapy; Biventricular pacing; Conduction system pacing

Outcome Measures

Primary Outcomes (1)

• Composite end-point: all-cause mortality, cardiac transplant, heart failure hospitalization, and left ventricular ejection fraction (LVEF) improvement <5 points.

  Non inferiority margin 10%.

  12 months

Secondary Outcomes (7)

• Change in left ventricular ejection fraction.

  6 months; 12 months

• Change in left ventricular end-systolic volume.

  6 months; 12 months

• Echocardiographic response (>=15% decrease in left ventricular end-systolic volume).

  6 months; 12 months

• Hospitalization due to heart failure, mortality or cardiac transplant (combined endpoint)

  6 months; 12 months

• QRS shortening

  Post-implantation (Electrophysiology Lab)

Study Arms (2)

Conduction system pacing

EXPERIMENTAL

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.

Device: Conduction system pacing

Biventricular pacing

ACTIVE COMPARATOR

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.

Device: Biventricular pacing

Interventions

Conduction system pacing DEVICE

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

Conduction system pacing

Biventricular pacing DEVICE

Lead is placed in a tributary of the coronary sinus.

Biventricular pacing

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• 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.

You may not qualify if:

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

Sponsors & Collaborators

• Hospital Clinic of Barcelona: lead

Study Sites (1)

Lluís Mont

Barcelona, Spain

Location

Related Publications (1)

• 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.

  PMID: 40372330 DERIVED

MeSH Terms

Interventions

Cardiac Resynchronization Therapy

Intervention Hierarchy (Ancestors)

Cardiac Pacing, Artificial; Electric Stimulation Therapy; Therapeutics

Study Officials

• Lluís Mont, MD, PhD

  Hospital Clinic of Barcelona

  STUDY DIRECTOR

• Jose M Tolosana, MD, PhD

  Hospital Clinic of Barcelona

  PRINCIPAL INVESTIGATOR

• Margarida Pujol Lopez, MD

  Hospital Clinic of Barcelona

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: SINGLE
• Who Masked: PARTICIPANT
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

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

Study Record Dates

• First Submitted: December 19, 2021
• First Posted: January 12, 2022
• Study Start: January 17, 2022
• Primary Completion: July 15, 2024
• Study Completion: April 1, 2025
• Last Updated: July 10, 2025

Record last verified: 2025-07

Locations

ES (1)