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

Study Overview
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Brief Summary
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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
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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)

Official Title
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Conduction System Pacing vs Biventricular Resynchronization Therapy in Systolic Dysfunction and Wide QRS: CONSYST-CRT Randomized Clinical Trial.

Conditions
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Resynchronization Therapy, Conduction System Pacing

Intervention / Treatment
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* Device: Conduction system pacing
* Device: Biventricular pacing


Participation Criteria
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Eligibility Criteria
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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.

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: The first 70 patients have been recruited in the context of the LEVELAT study (ClinicalTrials.gov Identifier: NCT04054895)
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Conduction system pacing<br>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<br>* Lead placed in the His-Purkinje system in order to achieve QRS shortening.<br>|
| Active Comparator: Biventricular pacing<br>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<br>* Lead is placed in a tributary of the coronary sinus.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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 Outcome Measures

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

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Resynchronization Therapy, Biventricular pacing, Conduction system pacing