Pacing in First-degree AV-block

Study Overview
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Brief Summary
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The purpose of this study is to explore if there is a less harmful way to pace patients with first-degree AV-block to ensure that the negative effects inferred by the pacing do not outweigh the positive effects of AV-synchrony. The main hypothesis of the study is that His-bundle pacing will offer a more physiological mode of pacing in patients with first-degree AV-block than conventional pacing. Patients scheduled for catheter ablation of atrial fibrillation (AF) in sinus rhythm, with first degree AV-block, normal QRS duration less than 120 ms and normal left ventricular ejection fraction will be included. During the AF ablation three different pacing modes (atrial, AV-synchronous and His-bundle pacing) at two different rates (5 to10 bpm above the basal rate and at 100 bpm) will be performed and evaluated using echocardiography. After the completion of all six pacing protocols (i.e., three modes at two different rates) the experimental part of the procedure ends. The primary end-point will be echocardiographic evidence of dyssynchrony. Secondary end-points will include left ventricular ejection fraction, left ventricular volume, mitral regurgitation, septal to posterior wall motion delay and inter-ventricular wall motion delay. Since the research study is conducted in parallel with the standard catheter ablation, we do not anticipate any additional side effects as a result of the study.

Official Title
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Optimal Pacing in Patients With First-degree AV-block

Conditions
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First-degree AV-block, Pacing

Intervention / Treatment
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* Other: Pacing


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients scheduled for catheter ablation of atrial fibrillation in sinus rhythm and PR prolongation exceeding or equal to 200 ms QRS duration less than 120 ms Normal left ventricular ejection fraction on echocardiography. Exclusion Criteria: Any bundle branch block Second- or third-degree AV-block Congestive heart failure, cardiomyopathy, myocardial infarction or major surgical procedure.

Ages Eligible for Study
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Minimum Age: 21 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
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Pacing - Cross-over<br>Pacing will be conducted in 3 different ways (atrial, dual chamber and His-bundle pacing) at 2 different rates (basal and 100 bpm). | Other: Pacing<br> <br> * Other names: Additional catheter may be used to evaluate heart performance during pacing. Does not require additional IV access;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Echocardiographic evidence of dyssynchrony (AV, intra- or inter-ventricular) |  | During each step of the pacing procedure the echocardiographic data will be recorded; over approximately 5-10 minutes |