Effect of Atrial Pacing on Right Ventricular Function After Cardiac Surgery

Study Overview
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Brief Summary
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Temporary pacing with an external pacemaker after open heart surgery - besides preventing arrhythmias and AV-conduction disorders - is used to improve cardiac output. In theory, postoperative stunning temporarily limits stroke volume and SA-node dysfunction compromises an adequate compensatory rise in heartrate to ensure sufficient cardiac output. There is a lack of consensus regarding the use of this form of pacing. Protocols vary widely between hospitals. Moreover, the scientific base for this form of pacing mainly comprises studies dating back to the nineteen sixties and seventies. Major changes in (operating) techniques have taken place since then. Also, the role of the right ventricle in this context has not been studied specifically. The current study aims to investigate the effects of atrial pacing on right ventricular function specifically and hemodynamics in general, in today's postoperative setting. We hypothesize that a reduction in heart rate may lead to decreased right ventricular function.

Detailed Description
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When a hemodynamically stable state is achieved, the external pacemaker will be switched off for 30 minutes. Hemodynamic parameters will be acquired directly prior to switching off, 15 respectively 30 minutes after switching off, and 15 minutes after switching back on. To gain insight in the natural course of stunning, this routine will be repeated the next morning. No additional hemodynamic interventions will be allowed in these periods.

Official Title
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Effect of Atrial Pacing on Right Ventricular Function After Cardiac Surgery

Conditions
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Right Ventricular Ejection Fraction

Intervention / Treatment
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* Procedure: external pacemaker switched off


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age 18 years or older admitted to the ICU after onpump open heart surgery Swan Ganz thermodilurion catheter in situ Exclusion Criteria: participation other trials off pump cardiac surgery

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: Diagnostic
Intervention Model: Single Group Assignment
Interventional Model Description: To investigate the effects of atrial pacing on right ventricular function and hemodynamics after open heart surgery.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: study group<br>When a hemodynamically stable state is achieved, the external pacemaker will be switched off for 30 minutes. Hemodynamic parameters will be acquired directly prior to switching off, 15 respectively 30 minutes after switching off, and 15 minutes after switching back on. To gain insight in the natural course of stunning, this routine will be repeated the next morning. | Procedure: external pacemaker switched off<br>* When a hemodynamically stable state is achieved, the external pacemaker will be switched off for 30 minutes. Hemodynamic parameters will be acquired directly prior to switching off, 15 respectively 30 minutes after switching off, and 15 minutes after switching back on. To gain insight in the natural course of stunning, this routine will be repeated the next morning.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| right ventricular ejection fraction | difference in right ventricular function expressed in RVEF | 30 minutes after procedure |