Left Ventricular Synchronous Versus Sequential MultiSpot Pacing for Cardiac Resynchronization Therapy (CRT)

Study Overview
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Brief Summary
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The SYNSEQ study intends to assess the positive left ventricular dP/dt max achieved by MultiSpot LV pacing (either simultaneously or sequentially) in comparison to the response achieved by the current (standard) BiV pacing configuration in patients indicated/recommended for cardiac resynchronization therapy.

Detailed Description
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The following pacing configurations will be evaluated. Biventricular pacing (BiV): Pacing will be performed on one LV electrode pair, (at 3 different longitudinal locations), and on the tip of the RV-lead. In total, three different pacing BiV settings will be evaluated. Configuration 1: RV + LV lateral Apex, Configuration 2: RV + LV lateral Mid, Configuration 3: RV + LV lateral Base (Reference: Standard CRT) MultiSpot simultaneous LV-ventricular pacing (MultiSpot-SYN): Pacing will be performed on 3 electrodes on the LV wall, placed at different longitudinal locations, and on the tip of the RV-lead simultaneously. Configuration 4: RV + LV lateral Apex + LV lateral Mid + LV lateral Base MultiSpot sequential LV-ventricular pacing (MultiSpot-SEQ): 3 electrodes on the LV wall will be paced sequentially. The RV electrode will be paced simultaneously with last paced LV electrode.The timing-sequence and the amount of spots will depend on the electrical delays measured during the experiments. Configuration 5: LV lateral Apex => LV lateral Mid => LV lateral Base + RV

Official Title
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Left Ventricular Synchronous Versus Sequential MultiSpot Pacing for CRT

Conditions
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Heart Failure

Intervention / Treatment
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* Procedure: Electrophysiological Study


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Subject is indicated or recommended for CRT-P or CRT-D device according to current applicable ESC/AHA guidelines Subject is in sinus rhythm Subject receives optimal heart failure oral medical therapy Subject is willing to sign the informed consent form Subject is 18 years or older Exclusion Criteria: Subject has permanent atrial fibrillation/flutter or tachycardia Subject has pure right bundle branch block (= no additional left ventricular conduction delays) Subject has left bundle branch block and QRS-duration of > 150 ms and no sign of myocardial scar indicated by late gadolinium enhancement MRI Subject experienced recent myocardial infarction, within 40 days prior to enrollment Subject underwent valve surgery, within 90 days prior to enrollment Subject is post heart transplantation, or is actively listed on the transplantation list Subject is implanted with a left ventricular assist device Subject has severe renal disease (up to physicians discretion) Subject is on continuous or uninterrupted infusion (inotropic) therapy for heart failure (≥ 2 stable infusions per week) Subject has severe aortic stenosis (with a valve area of <1.0 cm2 or significant valve disease expected to be operated within study period) Subject has complex and uncorrected congenital heart disease Subject has a mechanical heart valve Pregnant or breastfeeding women, or women of child bearing potential and who are not on a reliable form of birth control Subject is enrolled in another study that could confound the results of this study, without documented pre-approval from Medtronic study manager

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
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Electrophysiological Study<br>Subjects will receive pacing from one right ventricular lead and one left ventricular catheter/lead with multiple LV pacing spots during electrophysiological study procedure. | Procedure: Electrophysiological Study<br>* Subjects will receive pacing from one right ventricular lead and one left ventricular catheter/lead with multiple LV pacing spots during electrophysiological study procedure.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage Change in Positive Left Ventricular dP/dt Max (mmHG/Sec) | LV dP/dt max is a measurement of the initial velocity of myocardial contraction and is derivative of the LV-pressure. The percentage changes correspond to a percentage change between a pacing configuration (pacing on, e.g., Multispot pacing) and baseline (LV pacing off). There are several repetitions of pacing off and on for each pacing configuration. For one repetition, the percentage change is determined as ([median dP/dt max during pacing On] - (median baseline dP/dt max during pacing Off])/[median dP/dt max during pacing Off]. From all percentage changes for a given pacing configuration and subject, a regression analysis is performed to determine the regression predicted highest percentage change. The presented percentage change is the average over all subjects. | Participants were followed for the time of the EP procedure, which had a median duration of 48 min | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Correlation Between Percentage Change LV dP/dt Max and Percentage Change Blood Pressure | Measured by invasive arterial blood line connected to a sensitive membrane displacement sensor. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were collected.The percentage changes correspond to a percentage change between a pacing configuration (pacing on, e.g., Multispot pacing) and baseline (LV pacing off). There are several repetitions of pacing off and on for each pacing configuration. For one repetition, the percentage change is determined as ([median pressure during pacing On] - (median pressure during pacing Off])/[median pressure during pacing Off]. Correlation will be summarized over all pacing configurations and time points since the interest is in the overall correlation between LV dP/dt max and other measurements, not in the correlation per pacing configuration or per time point. The general linear model as described in Blank & Altman, Biometrical Journal 310 (1995), p 446, was used to determine the correlation. | Participants were followed for the time of the EP procedure, which had a median duration of 48 min | 
| Correlation Between Percentage Change LV dP/dt Max and Percentage Change Non-Invasive Blood Pressure | Acquired through finger volume clamp | Participants were followed for the time of the EP procedure, which had a median duration of 48 min | 
| Correlation Between Percentage Change LV dP/dt Max and Q-LV Ratio | Derived from intra-cardiac leads (invasive) and surface electrodes (non-invasive) respectively. The Q-LV interval is defined as the time from the onset of the QRS width of the surface ECG to the first large positive or negative peak of the LV electrogram (EGM) during a cardiac cycle. The Q-LV ratio will be calculated as Q-LV/QRS duration. Correlation will be summarized over all pacing configurations since the interest is in the overall correlation between LV dP/dt max and other measurements, not in the correlation per pacing configuration. The general linear model as described in Blank & Altman, Biometrical Journal 310 (1995), p 446, was used to determine the correlation between % change LV dP/dt max and Q-LV ratio. | Participants were followed for the time of the EP procedure, which had a median duration of 48 min | 
| Correlation Between Percentage Change LV dP/dt Max and % Change QRS Width | Derived from surface electrodes (non-invasive). The percentage change is determined as ([QRS width during pacing On] - (QRS width during pacing Off])/[QRS width during pacing Off]. The correlation between % change LV dP/dt max and % change QRS width will be summarized over all pacing configurations since the interest is in the overall correlation between LV dP/dt max and other measurements, not in the correlation per pacing configuration or per time point. The general linear model as described in Blank & Altman, Biometrical Journal 310 (1995), p 446, was used to determine the correlation. | Participants were followed for the time of the EP procedure, which had a median duration of 48 min |