Effect of Bi-ventricular Pacing on Autonomous Nervous System

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00190138
Recruitment Status : Unknown
Verified December 2004 by Far Eastern Memorial Hospital.
Recruitment status was:  Not yet recruiting
First Posted : September 19, 2005
Last Update Posted : October 7, 2010
Information provided by:
Far Eastern Memorial Hospital

Brief Summary:
Patients with congestive heart failure are often associated with delayed intraventricular depolarization which causing dyssynchrony and an inefficient pattern of left ventricular contraction. A number of studies have shown that bi-ventricular or left ventricular pacing improves indexes of systolic function as well as decreases sympathetic activation in patients with severe left ventricular systolic dysfunction, dilated cardiomyopathy and a major left-sided intraventricular conduction disorder such as left bundle branch block. One recent study also demonstrated that bi-ventricular pacing can shift heart rate variability (HRV) toward a more favorable profile. Baroreflex sensitivity (BRS) is a measure of the negative feedback properties that interact in modulating the dynamic heart rate and arterial pressure fluctuations. Blunted BRS is found to be associated with an increased risk for both cardiac deaths and arrhythmic events. However, the effect of bi-ventricular pacing on BRS has never been studied. In the present proposal, we plan to measure common hemodynamic parameters, BRS and HRV in a group of heart failure patients receiving open heart surgery in different pacing conditions (bi-ventricular pacing, single LV pacing, single RV pacing). The major aims are to investigate the effect of bi-ventricular pacing on BRS and to clarify the underlying mechanisms.

Condition or disease Intervention/treatment Phase
Congestive Heart Failure Device: Bi-ventricular pacing Not Applicable

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Detailed Description:

Operation and lead placement:

Off-pump coronary artery bypass (OPCAB) is performed based on patient's coronary angiography. Following the completion of coronary anastomoses, epicardial pacemaker leads are implanted by simple stitches in different locations. The right atrial (RA) lead is placed on the right atrial appendage. The right ventricle (RV) lead is placed on the RV free wall near the apex. The left ventricle (LV) lead is placed on the lateral wall of LV at the border zone between diagonal and obtuse marginal branches of coronary artery. All three ground leads are placed on the rectus abdominis muscle. All these leads are pulled out of the patient percutaneously. Medtronic dual-chamber pacemaker is used for this study. The change of different pacing protocol (RV pacing, LV pacing, or biventricular pacing) is through the connection of different pacemaker leads.

Hemodynamic study:

All patients underwent OPCAB have Swan-Ganz catheter in our institute. Cardiac output measurement is obtained by thermodilution method. Hemodynamic variables (systemic blood pressure, pulmonary artery pressure, central venous pressure, pulmonary capillary wedge pressure, systemic vascular resistance, and pulmonary vascular resistance, etc) are recorded during the measurement.

ECG and blood pressure monitoring system:

ECG and radial arterial blood pressure were recorded by an analog to digital converter system (National Instrument Inc.). The ananlog signals were digitized in a rate of 500Hz and were stored in a hard disk. The data were then analyzed by a program written with MATLAB language (version 5.2, Mathwork Co.). QRS complexes were automatically classified and manually verified as normal sinus rhythm, arterial or ventricular premature beats, or noise by comparison of the adjacent QRS morphologic features. The N-N interval time series were then transferred to a personal computer and post-processed.

Baroreflex sensitivity analysis:

The analysis of BRS was conducted by both the sequence method (19, 20) and the spectral (α-index) method. Sequence method: In brief, the beat-by-beat time series of systolic arterial blood pressure and ECG R-R intervals were scanned to identify sequences of over three consecutive beats in which the systolic blood pressure (SBP) and R-R intervals of the next beat changed concomitantly in increasing or decreasing sequence. Such beat-to-beat sequences were identified as baroreflex sequences. A linear regression was applied to the individual sequence and only r2 values >0.85 were accepted. The measure of each type of the integrated spontaneous BRS was obtained by averaging all accepted slopes of the same type during a 5-minute recording. Spectral (α-index) method: The α-index (α) was obtained by means of the simultaneous spectral analysis of the R-R intervals and the SBP variabilities, with the calculation being made from the square root of the ratio between the R-R intervals and the SBP variability in low frequency (LF) band (αLF, 0.04 to 0.15 Hz). The coherence between the R-R intervals and SBP was assessed by a cross-spectral analysis. The α-index was calculated only when the magnitude of squared coherence (K2) between the RR and the SBP signals exceed 0.5 in LF band.

Heart rate variability analysis:

The missing intervals of the raw N-N data were linearly interpolated and resampled at 4 Hz by the Ron-Berger method. Each 5-minute segment of N-N intervals was taken for HRV analysis. The time domain measurements of HRV included SDNN, r-MSSD. The frequency-domain measurements of HRV included LF and HF, which were calculated by Welch's averaged periodogram of the N-N intervals.

Study Type : Interventional  (Clinical Trial)
Allocation: Non-Randomized
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Effect of Bi-ventricular Pacing on Autonomous Nervous System

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Heart Failure
U.S. FDA Resources

Information from the National Library of Medicine

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Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Patients with normal sinus rhythm proposed to undergo coronary artery bypass surgery.

Exclusion Criteria:

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To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00190138

Sponsors and Collaborators
Far Eastern Memorial Hospital
Study Chair: Kuan-Ming Chiu, M.D. Far Eastern Memorial Hospital Identifier: NCT00190138     History of Changes
Other Study ID Numbers: FEMH-93014
First Posted: September 19, 2005    Key Record Dates
Last Update Posted: October 7, 2010
Last Verified: December 2004

Keywords provided by Far Eastern Memorial Hospital:
Bi-ventricular pacing
ventricular resynchronization
baroreflex sensitivity
heart rate variability

Additional relevant MeSH terms:
Heart Failure
Heart Diseases
Cardiovascular Diseases