Study to Determine the Safety and Feasibility of Utilizing the CD Leycom Pressure/Conductance Catheter to Determine Optimal LV Pacing Site

Study to Determine the Safety and Feasibility of Utilizing the CD Leycom Pressure/Conductance Catheter to Determine Optimal LV Pacing Site

Study to Determine the Safety and Feasibility of Utilizing the CD Leycom Pressure/Conductance Catheter to Determine Optimal LV Pacing Site

It is hypothesized that it is both safe and feasible to use an interventional approach to LV lead placement (placing the LV lead guided by acute hemodynamic measurements), and that the LV lead can be placed in a position that is superior to the initial empiric lateral wall LV lead location in less than 30 minutes without significant risk to patients. The time from RV capture to LV activation correlates with the optimal pacing site based on stroke volume & dP/dt measurements.

Background Cardiac synchronization therapy (CRT) is recognized as effective adjunctive therapy for heart failure; however, up to 40% of patients who undergo CRT device placement do not have a favorable response to therapy and are labeled non-responders. The lateral wall of the left ventricle (LV) is generally regarded as the optimal site for LV lead placement and some non-responders with LV leads not on the lateral wall can be converted to responders by repositioning the LV lead to the lateral wall. However, recent studies indicate that in some patients LV lead placement at a site other than the lateral wall may result in a better response to CRT. In such circumstances, empiric lateral wall lead positioning/repositioning may expose patients to the risks of another invasive procedure (including an increased risk of infection); in the case of lead repositioning to improve response to CRT the additional risk is doubled, as there is no certainty that the new position will be superior to the old. Several investigators have used the acute hemodynamic response to biventricular pacing to determine the optimal LV lead position. To make these measurements some groups used a Millar pigtail catheter (Millar Instruments, Houston, Texas) while other groups used real-time pressure volume loops with a combined pressure-conductance catheter (CD Leycom, Zoetermeer, the Netherlands). One criticism of this method is that acute hemodynamic measurements may not correlate to long term response. However, Delnoy et al demonstrated that acute improvements in LV function as measured by pressure-volume loops during implantation corresponded to clinical and echocardiographic improvement during follow-up. In addition, Duckett et al demonstrated that the acute dP/dt response to LV pacing is useful for predicting which patients are likely to remodel in response to CRT, for both dilated and ischemic cardiomyopathy. Despite these observations, few practitioners routinely utilize acute hemodynamic measurements for LV lead placement at the time of device implantation. Many practitioners believe targeted LV lead placement is impractical due to the time required to determine hemodynamic response to CRT and reposition the LV lead, and that venous anatomy, phrenic nerve pacing, and high pacing thresholds severely limit options for LV lead placement. Study Hypothesis It is hypothesized that it is both safe and feasible to use an interventional approach to LV lead placement (placing the LV lead guided by acute hemodynamic measurements), and that the LV lead can be placed in a position that is superior to the initial empiric lateral wall LV lead location in less than 30 minutes without significant risk to patients. The time from RV capture to LV activation correlates with the optimal pacing site based on stroke volume & dP/dt measurements. Study Purpose The purpose of this study is to determine whether utilizing the CD Leycom pressure-conductance catheter to measure dP/dt and pressure volume loops at the time of LV lead implant (whether for the initial CRT implant or revision of an existing system) is both safe and feasible. It is hoped that the study will determine whether it is possible to use a patient's hemodynamic response to pacing to locate an LV pacing site that provides better hemodynamic response to CRT than the empirically selected lateral wall pacing site without significant patient risk (in terms of radiation exposure, amount of contrast received, procedure time, potential injury).

Ten patients undergoing LV lead placement for either initial CRT device implant or revision of an existing system at Lancaster General Hospital who meet the inclusion and exclusion criteria will be screened and approached for enrollment in this safety and feasibility study. Study participants may have ischemic or non-ischemic cardiomyopathy; results for ischemic and non-ischemic patients will be analyzed separately. Any device system from any manufacturer may be used; the choice of device and leads will be at the implanting physician's discretion. Post implant procedures will be the same as those for any CRT implant. Outpatient follow-up other than the 1-month follow-up will be per the implanting physician's usual practice.

The physician will obtain right femoral arterial access and advance the pressure/conductance catheter to the LV utilizing the retrograde approach. Baseline dP/dt and stroke volume will be recorded in the patient's presenting rhythm. The dP/dt and stroke volume will be measured during biventricular pacing. Hemodynamic measurements will be made with the tip of the pacing lead in the distal vessel, followed by repeat measurements with the lead positioned in the mid and proximal portions of the initially selected vein. The pacing and hemodynamic measurements will be repeated with the CS lead positioned in two additional veins (if possible). The pressure/conductance catheter will be removed from the left ventricle after 30 minutes, regardless of the number of pacing sites identified/tested. The physician will make the choice of the LV lead placement based on the information gathered up to that point.

The secondary endpoint for the study is to determine the percentage of patients in whom the empirically selected "best" lateral wall LV lead location was the best site based on the hemodynamic measurements.

Inclusion Criteria Ischemic or non-ischemic cardiomyopathy Patient meets all current criteria for CRT (NYHA Class III-IV heart failure, QRS ≥ 120 ms, LVEF ≤ 35%, optimal medical therapy). Patient willing/able to sign study informed consent and HIPAA authorization. Exclusion Criteria Patient does not meet current criteria for CRT implant Mechanical aortic valve Left ventricular thrombus Aortic stenosis No palpable femoral pulse Extensive atherosclerotic disease of the aorta Serum creatinine > 2.5 Patient not willing/able to sign study informed consent/HIPAA authorization.

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