Single photon emission computed tomography myocardial perfusion imaging guided left ventricular lead implantation to improve the response to cardiac resynchronization therapy: rationale and design

Abstract

Background Cardiac resynchronization therapy (CRT) is an effective treatment for chronic heart failure patients.However, approximately 30% of recipients exhibit no response to CRT and the position of left ventricular (LV) lead is thought to be an important factor associated with no response.Majority of the related studies indicated that implantation of LV leads at the sites of the latest activation and away from scar can significantly improve the response to CRT. Single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) phase analysis (PA) is a novel method to assess LV mechanical dyssynchrony, the site of the latest activation and scar burden to recommend the suitable position for LV lead.Therefore, randomized, controlled trials using SPECT to guide LV lead implantation to improve CRT response is needed. Rationale GUIDE-CRT study applies pre-operation SPECT MPI AP to evaluate LV mechanical dyssynchrony and distribution of scar and identify the site of the latest activation segment away from scar as optimal pacing site. The feasibility and effectiveness of SPECT MPI PA in guiding LV lead implantation to improve CRT response will be verified. Design Patients with standard CRT indications will be enrolled in 19 centers in China and randomized to two groups (Guided vs.Control) . All the patients will undergo baseline echocardiographic assessment, and SPECT imaging to identify the optimal LV lead positions from 13 LV segments. In the Guided group, the implanters will receive SPECT imaging guidance and attempt to place the LV leads to the target positions define as the LV lead is at or close to the latest activation segment away from scar. In the Control group, the patients will undergo routine LV lead implantation. All patients receive 6-month follow-up echocardiographic assessment to evaluate CRT response. The primary endpoint is reduction of LV end-systolic volume (LVESV) . The secondary endpoints include reduction of LV end-diastolic volume, changes of LV ejection fraction, and CRT response rate defined as a relative decrease of LVESV by ≥ 15% from baseline to 6-month follow-up. Conclusion SPECT guided LV lead implantation will obviously improve CRT efficacy. Key words: Cardiac resynchronization therapy; Heart failure; Radionuclide imaging