Abstract
BackgroundPlacing the left ventricular (LV) lead in a viable segment with the latest mechanical activation (vSOLA) may be associated with optimal cardiac resynchronization therapy (CRT) response. We assessed the role of gated SPECT myocardial perfusion imaging (gSPECT MPI) in predicting clinical outcomes at 6 months in patients submitted to CRT. MethodsTen centers from 8 countries enrolled 195 consecutive patients. All underwent gSPECT MPI before and 6 months after CRT. The procedure was performed as per current guidelines, the operators being unaware of gSPECT MPI results. Regional LV dyssynchrony (Phase SD) and vSOLA were automatically determined using a 17 segment model. The lead was considered on-target if placed in vSOLA. The primary outcome was improvement in ≥1 of the following: ≥1 NYHA class, left ventricular ejection fraction (LVEF) by ≥5%, reduction in end-systolic volume by ≥15%, and ≥5 points in Minnesota Living With Heart Failure Questionnaire (MLHFQ). ResultsSixteen patients died before the follow-up gSPECT MPI. The primary outcome occurred in 152 out of 179 (84.9%) cases. Mean change in LV phase standard deviation (PSD) at 6 months was 10.5°. Baseline dyssynchrony was not associated with the primary outcome. However, change in LV PSD from baseline was associated with the primary outcome (OR 1.04, 95% CI 1.01-1.07, P = .007). Change in LV PSD had an AUC of 0.78 (0.66-0.90) for the primary outcome. Improvement in LV PSD of 4° resulted in the highest positive likelihood ratio of 7.4 for a favorable outcome. In 23% of the patients, the CRT lead was placed in the vSOLA, and in 42% in either this segment or in a segment within 10° of it. On-target lead placement was not significantly associated with the primary outcome (OR 1.53, 95% CI 0.71-3.28). ConclusionLV dyssynchrony improvement by gSPECT MPI, but not on-target lead placement, predicts clinical outcomes in patients undergoing CRT.
Highlights
Heart failure affects more than 15 million people worldwide and is growing globally at epidemic proportions, causing considerable increases in disability, mortality, and healthcare costs.[1]As a consequence of the epidemiologic transition and advances in health care, as well as the aging of the population and the high prevalence of coronary artery disease (CAD), hypertension, obesity, and diabetes mellitus are increasing and will have a significant impact on the incidence of heart failure in low-andmiddle income countries
The primary outcome was improvement in ‡1 of the following: ‡1 New York Heart Association (NYHA) class, left ventricular ejection fraction (LVEF) by ‡5%, reduction in end-systolic volume by ‡15%, and ‡5 points in Minnesota Living With Heart Failure Questionnaire (MLHFQ)
Sixteen patients died before the follow-up gated single photon emission computed tomography (gSPECT) myocardial perfusion imaging (MPI)
Summary
Heart failure affects more than 15 million people worldwide and is growing globally at epidemic proportions, causing considerable increases in disability, mortality, and healthcare costs.[1]As a consequence of the epidemiologic transition and advances in health care, as well as the aging of the population and the high prevalence of coronary artery disease (CAD), hypertension, obesity, and diabetes mellitus are increasing and will have a significant impact on the incidence of heart failure in low-andmiddle income countries. In a few years, the incidence and prevalence of heart failure may reach similar levels to those observed in high-income countries.[2] Cardiac resynchronization therapy (CRT) can benefit some patients with end-stage heart failure, depressed left ventricular ejection fraction (LVEF) (\35%), and a wide QRS complex on the surface electrocardiogram ([120 milliseconds).[3] these selection criteria are suboptimal, given that in previous CRT trials which used them, a significant percentage of patients (20-40%) did not benefit from CRT.[4,5] It has been recognized that electrical dyssynchrony as determined by QRS duration may not necessarily represent real mechanical dyssynchrony and, not the best predictor of CRT response.[6,7,8] assessment of cardiac mechanical dyssynchrony is needed to more accurately select patients who would benefit more consistently from CRT.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
