Elsevier

American Heart Journal

Volume 153, Issue 1, January 2007, Pages 105-112
American Heart Journal

Clinical Investigation
Congestive Heart Failure
Scar burden by myocardial perfusion imaging predicts echocardiographic response to cardiac resynchronization therapy in ischemic cardiomyopathy

https://doi.org/10.1016/j.ahj.2006.10.015Get rights and content

Background

About 30% of patients with heart failure do not respond to cardiac resynchronization therapy (CRT). We hypothesized that scar burden can predict poor response to CRT in patients with ischemic cardiomyopathy (ICM).

Methods

Fifty patients (age, 68.5 ± 9.2 years; 84% men; mean left ventricular ejection fraction (LVEF), 19.7% ± 5.2%) with ICM who underwent CRT-defibrillator implantation and 201Tl single photon emission computed tomography myocardial perfusion imaging were included. Myocardial perfusion imaging studies were read quantitatively, generating a summed perfusion score (SPS). Left ventricular (LV) lead position was determined by chest radiography. Echocardiograms were performed before and after (median, 11.0 months) CRT.

Results

Echocardiographic response, defined as ≥15% relative increase in LVEF, was documented in 28 (56%) patients. The mean SPS (18.8 ± 11.3 vs 33.7 ± 11.1; P = .000025) and the average scar density in the segments immediately adjacent to the LV lead (0.70 ± 0.91 vs 1.64 ± 0.82; P = .0004) were significantly lower in responders versus nonresponders. Global scar burden (r = −0.53; P = .00007), scar burden near the LV lead (r = −0.49; P = .0003), and the number of segments with a score of 4 (r = −0.53; P = .0007) inversely correlated with increase in LVEF after CRT. The hazard ratio for nonresponse increased with increasing tertiles of global SPS, scar density in the vicinity of the LV lead, and number of segments with transmural scar (ie, perfusion score = 4).

Conclusions

Higher overall scar burden, a larger number of severely scarred segments, and greater scar density near the LV lead tip portend an unfavorable response to CRT in ICM patients. Prospective confirmation of these findings is warranted.

Section snippets

Patient population

A database of all patients implanted with CRT-defibrillators (CRT-Ds) at the University of Pittsburgh Medical Center between 2000 and 2005 was searched for those patients who had undergone MPI. Patients with an ICM, defined as systolic dysfunction caused at least in part by angiographically proven coronary artery disease (≥70% stenosis in at least one major epicardial coronary artery), were selected for analysis.

All patients met the following standard criteria for CRT: (1) left ventricular

Patient population

Seventy-eight patients who received a CRT-D device at the University of Pittsburgh Medical Center between 2000 and 2005 also underwent MPI as a part of their clinical care for HF. Twenty-eight of these patients were excluded because of a lack of adequate echocardiographic follow-up (Figure 2). Of the 50 patients included in the present analysis, 28 (56%) had a significant echocardiographic response. Table I illustrates the clinical characteristics of these patients, along with outcome data. Of

Discussion

In this cohort of patients with ICM who underwent CRT-D implantation, we observed an echocardiographic response rate of nearly 60%, which is consistent with published data. Our echocardiographic results demonstrate that there is a negative impact upon CRT response rates as the proportion of overall scar rises and as dense scar becomes more anatomically extensive. In addition, there are diminished returns in those patients in whom the LV lead is implanted in a location with heavy scar burden.

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