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Aims: Prior studies using stress myocardial perfusion imaging (MPI), which examined the association between obstructive epicardial coronary disease and presence of myocardial ischemia did not provide a detailed assessment on a regional level. We examined this relationship in a large population of patients in whom the coronary anatomy was defined by invasive coronary angiography., Methods: We retrospectively extracted details on individuals undergoing MPI with single photon emission computed tomography (SPECT) who had coronary angiography within 12 months. A 17-segment model for native coronary anatomy and a 7-region model for myocardial perfusion were used with a dedicated matching algorithm., Results: A total of 2564 patients were included, yielding a total of 6279 stenoses matched with 17 948 myocardial regions. From such a cohort, 151 (5.9%) patients had normal perfusion, 1878 (73.2%) had myocardial ischemia (reversible defects), 260 (10.1%) had myocardial necrosis (scar or fixed defects), and 275 (10.7%) had ischemia and necrosis. At per-patient analysis, significant angiographic disease was more common in the ischemic group (prevalence between 69.6 and 80.0%) than other groups. At per-region analysis, abnormal perfusion in the coronary-specific regions varied depending on location of stenosis; it was 96% for left main disease, 81% for proximal left anterior descending disease, 85% for proximal left circumflex disease, and 82% for proximal right coronary artery disease and <60% for posterior descending artery disease., Conclusion: The correlation between significant coronary stenosis and presence of corresponding regional perfusion abnormality depends on the location of the lesion and the corresponding myocardial region.

Background: Studies of the effect of right ventricular ejection fraction (RVEF) on outcomes in heart failure (HF) are limited by small sample size and short follow-up., Methods and Results: We examined the effect of baseline RVEF on outcomes in 2008 Beta-Blocker Evaluation of Survival Trial (BEST) participants with HF and left ventricular ejection fraction or=40% (n=733), 30% to 39% (n=531), 20% to 29% (n=473), and <20% (n=271). Unadjusted rates for all-cause mortality in patients with RVEF >or=40%, 30% to 39%, 20% to 29%, and <20% were 27%, 32%, 35%, and 47%, respectively. When compared with patients with RVEF >or=40%, unadjusted hazard ratios and 95% confidence intervals for all-cause mortality for those with RVEF 30% to 39%, 20% to 29%, and <20% were 1.19 (0.97 to 1.46; P=0.087), 1.45 (1.17 to 1.78; P=0.001), and 1.98 (1.59 to 2.47; P<0.0001), respectively. Respective multivariable-adjusted hazard ratios (95% confidence intervals) for all-cause mortality associated with RVEF 30% to 39%, 20% to 29%, and <20% were 1.07 (0.87 to 1.32; P=0.518), 1.12 (0.89 to 1.40; P=0.328), and 1.32 (1.02 to 1.71; P=0.034), respectively. Adjusted hazard ratios (95% confidence intervals) for other outcomes associated with RVEF <20% (compared with >or=40%) were as follows: cardiovascular mortality, 1.33 (1.01 to 1.76; P=0.041); HF mortality, 1.61 (1.03 to 2.52; P=0.037); sudden cardiac death, 1.29 (0.87 to 1.91; P=0.212); all-cause hospitalization, 1.21 (1.00 to 1.47; P=0.056); and HF hospitalization, 1.39 (1.10 to 1.77; P=0.007)., Conclusions: Baseline RVEF <20% is a significant independent predictor of mortality and HF hospitalization in systolic HF.

Background: Single-photon emission computed tomography myocardial perfusion imaging defects are associated with increased all-cause mortality and cardiovascular death. However, it is unknown whether single-photon emission computed tomography myocardial perfusion imaging can identify patients at increased risk of sudden cardiac death (SCD)., Methods and Results: We analyzed a cohort of 6383 patients with angiographically documented coronary artery disease who underwent single-photon emission computed tomography imaging. Cox proportional hazards modeling was used to examine the relationship between patient characteristics and SCD. Among patients who died, the median time to SCD was 2.7 years (25(th), 75(th) percentiles 0.9, 4.9, respectively). The incidence of SCD was 3.4% (n=215) over 6.1 years (25(th), 75(th) percentiles 3.7, 9.2, respectively) of follow-up. Patients with SCD had more severe heart failure symptoms, greater comorbidity (Charlson index), and higher summed stress perfusion scores (all P<0.001). After adjusting for left ventricular ejection fraction and other clinical factors in the multivariable model, the summed stress perfusion score (fixed plus reversible defects) remained significantly associated with the occurrence of SCD: summed stress perfusion score (hazard ratios per 3 U: 1.16 [95% CI, 1.08 to 1.25], P<0.001), left ventricular ejection fraction (hazard ratios per 5 U: 0.90 [95% CI, 0.85 to 0.95], P<0.001), and Charlson index (hazard ratios 1.35 [95% CI, 1.23 to 1.49], P<0.001)., Conclusions: Myocardial perfusion imaging is a significant predictor of SCD and provides information independent of clinical history and left ventricular ejection fraction. Gated single-photon emission computed tomography imaging, which evaluates both myocardial perfusion and function, may represent a more effective means of risk stratification than solitary left ventricular ejection fraction determination and should be evaluated in prospective trials.

Background: A novel method to quantify dyssynchrony has been developed using phase analysis of gated single-photon emission computed tomography perfusion imaging. We report on the effect of variability in image reconstruction on the phase analysis results (repeatability) and on the interobserver and intraobserver reproducibility of the technique., Methods: Phase standard deviation (SD) and bandwidth are phase indices that quantify dyssynchrony. To evaluate repeatability, raw data sets were processed twice in 50 patients with left ventricular dysfunction and 50 normal controls. To determine the optimal processing method, two replicated phase analysis results were obtained using automated and manual base parameter placement. Reproducibility of the phase analysis was determined using the data from 20 patients., Results: In normal controls, manual base parameter placement improves repeatability of the phase analysis as measured by the mean absolute difference between two reads for phase SD (12.0 degrees vs. 1.2 degrees , P<0.0001) and bandwidth (33.7 degrees vs. 3.6 degrees , P<0.0001). Repeatability is better for normal controls than for patients with left ventricular dysfunction for phase SD (1.2 degrees vs. 6.0 degrees , P<0.0001) and bandwidth (3.6 degrees vs. 26.5 degrees , P<0.0001). Reproducibility of the phase analysis is high as measured by the intraclass correlation coefficients for phase SD and bandwidth of 0.99 and 0.99 for the interobserver comparisons and 1.00 and 1.00 for the intraobserver comparisons., Conclusion: A novel method to quantify dyssynchrony has been developed using gated single-photon emission computed tomography perfusion imaging. Manual base parameter placement reduces the effect that variability in image reconstruction has on phase analysis. A high degree of reproducibility of phase analysis is observed.

Background: Gated single photon emission computed tomography (SPECT) provides information on myocardial perfusion and left ventricular ejection fraction (LVEF), which correlates with risk of cardiac events in patients with known or suspected coronary artery disease (CAD). We hypothesize that decreased LVEF at time of renal transplant evaluation is an independent risk factor for cardiac death and nonfatal events after transplant., Methods and Results: A total of 653 recipients of renal allografts between 1998 and 2005 had stress SPECT imaging before transplantation. One hundred and nineteen (18%) patients had left ventricular (LV) systolic dysfunction (LVEF

Background: The appropriate management of patients with intermediate-risk Duke treadmill scores is not established. The purpose of this study was to determine the long-term risk of subsequent cardiovascular events in patients with an intermediate-risk treadmill score who do not have myocardial perfusion defects on radionuclide imaging., Methods and Results: The existing databases of the nuclear cardiology laboratories of 4 academic institutions were searched retrospectively. A total of 4649 patients were identified who had intermediate-risk Duke treadmill scores (-10 to 4), normal or near-normal exercise single photon-emission computed tomographic myocardial perfusion images using either thallium-201 or technetium-99m sestamibi, and no previous coronary revascularization. Follow-up was 95% complete. Cardiovascular survival was 99.8% at 1 year, 99.0% at 5 years, and 98.5% at 7 years. Cardiac survival free of myocardial infarction was similarly high at 96.6% at 7 years. Cardiac survival free of myocardial infarction or revascularization was 87.1% at 7 years. Near-normal scans and cardiac enlargement were independent predictors of time to cardiac death. Seven-year cardiac survival was still high at 97.0% in the 357 patients with near-normal scans and normal cardiac size and somewhat lower, at 89.0%, in the 167 patients with cardiac enlargement., Conclusions: Patients with an intermediate-risk treadmill score but with normal or near-normal exercise myocardial perfusion images and normal cardiac sizes are at low risk for subsequent cardiac death and can be safely managed medically until their symptoms warrant revascularization. The appropriate management of patients with cardiac enlargement will remain a matter of clinical judgment.

Background: In the present study, we examined the predictors of outcome of 103 patients with coronary artery disease and left ventricular dysfunction who had life-threatening ventricular arrhythmias and were treated with implantable cardioverter-defibrillators with the use of single-photon emission computed tomography (SPECT)., Methods and Results: During a mean follow-up of 29 months, there were 29 cardiac deaths. In comparison with patients who died, survivors had less diabetes mellitus (45% versus 19%, P < .007), higher left ventricular ejection fraction (23 +/- 9% versus 27 +/- 11%, P = .04), and fewer perfusion defects as determined with stress SPECT (15 +/- 5 versus 12 +/- 5, P < .004). Most of the perfusion defects were fixed, indicative of scarring; the extent of reversible defects did not differ (2 +/- 3 in survivors and 3 +/- 4 in nonsurvivors). Multivariate Cox survival analysis identified the number of fixed defects as the only independent predictor of death (chi 2 = 10, P = .002). There were six deaths among 42 patients (14%) with < 8 fixed defects compared with 23 deaths among 61 patients (38%) with > or = 8 defects (P = .005). The 4-year survival was better in patients with < 8 segmental fixed defects than in those with > or = 8 fixed defects (80% versus 36%) (chi 2 = 8, P = .005)., Conclusions: The myocardial perfusion pattern is an important determinant of outcome in patients with life-threatening ventricular arrhythmias who are treated with a implantable cardioverter-defibrillator. The extent of scarring separates patients into high- and low-risk groups with a 2.7-fold difference in death rate.