Background We hypothesized that the severity of resting perfusion abnormalities assessed by the summed rest score (SRS) would be associated with a higher rate of adverse outcomes in patients with heart failure (HF) and reduced left ventricular (LV) ejection fraction (EF).Methods A subset of 240 subjects from HF-ACTION underwent resting technetium-99m tetrofosmin-gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). Images were evaluated using a 17-segment model to derive the SRS and additional nuclear variables.Results After adjusting for prespecified covariates, SRS was significantly associated with the primary end point (hazard ratio 0.98, 95% confidence interval [CI] 0.97-1.00, P = .04), with a higher SRS corresponding to lower risk of an event. This association was not present in the unadjusted analysis. The relationship between SRS and the primary outcome was likely due to a higher event ratein patients with ischemic HF and a low SRS. The LV phase SD was not predictive of the primary outcome (hazard ratio 1.00, 95% confidence interval 0.99-1.01, P = .49). In a post hoc analysis, nuclear variables provided incremental prognostic information when added to clinical information (P = .006).Conclusions Gated SPECT MPI provides important information in patients with HF and reduced LVEF. In the adjusted analysis, SRS has an unexpected relationship with the primary end point. Phase SD was not associated with the primary end point. Rest-gated SPECT MPI provides incrementally greater prognostic information than clinical information alone. (Am Heart J 2011;161:1038-45.)

BACKGROUND:A novel method to quantify dyssynchrony using phase analysis of single-photon emission computed tomography (SPECT) myocardial perfusion imaging has been developed. We sought to determine the prevalence of SPECT-derived mechanical dyssynchrony, and we report clinical variables which predict mechanical dyssynchrony in patients with left ventricular dysfunction. METHODS:We used a count-based Fourier analysis method to convert the regional myocardial counts from discrete frames per cardiac cycle into a continuous thickening function which allows resolution of the phase of the onset of myocardial contraction. The standard deviation of left ventricular phases (Phase SD) describes the regional phase dispersion as a measure of dyssynchrony. Significant dyssynchrony was defined as Phase SD ≥ 43°. 260 patients with left ventricular ejection fraction ≤ 35% were examined. RESULTS:The prevalence of mechanical dyssynchrony in the entire cohort of patients studied was 52%. Univariate predictors of Phase SD were age (P = .03), black race (P = .0005), QRS duration, EF, EDV, summed stress score (SSS), and summed rest score (SRS) (all P = <.0001). Black race, male gender, QRS EF, and SRS were independent predictors of SPECT-based mechanical dyssynchrony. CONCLUSIONS:Significant SPECT-based mechanical dyssynchrony is relatively common among patients with left ventricular dysfunction. In a population of patients with predominantly ischemic heart disease referred for SPECT, a reduced EF, increasing QRS duration, severity and extent of myocardial scar on SPECT imaging are independent predictors of mechanical dyssynchrony and may serve to identify patients for dyssynchrony screening.

Background: There are currently limited data from large, prospective studies regarding the ability of single photon emission tomography (SPECT) myocardial perfusion imaging (MPI) variables to predict adverse outcomes in patients with heart failure (HF) and reduced left ventricular (LV) ejection fraction (EF). We hypothesize that the severity of resting perfusion defects (“myocardial scarring”) as measured by the summed rest score (SRS) by SPECT MPI will be associated with higher rates of adverse outcomes as defined by a composite primary endpoint of all-cause mortality and cardiovascular hospitalization in patients enrolled in the HF-ACTION trial.

CRT has been shown to be beneficial in the majority of patients with NYHA class III-IV symptoms, prolonged QRS duration, and an EF ≤35%. The use of imaging modalities to quantify dyssynchrony may help identify patients who may benefit from CRT, but do not meet current selection criteria. We hypothesize that patients with mild-to-moderate LV dysfunction have significant degrees of mechanical dyssynchrony.

Background There are currently limited data on the relationships between resting perfusion abnormalities, left ventricular ejection fraction (LVEF), New York Heart Association (NYHA) functional class, and exercise capacity as defined by peak VO2 and 6-minute walk test in patients with heart failure (HF) and reduced LVEF. Furthermore, the association between resting perfusion abnormalities and left ventricular dyssynchrony is currently unknown. This article addresses the Heart Failure and A Controlled Trial Investigating Outcomes of Exercise TraiNing (HF-ACTION) gated SPECT imaging (gSPECT) substudy baseline results.Methods HF-ACTION was a multicenter, randomized controlled trial of aerobic exercise training versus usual care in 2,331 stable patients with LVEF of <= 35% and NYHA class II to IV HF symptoms treated with optimal medical therapy. Subjects enrolled in the HF-ACTION substudy underwent resting Tc-99m tetrofosmin gSPECT at baseline (n = 240). Images were evaluated for extent and severity of perfusion abnormalities using a 17-segment and a 5-degree gradation severity score (summed rest score [SRS]). Left ventricular function and dyssynchrony were assessed using validated available commercial software.Results The average age of patients enrolled was 59, 69% were male, 63% were white, and 33% were African American. Of the 240 participants, 129 (54%) were ischemic and 111 (46%) were nonischemic in etiology. The median LVEF by gSPECT for the entire cohort was 26%. Among the nuclear variables, there was a modest correlation between LVEF and SRS (r=-0.31, P<.0001) and there were stronger correlations between phase SD and SRS (r=0.66, P<.0001) as well as phase SD and LVEF (r=-0.50, P<.0001). Patients with NYHA class III symptoms had more severe and significant degrees of dyssynchrony (median phase SD 54 degrees) than those with NYHA class II symptoms (median phase SD 39 degrees, P=.001). Patients with an ischemic etiology had a higher SRS (P<.0001) and significantly more dyssynchrony (P<.0001) than those who were nonischemic. However, there was no difference in LVEF or objective measures of exercise capacity between these groups. With respect to peak VO2, there was a weak correlation with LVEF (r=0.18, P=.006) and no correlation with SRS (r=-0.04, P=0.59) or with dyssynchrony (r=-0.13, P=.09). A weak but statistically significant correlation between SRS and 6-minute walk was observed (r=-0.15, P=.047).Conclusions Gated SPECT imaging can provide important information in patients with HIF due to severe LV dysfunction including quantitative measures of global systolic function, perfusion, and dyssynchrony. These measurements are modestly but significantly related to symptom severity and objective measures of exercise capacity. (Am Heart J 2009; 158:S53-S63.)

The athlete's heart is a constellation of cardiac morphologic changes, including increased left ventricular volume, increased left ventricular mass, increased left atrial volume, and right ventricular structural changes as a physiologic response to exercise training. These structural changes fall within the normal reference ranges of appropriately matched control subjects for most trained individuals; however, there are significant numbers of athletes who have “abnormal” measurements. The ability to distinguish between physiologic changes associated with the athlete's heart and structural abnormalities that may represent underlying cardiac disease is of paramount importance. Structural heart disease significantly increases risk for morbidity, mortality, and sudden death, especially during exercise or physical stress. This article reviews the morphologic changes associated with the athlete's heart.