Prognostic risk stratification based on left ventricular mechanical dyssynchrony in patients at low or intermediate risk of major cardiac events using the J-ACCESS risk model.

There have been no reports on prognostic prediction and risk stratification based on stress phase bandwidth (SPBW), or a left ventricular (LV) mechanical dyssynchrony index, in patients with known or suspected stable coronary artery disease (CAD) at low or intermediate risk of major cardiac events (MCEs) using the J-ACCESS risk model. We retrospectively investigated 4,996 consecutive patients with known or suspected CAD who underwent rest 201Tl and stress 99mTc-tetrofosmin electrocardiogram (ECG)-gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) and followed up for 3 years to confirm their prognosis. MCE risk over 3 years was estimated using an equation based on that used in the J-ACCESS study. The composite endpoint was the onset of MCEs consisting of cardiac death, non-fatal myocardial infarction (MI), and severe heart failure requiring hospitalization. SPBW was calculated by phase analysis with the Heart Risk View-F software and its normal upper limit was set to 38°. Based on the estimated 3-year incidence of MCEs obtained from the J-ACCESS risk model, 4,123 of the 4,996 consecutive patients were classified as low (n = 2,653) or intermediate risk (n = 1,470) and they were analyzed for follow-up. During the follow-up, 153 patients experienced MCEs: cardiac death (n = 38), non-fatal MI (n = 45), and severe heart failure (n = 70). The results of the multivariate analysis showed age, estimated glomerular filtration rate (eGFR), stress LV ejection fraction, and stress SPBW to be independent predictors of MCEs. The actual 3-year MCE rate in patients at intermediate risk was significantly higher than in those at low risk (6.7% vs. 2.1%, P < 0.0001). However, the actual 3-year MCE rate in patients with abnormal SPBW (> 38°) was 4.0% and 9.2% in low- and intermediate-risk patients, respectively, which corresponded to intermediate and high risk. Kaplan-Meier analysis also showed significant risk stratification by normal SPBW values for both low- and intermediate-risk patients. LV mechanical dyssynchrony assessed with ECG-gated SPECT MPI is useful for risk stratification of known or suspected stable CAD patients at low or intermediate risk of MCEs and may help identify higher risk patients who could not be identified as being at risk based on J-ACCESS risk assessment.

Prognostic value of the normalization of left ventricular mechanical dyssynchrony after revascularization in patients with coronary artery disease.

There are no reports indicating a prognostic difference based on normalization of left ventricular (LV) mechanical dyssynchrony after revascularization in patients with coronary artery disease (CAD). We retrospectively investigated 596 patients who underwent rest 201Tl and stress 99mTc-tetrofosmin electrocardiogram-gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging. All patients had significant stenosis with ≥ 75% narrowing of the coronary arterial diameter detected by coronary angiography performed after confirmation of ≥ 5% ischemia by the SPECT. Patients underwent revascularization and thereafter were re-evaluated by the SPECT during a chronic phase, and followed-up to confirm their prognosis for ≥ 1 year. The composite endpoint was the onset of major cardiac events (MCEs) consisting of cardiac death, non-fatal myocardial infarction (MI), unstable angina pectoris (UAP), and severe heart failure requiring hospitalization. The stress phase bandwidth (SPBW) was calculated by phase analysis with the Heart Risk View-F software and its normal upper limit was set to 38°. During the follow-up, 64 patients experienced MCEs: Cardiac death (n = 11), non-fatal MI (n = 5), UAP (n = 26), and severe heart failure (n = 22). The results of the multivariate analysis showed the ∆summed difference score %, ∆stress LV ejection fraction, and stress SPBW after revascularization to be independent predictors of MCEs. Additionally, the results of the multivariate logistic regression analysis showed the summed rest score%, summed difference score%, stress LV ejection fraction, and perfusion defects in the left circumflex artery region before revascularization to be independent predictors for normalized SPBW after revascularization. The prognosis of patients who normalized SPBW after revascularization was similar to that of patients with a normal SPBW before revascularization, while patients who did not normalize after revascularization had the worst prognosis. In conclusion, normalization of LV dyssynchrony after revascularization assessed with nuclear cardiology may help predict future MCEs and thus a useful indicator for predicting improved prognosis in patients with CAD.

Prognostic value of phase analysis on gated single photon emission computed tomography in patients with cardiac sarcoidosis.

BACKGROUND: We aimed to determine the correlation between phase analysis, reflecting the heterogeneity of perfusion defects, and the dyssynchrony of the left ventricle wall motion, and adverse cardiac events in cardiac sarcoidosis (CS) patients. METHODS: Fifty-seven consecutive patients with diagnosed CS (64 [IQR 55-71] years old, 14 males), who underwent 18F-FDG PET/CT and ECG-gated SPECT, were studied. FDG PET was analysed to measure cardiac metabolic volume (CMV), and total lesion glycolysis (TLG). The SPECT findings, such as LVEF, Summed Rest Score (SRS), bandwidth (BW) were evaluated. RESULTS: The median of BW was 56° (IQR 40-95). BW showed a strong inverse correlation with LVEF (r = - 0.60, P < 0.0001), and positive correlation with SRS (r = 0.82, P < 0.0001). However, there were no significant correlations between BW and CMV or TLG. The Kaplan-Meier curves revealed a significantly higher rate of MACE in the high BW group (BW > 56°) than the low BW group (BW ≤ 56°) (15.1%/years vs. 4.4%/years, P = 0.025). In multivariable analysis, BW was a significant independent predictor of MACE (P = 0.015). CONCLUSION: Phase analysis on gated SPECT was a significant and independent predictor of MACE in patients with CS.

Comparison of the dyssynchrony parameters recorded with gated SPECT in ischemic cardiomyopathy according to their repeatability at rest and to their ability to detect a synchrony reserve under dobutamine infusion.

BACKGROUND: This study aimed to determine whether the repeatability of dyssynchrony assessment using gated myocardial perfusion SPECT (GSPECT) allows the detection of synchrony reserve during low-dose dobutamine infusion. METHODS AND RESULTS: Sixty-one patients with ischemic cardiomyopathy and LV ejection fraction < 50% were prospectively included in 10 centers. Each patient underwent two consecutive rest GSPECT with 99mTc-labeled tracer (either tetrofosmin or sestamibi) to assess the repeatability of LV function and dyssynchrony parameters, followed by a GSECT acquisition during low-dose dobutamine infusion. LV dyssynchrony was assessed using QGS software through histogram bandwidth (BW), standard deviation of the phase (SD), and entropy. Repeatability was assessed with Lin's concordance correlation coefficient (CCC). Entropy showed a higher CCC (0.80) compared to BW (0.68) and SD (0.75). On average, dobutamine infusion yielded to improve both BW (P = .049) and entropy (P = .04) although significant improvements, setting outside the 95% confidence interval of the repeatability analysis, were documented in only 6 and 4 patients for BW and entropy, respectively. CONCLUSIONS: A synchrony reserve may be documented in patients with ischemic cardiomyopathy through the recording of BW and entropy with low-dose dobutamine GSPECT, with the additional advantage of a higher repeatability for entropy.

Prognostic Value of Left Ventricular Dyssynchrony Assessed with Nuclear Cardiology in Patients with Known or Suspected Stable Coronary Artery Disease with Preserved Left Ventricular Ejection Fraction.

Left ventricular (LV) mechanical dyssynchrony assessed with phase analysis of electrocardiogram (ECG) -gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) is useful for predicting major cardiac events (MCEs) in patients with cardiac dysfunction. However, there is no report on its usefulness in Japanese patients with known or suspected stable coronary artery disease (CAD) with preserved LV ejection fraction (LVEF).We retrospectively investigated 3,374 consecutive patients with known or suspected CAD who underwent rest 201Tl and stress 99mTc-tetrofosmin ECG-gated SPECT MPI and had preserved LVEF (≥ 45%), and followed them up to confirm their prognosis for three years. The composite endpoint was the onset of MCEs consisting of cardiac death, non-fatal myocardial infarction (MI), unstable angina pectoris, and severe heart failure requiring hospitalization. LV mechanical dyssynchrony was evaluated with phase analysis with the Heart Risk View-F software to obtain the phase bandwidth and standard deviation.During the follow-up, 179 patients experienced MCEs: cardiac death (n = 42); non-fatal MI (n = 34); unstable angina pectoris (n = 54); and severe heart failure (n = 49). Results of the multivariate analysis showed age, a history of MI, diabetes mellitus, summed stress score, and stress phase bandwidth to be independent predictors for MCEs. In Kaplan-Meier analysis, prognoses were significantly stratified with the tertiles of stress phase bandwidth.LV mechanical dyssynchrony assessed with ECG-gated SPECT MPI is useful for predicting a prognosis and stratifying the risk of MCEs in Japanese patients with known or suspected stable CAD with preserved LVEF.

Prediction of functional recovery after primary PCI using the estimate of myocardial salvage in gated SPECT early after acute myocardial infarction.

PURPOSE: Primary percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) aims to achieve myocardial salvage (MS). Because the reference method for measuring MS requires myocardial perfusion imaging (MPI) after tracer injection before PCI, alternative approaches have been proposed, but none has gained wide acceptance. Gated SPECT MPI can assess infarct size (IS), but can also show myocardial stunning. Thus, we compared functional and perfusion abnormalities early after AMI to estimate MS, and to predict left ventricular ejection fraction (LVEF) recovery at follow-up. METHODS: We studied 120 patients with AMI. Gated SPECT MPI was performed early (before hospital discharge) and at 6 months after AMI to measure IS, MS and functional outcome. MS was defined as the difference between the number of segments with abnormal thickening (i.e. the stunned area or area at risk) and the number of segments with abnormal perfusion (i.e. the final IS), expressed as a percentage of the total number of segments in the AHA model. LVEF was calculated using quantitative gated SPECT. RESULTS: The area at risk was 40 ± 25%, IS was 17.3 ± 16% and MS was 22 ± 19%. Early LVEF was 46.6 ± 11.6% and late LVEF was 51.4 ± 11.6%, with 54 patients showing at least an increase in LVEF of more than 5 units. ROC analysis showed that MS was able to predict LVEF recovery with an area under the curve (AUC) of 0.79 (p < 0.0001), and using a cut off >23% detected LVEF recovery with 74% sensitivity and 71% specificity. Conversely, IS was associated with an AUC 0.53 (not significant). CONCLUSION: MS assessed by a single early gated SPECT MPI study can accurately predict LVEF evolution after primary PCI for AMI.

Association between an Early Revascularization Strategy and Major Cardiac Events Based on Left Ventricular Dyssynchrony in Patients at Intermediate Risk of Major Cardiac Events Using the J-ACCESS Risk Model.

Objective This retrospective study aimed to investigate the association between therapeutic strategies and the development of major cardiac events (MCEs) in intermediate-risk patients by using the the Japanese Assessment of Cardiac Events and Survival Study by Quantitative Gated SPECT (JACCESS) risk model in combination with the stress phase bandwidth (SPBW), an index of left ventricular dyssynchrony. Methods Patients were followed-up for three years to confirm their prognosis. Based on the estimated propensity scores, the patients who underwent revascularization within the first 60 days after SPECT and those who did not were matched 1:1 (n=367 per group). The composite endpoint was the occurrence of MCEs, consisting of cardiac death, non-fatal myocardial infarction, and severe heart failure. SPBW was calculated by a phase analysis using the Heart Risk View-F software program, and the MCE rate was compared between the two groups by applying the normal value of SPBW (38°). Patients The study included 2,053 patients with either known or suspected coronary artery disease who underwent electrocardiogram-gated single-photon emission computed tomography myocardial perfusion imaging and were at intermediate risk of MCE according to the J-ACCESS risk model. Results During follow-up, 54 of the 734 patients (7.4%) experienced MCEs. The overall incidence of MCE in intermediate-risk patients was not significantly different between the two groups. However, the incidence of MCE in patients with an abnormal SPBW was significantly lower in those who underwent early revascularization (4.8% vs. 11.9%, p=0.0407). Conclusion The combination of the J-ACCESS risk model and the SPBW is thus considered to be an optimal treatment strategy for patients at intermediate risk of MCE, and early revascularization may lead to an improved prognosis in intermediate-risk patients with an abnormal SPBW.

Prediction of Cardiac Resynchronization Therapy Response Using Quantitative Gated Myocardial Perfusion Imaging.

Conventional selection criteria are not consistently able to discriminate between responders and non-responders to cardiac resynchronization therapy (CRT). The objective of this study was to evaluate the usefulness of quantitative gated single-photon emission computed tomography (SPECT) in predicting the response to CRT. This prospective cross-sectional study included 25 patients with advanced congestive heart failure who underwent quantitative gated SPECT before and after CRT implantation. Patients with the left ventricular (LV) lead positioned at the latest activation segment away from the scar had a significantly higher chance of responding than those with the lead positioned at a different area. Responders were likely to have a phase standard deviation (PSD) value of >33°, with 86.6% sensitivity and 90% specificity, and a phase histogram bandwidth (PHB) value of >153°, with 100% sensitivity and 80% specificity. Quantitative gated SPECT can help refine patient selection for CRT implantation, using PSD and PHB cutoff points, in addition to guiding the positioning of the LV lead.

The feasibility of 18F-FDG gated positron emission tomography (PET) for left ventricular dyssynchrony assessment in comparison with 99mTc-MIBI gated single-photon emission computed tomography (SPECT) among patients with prior myocardial infarction.

Background: Phase analysis by 99mTc-MIBI gated single-photon emission computed tomography (GSPECT) has been considered to be an adequate method in the validation of left ventricular (LV) dyssynchrony. Compared with GSPECT, prior myocardial infarction patients with myocardial perfusion defects but myocardial viability usually show preserved uptake of 18F-FDG, and extensive myocardium is detected by 18F-FDG gated positron emission tomography (GPET). Thus, theoretically, it should be more accurate. The aim of this study was to investigate the feasibility of GPET for LV dyssynchrony assessment in comparison with GSPECT among infarction patients. Methods: A total of 146 patients with infarction underwent 2 consecutive days of GSPECT and GPET examinations. Quantitative gated SPECT-derived LV phase analysis was applied to GPET and GSPECT data to assess the presence of LV dyssynchrony via histogram bandwidth (BW) and phase standard deviation (SD). The correlation and agreement of BW and SD between GSPECT and GPET were examined. Factors (i.e., total perfusion defect, scar and mismatch) related to the discrepancies of LV dyssynchrony (i.e., BW and SD) in GPET and GSPECT were assessed by univariate and multivariate regression analysis. Results: A moderate correlation between GPET and GSPECT was found in the measurements of BW (r=0.554) and SD (r=0.537). Bland-Altman analysis revealed that GPET overestimated both BW and SD (20.5° and 9.5°, respectively). In addition, the BW and SD measured by GPET were still overestimated after subgroup analysis. Between GPET and GSPECT, multivariate regression analysis revealed that total perfusion defects were related to the difference in BW measurement (P<0.001), and mismatch was associated with the difference in SD measurement (P<0.01). Conclusions: In patients with infarction, GPET moderately correlated with GSPECT in assessing LV dyssynchrony. GPET overestimated both BW and SD, so these analyses should not be interchangeable in individual patients.

Prognostic Significance of Left Ventricular Dyssynchrony Assessed with Nuclear Cardiology for the Prediction of Major Cardiac Events after Revascularization.

Objective This retrospective study was aimed at determining whether or not stress phase bandwidth (SPBW), a left ventricular (LV) mechanical dyssynchrony index, predicts major cardiac events (MCEs) and stratifies the risk of those in patients with coronary artery disease (CAD) who undergo revascularization. Methods Patients were followed up to confirm the prognosis for at least one year. The SPBW was calculated by a phase analysis using the Heart Risk View-F software program. The composite endpoint was the onset of MCEs, consisting of cardiac death, non-fatal myocardial infarction, unstable angina pectoris, and severe heart failure requiring hospitalization. Patients The study subjects were 332 patients with CAD who underwent coronary angiography and revascularization after confirming ≥5% ischemia detected by rest 201Tl and stress 99mTc-tetrofosmin electrocardiogram-gated single-photon emission computed tomography myocardial perfusion imaging. Results During the follow-up, 35 patients experienced MCEs of cardiac death (n=5), non-fatal myocardial infarction (n=3), unstable angina pectoris (n=11), and severe heart failure requiring hospitalization (n=16). A receiver operating characteristics analysis indicated that the optimal cut-off value of the SPBW was 52° for predicting MCEs, and the MCE rate was significantly higher in the patients with an SPBW >52° than in those with an SPBW ≤52°. Results of the multivariate analysis showed the SPBW and estimated glomerular filtration rate to be independent predictors for MCEs. In addition, the cut-off value of the SPBW significantly stratified the risk of MCEs according to the results of the Kaplan-Meier analysis. Conclusion Evaluating the SPBW before revascularization may help predict future MCEs in patients with CAD who intended to undergo treatment.

Frequent cyclic variation of heart rate is associated with left ventricular diastolic dysfunction in patients without ischemia.

BACKGROUND: Cyclic variation of heart rate (CVHR) associated with sleep-disordered breathing reflects cardiac autonomic responses to apneic/hypoxic stress. However, the association of CVHR with cardiac function is unclear. METHODS: We investigated a total of 181 patients who underwent both 24-hour Holter electrocardiography (ECG) and quantitative gated single-photon emission computed tomography (SPECT) myocardial functional imaging, excluding patients with atrial fibrillation, myocardial infarction, structural heart disease, and implantable devices, from January 2017 to July 2018. The number of CVHR per hour (CVHR index) in sleeping-time Holter ECG was compared with the parameters of left ventricular (LV) systolic and diastolic functions assessed by cardiac SPECT functional imaging, peak filling rate (PFR), first-third mean filling rate (1/3 MFR), and time to peak filling rate (TTPF). RESULTS: In all patients, the CVHR index was not associated with any parameters of cardiac functions. However, in a propensity score-matched subgroup of patients without ischemia (N = 39), the CVHR index was negatively correlated with PFR (r = -0.35, P < .05) and 1/3 MFR (r = -0.37, P < .05) but positively correlated with TTPF (r = 0.43, P < .01) and was not correlated with LV ejection fraction. Multivariate linear regression analysis revealed that high CVHR index was independently associated with LV diastolic dysfunction, even after adjusting for the relative wall thickness and LV mass index assessed by echocardiography. CONCLUSION: These results indicate that the high frequency of CVHR in sleeping time is associated with LV diastolic dysfunction in nonischemic patients, irrespective of LV geometry.

Technical Aspects and Errors of Triggering and Synchronization in Gated Single Photon Emission Computed Tomography Myocardial Perfusion Imaging.

Gated imaging, as a technically demanding procedure, requires special attention and effort to fulfill the technical adequacy and accuracy of the study, based on the available standard guidelines. One of the essential requirements to be met by both technologists and physicians, in nuclear cardiology, is triggering and synchronization as a fundamental subject of gating. There are many sources of gating errors that produce imaging artifacts and, in some occasions, render the images uninterpretable or the quantitative analyses less accurate. Sufficient knowledge of recognition of these artifacts and understanding of their related mechanisms (from physical and technical perspectives) enable the technologists and physicians to promote their performance in daily practice. In this article, intended as a readily practical technical review for nuclear medicine practitioners, it is aimed to present the technical and computer aspects of triggering and synchronization as well as the related errors during imaging.

The difference of risk factors predicting cardiac events in patients with chronic kidney disease between with and without diabetes.

OBJECTIVE: Chronic kidney disease (CKD) and diabetes are both associated with cardiovascular disease, but the effects of diabetes in patients with CKD remain unknown. This study aimed to compare the risk factors of cardiac events between patients with CKD accompanied and not by diabetes using myocardial perfusion imaging. METHODS: We initially classified 529 patients with CKD from the Japanese Assessment of Cardiac Events and Survival Study-3 (J-ACCESS-3) study who had been assessed by gated single-photon emission-computed tomography based on whether they had diabetes (n = 220) or not (n = 309) and then separated them into four subgroups based on the ejection fraction (EF) calculated by quantitative gated SPECT. After 3-year follow-up, the incidence of major cardiac events (cardiac death, sudden death, non-fatal myocardial infarction, and heart failure requiring hospitalization), risk factors among each group, and the ability of myocardial perfusion image to predict prognosis were evaluated. RESULTS: Major cardiac events occurred in 12.7% and 10.3% of patients with and without diabetes (not significant), and heart failure requiring hospitalization was the most frequent (75% and 78%, respectively) in both groups. Event-free survival rates were lower in the subgroups with low EF and high summed stress scores (SSS). Independent risk factors comprised currently smoking and a higher SSS, among patients with diabetes, while higher left ventricular end diastolic volumes and serum C-reactive protein values among those without diabetes. CONCLUSIONS: In patients with CKD, while the risk factors of major cardiac events differ between in patients with and without diabetes, quantitation with gated MPI could be used effectively in both groups.

Evaluation of left ventricular mechanical dyssynchrony with phase analysis in end-stage renal disease patients with normal gated SPECT-MPI.

Phase analysis using gated single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI) is a relatively new tool for the assessment of ventricular synchrony. Hypertension, diabetes, renal diseases, and dyslipidemia may affect the phase parameters though their impact is not well understood. The present study aimed to evaluate the incidence of the left ventricular mechanical dyssynchrony (LVMD) in end-stage renal disease (ESRD) patients with normal gated SPECT-MPI and QRS duration (<120 ms) on electrocardiogram. Data of 129 patients (86 males) referred for gated SPECT-MPI for their pretransplant evaluation with normal gated stress SPECT-MPI (SSS <3 and ejection fraction ≥50%) were included in the study analysis. Documented clinical history along with confounding factors such as hypertension, dyslipidemia, smoking, and alcoholism were evaluated. Left ventricle functional (end-diastolic, end-systolic, and LV myocardial volume) and phase parameters (phase standard deviation [PSD], phase bandwidth [PBW] and entropy) were calculated using the QPS-QGS program. LVMD was noted in 36 (28%) of ESRD patients with normal QRS duration and gated SPECT-MPI. The mean attenuated corrected LV myocardial volume, ejection fraction, mean PSD, and PBW values were 84.3 ± 38.1 ml, 65.3 ± 13.5%, 9.8° ± 3.9°, and 61.4° ± 24.7°, respectively. The LV myocardial volume shows statistically significant correlation with the phase parameters (r = 0.31-0.47; P < 0.001). LVMD is present in a significant number of ESRD patients, and its extent is more with increase in LV myocardial volume. It may have an additional role in risk-stratification for cardiovascular disease in ESRD patients.

Myocardial perfusion scintigraphy - interpretation of gated imaging. Part 2.

The first part of the review describes the basic aspects of interpreting myocardial perfusion defects in single photon emission computed tomography (SPECT) scintigraphy. It also presents indications for invasive diagnostics based on stress perfusion defects. This article provides basic information concerning the interpretation of gated SPECT imaging, including such parameters as left ventricular wall motion and thickening as well as left ventricular wall systolic and diastolic function. Gated examination combined with the assessment of myocardial perfusion reduces the rate of false positives results of myocardial perfusion scintigraphy in perfusion tests, additionally providing data on left ventricular systolic and diastolic function.

Comparison of Left Ventricular Phase Parameters Analysis between Two Software Programs in Patients with Normal Gated Single-photon Emission Computed Tomography-Myocardial Perfusion Imaging.

BACKGROUND: Phase analysis can be easily performed by different software to assess the left ventricular dyssynchrony from gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) with high precision. However, the normal values of histogram bandwidth (HBW) and phase standard deviation (PSD) and their comparison using different programs have not been fully elucidated and actively being evaluated at present. The aim of this study was to determine the phase analysis parameters values and to compare the phase indices of two commonly used programs in a group of patients with normal gated SPECT-MPI. METHODS: Phase parameters were retrospectively evaluated in 138 consecutive nondiabetic patients having a normal gated SPECT-MPI using the quantitative gated SPECT (QGS) and Emory Cardiac Toolbox (ECTb) software. HBW, PSD, and phase entropy were calculated separately using both programs. RESULTS: The fair correlation between software programs was observed. HBW and PSD in QGS and ECTb were 26.20 ± 9.7 and 25.46 ± 8.0 (r-value. 56, SEE 6.65) and 6.64 ± 2.5 and 7.65 ± 2.5 (r = 0.54, SEE 2.14), respectively. The value of phase entropy in QGS program was 45.08 ± 6.3. A fair correlation between phase entropy and PSD in QGS was observed (r = 0.44, 95% confidence interval-0.29-0.56). CONCLUSION: Phase analysis parameters derived from gated SPECT-MPI in patients with normal myocardial perfusion are program dependent and may differ. The results cannot be interchangeably used in the same patients.

Research of predictive factors for cardiac resynchronization therapy: a prospective study comparing data from phase-analysis of gated myocardial perfusion single-photon computed tomography and echocardiography : Trying to anticipate response to CRT.

BACKGROUND: Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in chronic systolic heart failure. About 20% of implanted patients are considered as "non-responders". This study aimed to evaluate gated myocardial perfusion single-photon emission computed tomography (GMPS) phase parameters as compared to echocardiography in the assessment of predictors for response to CRT before and after CRT activation. METHODS: Forty-two patients were prospectively included during 15 months. A single injection of 99mTc-tetrofosmin was used to acquire GMPS phase pre- and post-CRT activation. Indicators of positive CRT response were improvement of functional status and 15% reduction in left ventricular end-systolic volume at 3 months. RESULTS: Phase parameters at baseline were similar in the two groups with no influence of perfusion data. Phase parameters after CRT activation were significantly improved in the responders' group (Δ Bandwidth -19° ± 24° vs. 13° ± 31°, p = 0.001; Δ SD -20° ± 30° vs. 26° ± 46°, p = 0.001; Δ Entropy -11 ± 12 vs. 2 ± 6%, p = 0.001). Feasibility and reproducibility were higher for GMPS. CONCLUSION: Acute phase modifications after CRT activation may predict response to CRT immediately after implantation, but not at baseline, even when adjusted to perfusion data.

Comparison of left ventricular ejection fraction values obtained using invasive contrast left ventriculography, two-dimensional echocardiography, and gated single-photon emission computed tomography.

OBJECTIVES: Left ventricular ejection fraction can be measured by a variety of invasive and non-invasive cardiac techniques. This study assesses the relation of three diagnostic modalities to each other in the measurement of left ventricular ejection fraction: invasive contrast left ventriculography, two-dimensional echocardiography, and quantitative gated single-photon emission computed tomography. METHODS: Retrospective chart review was conducted on 58 patients hospitalized with chest pain, who underwent left ventricular ejection fraction evaluation using each of the aforementioned modalities within a 3-month period not interrupted by myocardial infarction or revascularization. RESULTS: The mean left ventricular ejection fraction values were as follows: invasive contrast left ventriculography (0.44±0.15), two-dimensional echocardiography (0.46±0.13), and gated single-photon emission computed tomography (0.37±0.10). Correlations coefficients and associated p values were as follows: invasive contrast left ventriculography versus two-dimensional echocardiography (r=0.69, p<0.001), invasive contrast left ventriculography versus gated single-photon emission computed tomography (r=0.80, p<0.0001), and gated single-photon emission computed tomography versus two-dimensional echocardiography (r=0.69, p<0.001). CONCLUSION: Our results indicate that strong positive correlations exist among the three techniques studied.

LV Dyssynchrony Assessed With Phase Analysis on Gated Myocardial Perfusion SPECT Can Predict Response to CRT in Patients With End-Stage Heart Failure.

BACKGROUND: Cardiac resynchronization therapy (CRT) is an established treatment in patients with end-stage heart failure and wide QRS complex. However, about 30% of patients do not benefit from CRT (non-responder). Recent studies with tissue Doppler imaging yielded disappointing results in predicting CRT responders. Phase analysis was developed to allow assessment of LV dyssynchrony by gated single photon emission computed tomography (SPECT) myocardial perfusion imaging (GMPS). OBJECTIVES: The aim of present study was to investigate the role of quantitative GMPS-derived LV dyssynchrony data to predict CRT responder. PATIENTS AND METHODS: Thirty eligible patients for CRT implantation underwent GMPS and echocardiography. Response to CRT was evaluated six months after the device implantation. Clinical response to CRT was defined as 50 meters increase in 6-minute walking test (6-MWT) distance. Echocardiographic response to CRT was defined as ≥ 15% decrease in left ventricular end-systolic volume (LVESV). The lead position was considered concordant if it was positioned at the area of latest mechanical activation, and discordant if located outside the area of latest mechanical activation. RESULTS: Clinical response to CRT was observed in 74% of patients. However, only 57% of patients were responder according to the echo criteria. There were statistically significant differences between CRT responders and non-responders for GMPS-derived variables, including phased histogram bandwidth (PHB), phase SD (PSD), and Entropy. Moreover, a cutoff value of 112° for PHB with a sensitivity of 72% and specificity of 70%, a cutoff value of 21° for PSD with a sensitivity of 90% and specificity of 74%, and a cutoff of 52% for Entropy with a sensitivity of 90% and a specificity of 80% were considered to discriminate responders and non-responders. CRT response was more likely in patients with concordant LV lead position compared to those with discordant LV lead position. CONCLUSIONS: GMPS-derived LV dyssynchrony variables can predict response to CRT with good sensitivity and specificity.

Utility of real-time three-dimensional echocardiography for Duchenne muscular dystrophy with echocardiographic limitations.

Duchenne muscular dystrophy (DMD) is strongly associated with a unique form of dilated cardiomyopathy. Cardiac complications are the leading cause of death in DMD; thus, longitudinal assessments and early intervention for cardiac dysfunction are necessary to improve prognosis. Two-dimensional echocardiography, which is routinely used for cardiac assessment, has some limitations for quantitative analyses in DMD patients with thoracic deformities and regional wall motion abnormalities in the left ventricle. Recently, real-time three-dimensional echocardiography has emerged as a feasible tool for cardiac assessment in various cardiac diseases. The aim of this study was to examine the utility of this technology in DMD. We evaluated left ventricular ejection fraction (LVEF), a major parameter of left ventricular function, in 17 male DMD patients. LVEF values measured by real-time three-dimensional echocardiography were compared with those determined by two established nuclear cardiology methods: "the first-pass method of radionuclide angiocardiography" and "quantitative electrocardiogram-gated single-photon emission computed tomography". A good correlation was observed for LVEF values, particularly between real-time three-dimensional echocardiography and "the first-pass method of radionuclide angiocardiography" (r=0.90, p<0.05). Thus, real-time three-dimensional echocardiography can provide an accurate measurement of LVEF in DMD patients with echocardiographic limitations.