Correlates of markers of dyssynchrony in patients with STEMI and multivessel disease: an analysis from the IAEA SPECT STEMI trial.

BACKGROUND: In this substudy of the Value of Gated-SPECT MPI for Ischemia- Guided PCI of non-culprit vessels in STEMI Patients with Multi vessel Disease after primary PCI trial after primary PCI we aim to assess if infarct size affects conventional measures of dyssynchrony at rest. Additionally, we explore if there is an independent correlation of stress-inducible ischemia with dyssynchrony at rest. METHODS: The 48 patients with imaging at randomization were analyzed. Gated-single-photon emission computed tomography (SPECT) MPI with vasodilator stress and technetium-99m-labeled tracers was performed. The phase histogram bandwidth (HBW), phase SD, and entropy were obtained with the QGS software. Correlation between dyssynchrony at rest and infarct size and inducible ischemia was performed using the Spearman test. RESULTS: According to normal database limits dyssynchrony parameters at rest were abnormal for men. In women only HBW was abnormal. Correlation between the summed rest score with dyssynchrony was significant only for entropy ( P  = 0.035). No correlation was observed for dyssynchrony and stress-induced ischemia. CONCLUSION: Entropy, as a measure of dyssynchrony, has potential in the assessment of patients with STEMI and multivessel disease after primary PCI. Smaller residual myocardial scars in PCI-reperfused patients with STEMI may contribute to the lack of correlation between dyssynchrony at rest and infarct size and stress-induced ischemia, respectively.

Cardiovascular testing recovery in Latin America one year into the COVID-19 pandemic: An analysis of data from an international longitudinal survey.

Background: The COVID-19 pandemic disproportionately impacted Latin America (LATAM), significantly disrupting cardiovascular testing. This study evaluated cardiac procedure recovery in LATAM one year after the outbreak. Methods: The International Atomic Energy Agency (IAEA) surveyed 669 centers in 107 countries worldwide, including 135 facilities in 19 LATAM countries, to assess cardiovascular procedure volumes in March 2019, April 2020, and April 2021, and changes in center practices and staffing conditions one year into the COVID-19 pandemic. Findings: LATAM centers reported a 21 % decrease in procedure volumes in April 2021 from pre-pandemic-baseline, vs. a 0 % change in the rest of the world (RoW), and greater volume reductions for almost all procedure types. Centers in Central America and Mexico reported the largest procedure reductions (47 % reduction) compared to the Caribbean (15 %), and South America (14 %, p = 0.01), and this LATAM region was a significant predictor of lower procedure recovery in multivariable regression. More LATAM centers reported reduced salaries and increased layoffs of clinical staff compared to RoW, and LATAM respondents estimated that half of physician and non-physician staff experienced excess psychological stress related to the pandemic, compared to 25 % and 30 % in RoW (p < 0.001). Conclusions: Cardiovascular testing recovery in LATAM trailed behind RoW for most procedure types, with centers in Central America and Mexico reporting the greatest volume reductions. This study found lasting impacts of COVID-19 on cardiovascular care in LATAM and the need for mental health support for LATAM healthcare workers in current and future pandemics.

A new method of modeling the multi-stage decision-making process of CRT using machine learning with uncertainty quantification.

Aims: Current machine learning-based (ML) models usually attempt to utilize all available patient data to predict patient outcomes while ignoring the associated cost and time for data acquisition. The purpose of this study is to create a multi-stage machine learning model to predict cardiac resynchronization therapy (CRT) response for heart failure (HF) patients. This model exploits uncertainty quantification to recommend additional collection of single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI) variables if baseline clinical variables and features from electrocardiogram (ECG) are not sufficient. Methods: 218 patients who underwent rest-gated SPECT MPI were enrolled in this study. CRT response was defined as an increase in left ventricular ejection fraction (LVEF) > 5% at a 6±1 month follow-up. A multi-stage ML model was created by combining two ensemble models: Ensemble 1 was trained with clinical variables and ECG; Ensemble 2 included Ensemble 1 plus SPECT MPI features. Uncertainty quantification from Ensemble 1 allowed for multi-stage decision-making to determine if the acquisition of SPECT data for a patient is necessary. The performance of the multi-stage model was compared with that of Ensemble models 1 and 2. Results: The response rate for CRT was 55.5% (n = 121) with overall male gender 61.0% (n = 133), an average age of 62.0±11.8, and LVEF of 27.7±11.0. The multi-stage model performed similarly to Ensemble 2 (which utilized the additional SPECT data) with AUC of 0.75 vs. 0.77, accuracy of 0.71 vs. 0.69, sensitivity of 0.70 vs. 0.72, and specificity 0.72 vs. 0.65, respectively. However, the multi-stage model only required SPECT MPI data for 52.7% of the patients across all folds. Conclusions: By using rule-based logic stemming from uncertainty quantification, the multi-stage model was able to reduce the need for additional SPECT MPI data acquisition without sacrificing performance.

Critical Appraisal of the Current Role of Myocardial Perfusion Imaging in the Management of Acute Chest Pain.

This paper describes the evolution of nuclear cardiology techniques in the setting of acute coronary syndromes. Since the 1970s, the contribution of nuclear cardiology has been fundamental in delineating the physiopathology and diagnosis of acute myocardial infarction, when electrocardiogram (ECG) did not provide the diagnosis and when cardiac enzyme assessments were at a very early stage. In this clinical situation, at that time the role of pyrophosphate scintigraphy and antimyosin antibodies was important in ensuring diagnostic precision. However, these methods showed limitations and were abandoned in the late 80s and early 90s when therapeutic applications such as thrombolytic therapy, and primary-and rescue-percutaneous coronary intervention (PCI) were introduced. Beginning in the mid-80s, the introduction and widespread use of perfusion tracers such as 99mTc labelled compounds and technological advances such as SPECT, allowed to assess the efficacy of thrombolysis and early revascularization, as well as to assess in depth myocardial salvage. Currently, perfusion SPECT, especially using fast imaging techniques and dedicated cardiac SPECT with solid-state detectors, allows a quick confirmation or exclusion of acute coronary syndromes, particularly in low-to-intermediate likelihood of coronary artery disease (CAD), especially when there are absolute or relative contraindications to the use of coronary computed tomographic angiography (CCTA).

Cancer and Postradiotherapy Cardiotoxicity: How to Face Damage in Women's Hearts?

Cancer and cardiovascular disease are the two main causes of death worldwide in both men and women. In the past decades, survival rate in cancer patients has substantially improved due to new treatments and developments in radiation therapy (RT). In women, breast cancer (BC) is the leading cause of cancer death and thoracic RT is a main component of the treatment in many cases. Nevertheless, despite new techniques that limit the area receiving RT, cardiac damage is still an important concern in BC patients. In this review, the following aspects will be addressed: pathophysiology of postradiotherapy heart damage in women with BC; mechanisms, diagnosis and prevention/management of heart damage; and future areas of potential research for radiotherapy injury in women.

Cardiac Imaging in Women with Ischemic Heart Disease.

Cardiac diseases are the main cause of death for both sexes worldwide. Treatment varies widely according to the sex of a patient, as there are differences in physiopathology, epidemiology, clinical presentation and management. However, women have been largely excluded from research studies in this field. At present, differences are starting to be recognized and more attention is being paid to the identification of female-specific (or emergent) atherosclerotic risk factors. Diagnostic testing also merits attention because cardiac imaging offers important information to help diagnosis and guide cardiac disease management. In this sense, multimodal imaging should be used with the most cost-effective approach, integrating this information into the clinical sphere according to the pretest probability of the disease. In this review, we address sex-specific features of ischemic heart disease that should be considered in the clinical assessment of women, as well as the value of different imaging techniques (including technical and clinical aspects) for management of women with ischemic heart disease, and identify future areas of action concerning ischemic heart disease in women.

A machine learning method integrating ECG and gated SPECT for cardiac resynchronization therapy decision support.

PURPOSE: Cardiac resynchronization therapy (CRT) has been established as an important therapy for heart failure. Mechanical dyssynchrony has the potential to predict responders to CRT. The aim of this study was to report the development and the validation of machine learning models which integrate ECG, gated SPECT MPI (GMPS), and clinical variables to predict patients' response to CRT. METHODS: This analysis included 153 patients who met criteria for CRT from a prospective cohort study. The variables were used to model predictive methods for CRT. Patients were classified as "responders" for an increase of LVEF ≥ 5% at follow-up. In a second analysis, patients were classified as "super-responders" for an increase of LVEF ≥ 15%. For ML, variable selection was applied, and Prediction Analysis of Microarrays (PAM) approach was used to model response while Naïve Bayes (NB) was used to model super-response. These ML models were compared to models obtained with guideline variables. RESULTS: PAM had AUC of 0.80 against 0.72 of partial least squares-discriminant analysis with guideline variables (p = 0.52). The sensitivity (0.86) and specificity (0.75) were better than for guideline alone, sensitivity (0.75) and specificity (0.24). Neural network with guideline variables was better than NB (AUC = 0.93 vs. 0.87) however without statistical significance (p = 0.48). Its sensitivity and specificity (1.0 and 0.75, respectively) were better than guideline alone (0.78 and 0.25, respectively). CONCLUSIONS: Compared to guideline criteria, ML methods trended toward improved CRT response and super-response prediction. GMPS was central in the acquisition of most parameters. Further studies are needed to validate the models.

Ischemia-guided vs routine non-culprit vessel angioplasty for patients with ST segment elevation myocardial infarction and multi-vessel disease: the IAEA SPECT STEMI trial.

BACKGROUND: In patients with multi-vessel disease presenting with ST elevation myocardial infarction (STEMI), the efficacy and safety of ischemia-guided, vs routine non-culprit vessel angioplasty has not been adequately studied. METHODS: We conducted an international, randomized, non-inferiority trial comparing ischemia-guided non-culprit vessel angioplasty to routine non-culprit vessel angioplasty, following primary PCI for STEMI. The primary outcome was the between-group difference in percent ischemic myocardium at follow-up stress MPI. All MPI images were processed and analyzed at a central core lab, blinded to treatment allocation. RESULTS: In all, 109 patients were enrolled from nine countries. In the ischemia-guided arm, 25/48 (47%) patients underwent non-culprit vessel PCI following stress MPI. In the routine non-culprit PCI arm, 43/56 (77%) patients underwent angioplasty (86% within 6 weeks of randomization). The median percentage of ischemic myocardium on follow-up imaging (mean 16.5 months) was low, and identical (2.9%) in both arms (difference 0.13%, 95%CI - 1.3%-1.6%, P < .0001; non-inferiority margin 5%). CONCLUSION: A strategy of ischemia-guided non-culprit PCI resulted in low ischemia burden, and was non-inferior to a strategy of routine non-culprit vessel PCI in reducing ischemia burden. Selective non-culprit PCI following STEMI offers the potential for cost-savings, and may be particularly relevant to low-resource settings. (CTRI/2018/08/015384).

Current status of nuclear cardiology practice in Latin America and the Caribbean, in the era of multimodality cardiac imaging approach: 2022 update.

Cardiovascular diseases (CVDs) are the leading cause of mortality in Latin America and the Caribbean (LAC), with the risk in men being slightly higher than in women. The coronavirus disease 2019 (COVID-19) pandemic caused a significant reduction in the number of cardiac diagnostic procedures globally and in particular in LAC. Nuclear cardiology is available in the region, but there is variability in terms of existing technology, radiopharmaceuticals, and human resources. In the region, there are 2385 single photon emission computed tomography (SPECT) and 315 PET scanners, Argentina and Brazil have the largest number. There is an increasing number of new technologies such as cadmium-zinc-telluride (CZT) cardiac-dedicated gamma cameras, SPECT/computed tomography (CT), and PET/CT. All countries performed myocardial perfusion imaging studies, mainly gated-SPECT; the rest are multi-gated acquisition, mainly for cardiac toxicity; detection of viability; rest gated SPECT in patients with dilated cardiomyopathy, and bone-avid tracer cardiac scintigraphy for transthyretin cardiac amyloidosis diagnosis. Regarding other non-nuclear cardiac imaging modalities, Argentina, Colombia, and Chile have the highest ratio of CT scanners, while Brazil, Argentina, and Chile show the highest ratio of MRI scanners. The development of nuclear cardiology and other advanced imaging modalities is challenged by the high cost of equipment, lack of equipment maintenance and service, insufficient-specific training both for imaging specialists and referring clinicians, and lack of awareness of cardiologists or other referring physicians on the clinical applications of nuclear cardiology. Another important aspect to consider is the necessity of implementing cardiac imaging multimodality training. A joint work of nuclear medicine specialists, radiologists, cardiologists, and clinicians, in general, is mandatory to achieve this goal. National, regional, and international cooperation including support from scientific professional societies such as the American Society of Nuclear Cardiology and Latin American Association of Biology and Nuclear Medicine Societies, cardiological societies, and organizations such as the International Atomic Energy Agency, and Pan American Health Organization, as well as government commitment are key factors in the overall efforts to tackle the burden of cardiovascular diseases in the region.

O Impacto da COVID-19 no Diagnóstico de Doenças Cardíacas na América Latina Uma Subanálise do INCAPS COVID / The Impact of COVID-19 on Diagnosis of Heart Disease in Latin America an INCAPS COVID Sub-analysis

Resumo Fundamento A pandemia de COVID-19 interferiu na prestação de atendimento a doenças cardiovasculares na América Latina. No entanto, o efeito da pandemia nos volumes de procedimentos cardíacos diagnósticos ainda não foi quantificado. Objetivo Avaliar (1) o impacto de COVID-19 nos volumes de diagnóstico cardíaco na América Latina e (2) determinar sua relação com a incidência de casos de COVID-19 e as medidas de distanciamento social. Métodos A International Atomic Energy Agency realizou uma pesquisa mundial avaliando mudanças nos volumes diagnósticos cardíacos decorrentes da COVID-19. Foram obtidos os volumes diagnósticos cardíacos dos locais participantes para março e abril de 2020 e comparados com março de 2019. Foram coletados dados de distanciamento social a partir dos Relatórios de mobilidade da comunidade de Google e a incidência de COVID-19 por país a partir de Our World in Data. Resultados Foram realizadas pesquisas em 194 centros que realizam procedimentos diagnósticos cardíacos, em 19 países da América Latina. Em comparação com o mês de março de 2019, os volumes dos procedimentos diagnósticos cardíacos diminuíram 36% em março de 2020 e 82% em abril de 2020.As maiores reduções ocorreram em relação aos testes de estresse ecocardiográfico (91%), testes ergométricos de esteira (88%) e escore de cálcio por tomografia computadorizada (87%), com pequenas variações entre as sub-regiões da América Latina. As mudanças em padrões de distanciamento social (p < 0,001) estavam mais fortemente associadas com a redução do volume do que a incidência de COVID-19 (p = 0,003). Conclusões A COVID-19 foi associada a uma redução significativa de procedimentos diagnósticos cardíacos na América Latina, a qual foi mais relacionada ao distanciamento social do que ao aumento da incidência da COVID-19. São necessários melhor equilíbrio e timing de medidas de distanciamento social e planejamento para manter o acesso ao atendimento médico durante um surto pandêmico, especialmente em regiões com alta mortalidade cardiovascular.

Abstract Background The COVID-19 pandemic has disrupted the delivery of care for cardiovascular diseases in Latin America. However, the effect of the pandemic on the cardiac diagnostic procedure volumes has not been quantified. Objective To assess (1) the impact of COVID-19 on cardiac diagnostic volumes in Latin America and (2) determine its relationship with COVID-19 case incidence and social distancing measures. Methods The International Atomic Energy Agency conducted a worldwide survey assessing changes in cardiac diagnostic volumes resulting from COVID-19. Cardiac diagnostic volumes were obtained from participating sites for March and April 2020 and compared to March 2019. Social distancing data were collected from Google COVID-19 community mobility reports and COVID-19 incidence per country from the Our World in Data. Results Surveys were conducted in 194 centers performing cardiac diagnostic procedures, in 19 countries in Latin America. Procedure volumes decreased 36% from March 2019 to March 2020, and 82% from March 2019 to April 2020. The greatest decreases occurred in echocardiogram stress tests (91%), exercise treadmill tests (88%), and computed tomography calcium scores (87%), with slight variations between sub-regions of Latin America. Changes in social distancing patterns (p < 0.001) were more strongly associated with volume reduction than COVID-19 incidence (p = 0.003). Conclusions COVID-19 was associated with a significant reduction in cardiac diagnostic procedures in Latin America, which was more related to social distancing than to the COVID-19 incidence. Better balance and timing of social distancing measures and planning to maintain access to medical care is warranted during a pandemic surge, especially in regions with high cardiovascular mortality.

Nuclear Cardiology in Women and Underrepresented Minority Populations.

PURPOSE OF REVIEW: To outline sex-specific features of coronary artery disease (CAD) that should be considered in the assessment of women, including those from ethnic minority populations with suspected stable ischemic heart disease (IHD). Second, to determine the latest nuclear imaging tools available to assess microvascular CAD. RECENT FINDINGS: Latest studies indicate that women are more likely to have ischemia with no obstructive coronary arteries (INOCA) and paradoxically have worse outcomes. Therefore, the evaluation of women with suspected IHD should include assessing microvascular and epicardial coronary circulation. The prevalence of CAD is increasing in younger women due to the increased cardiovascular disease (CVD) risk burden. CAD is often underrecognized in these patients. There is increasing recognition that INOCA is not benign and should be accurately diagnosed and managed. Nuclear imaging assesses the full spectrum of CAD from microvascular CAD to multivessel obstructive epicardial CAD. Further research on myocardial blood flow (MBF) assessment with PET MPI is needed.

The Impact of COVID-19 on Diagnosis of Heart Disease in Latin America an INCAPS COVID Sub-analysis. / O Impacto da COVID-19 no Diagnóstico de Doenças Cardíacas na América Latina Uma Subanálise do INCAPS COVID.

BACKGROUND: The COVID-19 pandemic has disrupted the delivery of care for cardiovascular diseases in Latin America. However, the effect of the pandemic on the cardiac diagnostic procedure volumes has not been quantified. OBJECTIVE: To assess (1) the impact of COVID-19 on cardiac diagnostic volumes in Latin America and (2) determine its relationship with COVID-19 case incidence and social distancing measures. METHODS: The International Atomic Energy Agency conducted a worldwide survey assessing changes in cardiac diagnostic volumes resulting from COVID-19. Cardiac diagnostic volumes were obtained from participating sites for March and April 2020 and compared to March 2019. Social distancing data were collected from Google COVID-19 community mobility reports and COVID-19 incidence per country from the Our World in Data. RESULTS: Surveys were conducted in 194 centers performing cardiac diagnostic procedures, in 19 countries in Latin America. Procedure volumes decreased 36% from March 2019 to March 2020, and 82% from March 2019 to April 2020. The greatest decreases occurred in echocardiogram stress tests (91%), exercise treadmill tests (88%), and computed tomography calcium scores (87%), with slight variations between sub-regions of Latin America. Changes in social distancing patterns (p < 0.001) were more strongly associated with volume reduction than COVID-19 incidence (p = 0.003). CONCLUSIONS: COVID-19 was associated with a significant reduction in cardiac diagnostic procedures in Latin America, which was more related to social distancing than to the COVID-19 incidence. Better balance and timing of social distancing measures and planning to maintain access to medical care is warranted during a pandemic surge, especially in regions with high cardiovascular mortality.

FUNDAMENTO: A pandemia de COVID-19 interferiu na prestação de atendimento a doenças cardiovasculares na América Latina. No entanto, o efeito da pandemia nos volumes de procedimentos cardíacos diagnósticos ainda não foi quantificado. OBJETIVO: Avaliar (1) o impacto de COVID-19 nos volumes de diagnóstico cardíaco na América Latina e (2) determinar sua relação com a incidência de casos de COVID-19 e as medidas de distanciamento social. MÉTODOS: A International Atomic Energy Agency realizou uma pesquisa mundial avaliando mudanças nos volumes diagnósticos cardíacos decorrentes da COVID-19. Foram obtidos os volumes diagnósticos cardíacos dos locais participantes para março e abril de 2020 e comparados com março de 2019. Foram coletados dados de distanciamento social a partir dos Relatórios de mobilidade da comunidade de Google e a incidência de COVID-19 por país a partir de Our World in Data. RESULTADOS: Foram realizadas pesquisas em 194 centros que realizam procedimentos diagnósticos cardíacos, em 19 países da América Latina. Em comparação com o mês de março de 2019, os volumes dos procedimentos diagnósticos cardíacos diminuíram 36% em março de 2020 e 82% em abril de 2020.As maiores reduções ocorreram em relação aos testes de estresse ecocardiográfico (91%), testes ergométricos de esteira (88%) e escore de cálcio por tomografia computadorizada (87%), com pequenas variações entre as sub-regiões da América Latina. As mudanças em padrões de distanciamento social (p < 0,001) estavam mais fortemente associadas com a redução do volume do que a incidência de COVID-19 (p = 0,003). CONCLUSÕES: A COVID-19 foi associada a uma redução significativa de procedimentos diagnósticos cardíacos na América Latina, a qual foi mais relacionada ao distanciamento social do que ao aumento da incidência da COVID-19. São necessários melhor equilíbrio e timing de medidas de distanciamento social e planejamento para manter o acesso ao atendimento médico durante um surto pandêmico, especialmente em regiões com alta mortalidade cardiovascular.

Reproducibility of global LV function and dyssynchrony parameters derived from phase analysis of gated myocardial perfusion SPECT: A multicenter comparison with core laboratory setting.

BACKGROUND: Gated myocardial perfusion scintigraphy (GMPS) phase analysis is an important tool to investigate the physiology of left ventricular (LV) dyssynchrony. We aimed to test the performance of GMPS LV function and phase analysis in different clinical settings and on a diverse population. METHODS: This is a post hoc analysis of a prospective, non-randomized, multinational, multicenter cohort study. Clinical evaluation and GMPS prior to cardiac resynchronization therapy (CRT)(baseline) and 6-month post CRT (follow-up) were done. LV end-systolic volume (LVESV), LV end-diastolic volume (LVEDV), LV ejection fraction (LVEF), LV phase standard deviation (LVPSD), and percentage of left ventricle non-viable (PLVNV) were obtained by 10 centers and compared to the core lab. RESULTS: 276 GMPS studies had all data available from individual sites and from core lab. There were no statistically significant differences between all variables except for LVPSD. When subjects with no mechanical dyssynchrony were excluded, LVPSD difference became non-significant. LVESV, LVEF, LVPSD and PLVNV had strong correlation in site against core lab comparison. Bland-Altman plots demonstrated good agreement. CONCLUSIONS: The presented correlation and agreement of LV function and dyssynchrony analysis over different sites with a diverse sample corroborate the strength of GMPS in the management of heart failure in clinical practice.

Clinical and gated SPECT MPI parameters associated with super-response to cardiac resynchronization therapy.

PURPOSE: We sought to evaluate the behavior of cardiac mechanical synchrony as measured by phase SD (PSD) derived from gated MPI SPECT (gSPECT) in patients with super-response after CRT and to evaluate the clinical and imaging characteristics associated with super-response. METHODS: 158 subjects were evaluated with gSPECT before and 6 months after CRT. Patients with an improvement of LVEF > 15% and NYHA class I/II or reduction in LV end-systolic volume > 30% and NYHA class I/II were labeled as super-responders (SR). RESULTS: 34 patients were classified as super-responders (22%) and had lower PSD (32° ± 17°) at 6 months after CRT compared to responders (45° ± 24°) and non-responders 46° ± 28° (P = .02 for both comparisons). Regression analysis identified predictors independently associated with super-response to CRT: absence of previous history of CAD (odds ratio 18.7; P = .002), absence of diabetes mellitus (odds ratio 13; P = .03), and history of hypertension (odds ratio .2; P = .01). CONCLUSION: LV dyssynchrony after CRT implantation, but not at baseline, was significantly better among super-responders compared to non-super-responders. The absence of diabetes, absence of CAD, and history of hypertension were independently associated with super-response after CRT.

Choosing between anatomy and function is not always evident for the heart of end-stage renal disease patients. How low can we go?

Patients with chronic kidney disease (CKD) are at a very high risk of adverse cardiovascular events. In CKD patients, vascular calcification is more prevalent, appears at an earlier age, and is more severe than in the general population. CKD physiology rather than the effects of dialysis is the primary driver of microvascular disease in these patients. Considering the significant morbidity and mortality attributable to cardiovascular disease in the CKD population, risk stratification remains an important challenge. Topics such as function vs anatomy to properly risk stratify these patients, as well as future perspectives on non-invasive techniques, will be addressed.

Value of intraventricular dyssynchrony assessment by gated-SPECT myocardial perfusion imaging in the management of heart failure patients undergoing cardiac resynchronization therapy (VISION-CRT).

BACKGROUND: Placing 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. METHODS: Ten 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). RESULTS: Sixteen 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). CONCLUSION: LV dyssynchrony improvement by gSPECT MPI, but not on-target lead placement, predicts clinical outcomes in patients undergoing CRT.

Diastolic dyssynchrony assessment by gated myocardial perfusion-SPECT in subjects who underwent cardiac resynchronization therapy.

BACKGROUND: Left ventricular diastolic dyssynchrony (LVDD) can be assessed by gated myocardial perfusion single-photon emission computed tomography (GMP-SPECT). LVDD is an area of interest in subjects who underwent cardiac resynchronization therapy (CRT). The aim of this post hoc analysis was to assess the role of LVDD in subjects with CRT who were followed up at 6-month period. MATERIAL & METHODS: Left ventricular diastolic dyssynchrony was assessed by GMP-SPECT at baseline and after CRT procedure in 160 subjects from 10 different cardiological centers. CRT procedure was performed as per current guidelines. Outcomes were defined as improvement in ≥1 New York Heart Association (NYHA) class, left ventricular ejection fraction (LVEF) by 5%, and reduction in end-systolic volume (ESV) by 15% and 5% points in Minnesota Living with Heart Failure Questionnaire. LVDD was defined as diastolic phase standard deviation ≥40 ± 14°. RESULTS: Improvement in NYHA functional class occurred in 105 (65.6%), LVEF in 74 (46.3%), decrease in ESV in 86 (53.8%), and Minnesota score in 85 (53.1%) cases. Baseline LV diastolic standard deviation was 53.53° ± 20.85 and at follow-up 40.44° ± 26.1283; (P < 0.001). LVDD was not associated with improvement in clinical outcomes at follow-up. CONCLUSION: CRT improves both systolic and diastolic dyssynchrony values at 6-month follow-up. LVDD at baseline is correlated with cardiac functionality at follow-up, but not with overall favorable clinical outcomes.