Cardiac positron emission tomography (PET) is increasingly utilized in clinical practice. This review examines the latest clinical practice guidelines from the American College of Cardiology/American Heart Association (ACC/AHA), the European Society of Cardiology (ESC), the International Society for Heart and Lung Transplantation (ISHLT), and multi-societal consensus statements as of December 2024 to assess the extent to which cardiac PET is incorporated into their recommendations.

The significance of evaluating myocardial viability in making decisions regarding coronary artery bypass grafting (CABG) for patients with ischemic left ventricular dysfunction (ILVD) remains controversial. This study aimed to examine the impact of integrated assessment of hibernating myocardium and scars on the survival benefit associated with CABG in patients with ILVD.

Consecutive patients with ILVD who underwent fluorine-18 fluorodeoxyglucose positron emission tomography and cardiac magnetic resonance imaging with late gadolinium enhancement viability testing from January 2015 and April 2018 were retrospectively enrolled. The primary end point was all-cause death. The secondary end point was a composite of cardiovascular death, cardiovascular hospitalization, heart transplantation, revascularization, insertion of an implantable cardioverter-defibrillator, or nonfatal stroke. Cox models calculated hazard ratios (HRs) and CIs for CABG vs medical therapy alone for subgroups with different levels of hibernation and scars.

During a median follow-up of 71.5 months in 507 patients, 98 patients reached the primary end point and 194 reached the secondary end point. After adjustment, CABG was associated with lower risks of all-cause mortality (HR, 0.249; 95% CI, 0.154-0.428; P<.001) and lower incidences of secondary outcomes (HR, 0.457; 95% CI, 0.318-0.658; P<.001) compared with medical treatment alone in the population. Across all 4 subgroups classified by the optimal cutoff value (10% hibernation and 26% scar), CABG was associated with favorable outcomes regardless of the hibernation and scar level.

The extent and severity of hibernating myocardium and scars appear not to influence the effects of CABG in patients with ILVD.

Ischemic cardiomyopathy remains a leading cause of heart failure, yet the optimal revascularization approach for patients with reduced left ventricular function remains uncertain. This review synthesizes current evidence on coronary revascularization strategies, emphasizing real-world applicability and individualized treatment. It critically evaluates the benefits and limitations of coronary artery bypass grafting [CABG] and percutaneous coronary intervention [PCI], highlighting key knowledge gaps. Findings from the STICH trial demonstrate that CABG improves long-term survival despite an elevated early procedural risk, particularly in patients with extensive multivessel disease. In contrast, the REVIVED-BCIS2 trial suggests that PCI enhances quality of life but does not significantly reduce mortality compared to optimal medical therapy, making it a viable alternative for high-risk patients ineligible for surgery. This review underscores the role of advanced imaging techniques in myocardial viability assessment and emphasizes the importance of comprehensive risk stratification in guiding revascularization decisions. Special attention is given to managing high-risk patients unsuitable for CABG and the potential benefits of PCI in symptom relief despite uncertain survival benefits. A stepwise algorithm is proposed to assist clinicians in tailoring revascularization strategies, reinforcing the need for a multidisciplinary Heart Team approach to optimize outcomes.

Management of ischemic cardiomyopathy is challenging, especially when treatment benefits do not clearly exceed the estimated risk of procedures. Myocardial viability assessment provides additional data in this setting to anticipate potential functional recovery and possibly prognostic improvement following revascularization. This evidence comes from the positive signals received from posthoc analyses of some clinical trials. There are multiple clinically available modalities to evaluate myocardial viability among which more sensitive ones such as cardiac magnetic resonance and PET are more preferrable. Yet, there are emerging tools that may further escalate the utility of these modalities.

Coronary artery bypass grafting is the major modality of coronary revascularization in patients with ischemic cardiomyopathy as it provides surgical collateralization of the coronary bed protecting the functional myocardium. Myocardial viability testing does not have an established role in the surgical evaluation. Concomitant surgical ventricular restoration does not improve symptoms or survival, though patients with large aneurysms and significant reduction in ventricular size could benefit. Correction of functional mitral regurgitation does not improve survival, and severe functional mitral regurgitation should be addressed via mitral valve replacement. Temporary mechanical circulatory support can be used as a bridge to recovery.

The role of revascularization and percutaneous coronary intervention (PCI) in patients with acute coronary syndrome is well established. However, the incremental value of revascularization over guideline-directed medical therapy is controversial. Currently available data supports the use of PCI to improve angina and quality of life for chronic coronary disease and heart failure (HF). However, there is insufficient data to support revascularization with PCI to improve mortality, reduce cardiovascular events, or improve ejection fraction over medical therapy alone. Additional trials are necessary to identify HF patients who may benefit from revascularization, and the optimal revascularization strategy for this population.

Acute MI (AMI) is a leading cause of mortality globally. Swift diagnosis is imperative, with timely reperfusion crucial to minimise adverse outcomes. Revascularisation strategies include culprit-vessel-only therapy, staged complete revascularisation or immediate complete revascularisation. Evidence from randomised trials strongly favours complete revascularisation in ST-elevation MI (STEMI). Data regarding immediate complete revascularisation compared to a staged approach are limited, with uncertainties regarding the advantages of physiology-guided treatment compared to angiographic assessment alone. Non-STEMI (NSTEMI) patients with multivessel disease are often complex and current guidelines offer limited recommendations for this patient group, emphasising the need for individualised treatment. Observational studies have sought to find the optimal approach, yet conflicting data prevails. Dedicated trials for this issue in NSTEMI patients are currently unavailable. To enhance the decision-making processes for patients with AMI, future trials should consider the inclusion of functional health status and health-related quality of life outcomes. The existing gaps in knowledge underscore the intricacies of managing AMI and the ongoing necessity for comprehensive research to refine treatment strategies.

Myocardial viability assessment is used to determine if chronically dysfunctional myocardium may benefit from coronary revascularization. Cardiac magnetic resonance with late gadolinium enhancement is the current gold standard for visualizing myocardial scar and provides valuable insight into myocardial viability. Viability assessments can also be made with Cardiac Positron Emission Tomography, Echocardiography, Single Photon Emission Tomography, and Cardiac Computed Tomography with each having advantages and disadvantages. Despite the classical interpretation that viability predicts segmental functional improvement, more recent studies have found that revascularization of viable myocardium has conflicting roles in predicting benefits for patients, especially as it relates to major adverse cardiovascular events, development of heart failure symptoms, and all-cause mortality. This review covers these conflicts along with an in-depth review of the pathophysiologic processes that are fundamental to myocardial viability and the various methods used for determining viability.

Ischemic cardiomyopathy (ICM) is characterized by myocardial dysfunction due to myocardial ischemia, associated with the presence of significant coronary artery disease (CAD). We provide a comprehensive review of the current evidence for coronary revascularization in ICM, including consideration of the different modalities of coronary artery bypass grafting and percutaneous coronary intervention. In addition to a contemporary assessment of the literature, we aim to provide real-world insights and perspectives to guide clinical decision-making in this heterogeneous and complex patient population.

In this review, the authors examine recent advancements in noninvasive cardiac imaging, focusing on cardiac CT, MRI, and PET, reviewing key publications from imaging and multidisciplinary journals from 2023. The authors discuss the increasing adoption of photon-counting CT and its applications in coronary and structural imaging, and explore various aspects of plaque and functional assessment, emphasizing their clinical implications. Radiation exposure analysis from the SCOT-HEART (Scottish Computed Tomography of the Heart) trial is also discussed. The authors highlight the integration of artificial intelligence applications in cardiac imaging. Three-year follow-up data from the ADVANCE Registry are described, showcasing the potential of using artificial intelligence to improve diagnostic accuracy and patient outcomes in cardiovascular care. The authors explore the latest studies evaluating different cardiomyopathies using cardiac MRI. Radiologists' growing understanding of the brain-heart axis is presented through discussion of several studies. The authors also discuss the prognostic advantages of MRI over PET in patients with cardiac sarcoidosis. Finally, the authors outline society statements and guidelines from 2023 that are pertinent to cardiac imaging, offering a comprehensive review of current trends and applications in noninvasive imaging modalities.

To identify preoperative predictors of postcardiotomy cardiogenic shock in patients with ischemic and nonischemic cardiomyopathy and evaluate trajectory of postoperative ventricular function.

From January 2017 to January 2020, 238 patients with ejection fraction <30% (206/238) or 30% to 34% with at least moderately severe mitral regurgitation (32/238) underwent conventional cardiac surgery at Cleveland Clinic, 125 with ischemic and 113 with nonischemic cardiomyopathy. Preoperative ejection fraction was 25 ± 4.5%. The primary outcome was postcardiotomy cardiogenic shock, defined as need for microaxial temporary left ventricular assist device, extracorporeal membrane oxygenation, or vasoactive-inotropic score >25. RandomForestSRC was used to identify its predictors.

Postcardiotomy cardiogenic shock occurred in 27% (65/238). Pulmonary artery pulsatility index <3.5 and pulmonary capillary wedge pressure >19 mm Hg were the most important factors predictive of postcardiotomy cardiogenic shock in ischemic cardiomyopathy. Cardiac index <2.2 L·min-1 m-2 and pulmonary capillary wedge pressure >21 mm Hg were the most important predictive factors in nonischemic cardiomyopathy. Operative mortality was 1.7%. Ejection fraction at 12 months after surgery increased to 39% (confidence interval, 35-40%) in the ischemic group and 37% (confidence interval, 35-38%) in the nonischemic cardiomyopathy group.

Predictors of postcardiotomy cardiogenic shock were different in ischemic and nonischemic cardiomyopathy. Right heart dysfunction, indicated by low pulmonary artery pulsatility index, was the most important predictor in ischemic cardiomyopathy, whereas greater degree of cardiac decompensation was the most important in nonischemic cardiomyopathy. Therefore, preoperative right heart catheterization will help identify patients with low ejection fraction who are at greater risk of postcardiotomy cardiogenic shock.

The influence of computed tomography attenuation correction (CTAC) on the accuracy of diagnosing viable myocardium using Tc-99m-MIBI dedicated cardiac cadmium-zinc-telluride (CZT) single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) combined with F-18-FDG Positron Emission Tomography/Computed Tomography (PET/CT) metabolic imaging, compared with conventional SPECT MPI, remains to be fully elucidated. To evaluate the impact of CTAC on the accuracy of diagnosing viable myocardium using Tc-99m-MIBI dedicated cardiac CZT SPECT MPI combined with F-18-FDG PET/CT, compared to conventional SPECT MPI. 193 patients underwent CZT SPECT and F-18-FDG PET/CT imaging, while 39 patients underwent conventional SPECT and F-18-FDG PET/CT imaging, with both groups utilizing CT for attenuation correction. The injured myocardium (hibernating and scarring) was quantified using the Q.PET software. After CTAC, both groups showed significant improvements in perfusion of the injured myocardial areas, particularly in the inferior wall (INF). The reduction in perfusion was more notable in the CZT SPECT group than that in the conventional group, particularly in the inferior and lateral walls. Among patients with large cardiac chambers, those undergoing MPI with CZT, with normal weights, or males, hibernating myocardium (HM) and scar post-CTAC reductions were particularly significant in the INF. If HM ≥ 10% is considered an indicator for recommended revascularization, among the 87 patients without prior cardiac bypass, 25 (28.7%) might not require revascularization treatment. Dedicated cardiac CZT SPECT and conventional SPECT MPI combined with F-18-FDG PET/CT significantly influenced the assessment of viable myocardium. The impact of CTAC was more profound in dedicated cardiac CZT SPECT, particularly in the INF region. CTAC significantly enhances the accuracy of viable myocardial assessment and may influence clinical decisions regarding revascularization therapy. Therefore, CTAC should be routinely used in dedicated cardiac CZT SPECT MPI combined with F-18-FDG PET/CT for myocardial viability diagnosis.

This article revisits the severity threshold for secondary mitral regurgitation (MR), focusing on insights and lessons from the RESHAPE-HF2 trial. It aims to challenge the traditional effective regurgitant orifice area (EROA) threshold of ≥0.40 cm2 used for intervention, suggesting that earlier intervention may benefit patients with lower EROA. It also explores how transcatheter edge-to-edge repair (TEER) improves outcomes in patients with secondary MR and assesses the impact of left ventricular (LV) remodeling on treatment success.

The RESHAPE-HF2 trial evaluated the use of TEER in patients with moderate-to-severe secondary MR, comparing outcomes in those with an EROA ≥0.2 cm2 and no extensive LV remodeling. TEER significantly reduced heart failure hospitalizations and improved quality of life in these patients. This supports the notion that patients with less severe MR, who still show symptoms despite optimal medical therapy, may benefit from earlier intervention. Comparisons with COAPT and MITRA-FR trials underscored the importance of selecting patients based on MR severity relative to LV dilatation.

The RESHAPE-HF2 trial highlights the need to reconsider the current EROA threshold for secondary MR intervention. TEER has shown to be beneficial even in patients with lower MR severity, suggesting that earlier intervention could improve outcomes. A more dynamic and integrated approach, considering both MR severity and LV remodeling, is essential for optimizing patient selection and treatment success.

Molecular imaging can detect and quantify pathophysiological processes underlying heart failure, complementing evaluation of cardiac structure and function with other imaging modalities. Targeted tracers have enabled assessment of various cellular and subcellular mechanisms of heart failure aiming for improved phenotyping, risk stratification, and personalized therapy. This review outlines the current status of molecular imaging in heart failure, accompanied with discussion on novel developments. The focus is on radionuclide methods with data from clinical studies. Imaging of myocardial metabolism can identify left ventricle dysfunction caused by myocardial ischemia that may be reversible after revascularization in the presence of viable myocardium. In vivo imaging of active inflammation and amyloid deposition have an established role in the detection of cardiac sarcoidosis and transthyretin amyloidosis. Innervation imaging has well documented prognostic value in predicting heart failure progression and arrhythmias. Tracers specific for inflammation, angiogenesis and myocardial fibrotic activity are in earlier stages of development, but have demonstrated potential value in early characterization of the response to myocardial injury and prediction of cardiac function over time. Early detection of disease activity is a key for transition from medical treatment of clinically overt heart failure towards a personalized approach aimed at supporting repair and preventing progressive cardiac dysfunction.

Heart failure (HF) is a clinical syndrome characterized by well-defined signs and symptoms due to structural and/or myocardial functional impairment, resulting in raised intracardiac pressures and/or inadequate cardiac stroke volume at rest or during exercise. This could derive from direct ischemic myocardial injury or other chronic pathological conditions, including valvular heart disease (VHD) and primary myocardial disease. Early identification of HF etiology is essential for accurate diagnosis and initiation of early and appropriate treatment. Thus, the presence of accurate means for early diagnosis of HF symptoms or subclinical phases is fundamental, among which echocardiography being the first line diagnostic investigation. Echocardiography could be performed at rest, to identify overt structural and functional abnormalities or during physical or pharmacological stress, in order to elicit subclinical myocardial function impairment e.g. wall motion abnormalities and raised ventricular filling pressures. Beyond diagnosis of ischemic heart disease, stress echocardiography (SE) has recently shown its unique value for the evaluation of diastolic heart failure, VHD, non-ischemic cardiomyopathies and pulmonary hypertension, with recommendations from international societies in several clinical settings. All these features make SE an important additional tool, not only for diagnostic assessment, but also for prognostic stratification and therapeutic management of patients with HF. In this review, the unique value of SE in the evaluation of HF patients will be described, with the objective to provide an overview of the validated methods for each setting, particularly for HF management.

Background To assess the feasibility of a machine learning (ML) approach using radiomics features of perfusion defects on rest myocardial perfusion imaging (MPI) to detect the presence of hibernating myocardium. Methodology Data of patients who underwent 99mTc-sestamibi MPI and 18F-FDG PET/CT for myocardial viability assessment were retrieved. Rest MPI data were processed on ECToolbox, and polar maps were saved using the NFile PMap tool. The reference standard for defining hibernating myocardium was the presence of mismatched perfusion-metabolism defect with impaired myocardial contractility at rest. Perfusion defects on the polar maps were delineated with regions of interest (ROIs) after spatial resampling and intensity discretization. Replicable random sampling allocated 80% (257) of the perfusion defects of the patients from January 2017 to September 2022 to the training set and the remaining 20% (64) to the validation set. An independent dataset of perfusion defects from 29 consecutive patients from October 2022 to January 2023 was used as the testing set for model evaluation. One hundred ten first and second-order texture features were extracted for each ROI. After feature normalization and imputation, 14 best-ranked features were selected using a multistep feature selection process including the Logistic Regression and Fast Correlation-Based Filter. Thirteen supervised ML algorithms were trained with stratified five-fold cross-validation on the training set and validated on the validation set. The ML algorithms with a Log Loss of <0.688 and <0.672 in the cross-validation and validation steps were evaluated on the testing set. Performance matrices of the algorithms assessed included area under the curve (AUC), classification accuracy (CA), F1 score, precision, recall, and specificity. To provide transparency and interpretability, SHapley Additive exPlanations (SHAP) values were assessed and depicted as beeswarm plots. Results Two hundred thirty-nine patients (214 males; mean age 56 ± 11 years) were enrolled in the study. There were 371 perfusion defects (321 in the training and validation sets; 50 in the testing set). Based on the reference standard, 168 perfusion defects had hibernating myocardium (139 in the training and validation sets; 29 in the testing set). On cross-validation, six ML algorithms with Log Loss <0.688 had AUC >0.800. On validation, 10 ML algorithms had a Log Loss value <0.672, among which six had AUC >0.800. On model evaluation of the selected models on the unseen testing set, nine ML models had AUC >0.800 with Gradient Boosting Random Forest (xgboost) [GB RF (xgboost)] achieving the highest AUC of 0.860 and could detect the presence of hibernating myocardium in 21/29 (72.4%) perfusion defects with a precision of 87.5% (21/24), specificity 85.7% (18/21), CA 78.0% (39/50) and F1 Score 0.792. Four models depicted a clear pattern of model interpretability based on the beeswarm SHAP plots. These were GB RF (xgboost), GB (scikit-learn), GB (xgboost), and Random Forest. Conclusion Our study demonstrates the potential of ML in detecting hibernating myocardium using radiomics features extracted from perfusion defects on rest MPI images. This proof-of-concept underscores the notion that radiomics features capture nuanced information beyond what is perceptible to the human eye, offering promising avenues for improved myocardial viability assessment.

This review summarises the shifting paradigms in the treatment of ischemic left ventricular dysfunction, spotlighting the revascularization for ischemic ventricular dysfunction-British cardiovascular intervention society-2 (REVIVED-BCIS2) trial results and its impact on key therapeutic goals: survival, left ventricular function, arrhythmia prevention, quality of life and viability testing.

The REVIVED-BCIS2 trial, and its subsequent sub studies highlighted that (PCI) does not provide additional benefits to optimal medical therapy in terms of improving survival, left ventricular (LV) function, arrhythmic risk or quality of life. Additionally, viability testing did not differentiate patients who could benefit from PCI, although scar burden was found to be a significant predictor of outcome in these patients.

The outcomes of REVIVED have challenged multiple existing beliefs in the field of ischaemic left ventricular dysfunction management, emphasising the importance of investigating evidence free areas in our practice. Future work, including the STICH3 international consortium of trials, aims to answer some of the remaining unanswered questions.

 This study was conducted to evaluate whether myocardial viability assessed with cardiac magnetic resonance (CMR) affected long-term clinical outcomes after coronary artery bypass grafting (CABG) in patients with ischemic cardiomyopathy (ICMP).

 Preoperative CMR with late gadolinium enhancement (LGE) was performed in 103 patients (64.9 ± 10.1 years, male:female = 82:21) with 3-vessel disease and left ventricular dysfunction (ejection fraction ≤ 0.35). Transmural extent of LGE was evaluated on a 16-segment model, and transmurality was graded on a 5-point scale: grades-0, absence; 1, 1 to 25%; 2, 26 to 50%; 3, 51 to 75%; 4, 76 to 100%. Median follow-up duration was 65.5 months (interquartile range = 27.5-95.3 months). Primary endpoint was the composite of all-cause mortality or hospitalization for congestive heart failure.

 Operative mortality was 1.9%. During the follow-up, all-cause mortality and readmission for congestive heart failure occurred in 29 and 8 patients, respectively. The cumulative incidence of the primary endpoint was 31.3 and 46.8% at 5 and 10 years, respectively. Multivariable analysis demonstrated that the number of segments with LGE grade 4 was a significant risk factor (hazard ratio 1.42, 95% confidence interval 1.10-1.83, p = 0.007) for the primary endpoint among the variables assessed by CMR. Other risk factors included age, dialysis, chronic obstructive pulmonary disease, and EuroSCORE II.

 The number of myocardial segments with transmurality of LGE >75% might be a prognostic factor associated with the composite of all-cause mortality or hospitalization for congestive heart failure after CABG in patients with 3-vessel disease and ICMP.

Revascularization in patients with left ventricular (LV) dysfunction has been a subject of ongoing uncertainty and conflicting results. This is further complicated by factors including viability, severity of LV dysfunction, and method of revascularization using percutaneous coronary intervention (PCI) versus coronary-artery bypass grafting (CABG).

The purpose of this meta-analysis is to evaluate the association of coronary revascularization with outcomes in patients with ischemic LV dysfunction.

A literature search was conducted for studies reporting on cardiovascular outcomes after revascularization compared to optimal medical therapy (OMT) in patients with ischemic LV dysfunction.

A total of 23 studies with 10,110 participants met inclusion criteria. Revascularization was significantly associated with lower all-cause mortality and CV mortality compared to OMT. The association was statistically significant regardless of severity of LV dysfunction or method of revascularization. Subgroup analysis demonstrated that revascularization was significantly associated with lower all-cause and CV mortality compared to OMT for patients with viable myocardium and mixed cohorts with variable viability, but not patients without viable myocardium. Revascularization was not associated with a significant difference in risk of heart failure (HF) hospitalization or acute myocardial infarction (AMI) compared to OMT.

Revascularization in patients with ischemic LV dysfunction is associated with lower risk of all-cause and CV mortality independent of severity of LV dysfunction or method of revascularization. Revascularization is not associated with lower risk of mortality in patients without evidence of viable myocardium and is not associated with lower risk of AMI or HF hospitalization.

Coronary artery disease (CAD) is a prevalent cause of left ventricular dysfunction. Nevertheless, effective elective revascularization, particularly surgical revascularization, can enhance long-term outcomes and, in selected cases, global left ventricular contractility. The assessment of myocardial viability and scars is still relevant in guiding treatment decisions and selecting patients who are likely to benefit most from blood flow restoration. Although the most recent randomized studies challenge the notion of "hibernating myocardium" and the clinical usefulness of assessing myocardial viability, the advancement of imaging techniques still renders this assessment valuable in specific situations. According to the guidelines of the European Society of Cardiology, non-invasive stress imaging may be employed to define myocardial ischemia and viability in patients with CAD and heart failure before revascularization. Currently, several non-invasive imaging techniques are available to evaluate the presence and extent of viable myocardium. The selection of the most suitable technique should be based on the patient, clinical context, and resource availability. This narrative review evaluates the characteristics of available imaging modalities for assessing myocardial viability to determine the most appropriate therapeutic strategy.

Ischemic cardiomyopathy patients with severe left ventricular dysfunction are a specific group of patients with poor surgical outcomes. There are few surgical treatment options in practice for the treatment of these patients such as heart transplantation, coronary artery bypass surgery, surgical ventricular restoration, etc. Despite multiple treatment options, there are no explicit clinical guidelines available to guide surgeons in choosing the most appropriate option and ensuring that the specific patient can benefit from the selected surgical treatment. Heart transplantation is the gold standard treatment for ischemic cardiomyopathy patients with severe left ventricular dysfunction, but it is limited to very few highly equipped centers around the world due to donor shortages, complex perioperative and surgical management, and limited technological and human resources. It is evident from some studies that heart transplant-eligible candidates can benefit from alternative surgical options such as coronary artery bypass surgery alone or combined with surgical ventricular restoration. Therefore, alternative surgical options that are used for most of the population, especially in developing and underdeveloped countries, need to be discussed to improve their outcomes. A challenge in the recent era which has yet to find a solution is to determine which heart transplant candidate can benefit from simple revascularization compared to a complex heart transplantation procedure. Myocardial viability testing was one of the most important determinants in deciding whether a patient should undergo revascularization, but its role in guiding appropriate surgical options has been challenged. This review aims to discuss the available surgical management options and their long-term outcomes for patients with ischemic cardiomyopathy, which will eventually help surgeons when choosing a surgical procedure.

Myocardial fibrosis (MF) is defined as excessive production and deposition of extra-cellular matrix proteins that result in pathologic myocardial remodeling. Three types of MF have been identified: replacement fibrosis from tissue necrosis, reactive fibrosis from myocardial stress, and infiltrative interstitial fibrosis from progressive deposition of nondegradable material such as amyloid. Although echocardiography, nuclear medicine, and CT play important roles in the assessment of MF, MRI is pivotal in the evaluation of MF, with the late gadolinium enhancement (LGE) technique used as a primary end point. The LGE technique focuses on the pattern and distribution of gadolinium accumulation in the myocardium and assists in the diagnosis and establishment of the cause of both ischemic and nonischemic cardiomyopathy. LGE MRI also aids prognostication and risk stratification. In addition, LGE MRI is used to guide the management of patients considered for ablation for arrhythmias. Parametric mapping techniques, including T1 mapping and extracellular volume measurement, allow detection and quantification of diffuse fibrosis, which may not be detected by LGE MRI. These techniques also allow monitoring of disease progression and therapy response. This review provides an update on the imaging of MF, including prognostication and risk stratification tools, electrophysiologic considerations, and disease monitoring.

Ventricular aneurysm represents a rare complication of transmural acute myocardial infarction, although other cardiac, congenital, or metabolic diseases may also predispose to such condition. Ventricular expansion includes all the cardiac layers, usually with a large segment involved. Adverse events include recurrent angina, reduced ventricular stroke volume with congestive heart failure, mitral regurgitation, thromboembolism, and ventricular arrhythmias. Multimodality imaging is paramount to provide comprehensive assessment, allowing for appropriate therapeutic decision-making. When indicated, surgical intervention remains the gold standard, although additional therapy (heart failure, anticoagulation, and advanced antiarrhythmic treatment) might be required. However, the STICH (Surgical Treatment for Ischemic Heart Failure) trial did not show any advantage from adding surgical ventricular reconstruction to coronary artery bypass surgery in terms of survival, rehospitalization or symptoms, compared with revascularization alone. Finally, implantable cardiac defibrillator may reduce the risk of fatal arrhythmias.

This article presents a comprehensive review of coronary revascularization versus optimal medical therapy (OMT) in patients with severe ischemic left ventricular dysfunction.

The REVIVED-BCIS2 trial randomized 700 patients with extensive coronary artery disease and left ventricular (LV) ejection fraction (LVEF) ≤ 35% and viability in more than four dysfunctional myocardial segments to percutaneous coronary intervention (PCI) plus OMT versus OMT alone. Over a median duration of 41 months, there was no difference in the composite of all-cause mortality, heart failure hospitalization, or improvement in LVEF with PCI plus OMT versus OMT alone at 6 and 12 months, quality of life scores at 24 months, or fatal ventricular arrhythmia. The STICH randomized trial was conducted between 2002 and 2007, involving patients with LV dysfunction and coronary artery disease. The patients were assigned to either CABG plus medical therapy or medical therapy alone. At the 5-year follow-up, the trial showed that CABG plus medical therapy reduced cardiovascular disease-related deaths and hospitalizations but no reduction in all-cause mortality. However, a 10-year follow-up showed a significant decrease in all-cause mortality with CABG. The currently available evidence showed no apparent benefit of PCI in severe ischemic cardiomyopathy as compared to OMT, but that CABG improves outcomes in this patient population. The paucity of data on the advantages of PCI in this patient population underscores the critical need for optimization of medical therapy for better survival and quality of life until further evidence from RCTs is available.

Ischemic cardiomyopathy (ICM) is the most common underlying etiology of heart failure in the United States and is a significant contributor to deaths due to cardiovascular disease worldwide. The diagnosis and management of ICM has advanced significantly over the past few decades, and the evidence for medical therapy in ICM is both compelling and robust. This contrasts with evidence for coronary revascularization, which is more controversial and favors surgical approaches. This review will examine landmark clinical trial results in detail as well as provide a comprehensive overview of the current epidemiology, diagnostic approaches, and management strategies of ICM.

Patients who undergo coronary artery bypass graft (CABG) surgery in ischemic cardiomyopathy have a survival advantage over medical therapy at 10 years. The survival advantage of CABG over medical therapy is due to its ability to reduce future myocardial infarction, and by conferring electrical stability. The presence of myocardial viability does not provide a differential survival advantage for CABG over medical therapy. Presence of angina and inducible ischemia are also less predictive of outcome. Moreover, CABG is associated with significant early mortality. Hence, careful patient selection is more important for reducing the early mortality and improving the long-term outcome than relying on results of myocardial viability. Younger patients with good exercise tolerance benefit the most, while patients who are frail and patients with renal dysfunction and dysfunctional right ventricle seem to have very high operative mortality. Elderly patients, because of poor life expectancy, do not benefit from CABG, but the age cutoff is not clear. Patients also need to have revascularizable targets, but this decision is often based on experience of the surgical team and heart team discussion. These recommendations are irrespective of the myocardial viability tests. Optimal medical treatment remains the cornerstone for management of ischemic cardiomyopathy.

There is growing evidence in support of coronary complete revascularization (CR). Nonetheless, there is no universally accepted definition of CR in patients who undergo coronary bypass grafting surgery (CABG). We sought to investigate the outcomes of CR, defined as surgical revascularization of any territory supplied by a suitable coronary artery with ≥50% stenosis. We performed a preplanned subanalysis in the Randomized Trial of Endoscopic or Open Saphenous Vein Graft Harvesting (REGROUP) clinical trial cohort. Of 1,147 patients who underwent CABG, 810 (70.6%) received CR. The primary outcome was a composite of major adverse cardiac events (MACEs), including death from any cause, nonfatal myocardial infarction, or repeat revascularization over a median 4.7 years of follow-up. MACE occurred in 175 patients (21.6%) in the CR group and 86 patients (25.5%) in the incomplete revascularization (IR) group (hazard ratio [HR] 0.87, 95% confidence interval [CI] 0.67 to 1.13, p = 0.29). A total of 97 patients (12.0%) in the CR group and 48 patients (14.2%) in the IR group died (HR 0.93, 95% CI 0.65 to 1.32, p = 0.67); nonfatal myocardial infarction occurred in 49 patients (6.0%) in the CR group and 30 patients (8.9%) in the IR group (HR 0.76, 95% CI 0.48 to 1.2, p = 0.24), and repeat revascularization occurred in 62 patients (7.7%) in the CR group and 39 patients (11.6%) in the IR group (HR 0.64; 95% CI 0.42 to 0.95, p = 0.027). In conclusion, in patients with a great burden of co-morbidities who underwent CABG in the REGROUP trial over a median follow-up period of a median 4.7 years, CR was associated with similar MACE rates but a reduced risk of repeat revascularization. Longer-term follow-up is warranted.

The concept of myocardial viability is usually referred to areas of the myocardium, which show contractile dysfunction at rest and in which contractility is expected to improve after revascularization. The traditional paradigm states that an improvement in function after revascularization leads to improved health outcomes and that assessment of myocardial viability in patients with ischaemic left ventricular dysfunction (ILVD) is a prerequisite for clinical decisions regarding treatment. A range of retrospective observational studies supported this 'viability hypothesis'. However, data from prospective trials have diverged from earlier retrospective studies and challenge this hypothesis. Traditional binary viability assessment may oversimplify ILVD's complexity and the nuances of revascularization benefits. A conceptual shift from the traditional paradigm centred on the assessment of viability as a dichotomous variable to a more comprehensive approach encompassing a thorough understanding of ILVD's complex pathophysiology and the salutary effect of revascularization in the prevention of myocardial infarction and ventricular arrhythmias is required.

Study aims to investigate the consistency of delayed enhancement cardiac magnetic resonance imaging (DE-CMR) and 18F-FDG PET myocardial imaging in evaluating myocardial viability before CABG.

The study analyzed data from 100 patients who were examined with DE-CMR, PET imaging, and echocardiography before and after CABG. All subjects were followed up for 6-12 month post- CABG.

DE-CMR and PET imaging have high consistency (90.1%; Kappa value = 0.71, p < 0.01) in determining myocardial viability. The degree of delayed enhancement was negatively correlated with the improvement in myocardial contractile function in this segment after revascularization (P < 0.001). The ratio of scarred myocardial segments and total DE score was significantly lower in the improvement group than non-improvement group. Multivariate regression identified that hibernating myocardium (OR = 1.229, 95%CI: 1.053-1.433, p = 0.009) was influencing factor of LVEF improvement after CABG.

Both imaging techniques are consistent in evaluating myocardial viability. Detecting the number of hibernating myocardium by PET is also important to predict the left heart function improvement after CABG.

Treatment of ischemic cardiomyopathy has been the focus of increased attention by cardiologists due to recent evidence of an important outcome study comparing percutaneous coronary intervention (PCI) plus optimal medical treatment vs optimal medical treatment alone, concluding for the futility of myocardial revascularization by PCI. A relatively older trial of coronary artery bypass grafting (CABG) in the same condition, on the other hand, had concluded for some prognostic improvement at a long-term follow-up. This short manuscript addresses how to triage such patients, frequently encountered in medical practice and considering clinical presentation, imaging results, and surgical risk, to provide practical guidance to treatment.

There is debate on the best treatment for significant stenoses of the left main (LM) coronary artery. The available evidence is based on four randomized trials, which were either performed specifically to assess patients with LM disease (EXCEL, NOBLE, PRECOMBAT) or had a significant fraction of patients with this disease pattern (SYNTAX). A meta-analysis revealed no difference in periprocedural and 5-year mortality but demonstrated a significant reduction of spontaneous myocardial infarction (MI) with CABG. Furthermore, the recently published SWEDEHEART registry data have shown survival advantage and fewer MACCE with CABG for LM disease after adjustment. In general, patients with more severe coronary artery disease (CAD) appear to have a survival advantage with CABG both over PCI and medical therapy (independent of the presence or absence of LM stenosis), which is always associated with a reduction of spontaneous MI in the CABG arm. Since the nomenclature of LM disease does not automatically reflect the complexity of CAD, we review the nature of LM disease in this article. We mechanistically assess the treatment effects of PCI and CABG for patients with LM disease, which is rarely isolated, often distal, and mostly associated with varying degrees of single and multi-vessel disease. We conclude that in patients with isolated LM shaft lesions and associated diseases of low complexity, the risk of spontaneous MI is lower, and PCI may achieve similar long-term outcomes compared to CABG. Thus, heart teams are essential for selecting the best treatment option and should focus on assessing infarction risk in chronic CAD.

There are no guidelines on the surgical management for ischemic cardiomyopathy (ICM) patients with severe left ventricular dysfunction. The present study aims to assess the long-term survival of these patients treated with two different surgical techniques, coronary artery bypass grafting (CABG) and heart transplantation (HTx).

This retrospective study included 218 ICM patients with left ventricular ejection fraction (LVEF) ≤35% who underwent CABG (n = 106) and HTx (n = 112) from 2011 to 2021 in a single center. After propensity adjustment analysis each group consisted of 51 patients. Clinical characteristics were evaluated for all-cause follow-up mortality by the Cox proportional hazards regression model. A risk prediction model was generated from multivariable-adjusted Cox regression analysis and applied to stratify patients with different clinical risks. The long-term survival was estimated by Kaplan-Meier analysis for different surgery groups.

Long-term survival was comparable between CABG and HTx groups. After being stratified into different risk subgroups according to risk predictors, the HTx group exhibited superior survival outcomes compared to the CABG group among the high-risk patients (67.8% vs 44.4%, 64.1% vs 38.9%, and 64.1% vs 33.3%, p = 0.047) at 12, 36, and 60 months respectively, while the survival was comparable between HTx and CABG groups among low-risk patients (87.0% vs 97.0%, 82.4% vs 97.0%, and 70.2% vs 91.6%, p = 0.11) at 12, 36, and 60 months respectively in the PSM cohort.

Long-term survival in ICM patients with severe left ventricular dysfunction who received CABG or HTx was comparable in general. Nonetheless, a favorable outcome of HTx surgery compared to CABG was observed among high-risk patients.

In the Revascularization for Ischemic Ventricular Dysfunction (REVIVED-BCIS2) trial, percutaneous coronary intervention (PCI) did not improve outcomes for patients with ischemic left ventricular dysfunction. Whether myocardial viability testing had prognostic utility for these patients or identified a subpopulation who may benefit from PCI remained unclear.

To determine the effect of the extent of viable and nonviable myocardium on the effectiveness of PCI, prognosis, and improvement in left ventricular function.

Prospective open-label randomized clinical trial recruiting between August 28, 2013, and March 19, 2020, with a median follow-up of 3.4 years (IQR, 2.3-5.0 years). A total of 40 secondary and tertiary care centers in the United Kingdom were included. Of 700 randomly assigned patients, 610 with left ventricular ejection fraction less than or equal to 35%, extensive coronary artery disease, and evidence of viability in at least 4 myocardial segments that were dysfunctional at rest and who underwent blinded core laboratory viability characterization were included. Data analysis was conducted from March 31, 2022, to May 1, 2023.

Percutaneous coronary intervention in addition to optimal medical therapy.

Blinded core laboratory analysis was performed of cardiac magnetic resonance imaging scans and dobutamine stress echocardiograms to quantify the extent of viable and nonviable myocardium, expressed as an absolute percentage of left ventricular mass. The primary outcome of this subgroup analysis was the composite of all-cause death or hospitalization for heart failure. Secondary outcomes were all-cause death, cardiovascular death, hospitalization for heart failure, and improved left ventricular function at 6 months.

The mean (SD) age of the participants was 69.3 (9.0) years. In the PCI group, 258 (87%) were male, and in the optimal medical therapy group, 277 (88%) were male. The primary outcome occurred in 107 of 295 participants assigned to PCI and 114 of 315 participants assigned to optimal medical therapy alone. There was no interaction between the extent of viable or nonviable myocardium and the effect of PCI on the primary or any secondary outcome. Across the study population, the extent of viable myocardium was not associated with the primary outcome (hazard ratio per 10% increase, 0.98; 95% CI, 0.93-1.04) or any secondary outcome. The extent of nonviable myocardium was associated with the primary outcome (hazard ratio, 1.07; 95% CI, 1.00-1.15), all-cause death, cardiovascular death, and improvement in left ventricular function.

This study found that viability testing does not identify patients with ischemic cardiomyopathy who benefit from PCI. The extent of nonviable myocardium, but not the extent of viable myocardium, is associated with event-free survival and likelihood of improvement of left ventricular function.

ClinicalTrials.gov Identifier: NCT01920048.

Background and Objectives: Patients with chronic total occlusions of the coronary arteries are either treated with PCI or referred for surgical revascularization. We analyzed the patients with chronic occluded coronary arteries that were surgically treated and aimed to describe the anatomical characteristics, revascularization rates, and in-hospital outcomes achieved with coronary artery bypass grafting. Methods: Angiographic data of 2005 patients with coronary artery disease treated in our institution between January 2005 and December 2014 were retrospectively analyzed. A total of 1111 patients with at least one coronary total occlusion were identified. We reviewed the preoperative coronary angiograms and surgical protocols to determine the presence, localization, and revascularization of coronary occlusions. We also evaluated the perioperative data and in-hospital outcomes. Results: The median age of the study population was 68 years (25th-75th percentiles, 61.0-74.0). Three-vessel disease was present in 94.8% of patients and the rest (5.8%) had a two-vessel disease. The localizations of the occlusions were as follows: 68.4% in the RCA system, 26.4% in the LAD, and 28.5% in the LCX system. Multiple occlusions were present in 22.6% of the patients. Complete coronary total occlusion revascularization was achieved in 86.1% of the patients. The overall in-hospital mortality was 2.3%. The median in-hospital stay was 14.0 days. After logistic regression analysis, age (odds ratio 3.44 [95% confidence interval, 1.81-6.53], p < 0.001, for a 10-year increase) and the presence of peripheral artery disease (odds ratio 3.32 [1.39-7.93], p = 0.007) were the only statistically significant independent predictors of in-hospital mortality. Conclusions: A high revascularization rate and favorable in-hospital outcomes are achieved with coronary artery bypass surgery in patients with multi-vessel diseases and coronary total occlusions. Older age and the presence of peripheral artery disease are independent predictors of in-hospital mortality. A long-term follow-up and the type of graft (arterial vs. venous) used would bring more useful data for this type of revascularization.