Ventricular septal defect following mitral valve replacement.

Mitral valve surgery (MVS), with repair preferred to replacement, is a common procedure for the treatment of severe primary mitral regurgitation related to leaflet prolapse. Structural complications after MVS include left ventricular outflow obstruction, paravalvular leak and atrial septal defect. Intraoperative transoesophageal echocardiography and predischarge transthoracic echocardiography (TTE) specifically screen for these complications. Ventricular septal defect (VSD), a known complication after aortic valve surgery, is rarely reported after MVS. Recently, unsuccessful valvuloplasty prior to replacement was suggested as a risk factor. We present such a case and explore mechanisms with advanced cardiac imaging. In this case, the patient was found to have an elongated membranous septum that likely predisposed her to septal injury. Finally, we provide guidance on specific transoesophageal/transthoracic echocardiography views to avoid a missed diagnosis.

Impact of lung transplantation on diastolic dysfunction in recipients with pretransplant pulmonary hypertension.

OBJECTIVE: Pulmonary hypertension can cause left ventricular diastolic dysfunction through ventricular interdependence. Moreover, diastolic dysfunction has been linked to adverse outcomes after lung transplant. The impact of lung transplant on diastolic dysfunction in recipients with pretransplant pulmonary hypertension is not defined. In this cohort, we aimed to assess the prevalence of diastolic dysfunction, the change in diastolic dysfunction after lung transplant, and the impact of diastolic dysfunction on lung transplant outcomes. METHODS: In a large, single-center database from January 2011 to September 2021, single or bilateral lung transplant recipients with pulmonary hypertension (mean pulmonary artery pressure > 20 mm Hg) were retrospectively identified. Those without a pre- or post-transplant echocardiogram within 1 year were excluded. Diastolic dysfunction was diagnosed and graded according to the American Society of Echocardiography 2016 guideline on assessment of diastolic dysfunction (present, absent, indeterminate). McNemar's test was used to examine association between diastolic dysfunction pre- and post-transplant. Kaplan-Meier and Cox regression analysis were used to assess associations between pre-lung transplant diastolic dysfunction and post-lung transplant 1-year outcomes, including mortality, major adverse cardiac events, and bronchiolitis obliterans syndrome grade 1 or higher-free survival. RESULTS: Of 476 primary lung transplant recipients, 205 with pulmonary hypertension formed the study cohort (mean age, 56.6 ± 11.9 years, men 61.5%, mean pulmonary artery pressure 30.5 ± 9.8 mm Hg, left ventricular ejection fraction < 55% 9 [4.3%]). Pretransplant, diastolic dysfunction was present in 93 patients (45.4%) (grade I = 8, II = 84, III = 1), absent in 16 patients (7.8%), and indeterminate in 89 patients (43.4%), and 7 patients (3.4%) had missing data. Post-transplant, diastolic dysfunction was present in 7 patients (3.4%) (grade I = 2, II = 5, III = 0), absent in 164 patients (80.0%), and indeterminate in 15 patients (7.3%), and 19 patients (9.3%) had missing data. For those with diastolic dysfunction grades in both time periods (n = 180), there was a significant decrease in diastolic dysfunction post-transplant (148/169 patients with resolved diastolic dysfunction; McNemar's test P < .001). Pretransplant diastolic dysfunction was not associated with major adverse cardiac events (hazard ratio [HR], 1.08, 95% CI, 0.72-1.62; P = .71), bronchiolitis obliterans syndrome-free survival (HR, 0.67, 95% CI, 0.39-1.56; P = .15), or mortality (HR, 0.70, 95% CI, 0.33-1.46; P = .34) at 1 year. CONCLUSIONS: Diastolic dysfunction is highly prevalent in lung transplant candidates with normal left ventricular systolic function and pulmonary hypertension, and resolves in most patients after lung transplant regardless of patient characteristics. Pre-lung transplant diastolic dysfunction was not associated with adverse lung or cardiac outcomes after lung transplant. Collectively, these findings suggest that the presence of diastolic dysfunction in lung transplant recipients with pulmonary hypertension has no prognostic significance, and as such diastolic dysfunction and the associated clinical syndrome of heart failure with preserved ejection fraction should not be considered a relative contraindication to lung transplant in such patients.

Integrated smoking cessation and mood management following acute coronary syndrome: Protocol for the post-acute cardiac event smoking (PACES) trial.

BACKGROUND: Approximately 400,000 people who smoke cigarettes survive Acute Coronary Syndrome (ACS; unstable angina, ST and non-ST elevation myocardial infarction) each year in the US. Continued smoking following ACS is an independent predictor of mortality. Depressed mood post-ACS is also predictive of mortality, and smokers with depressed mood are less likely to abstain from smoking following an ACS. A single, integrated treatment targeting depressed mood and smoking could be effective in reducing post-ACS mortality. METHOD/DESIGN: The overall aim of the current study is to conduct a fully powered efficacy trial enrolling 324 smokers with ACS and randomizing them to 12 weeks of an integrated smoking cessation and mood management treatment [Behavioral Activation Treatment for Cardiac Smokers (BAT-CS)] or control (smoking cessation and general health education). Both groups will be offered 8 weeks of the nicotine patch if medically cleared. Counseling in both arms will be provided by tobacco treatment specialists. Follow-up assessments will be conducted at end-of-treatment (12-weeks) and 6, 9, and 12 months after hospital discharge. We will track major adverse cardiac events and all-cause mortality for 36 months post-discharge. Primary outcomes are depressed mood and biochemically validated 7-day point prevalence abstinence from smoking over 12 months. DISCUSSION: Results of this study will inform smoking cessation treatments post-ACS and provide unique data on the impact of depressed mood on success of post-ACS health behavior change attempts. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03413423. Registered 29 January 2018. https://beta. CLINICALTRIALS: gov/study/NCT03413423 .

New-onset postoperative atrial fibrillation after mitral valve surgery: Determinants and the effect on survival.

Objective: Mitral valve surgery (MVS) carries substantial risk of postoperative atrial fibrillation (PAF). Identifying patients who benefit from prophylactic left atrial appendage amputation (LAAA) or maze is ill-defined. To guide such interventions, we determined preoperative predictors of PAF and investigated 3-year survival of patients with PAF. Methods: We performed a retrospective analysis of patients undergoing isolated MVS (N = 670) between 2011 and 2021. Patients with preoperative atrial fibrillation, LAAA or pulmonary vein isolation were excluded. Patient characteristics were compared between those without PAF and those who developed transient or prolonged PAF. Predictors of any PAF and prolonged PAF were identified using multivariable regression analysis. Results: In total, 504 patients without preoperative atrial fibrillation underwent isolated MVS. Of them, 303 patients (60.2%) developed PAF; 138 (27.3%) developed transient and 165 (32.7%) developed prolonged (beyond 30 days) PAF. Patients with PAF were older (65.7 vs 54.3 years, P < .001), with larger left atria (4.8 vs 4.3 cm, P < .001), greater prevalence of hypertension (60% vs 47.8%, P < .05), and were New York Heart Association class III/IV (36% vs 8.5%, P < .001). Independent predictors of PAF included left atria volume index (odds ratio [OR], 1.02; P < .003), older age (OR, 1.04; P < .001), heart failure (OR, 6.73; P < .001), and sternotomy (OR, 2.19; P < .002). Age, heart failure, and sternotomy were independent predictors of prolonged PAF. Patients with PAF had greater mortality at 3 years compared with those without PAF (5.3% vs 0.5%, P < .005). On multivariable analysis, PAF was associated with increased mortality (hazard ratio, 7.81; P < .046). Conclusions: PAF is common after MVS and associated with late mortality. Older age, advanced heart failure, and sternotomy are associated with prolonged PAF. These factors may identify patients who would benefit from prophylactic LAAA or ablation during MVS.

Incidental coronary calcium in cancer patients treated with anthracycline and/or trastuzumab.

AIMS: Cancer patients are at increased risk of cardiovascular disease (CVD) after treatment with potentially cardiotoxic treatments. Many cancer patients undergo non-gated chest computed tomography (NCCT) for cancer staging prior to treatment. We aimed to assess whether coronary artery calcification on NCCT predicts CVD risk in cancer patients. METHODS AND RESULTS: Six hundred and three patients (mean age: 61.3 years, 30.8% male) with either breast cancer, lymphoma, or sarcoma were identified retrospectively. Primary endpoint was a major adverse cardiac event (MACE) composite including non-fatal myocardial infarction, new heart failure (HF) diagnosis, HF hospitalization, and cardiac death, with Fine-Gray analysis for non-cardiac death as competing risk. Secondary endpoints included a coronary composite and a HF composite. Coronary artery calcification was present in 194 (32.2%) and clinically reported in 85 (43.8%) patients. At a median follow-up of 5.3 years, 256 (42.5%) patients died of non-cardiac causes. Coronary artery calcification presence or extent was not an independent predictor of MACE [sub-distribution hazards ratio (SHR) 1.28; 0.73-2.27]. Coronary artery calcification extent was a significant predictor of the coronary composite outcome (SHR per two-fold increase 1.14; 1.01-1.28), but not of the HF composite outcome (SHR per two-fold increase 1.04; 0.95-1.14). CONCLUSION: Coronary artery calcification detected incidentally on NCCT scans in cancer patients is prevalent and often not reported. Coronary artery calcification presence or extent did not independently predict MACE. Coronary artery calcification extent was independently associated with increased risk of CAD events but not HF events.

Impact of pectoralis muscle loss on cardiac outcome and survival in Cancer patients who received anthracycline based chemotherapy: retrospective study.

INTRODUCTION: The impact of pectoralis muscle mass index (PMI) on cardiac events is not well studied in cancer patients, especially in those who have received chemotherapy with high potential cardiac toxicity such as anthracyclines. METHODS: Individuals aged ≥18 years with a diagnosis of breast cancer, sarcoma, or lymphoma who received anthracycline-based chemotherapy at the University of Minnesota MHealth Fairview between 2009 and 2014. Eligible patients had to have two CT scans: a baseline CT scan within 6 months prior to chemotherapy and a follow-up CT scan within 2 years after treatment. The PMI was calculated as the right pectoralis muscle area indexed to height squared. Multivariable linear regression was used to analyze factors associated with PMI at follow-up, overall mortality, and major cardiac events (MACE). RESULTS: A total of 474 patients (breast cancer 192; lymphoma 184; sarcoma 98) participated with a median age of 61 years at the time of baseline CT scan; 161 (34%) were male. Almost all patients received anthracyclines except 12% who received trastuzumab only. The median baseline PMI was 5.8 cm2/m2 (4.9, 7.7) which decreased 10.5% after chemotherapy, to 5.2 cm2/m2 (4.4, 6.4). Baseline PMI was not significantly associated with OS, but we detected lower risks of MACE with larger PMI at baseline. Greater baseline PMI was associated with greater follow-up PMI, but also with greater relative PMI loss. Female gender, older age, and history of smoking were also associated with greater PMI losses. CONCLUSION: Greater pre-treatment pectoralis muscle index in patients treated with anthracyclines have a lower risk of MACE. Early identification of sarcopenia using PMI could trigger proactive engagement for intervention and risk-stratified therapies.

Long-term prognostic value of right ventricular dysfunction on cardiovascular magnetic resonance imaging in anthracycline-treated cancer survivors.

AIMS: We aimed to determine the prevalence of right ventricular (RV) systolic dysfunction on cardiovascular magnetic resonance imaging (CMR) and its impact on long-term adverse outcomes in a large cohort of cancer survivors treated with anthracycline-based chemotherapy. METHODS AND RESULTS: Consecutive cancer survivors treated with anthracyclines who underwent clinical CMR for suspected anthracycline-related cardiomyopathy were studied. The primary endpoint was a composite of all-cause death or major adverse cardiac events (MACE): heart failure hospitalization, heart transplantation, ventricular assist device implantation, resuscitated cardiac arrest, or life-threatening ventricular arrhythmia. The secondary endpoints were all-cause death, and cardiac death or MACE. Among 249 survivors who underwent CMR at a median of 2.9 years after cancer treatment, RV systolic dysfunction was present in 54 (21.7%). Of these, 50 (92.6%) had an abnormal left ventricular ejection fraction (LVEF). At a median follow-up time after the CMR of 2.7 years, 105 survivors experienced the primary endpoint. On Kaplan-Meier analyses, the cumulative incidence of the primary endpoint was significantly higher in survivors with abnormal RVEF compared with those with normal RVEF (P = 0.002). However, on Cox multivariable analyses, RVEF was not associated with the primary endpoint (HR 1.04 per 5% decrease; 95% CI 0.93-1.17; P = 0.46) after adjustment for non-imaging variables and LVEF. RVEF was also not associated with the secondary endpoints. CONCLUSION: Among anthracycline-treated cancer survivors undergoing CMR for suspected cardiotoxicity, RV systolic dysfunction was present in one in five cases, accompanied by LV systolic dysfunction in nearly all cases, and was not independently associated with long-term outcomes.

Myocardial damage assessed by late gadolinium enhancement on cardiovascular magnetic resonance imaging in cancer patients treated with anthracyclines and/or trastuzumab.

AIMS: In cancer patients with cardiomyopathy related to anthracyclines and/or trastuzumab, data regarding late gadolinium enhancement (LGE) on cardiovascular magnetic resonance imaging are confusing. The prevalence ranges from 0% to 30% and the patterns are ill-defined. Whether treatment with anthracyclines and/or trastuzumab is associated with LGE is unclear. We aimed to investigate these topics in a large cohort of consecutive cancer patients with suspected cardiotoxicity from anthracyclines and/or trastuzumab. METHODS AND RESULTS: We studied 298 patients, analysed the prevalence, patterns, and correlates of LGE, and determined their causes. We compared the findings with those from 100 age-matched cancer patients who received neither anthracyclines nor trastuzumab. Amongst those who received anthracyclines and/or trastuzumab, 31 (10.4%) had LGE. It had a wide range of extent (3.9-34.7%) and locations. An ischaemic pattern was present in 20/31 (64.5%) patients. There was an alternative explanation for the non-ischaemic LGE in 7/11 (63.6%) patients. In the age-matched patients who received neither anthracyclines nor trastuzumab, the prevalence of LGE was higher at 27.0%, while the extent of LGE and the proportion with ischaemic pattern were not different. CONCLUSION: LGE was present in only a minority. Its patterns and locations did not fit into a single unique profile. It had alternative explanations in virtually all cases. Finally, LGE was also present in cancer patients who received neither anthracyclines nor trastuzumab. Therefore, treatment with anthracyclines and/or trastuzumab is unlikely to be associated with LGE. The absence of LGE can help distinguish anthracycline- and/or trastuzumab-related cardiomyopathy from unrelated cardiomyopathies.

Utility of CT in the diagnosis of prosthetic valve abnormalities.

BACKGROUND: Patients with prosthetic heart valves (PHV) are at an increased risk of endocarditis and dysfunction. Knowledge about the etiology of dysfunction and extent of endocarditis can have distinct treatment implications. Echocardiography has limitations due to PHV-related artifacts. We hypothesized that computed tomography (CT) will have incremental value over echocardiography for evaluation of PHV abnormalities with surgical findings as the reference standard. METHODS: Consecutive patients with PHV that had a reoperation for valve replacement, had a contrast chest CT and echocardiogram within 1 year of the reoperation, between 2010 and 2018 at a single academic center formed the study cohort. CTs and echocardiograms were assessed for potential etiologies of dysfunction (valve degeneration, pannus and thrombus); and for extent of endocarditis (vegetation, abscess, and pseudoaneurysm). RESULTS: Seventy-three patients (65.8% male, mean age 62.1 ± 16.5 years) formed the study cohort. The indication for reoperation was PHV dysfunction in 51 and PHV endocarditis in 22. Compared to echocardiography, CT diagnosed the etiology of PHV dysfunction in 17 (33.3%) more patients (9 valve degeneration, 8 pannus). In the PHV endocarditis cohort, CT failed to detect one vegetation and one abscess, whereas echocardiography failed to detect 1 abscess. In combination, CT and echocardiography demonstrated all the vegetations and abscesses. CONCLUSION: CT may provide superior characterization in comparison to echocardiography for the identification of the cause of prosthetic valve dysfunction, and complementary information to echocardiography for the evaluation of prosthetic valve endocarditis.

Right Ventricular Abnormalities on Cardiovascular Magnetic Resonance Imaging in Patients With Sarcoidosis.

OBJECTIVES: This study aimed to determine the prevalence on cardiac magnetic resonance (CMR) of right ventricular (RV) systolic dysfunction and RV late gadolinium enhancement (LGE), their determinants, and their influences on long-term adverse outcomes in patients with sarcoidosis. BACKGROUND: In patients with sarcoidosis, RV abnormalities have been described on many imaging modalities. On CMR, RV abnormalities include RV systolic dysfunction quantified as an abnormal right ventricular ejection fraction (RVEF), and RV LGE. METHODS: Consecutive patients with biopsy-proven sarcoidosis who underwent CMR for suspected cardiac involvement were studied. They were followed for 2 endpoints: all-cause death, and a composite arrhythmic endpoint of sudden cardiac death or significant ventricular arrhythmia. RESULTS: Among 290 patients, RV systolic dysfunction (RVEF <40% in men and <45% in women) and RV LGE were present in 35 (12.1%) and 16 (5.5%), respectively. The median follow-up time was 3.2 years (interquartile range [IQR]: 1.6 to 5.7 years) for all-cause death and 3.0 years (IQR: 1.4 to 5.5 years) for the arrhythmic endpoint. On Cox proportional hazards regression multivariable analyses, only RVEF was independently associated with all-cause death (hazard ratio [HR]: 1.05 for every 1% decrease; 95% confidence interval [CI]: 1.01 to 1.09; p = 0.022) after adjustment for left ventricular EF, left ventricular LGE extent, and the presence of RV LGE. RVEF was not associated with the arrhythmic endpoint (HR: 1.01; 95% CI: 0.96 to 1.06; p = 0.67). Conversely, RV LGE was not associated with all-cause death (HR: 2.78; 95% CI: 0.36 to 21.66; p = 0.33), while it was independently associated with the arrhythmic endpoint (HR: 5.43; 95% CI: 1.25 to 23.47; p = 0.024). CONCLUSIONS: In this study of patients with sarcoidosis, RV systolic dysfunction and RV LGE had distinct prognostic associations; RV systolic dysfunction but not RV LGE was independently associated with all-cause death, whereas RV LGE but not RV systolic dysfunction was independently associated with sudden cardiac death or significant ventricular arrhythmia. These findings may indicate distinct implications for the management of RV abnormalities in sarcoidosis.

Assessment of the 2017 AHA/ACC/HRS Guideline Recommendations for Implantable Cardioverter-Defibrillator Implantation in Cardiac Sarcoidosis.

BACKGROUND: Implantable cardioverter-defibrillators are used to prevent sudden cardiac death in patients with cardiac sarcoidosis. The most recent recommendations for implantable cardioverter-defibrillator implantation in these patients are in the 2017 American Heart Association/American College of Cardiology/Heart Rhythm Society Guideline for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death. These recommendations, based on observational studies or expert opinion, have not been assessed. We aimed to assess them. METHODS: We performed a large retrospective cohort study of patients with biopsy-proven sarcoidosis and known or suspected cardiac sarcoidosis that underwent cardiovascular magnetic resonance imaging. Patients were followed for a composite end point of significant ventricular arrhythmia or sudden cardiac death. The discriminatory performance of the Guideline recommendations was tested using time-dependent receiver operating characteristic analyses. The optimal cutoff for the extent of late gadolinium enhancement predictive of the composite end point was determined using the Youden index. RESULTS: In 290 patients, the class I and IIa recommendations identified all patients who experienced the composite end point during a median follow-up of 3.0 years. Patients meeting class I recommendations had a significantly higher incidence of the composite end point than those meeting class IIa recommendations. Left ventricular ejection fraction (LVEF) >35% with >5.7% late gadolinium enhancement on cardiovascular magnetic resonance imaging was as sensitive as and significantly more specific than LVEF >35% with any late gadolinium enhancement. Patients meeting 2 class IIa recommendations, LVEF >35% with the need for a permanent pacemaker and LVEF >35% with late gadolinium enhancement >5.7%, had high annualized event rates. Excluding 2 class IIa recommendations, LVEF >35% with syncope and LVEF >35% with inducible ventricular arrhythmia, resulted in improved discrimination for the composite end point. CONCLUSIONS: We assessed the Guideline recommendations for implantable cardioverter-defibrillator implantation in patients with known or suspected cardiac sarcoidosis and identified topics for future research.

Safety and prognostic value of regadenoson stress cardiovascular magnetic resonance imaging in heart transplant recipients.

BACKGROUND: There is a critical need for non-invasive methods to detect coronary allograft vasculopathy and to risk stratify heart transplant recipients. Vasodilator stress testing using cardiovascular magnetic resonance imaging (CMR) is a promising technique for this purpose. We aimed to evaluate the safety and the prognostic value of regadenoson stress CMR in heart transplant recipients. METHODS: To evaluate the safety, we assessed adverse effects in a retrospective matched cohort study of consecutive heart transplant recipients who underwent regadenoson stress CMR matched in a 2:1 ratio to age- and gender-matched non-heart transplant patients. To evaluate the prognostic value, we compared the outcomes of patients with abnormal vs. normal regadenoson stress CMRs using a composite endpoint of myocardial infarction, percutaneous intervention, cardiac hospitalization, retransplantation or death. RESULTS: For the safety analysis, 234 regadenoson stress CMR studies were included - 78 performed in 57 heart transplant recipients and 156 performed in non-heart transplant patients. Those in heart transplant recipients were performed at a median of 2.74 years after transplantation. Thirty-four (44%) CMR studies were performed in the first two years after heart transplantation. There were no differences in the rates of adverse effects between heart transplant recipients and non-heart transplant patients. To study the prognostic value of regadenoson stress CMRs, 20 heart transplant recipients with abnormal regadenoson stress CMRs were compared to 37 with normal regadenoson stress CMRs. An abnormal regadenoson stress CMR was associated with a significantly higher incidence of the composite endpoint compared with a normal regadenoson stress CMR (3-year cumulative incidence estimates of 32.1% vs. 12.7%, p = 0.034). CONCLUSIONS: Regadenoson stress CMR is safe and well tolerated in heart transplant recipients, with no incidence of sinus node dysfunction or high-degree atrioventricular block, including in the first two years after heart transplantation. An abnormal regadenoson stress CMR identifies heart transplant recipients at a higher risk for major adverse cardiovascular events.

Impact of Cardiovascular Magnetic Resonance Imaging on Identifying the Etiology of Cardiomyopathy in Patients Undergoing Cardiac Transplantation.

Errors in identifying the etiology of cardiomyopathy have been described in patients undergoing cardiac transplantation. There are increasing data that cardiovascular magnetic resonance imaging (CMR) provides unique diagnostic information in heart failure. We investigated the association of the performance of CMR prior to cardiac transplantation with rates of errors in identifying the etiology of cardiomyopathy. We compared pre-transplantation clinical diagnoses with post-transplantation pathology diagnoses obtained from the explanted native hearts. Among 338 patients, there were 23 (7%) errors in identifying the etiology of cardiomyopathy. Of these, 22 (96%) occurred in patients with pre-transplantation clinical diagnoses of non-ischemic cardiomyopathy (NICM). Only 61/338 (18%) had CMRs prior to transplantation. There was no significant association between the performance of CMR and errors in the entire study cohort (p = 0.093). Among patients with pre-transplantation clinical diagnoses of NICM, there was a significant inverse association between the performance of CMR and errors (2.4% vs. 14.6% in patients with and without CMR respectively; p = 0.030). In conclusion, CMR was underutilized prior to cardiac transplantation. In patients with pre-transplantation clinical diagnoses of NICM - in whom 96% of errors in identifying the etiology of cardiomyopathy occurred - the performance of CMR was associated with significantly fewer errors.

Feasibility of ultra low-dose coronary computed tomography angiography.

There is an urgent need to develop new protocols to reduce radiation dose of coronary computed tomography angiography (CTA). The aim of this pilot study was to demonstrate the feasibility of an ultra-low dose CTA scanning.

Accuracy of left ventricular ejection fraction by contemporary multiple gated acquisition scanning in patients with cancer: comparison with cardiovascular magnetic resonance.

BACKGROUND: Multiple gated acquisition scanning (MUGA) is a common imaging modality for baseline and serial assessment of left ventricular ejection fraction (LVEF) for cardiotoxicity risk assessment prior to, surveillance during, and surveillance after administration of potentially cardiotoxic cancer treatment. The objective of this study was to compare the accuracy of left ventricular ejection fractions (LVEF) obtained by contemporary clinical multiple gated acquisition scans (MUGA) with reference LVEFs from cardiovascular magnetic resonance (CMR) in consecutive patients with cancer. METHODS: In a cross-sectional study, we compared MUGA clinical and CMR reference LVEFs in 75 patients with cancer who had both studies within 30 days. Misclassification was assessed using the two most common thresholds of LVEF used in cardiotoxicity clinical studies and practice: 50 and 55%. RESULTS: Compared to CMR reference LVEFs, MUGA clinical LVEFs were only lower by a mean of 1.5% (48.5% vs. 50.0%, p = 0.17). However, the limits of agreement between MUGA clinical and CMR reference LVEFs were wide at -19.4 to 16.5%. At LVEF thresholds of 50 and 55%, there was misclassification of 35 and 20% of cancer patients, respectively. CONCLUSIONS: MUGA clinical LVEFs are only modestly accurate when compared with CMR reference LVEFs. These data have significant implications on clinical research and patient care of a population with, or at risk for, cardiotoxicity.