Characteristics and clinical outcomes of patients with sarcoidosis admitted for ST-elevation myocardial infarction in the United States: a propensity matched analysis from the National Inpatient Sample.

Introduction: Sarcoidosis is a systemic inflammatory disorder characterised by non-caseating granulomas. Cardiac sarcoidosis (CS) normally causes conduction abnormalities, ventricular arrhythmias, and heart failure. Little is known about the characteristics and impact of sarcoidosis in patients admitted with ST-elevation myocardial infarction (STEMI). This study aims to fill this void. Material and methods: Utilising the National Inpatient Sample (NIS) database (2016-2020), individuals with STEMI were identified and categorised based on sarcoidosis presence whilst adjusting for confounders via logistic regression models. Results: Among 851,290 STEMI patients, 1215 had sarcoidosis. Before propensity matching, sarcoidosis patients were notably different in demographics and comorbidities compared to non-sarcoidosis patients. After propensity score matching (PSM), sarcoidosis patients were found to have a higher incidence of supraventricular tachycardia (SVT) (2.5% vs. 1.3%, p = 0.024) and acute kidney injury (AKI) (23.3% vs. 20.8%, aOR = 1.269, 95% CI: 1.02-1.58, p = 0.033) but a lower incidence of undergoing coronary artery bypass graft (CABG) (5.5% vs. 8.5%, aOR = 0.663; 95% CI: 0.472-0.931, p = 0.018), while no significant disparities were noted in PCI, cardiogenic shock, mortality, or mean length of stay (LOS). Conclusions: Using propensity-matched large real-world data of STEMI patients, sarcoidosis was associated with fewer cases of CABG and a greater incidence of AKI and SVT compared to non-sarcoidosis patients.

Heart failure with preserved ejection fraction management: a systematic review of clinical practice guidelines and recommendations.

Multiple guidelines exist for the diagnosis and management of heart failure with preserved ejection fraction (HFpEF). We systematically reviewed current guidelines and recommendations, developed by national and international medical organizations, on the management of HFpEF in adults to aid clinical decision-making. We searched MEDLINE and EMBASE on 28 February 2024 for publications over the last 10 years as well as websites of organizations relevant to guideline development. Of the ten guidelines and recommendations retrieved, seven showed considerable rigour of development and were subsequently retained for analysis. There was consensus on the definition of HFpEF and the diagnostic role of serum natriuretic peptides and resting transthoracic echocardiography. Discrepancies were identified in the thresholds of serum natriuretic peptides and transthoracic echocardiography parameters used to diagnose HFpEF. There was agreement on the general pharmacological and supportive management of acute and chronic HFpEF. However, differences exist in strategies to identify and address specific phenotypes. Contemporary guidelines for HFpEF management agree on measures to avoid its development and the consideration of cardiac transplantation in advanced disease. There were discrepancies in recommended frequency of surveillance for patients with HFpEF and sparse recommendations on screening for HFpEF in the general population, use of diagnostic scoring systems, and the role of newly emerging therapies.

Response to letter to editor, re-predictors of morbidity and in-hospital mortality following procedure-related cardiac tamponade.

We had included only the patients with cardiac tamponade, excluded those coded for pericardial effusion. The feasibility of comparison of the databases of two regions needs to be evaluated. There are some inherent limitations for the studies carried out from the National In-patient Samples (NIS) database.

Racial disparities among patients with cardiac sarcoidosis and arrhythmias in the United States: A propensity matched-analysis from the national inpatient sample database 2016-2020.

BACKGROUND: Cardiac sarcoidosis (CS) is frequently associated with conduction abnormalities and arrhythmias. In this study, we aim to evaluate racial disparities in the frequency of arrhythmias, and associated co-morbidities, among patients with CS. METHODS: White and African American (AA) patients diagnosed with CS were identified and compared from the 2016-2020 National Inpatient Sample (NIS) database whilst adjusting for confounders via logistic regression models. RESULTS: A total of 7,935 patients with CS were included in the study. The propensity-matched sample comprised of 5,570 patients, of whom 2,785 were White and 2,785 were AA. AA patients had a longer mean length of hospital stay (LOS) (7.84 vs. 6.94, p<0.01), a higher mean Charlson Comorbidity Index (CCI) score (3.10 vs. 2.84, p<0.01), and significantly higher incidences of cardiogenic shock [(9.2% vs 6.3%, p<0.01), aOR 1.45 (95% CI 1.17-1.78), p<0.01] and acute kidney injury (AKI) [(34.3% vs. 26.9%, p<0.01), aOR 1.41 (95% CI 1.24-1.61), p<0.01]. From an arrhythmia perspective, AA CS patients were shown to have a lower frequency of: (1) ventricular tachycardia (32.5% vs. 37.9%, p<0.01), (2) ventricular fibrillation (5.4% vs.7.2%, p<0.01), (3) first-degree AV block (1.8% vs. 4.1%, p<0.01), (4) complete AV block (6.3% vs. 14.2%, p<0.01), and (5) atrial fibrillation (31.8% vs. 34.8%, p=0.016) when compared to Whites with CS. Mortality remained higher for AAs (3.8% vs. 2.7%, p=0.024). CONCLUSION: Our study demonstrates a higher incidence of cardiac arrhythmias among White patients but a higher incidence of cardiogenic shock, AKI, mean LOS, and mortality among AA patients with cardiac sarcoidosis.

Surgical management of atrial fibrillation in patients undergoing cardiac surgery: a systematic review of clinical practice guidelines and recommendations.

AIMS: Surgical ablation of atrial fibrillation (AF) has been demonstrated to be a safe procedure conducted concomitantly alongside cardiac surgery. However, there are conflicting guideline recommendations surrounding indications for surgical ablation. We conducted a systematic review of current recommendations on concomitant surgical AF ablation. METHODS AND RESULTS: We identified publications from MEDLINE and EMBASE between January 2011 and December 2022 and additionally searched Guideline libraries and websites of relevant organizations in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Of 895 studies screened, 4 were rigorously developed (AGREE-II > 50%) and included. All guidelines agreed on the definitions of paroxysmal, persistent, and longstanding AF based on duration and refraction to current treatment modalities. In the Australia-New Zealand (CSANZ) and European (EACTS) guidelines, opportunistic screening for patients >65 years is recommended. The EACTS recommends systematic screening for those aged >75 or at high stroke risk (Class IIa, Level B). However, this was not recommended by American Heart Association or Society of Thoracic Surgeons guidelines. All guidelines identified surgical AF ablation during concomitant cardiac surgery as safe and recommended for consideration by a Heart Team with notable variation in recommendation strength and the specific indication (three guidelines fail to specify any indication for surgery). Only the STS recommended left atrial appendage occlusion (LAAO) alongside surgical ablation (Class IIa, Level C). CONCLUSION: Disagreements exist in recommendations for specific indications for concomitant AF ablation and LAAO, with the decision subject to Heart Team assessment. Further evidence is needed to develop recommendations for specific indications for concomitant AF procedures and guidelines need to be made congruent.

Predictors of morbidity and in-hospital mortality following procedure-related cardiac tamponade.

Background: Cardiac tamponade (CT) can be a complication following invasive cardiac procedures. We assessed CT following common cardiac electrophysiology (EP) procedures to facilitate risk prediction of associated morbidity and in-hospital mortality. Methods: Patients who underwent various EP procedures in the cardiac catheterization lab (ablations and device implantations) were identified using the International Classification of Diseases, Ninth and Tenth Edition, Clinical Modification (ICD-9-CM and ICD-10-CM, respectively) from the Nationwide Inpatient Sample (NIS) database. Patient demographics, presence of comorbidities, CT-related events, and in-hospital death were also abstracted from the NIS database. Results: The frequency of CT-related events in patients with EP intervention from 2010 to 2017 ranged from 3.4% to 7.0%. In-hospital mortality related to CT-related events was found to be 2.2%. Increasing age was the only predictor of higher mortality in atrial fibrillation (AF) ablation and cardiac resynchronization therapy (CRT) groups (OR [95% CI]: AF ablation = 11.15 [1.70-73.34], p = .01; CRT = 1.41 [1.05-1.90], p = .02). Conclusions: In the real-world setting, CT-related events in EP procedures were found to be 3.4%-7.0% with in-hospital mortality of 2.2%. Older patients undergoing AF ablation were found to have higher mortality.

Revisiting Diagnosis and Treatment of Hypertrophic Cardiomyopathy: Current Practice and Novel Perspectives.

Sarcomeric hypertrophic cardiomyopathy (HCM) is a prevalent genetic disorder characterised by left ventricular hypertrophy, myocardial disarray, and an increased risk of heart failure and sudden cardiac death. Despite advances in understanding its pathophysiology, treatment options for HCM remain limited. This narrative review aims to provide a comprehensive overview of current clinical practice and explore emerging therapeutic strategies for sarcomeric HCM, with a focus on cardiac myosin inhibitors. We first discuss the conventional management of HCM, including lifestyle modifications, pharmacological therapies, and invasive interventions, emphasizing their limitations and challenges. Next, we highlight recent advances in molecular genetics and their potential applications in refining HCM diagnosis, risk stratification, and treatment. We delve into emerging therapies, such as gene editing, RNA-based therapies, targeted small molecules, and cardiac myosin modulators like mavacamten and aficamten, which hold promise in modulating the underlying molecular mechanisms of HCM. Mavacamten and aficamten, selective modulators of cardiac myosin, have demonstrated encouraging results in clinical trials by reducing left ventricular outflow tract obstruction and improving symptoms in patients with obstructive HCM. We discuss their mechanisms of action, clinical trial outcomes, and potential implications for the future of HCM management. Furthermore, we examine the role of precision medicine in HCM management, exploring how individualised treatment strategies, including exercise prescription as part of the management plan, may optimise patient outcomes. Finally, we underscore the importance of multidisciplinary care and patient-centred approaches to address the complex needs of HCM patients. This review also aims to encourage further research and collaboration in the field of HCM, promoting the development of novel and more effective therapeutic strategies, such as cardiac myosin modulators, to hopefully improve the quality of life and outcome of patients with sarcomeric HCM.

Health Care Resource, Economic, and Readmission Implications After Acute Decompensated Aortic Stenosis-A Nationwide Study.

Acute decompensated aortic stenosis (ADAS) is common. The cumulative burden of ADAS from a clinical, health care resource, and financial perspective is unknown. This study sought to assess the national impact of ADAS compared with electively treated, stable patients with aortic stenosis (non-ADAS). Using the National Readmissions Database between 2016 and 2019, patients with ADAS and non-ADAS were identified using International Classification of Diseases, Tenth Revision codes. Patients with ADAS were propensity-matched to non-ADAS patients (1:2) using age, gender, and Charlson co-morbidity index. We compared in-hospital mortality, length of stay (LOS), health care-associated costs, and 90-day readmission data between the 2 cohorts. A total of 51,498 propensity-matched patients were included in this study: median age 75 years, 64% men. The in-hospital mortality for ADAS was higher than non-ADAS (2.8% vs 1.5%, p <0.0001). The LOS during the index admission was longer for ADAS (9 [5 to 13] vs 4 [2 to 6] days, p <0.0001). The health care-associated costs per patient was greater for ADAS ($55,450.0 [41,860.4 to 74,500.7] vs $43,405.7 [34,218.5 to 56,034.8], p <0.0001). Readmission to hospital within 90 days was more frequent in ADAS (21.1 vs 16.8%, p <0.001). The in-hospital mortality during readmission was higher with ADAS (3.9% vs 2.8%, p = 0.004). The readmission LOS was longer with ADAS (4 [2 to 7] vs 3 [2 to 6] days, p <0.0001). In conclusion, ADAS imposes a significant burden clinically and financially and on health care resources compared with non-ADAS during the index admission and 90-day follow-up. There is an urgent need to predict ADAS and optimize the timing of aortic valve replacement to reduce the incidence and the burden associated with ADAS.

Sex-specific associations between daytime sleepiness, chronic diseases and mortality in obstructive sleep apnea.

Objective: Excessive daytime sleepiness (EDS) is common in obstructive sleep apnea (OSA) and has been linked to adverse outcomes, albeit inconsistently. Furthermore, whether the prognostic impact of EDS differs as a function of sex is unclear. We aimed to assess the associations between EDS and chronic diseases and mortality in men and women with OSA. Methods: Newly-diagnosed adult OSA patients who underwent sleep evaluation at Mayo Clinic between November 2009 and April 2017 and completed the Epworth Sleepiness Scale (ESS) for assessment of perceived sleepiness (N = 14,823) were included. Multivariable-adjusted regression models were used to investigate the relationships between sleepiness, with ESS modeled as a binary (ESS > 10) and as a continuous variable, and chronic diseases and all-cause mortality. Results: In cross-sectional analysis, ESS > 10 was independently associated with lower risk of hypertension in male OSA patients (odds ratio [OR], 95% confidence interval [CI]: 0.76, 0.69-0.83) and with higher risk of diabetes mellitus in both OSA men (OR, 1.17, 95% CI 1.05-1.31) and women (OR 1.26, 95% CI 1.10-1.45). Sex-specific curvilinear relations between ESS score and depression and cancer were noted. After a median 6.2 (4.5-8.1) years of follow-up, the hazard ratio for all-cause death in OSA women with ESS > 10 compared to those with ESS ≤ 10 was 1.24 (95% CI 1.05-1.47), after adjusting for demographics, sleep characteristics and comorbidities at baseline. In men, sleepiness was not associated with mortality. Conclusion: The implications of EDS for morbidity and mortality risk in OSA are sex-dependent, with hypersomnolence being independently associated with greater vulnerability to premature death only in female patients. Efforts to mitigate mortality risk and restore daytime vigilance in women with OSA should be prioritized.

Autonomic Cardiovascular Control in Health and Disease.

Autonomic neural control of the cardiovascular system is formed of complex and dynamic processes able to adjust rapidly to mitigate perturbations in hemodynamics and maintain homeostasis. Alterations in autonomic control feature in the development or progression of a multitude of diseases with wide-ranging physiological implications given the neural system's responsibility for controlling inotropy, chronotropy, lusitropy, and dromotropy. Imbalances in sympathetic and parasympathetic neural control are also implicated in the development of arrhythmia in several cardiovascular conditions sparking interest in autonomic modulation as a form of treatment. A number of measures of autonomic function have shown prognostic significance in health and in pathological states and have undergone varying degrees of refinement, yet adoption into clinical practice remains extremely limited. The focus of this contemporary narrative review is to summarize the anatomy, physiology, and pathophysiology of the cardiovascular autonomic nervous system and describe the merits and shortfalls of testing modalities available. © 2023 American Physiological Society. Compr Physiol 13:4493-4511, 2023.

Interpreting Incidentally Identified Variants in Genes Associated With Heritable Cardiovascular Disease: A Scientific Statement From the American Heart Association.

Rapid advances in genetic technologies have led to expanding use of diagnostic, research, and direct-to-consumer exome and genome sequencing. Incidentally identified variants from this sequencing represent a significant and growing challenge to interpret and translate into clinical care and include variants in genes associated with heritable cardiovascular disease such as cardiac ion channelopathies, cardiomyopathies, thoracic aortic disease, dyslipidemias, and congenital/structural heart disease. These variants need to be properly reported, the risk of associated disease accurately assessed, and clinical management implemented to prevent or lessen the disease so that cardiovascular genomic medicine can become both predictive and preventive. The goal of this American Heart Association consensus statement is to provide guidance to clinicians who are called on to evaluate patients with incidentally identified genetic variants in monogenic cardiovascular disease genes and to assist them in the interpretation and clinical application of variants. This scientific statement outlines a framework through which clinicians can assess the pathogenicity of an incidental variant, which includes a clinical evaluation of the patient and the patient's family and re-evaluation of the genetic variant in question. Furthermore, this guidance underscores the importance of a multidisciplinary team to address these challenging clinical evaluations and highlights how clinicians can effectively interface with specialty centers.

Impact of Sleep Duration and Chronotype on Cardiac Structure and Function: The UK Biobank Study.

Sleep duration and chronotype have been associated with increased morbidity and mortality. We assessed for associations between sleep duration and chronotype on cardiac structure and function. UK Biobank participants with CMR data and without known cardiovascular disease were included. Self-reported sleep duration was categorized as short (<7 h/d), normal (7-9 h/d) and long (>9 h/d). Self-reported chronotype was categories as "definitely morning" or "definitely evening." Analysis included 3903 middle-aged adults: 929 short, 2924 normal and 50 long sleepers; with 966 definitely-morning and 355 definitely-evening chronotypes. Long sleep was independently associated with lower left ventricular (LV) mass (-4.8%, P = 0.035), left atrial maximum volume (-8.1%, P = 0.041) and right ventricular (RV) end-diastolic volume (-4.8%, P = 0.038) compared to those with normal sleep duration. Evening chronotype was independently associated with lower LV end-diastolic volume (-2.4%, P = 0.021), RV end-diastolic volume (-3.6%, P = 0.0006), RV end systolic volume (-5.1%, P = 0.0009), RV stroke volume (RVSV -2.7%, P = 0.033), right atrial maximal volume (-4.3%, P = 0.011) and emptying fraction (+1.3%, P = 0.047) compared to morning chronotype. Sex interactions existed for sleep duration and chronotype and age interaction for chronotype even after considering potential confounders. In conclusion, longer sleep duration was independently associated with smaller LV mass, left atrial volume and RV volume. Evening chronotype was independently associated with smaller LV and RV and reduced RV function compared to morning chronotype. Sex interactions exist with cardiac remodeling most evident in males with long sleep duration and evening chronotype. Recommendations for sleep chronotype and duration may need to be individualized based on sex.

Accelerated Aging in LMNA Mutations Detected by Artificial Intelligence ECG-Derived Age.

OBJECTIVE: To demonstrate early aging in patients with lamin A/C (LMNA) gene mutations after hypothesizing that they have a biological age older than chronological age, as such a finding impacts care. PATIENT AND METHODS: We applied a previously trained convolutional neural network model to predict biological age by electrocardiogram (ECG) [Artificial Intelligence (AI)-ECG age] to LMNA patients evaluated by multiple ECGs from January 1, 2003, to December 31, 2019. The age gap was the difference between chronological age and AI-ECG age. Findings were compared with age-/sex-matched controls. RESULTS: Thirty-one LMNA patients who had a total of 271 ECGs were studied. The median age at symptom onset was 22 years (range, <1-53 years; n=23 patients); eight patients were asymptomatic family members carrying the LMNA mutation. Cardiac involvement was detected by ECG and echocardiogram in 16 patients and consisted of ventricular arrhythmias (13), atrial fibrillation (12), and cardiomyopathy (6). Four patients required cardiac transplantation. Fourteen patients had neurological manifestations, mainly muscular dystrophy. LMNA mutation carriers, including asymptomatic carriers, were 16 years older by AI-ECG than non-LMNA carriers, suggesting accelerated biological age. Most LMNA patients had an age gap of more than 10 years, compared with controls (P<.001). Consecutive AI-ECG analysis showed accelerated aging in the LMNA group compared with controls (P<.0001). There were no significant differences in age-gap among LMNA patients based on phenotype. CONCLUSION: AI-ECG predicted that LMNA patients have a biological age older than chronological age and accelerated aging even in the absence of cardiac abnormalities by traditional methods. Such a finding could translate into early medical intervention and serve as a disease biomarker.

Impact of Cardiac Implantable Electronic Devices on Cost and Length of Stay in Patients With Surgical Aortic Valve Replacement and Transcutaneous Aortic Valve Implantation.

Surgical aortic valve replacement (SAVR) and transcatheter aortic valve implantation (TAVI) in aortic stenosis are associated with arrhythmic complications that can require cardiac implantable electronic device (CIED) implantation, but impact on healthcare-associated cost (HAC) and length of stay (LOS) are unknown. This study aimed to assess differences among SAVR/TAVI patients with CIED implantation on HAC and LOS. Patients hospitalized for SAVR or TAVI between 2011 and 2017 on the National Inpatient Sample database were identified and stratified according to presence/type of CIED implantation. During this period, 95,262 patients were identified; 6,435 (6.8%) patients received CIED (median [interquartile range] age: 74.0 [66.0 to 82.0] years). The median adjusted HAC was $44,271 and LOS was 6 days. CIED implantation was associated with longer LOS and higher adjusted HAC in patients with SAVR and TAVI (p <0.0001). Patients with in-hospital death and complications because of SAVR or TAVI had longer preceding in-hospital days of admission. Male patients admitted to small hospitals and the West region had the highest HAC. In conclusion, CIED implantation for arrhythmias results in higher HAC and longer LOS in patients with aortic stenosis for both SAVR and TAVI.

Trends, Burden, and Impact of Arrhythmias on Cardiac Transplant Recipients: A 16-year Nationwide Study.

Orthotopic heart transplantation is the most effective long-term therapy for end-stage heart disease. Denervation with the loss of autonomic modulation, vasculopathy, utilization of immunosuppressant drugs, and allograft rejection may result in an increased prevalence of arrhythmias in transplanted hearts. We aim to describe the trends, distribution, and the clinical impact of arrhythmias in patients with transplanted hearts. We queried the National Inpatient Sample with administrative codes for cardiac transplant patients using procedure ICD-9-CM codes 37.5 and 33.6. Arrhythmias were extracted using validated ICD-9-CM codes. Statistical Analysis System (SAS) version 9.4 was used for analysis. There were a total of 30,020 hospitalizations of heart transplant recipients between 1999 and 2014 in the United States of which 1,6342 (54.4%) had an arrhythmia. The frequency of total arrhythmias increased from 53.6% (n=1,158) in 1999 to 67.3% (n=1,575) in 2014. Transplant patients with arrythmias was not associated with significantly higher inpatient mortality (7.72% vs 6.90%, P = 0.225). The most common arrythmia was atrial fibrillation ([AF]26.83%) followed by ventricular tachycardia (22.86%). Trends in mortality associated with arrhythmias following heart transplant has been decreasing from 12.3% in 1999 to 8.9% in 2014 (P = 0.04). Subgroup analysis of ventricular arrythmias (VA) following heart transplant were associated with increased mortality (8.61% vs 6.94%, P = 0.0229). Over half of patients develop 1 or more cardiac arrhythmia after heart transplant. There is an increasing secular trend in the frequency of arrhythmias post cardiac transplant with atrial fibrillation determined to be the most common arrhythmia.

Acute Decompensated Aortic Stenosis: State of the Art Review.

Aortic stenosis (AS) is a progressive disease that carries a poor prognosis. Patients are managed conservatively until satisfying an indication for transcatheter aortic valve implantation (TAVI) or surgical aortic valve replacement (SAVR) based on AS severity and the presence of symptoms or adverse impact on the myocardium. Up to 1 in 3 TAVIs are performed for patients with acute symptoms of dyspnea at rest, angina, and/or syncope - termed acute decompensated aortic stenosis (ADAS) and require urgent aortic valve replacement. These patients have longer hospital length of stay, undergo physical deconditioning, and have a higher rate of acute kidney injury and mortality compared to stable patients with less severe symptoms. There is an urgent need to prevent ADAS and to deliver pathways to manage and improve ADAS-related outcomes. We provide here a contemporary review on epidemiological and pathophysiological aspects of ADAS, with a focus on the impact of ADAS from clinical and economic perspectives. We offer a global overview of the available evidence for treatment of ADAS and with priorities suggested for addressing current gaps in the literature and unmet clinical needs to improve outcomes for AS patients.

Impact of Atrial Fibrillation on Outcomes of Aortic Valve Implantation.

New or preexisting atrial fibrillation (AF) is frequent in patients undergoing aortic valve replacement. We evaluated whether the presence of AF during transcatheter aortic valve implantation (TAVI) or surgical aortic valve replacement (SAVR) impacts the length of stay, healthcare adjusted costs, and inpatient mortality. The median length of stay in the patients with AF increased by 33.3% as compared with those without AF undergoing TAVI and SAVR (5 [3 to 8] days vs 3 [2 to 6] days, p <0.0001 and 8 [6 to 12] days vs 6 [5 to 10] days, p <0.0001, respectively). AF increased the median value of adjusted healthcare associated costs of both TAVI ($46,754 [36,613 to 59,442] vs $49,960 [38,932 to 64,201], p <0.0001) and SAVR ($40,948 [31,762 to 55,854] vs $45,683 [35,154 to 63,026], p <0.0001). The presence of AF did not independently increase the in-hospital mortality. In conclusion, in patients undergoing SAVR or TAVI, AF significantly increased the length of stay and adjusted healthcare adjusted costs but did not independently increase the in-hospital mortality.

Substrate Characterization and Outcome of Catheter Ablation of Ventricular Tachycardia in Patients With Nonischemic Cardiomyopathy and Isolated Epicardial Scar.

BACKGROUND: The substrate for ventricular tachycardia (VT) in left ventricular (LV) nonischemic cardiomyopathy may be epicardial. We assessed the prevalence, location, endocardial electrograms, and VT ablation outcomes in LV nonischemic cardiomyopathy with isolated epicardial substrate. METHODS: Forty-seven of 531 (9%) patients with LV nonischemic cardiomyopathy and VT demonstrated normal endocardial (>1.5 mV)/abnormal epicardial bipolar low-voltage area (LVA, <1.0 mV and signal abnormality). Abnormal endocardial unipolar LVA (≤8.3 mV) and endocardial bipolar split electrograms and predictors of ablation success were assessed. RESULTS: Epicardial bipolar LVA (27.3 cm2 [interquartile range, 15.8-50.0]) localized to basal (40), mid (8), and apical (3) LV with basal inferolateral LV most common (28/47, 60%). Of 44 endocardial maps available, 40 (91%) had endocardial unipolar LVA (24.5 cm2 [interquartile range, 9.4-68.5]) and 29 (67%) had characteristic normal amplitude endocardial split electrograms opposite the epicardial LVA. At mean of 34 months, the VT-free survival was 55% after one and 72% after multiple procedures. Greater endocardial unipolar LVA than epicardial bipolar LVA (hazard ratio, 10.66 [CI, 2.63-43.12], P=0.001) and number of inducible VTs (hazard ratio, 1.96 [CI, 1.27-3.00], P=0.002) were associated with VT recurrence. CONCLUSIONS: In patients with LV nonischemic cardiomyopathy and VT, the substrate may be confined to epicardial and commonly basal inferolateral. LV endocardial unipolar LVA and normal amplitude bipolar split electrograms identify epicardial LVA. Ablation targeting epicardial VT and substrate achieves good long-term VT-free survival. Greater endocardial unipolar than epicardial bipolar LVA and more inducible VTs predict VT recurrence.