Machine Learning - Based Bleeding Risk Predictions in Atrial Fibrillation Patients on Direct Oral Anticoagulants.

Importance: Accurately predicting major bleeding events in non-valvular atrial fibrillation (AF) patients on direct oral anticoagulants (DOACs) is crucial for personalized treatment and improving patient outcomes, especially with emerging alternatives like left atrial appendage closure devices. The left atrial appendage closure devices reduce stroke risk comparably but with significantly fewer non-procedural bleeding events. Objective: To evaluate the performance of machine learning (ML) risk models in predicting clinically significant bleeding events requiring hospitalization and hemorrhagic stroke in non-valvular AF patients on DOACs compared to conventional bleeding risk scores (HAS-BLED, ORBIT, and ATRIA) at the index visit to a cardiologist for AF management. Design: Prognostic modeling with retrospective cohort study design using electronic health record (EHR) data, with clinical follow-up at one-, two-, and five-years. Setting: University of Pittsburgh Medical Center (UPMC) system. Participants: 24,468 non-valvular AF patients aged ≥18 years treated with DOACs, excluding those with prior history of significant bleeding, other indications for DOACs, on warfarin or contraindicated to DOACs. Exposures: DOAC therapy for non-valvular AF. Main Outcomes and Measures: The primary endpoint was clinically significant bleeding requiring hospitalization within one year of index visit. The models incorporated demographic, clinical, and laboratory variables available in the EHR at the index visit. Results: Among 24,468 patients, 553 (2.3%) had bleeding events within one year, 829 (3.5%) within two years, and 1,292 (5.8%) within five years of index visit. We evaluated multivariate logistic regression and ML models including random forest, classification trees, k-nearest neighbor, naive Bayes, and extreme gradient boosting (XGBoost) which modestly outperformed HAS-BLED, ATRIA, and ORBIT scores in predicting clinically significant bleeding at 1-year follow-up. The best performing model (random forest) showed area under the curve (AUC-ROC) 0.76 (0.70-0.81), G-Mean score of 0.67, net reclassification index 0.14 compared to 0.57 (0.50-0.63), G-Mean score of 0.57 for HASBLED score, p-value for difference <0.001. The ML models had improved performance compared to conventional risk across time-points of 2-year and 5-years and within the subgroup of hemorrhagic stroke. SHAP analysis identified novel risk factors including measures from body mass index, cholesterol profile, and insurance type beyond those used in conventional risk scores. Conclusions and Relevance: Our findings demonstrate the superior performance of ML models compared to conventional bleeding risk scores and identify novel risk factors highlighting the potential for personalized bleeding risk assessment in AF patients on DOACs.

Long-Term Changes in Atrial Arrhythmia Burden After Renal Denervation Combined With Pulmonary Vein Isolation: SYMPLICITY-AF.

BACKGROUND: The autonomic nervous system plays an important role in atrial fibrillation (AF) and hypertension. Renal denervation (RDN) lowers blood pressure (BP), but its role in AF is poorly understood. OBJECTIVES: The purpose of this study was to investigate whether RDN reduces AF recurrence after pulmonary vein isolation (PVI). METHODS: This study randomized patients from 8 centers (United States, Germany) with drug-refractory AF for treatment with PVI+RDN vs PVI alone. A multielectrode radiofrequency Spyral catheter system was used for RDN. Insertable cardiac monitors were used for continuous rhythm monitoring. The primary efficacy endpoint was ≥2 minutes of AF recurrence or repeat ablation during all follow-up. The secondary endpoints included atrial arrhythmia (AA) burden, discontinuation of class I/III antiarrhythmic drugs, and BP changes from baseline. RESULTS: A total of 70 patients with AF (52 paroxysmal, 18 persistent) and uncontrolled hypertension were randomized (RDN+PVI, n = 34; PVI, n = 36). At 3.5 years, 26.2% and 21.4% of patients in RDN+PVI and PVI groups, respectively, were free from the primary efficacy endpoint (log rank P = 0.73). Patients with mean ≥1 h/d AA had less daily AA burden after RDN+PVI vs PVI (4.1 hours vs 9.2 hours; P = 0.016). More patients discontinued class I/III antiarrhythmic drugs after RDN+PVI vs PVI (45% vs 14%; P = 0.040). At 1 year, systolic BP changed by -17.8 ± 12.8 mm Hg and -13.7 ± 18.8 mm Hg after RDN+PVI and PVI, respectively (P = 0.43). The composite safety endpoint was not significantly different between groups. CONCLUSIONS: In patients with AF and uncontrolled BP, RDN+PVI did not prevent AF recurrence more than PVI alone. However, RDN+PVI may reduce AF burden and antiarrhythmic drug usage, but this needs further prospective validation.

Impact of Weight Gain on Cardiovascular Outcomes in Patients With Atrial Fibrillation.

BACKGROUND: The long-term impact of weight gain (WG) on cardiovascular outcomes among patients with atrial fibrillation (AF) is unclear. METHODS AND RESULTS: We studied 62 871 (mean age, 72±12, 43% women) adult patients with AF evaluated at the University of Pittsburgh Medical Center between January 1, 2010, and May 13, 2021. Serial body mass index, risk factors, comorbidities, and subsequent death and hospitalization were ascertained and stratified according to percentage WG (≥0% to <5%, ≥5% to <10%, and ≥10%). Over 4.9±3.19 years of follow-up, 27 114 (43%) patients gained weight (61%, ≥0% to <5%; 23%, ≥5% to <10%; 16%, ≥10%). Patients with progressive WG were incrementally younger (P<0.001) women (40%, 42%, and 47%) with lower median household income (P=0.002) and active smoking (8%, 13% and 13%), and they were less likely to be on a non-vitamin K oral anticoagulant (39%, 37%, and 32%). WG was incrementally associated with a significant increase in risk of hospitalization for AF (≥10% WG; hazard ratio [HR], 1.2 [95% CI, 1.2-1.3]; P<0.0001), heart failure (≥10% WG; HR, 1.44 [95% CI, 1.3-1.6]; P<0.001; ≥5% to <10% WG; HR, 1.17 [95% CI, 1.1-1.2]; P<0.001), myocardial infarction (≥10% WG; HR, 1.2 [95% CI, 1.3-1.6]; P<0.001) and all-cause stroke (4.2%, 4.3%, and 5.6%) despite significantly lower mean CHADS2Vasc score (2.9±1.7, 2.7±1.6, and 2.7±1.7). Patients with more WG were significantly more likely to receive cardiac and electrophysiologic interventions. CONCLUSIONS: Among patients with AF, WG is incrementally associated with increased hospitalization for cardiovascular causes, particularly heart failure, stroke, myocardial infarction, and AF.

Mortality, Hospitalization, and Cardiac Interventions in Patients With Atrial Fibrillation Aged <65 Years.

BACKGROUND: The risk factor (RF) burden, clinical course, and long-term outcome among patients with atrial fibrillation (AF) aged <65 years is unclear. METHODS: Adult (n=67 221; mean age, 72.4±12.3 years; and 45% women) patients with AF evaluated at the University of Pittsburgh Medical Center between January 2010 and December 2019 were studied. Hospital system-wide electronic health records and administrative data were utilized to ascertain RFs, comorbidities, and subsequent hospitalization and cardiac interventions. The association of AF with all-cause mortality among those aged <65 years was analyzed using an internal contemporary cohort of patients without AF (n=918 073). RESULTS: Nearly one-quarter (n=17 335) of the cohort was aged <65 years (32% women) with considerable cardiovascular RFs (current smoker, 16%; mean body mass index, 33.0±8.3; hypertension, 55%; diabetes, 21%; heart failure, 20%; coronary artery disease, 19%; and prior ischemic stroke, 6%) and comorbidity burden (chronic obstructive pulmonary disease, 11%; obstructive sleep apnea, 18%; and chronic kidney disease, 1.3%). Over mean follow-up of >5 years, 2084 (6.7%, <50 years; 13%, 50-65 years) patients died. The proportion of patients with >1 hospitalization for myocardial infarction, heart failure, and stroke was 1.3%, 4.8%, and 1.1% for those aged <50 years and 2.2%, 7.4%, and 1.1% for the 50- to 65-year subgroup, respectively. Multiple cardiac and noncardiac RFs were associated with increased mortality in younger patients with AF with heart failure and hypertension demonstrating significant age-related interaction (P=0.007 and P=0.013, respectively). Patients with AF aged <65 years experienced significantly worse survival compared with comorbidity-adjusted patients without AF (men aged <50 years and hazard ratio, 1.5 [95% CI, 1.24-1.79]; 50-65 years and hazard ratio, 1.3 [95% CI, 1.26-1.43]; women aged <50 years and hazard ratio, 2.4 [95% CI, 1.82-3.16]; 50-65 years and hazard ratio, 1.7 [95% CI, 1.6-1.92]). CONCLUSIONS: Patients with AF aged <65 years have significant comorbidity burden and considerable long-term mortality. They are also at a significantly increased risk of hospitalization for heart failure, stroke, and myocardial infarction. These patients warrant an aggressive focus on RF and comorbidity evaluation and management.

Heart Rate at Rest and Incident Atrial Fibrillation in Patients With Diastolic Dysfunction.

Diastolic dysfunction (DD) is associated with incident atrial fibrillation (AF). The influence of heart rate at rest (RHR) on incident AF in patients with DD has not been investigated. The goal of this study is to assess the influence of RHR on incident AF in patients with DD. Patients from a large health system with no previous history of AF, a left ventricular ejection fraction ≥50%, and documented DD on echocardiography were divided into quartiles (<66, 66 to 76, 77 to 91, >91 beats per minute) based on RHR. Incident AF was estimated using AF hospitalization during follow-up. Hazard ratios (HR) for AF hospitalization and all-cause death were calculated with a Cox proportional hazards model. A total of 19,046 patients were analyzed. Over a median follow-up of 42.2 months, 742 (3.9%) patients were hospitalized for AF. Both slower and faster RHR were associated with increased risk of AF hospitalization (HR 1.40, confidence interval [CI] 1.14 to 1.71, p = 0.001, HR 1.23, CI 0.99 to 1.53, p = 0.06 and HR 1.72, CI 1.38 to 2.14, p <0.001, for quartiles 1, 2, and 4, respectively), suggesting a J-shaped relation. Progressive increase in all-cause death was noted with faster RHR (HR1.19 per quartile increase, CI 1.16 to 1.22, p <0.001). These results persisted after adjustment for age, cardiovascular co-morbidities, grade of DD, and ß-blocker use. In conclusion, this large, real-world analysis indicates increased risk of incident AF with slower and faster RHR in patients with DD. Randomized trials are needed to evaluate the potential of RHR modification to mitigate the risk of incident AF.

Ventricular arrhythmia inducibility in porcine infarct model after stereotactic body radiation therapy.

BACKGROUND: Ventricular arrhythmia (VA) is the primary mechanism of sudden death in patients with structural heart disease. Cardiac stereotactic body radiation therapy (SBRT) delivered to the scar in the left ventricle significantly reduces the burden of VA. OBJECTIVE: The goal of this study was to investigate the impact of SBRT on scar morphology and VA inducibility in a porcine infarct model. METHODS: Myocardial infarction (MI) was created in 10 Yorkshire pigs involving the left anterior descending artery territory. Cardiac positron emission tomography and computed tomography were performed for targeted SBRT. Alternative pigs received SBRT at 25 Gy in a single fraction. The terminal experiment included endocardial mapping, programmed ventricular stimulation, and tissue harvesting. RESULTS: Of the 10 pigs infarcted, 2 died prematurely after MI and 8 (4 MI and 4 MI+SBRT) survived. Mean time from MI to SBRT was 48 ± 12 days, and mean time from SBRT to harvest was 32 ± 12 days. Scar was localized on intracardiac mapping in all pigs, and the scar was denser in the MI+SBRT compared with the MI-only group (33% ± 20% vs 14% ± 11%; P = .07). All 4 MI pigs had inducible VA during programmed stimulation, whereas only 1 of 4 pigs had inducible VA in the MI+SBRT arm (100% vs 25%; P = .07). No myocardial fibrosis was seen in the remote areas in either group. CONCLUSION: SBRT reduced VA inducibility in pigs with scarring after MI. Endocardial mapping revealed denser scar in pigs receiving SBRT compared with those that did not, suggesting that SBRT suppresses VA inducibility through better scar homogenization.

Patient Outcomes by Ventricular Systolic and Diastolic Function.

BACKGROUND: Left ventricular dysfunction is characterized by systolic and diastolic parameters, leading to heart failure (HF) with reduced or preserved ejection fraction (EF), respectively. The goal of this study is to examine the impact of left ventricular systolic and diastolic dysfunction (DD) on patient outcomes. METHODS AND RESULTS: Two cohorts were used in this analysis: Cohort A included 136 455 patients with EF ≥50%, stratified by the presence and grade of DD. Cohort B included 16 850 patients with EF <50%, stratified by EF quartiles. Patients were followed to the end points of all-cause death and cardiovascular, HF, or cardiac arrest hospitalizations. Over a median follow-up of 3.42 years, 23 946 (16%) patients died and 31 113 (20%), 13 305 (9%), and 1269 (1%) were hospitalized for cardiovascular, HF, or cardiac arrest causes, respectively. With adjustment for comorbidities, the risk of all-cause mortality and of cardiovascular and HF hospitalizations increased steadily with increasing grade of DD in patients with normal EF, and even more so in patients with worsening EF. The risk of hospitalization for cardiac arrest in patients with grade III DD, however, was comparable to that of patients with EF <25% (hazard ratio, 1.00 [95% CI, 0.98-1.01]) and worse than that of patients in better EF quartiles. CONCLUSIONS: Although systolic dysfunction is associated with a greater risk of overall death and HF hospitalizations than DD, the risk of cardiac arrest in patients with grade II and III DD is comparable to that of patients with moderate and severe systolic dysfunction, respectively. Future studies are needed to examine treatment strategies than can improve these outcomes.

COVID-19 pandemic and initiation of treatment for atrial fibrillation: a nationwide analysis of claims data.

BACKGROUND: The COVID-19 pandemic profoundly disrupted the delivery of medical care. It remains unclear whether individuals diagnosed with new onset disease during the pandemic were less likely to initiate treatments after diagnosis. We sought to evaluate changes in the treatment initiation of patients newly diagnosed with atrial fibrillation (AF) after the onset of the COVID-19 pandemic. METHODS: In this retrospective cohort study, we identified individuals with incident AF from 01/01/2016-09/30/2021 using Optum's de-identified Clinformatics® Data Mart Database. The primary outcome was initiation of oral anticoagulation (OAC) within 30 days of AF diagnosis. Secondary outcomes included initiation of OAC within 180 days of diagnosis, initiation of warfarin, direct oral anticoagulants (DOACs), rhythm control medications and electrical cardioversion within 30 days of diagnosis. We constructed interrupted time series analyses to examine changes in the outcomes following the onset of the pandemic. RESULTS: A total of 573,524 patients (age 73.0 ± 10.9 years) were included in the study. There were no significant changes in the initiation of OAC, DOAC, and rhythm control medications associated with the onset of the pandemic. There was a significant decrease in initiation of electrical cardioversion associated with the onset of the pandemic. The rate of electronic cardioversion within 30 days of diagnosis decreased by 4.9% per 1,000 patients after the onset of the pandemic and decreased by about 35% in April 2020, compared to April 2019, from 5.53% to 3.58%. CONCLUSION: The COVID-19 pandemic did not affect the OAC initiation within 30 days of AF diagnosis but was associated with a decline in the provision of procedures for patients newly diagnosed with AF.

Association of pre-left ventricular assist device defibrillator shocks for ventricular arrhythmia with clinical outcomes after left ventricular assist device implantation.

Background: Implantable cardioverter-defibrillation (ICD) shocks after left ventricular assist device therapy (LVAD) are associated with adverse clinical outcomes. Little is known about the association of pre-LVAD ICD shocks on post-LVAD clinical outcomes and whether LVAD therapy affects the prevalence of ICD shocks. Objectives: The purpose of this study was to determine whether pre-LVAD ICD shocks are associated with adverse clinical outcomes post-LVAD and to compare the prevalence of ICD shocks before and after LVAD therapy. Methods: Patients 18 years or older with continuous-flow LVADs and ICDs were retrospectively identified within the University of Pittsburgh Medical Center system from 2006-2020. We analyzed the association between appropriate ICD shocks within 1 year pre-LVAD with a primary composite outcome of death, stroke, and pump thrombosis and secondary outcomes of post-LVAD ICD shocks and ICD shock hospitalizations. Results: Among 309 individuals, average age was 57 ± 12 years, 87% were male, 80% had ischemic cardiomyopathy, and 42% were bridge to transplantation. Seventy-one patients (23%) experienced pre-LVAD shocks, and 69 (22%) experienced post-LVAD shocks. The overall prevalence of shocks pre-LVAD and post-LVAD were not different. Pre-LVAD ICD shocks were not associated with the composite outcome. Pre-LVAD ICD shocks were found to predict post-LVAD shocks (hazard ratio [HR] 5.7; 95% confidence interval [CI] 3.42-9.48; P <.0001) and hospitalizations related to ICD shocks from ventricular arrhythmia (HR 10.34; 95% CI 4.1-25.7; P <.0001). Conclusion: Pre-LVAD ICD shocks predicted post-LVAD ICD shocks and hospitalizations but were not associated with the composite outcome of death, pump thrombosis, or stroke at 1 year. The prevalence of appropriate ICD shocks was similar before and after LVAD implantation in the entire cohort.

Cardiovascular Hospitalizations and Resource Use Following Atrial Fibrillation Ablation.

Background Over the next few years, atrial fibrillation (AF)-related morbidity and costs will increase significantly. Thus, it is prudent to examine the impact of AF treatment on health care resource use. This study examined the impact of AF ablation on hospitalization, length of stay, and resource use for patients undergoing AF ablation in a multihospital system. Methods and Results In an observational analysis, outcomes of total, cardiovascular, and AF hospitalizations, emergency department visits, and length of stay were compared for 3417 patients between 12 months before and 24 months following AF ablation. Use of electrical cardioversions and antiarrhythmic use were also compared 1 year before to 2 years after AF ablation. There were fewer total (0.7±1.3 versus 0.3±0.7; P<0.001), cardiovascular (0.7±1.2 versus 0.2±0.6; P<0.001), and AF (0.6±1.1 versus 0.1±0.3; P<0.001) hospitalizations and emergency department visits (0.8±2.1 versus 0.4±0.9; P<0.001) per patient-year for the 2 years following AF ablation compared with 1 year before. Average length of stay per patient-year (1.4±7.9 versus 3.6±5.3 days; P<0.0001), the percentage of patients on antiarrhythmic therapy (21.2% versus 58.5%; P<0.0001), and those undergoing electrical cardioversions (16.1% versus 28.1%; P<0.0001) were lower 2 years following AF ablation versus 1 year before. Conclusions We noted a decrease in total, cardiovascular, and AF hospitalizations and health care resource use during the 2-year period after index AF ablation, compared with the 1 year before. AF ablation may portend a decline in patient morbidity and health care costs.

Targeted left ventricular lead positioning to the site of latest activation in cardiac resynchronization therapy: a systematic review and meta-analysis.

AIMS: Several studies have evaluated the use of electrically- or imaging-guided left ventricular (LV) lead placement in cardiac resynchronization therapy (CRT) recipients. We aimed to assess evidence for a guided strategy that targets LV lead position to the site of latest LV activation. METHODS AND RESULTS: A systematic review and meta-analysis was performed for randomized controlled trials (RCTs) until March 2023 that evaluated electrically- or imaging-guided LV lead positioning on clinical and echocardiographic outcomes. The primary endpoint was a composite of all-cause mortality and heart failure hospitalization, and secondary endpoints were quality of life, 6-min walk test (6MWT), QRS duration, LV end-systolic volume, and LV ejection fraction. We included eight RCTs that comprised 1323 patients. Six RCTs compared guided strategy (n = 638) to routine (n = 468), and two RCTs compared different guiding strategies head-to-head: electrically- (n = 111) vs. imaging-guided (n = 106). Compared to routine, a guided strategy did not significantly reduce the risk of the primary endpoint after 12-24 (RR 0.83, 95% CI 0.52-1.33) months. A guided strategy was associated with slight improvement in 6MWT distance after 6 months of follow-up of absolute 18 (95% CI 6-30) m between groups, but not in remaining secondary endpoints. None of the secondary endpoints differed between the guided strategies. CONCLUSION: In this study, a CRT implantation strategy that targets the latest LV activation did not improve survival or reduce heart failure hospitalizations.

Safety of Catheter Ablation Therapy for Atrial Fibrillation in Cardiac Amyloidosis.

Background Despite the high burden of atrial fibrillation in cardiac amyloidosis (CA), the safety of catheter ablation therapy in CA is not well established. We sought to examine short-term safety outcomes following atrial fibrillation ablation in patients with CA compared with matched patients with dilated cardiomyopathy (DCM). Methods and Results Using data from the National Inpatient Sample, we identified all hospitalizations for atrial fibrillation ablation from the fourth quarter of 2015 through 2019. Admissions for CA and DCM were matched in a 1:5 ratio using propensity scores based on the following sociodemographics: age, sex, race or ethnicity, payor, median income, comorbidities, and hospital characteristics. We compared in-hospital outcomes between both cardiomyopathies. We identified 1395 unweighted hospitalizations (representing 6750 national hospitalizations) for atrial fibrillation ablation, out of which 45 (3.2%) were admissions for CA. Compared with DCM, patients with CA were older (72.9 versus 65.1 years), had a higher burden of prior stroke (20.0% versus 8.6%) and chronic kidney disease (53.3% versus 33.6%), and were less likely to have a prior implantable cardioverter-defibrillator (4.4% versus 23.0%). We successfully matched 42 CAs to 210 DCM hospitalizations. After matching, there was no difference in total complications (14.3% versus 10.5%, P=0.60), length-of-stay (3.1 versus 2.1 days, P=0.23), home disposition (97.6% versus 96.2%, P=0.65), and total charges ($137 250 versus $133 910, P=0.24). Conclusions In this nationally representative study of atrial fibrillation catheter ablation in CA, short-term safety outcomes and complication rates were similar to a propensity score-matched cohort of DCM. Further studies exploring long-term safety outcomes are needed.

Machine learning for ECG diagnosis and risk stratification of occlusion myocardial infarction.

Patients with occlusion myocardial infarction (OMI) and no ST-elevation on presenting electrocardiogram (ECG) are increasing in numbers. These patients have a poor prognosis and would benefit from immediate reperfusion therapy, but, currently, there are no accurate tools to identify them during initial triage. Here we report, to our knowledge, the first observational cohort study to develop machine learning models for the ECG diagnosis of OMI. Using 7,313 consecutive patients from multiple clinical sites, we derived and externally validated an intelligent model that outperformed practicing clinicians and other widely used commercial interpretation systems, substantially boosting both precision and sensitivity. Our derived OMI risk score provided enhanced rule-in and rule-out accuracy relevant to routine care, and, when combined with the clinical judgment of trained emergency personnel, it helped correctly reclassify one in three patients with chest pain. ECG features driving our models were validated by clinical experts, providing plausible mechanistic links to myocardial injury.

Evaluation of Wearable Acoustic Sensors and Machine Learning Algorithms for Automated Measurement of Left Ventricular Ejection Fraction.

Left ventricular ejection fraction (EF) is a predictor of mortality and guides clinical decisions. Although transthoracic echocardiography (TTE) is commonly used for measuring EF, it has limitations, such as subjectivity and requires expert personnel. Advancements in biosensor technology and artificial intelligence are allowing systems capable of determining left ventricular function and providing automated measurement of EF. In this study, we tested new wearable automated real-time biosensors (Cardiac Performance System [CPS]) that compute EF using waveform machine learning on cardiac acoustic signals. The primary aim was to compare the accuracy of CPS EF with TTE EF. Adult patients presenting to cardiology, presurgical, and diagnostic radiology clinical settings in an academic center were enrolled. TTE examination was performed by a sonographer, followed immediately by a 3-minute recording of acoustic signals from CPS biosensors placed on the chest by nonexpert personnel. TTE EF was calculated offline using the Simpson biplane method. A total of 81 patients (aged 19 to 88 years, 27 women, 20% to 80% EF) were included. Deming regression and Bland-Altman analysis were performed to assess the accuracy of CPS EF against TTE EF. Both Deming regression (slope 0.9981; intercept 0.03415%) and Bland-Altman analysis (bias -0.0247%; limits of agreement [-11.65, 11.60]%) demonstrated equivalency between CPS EF and TTE EF. The receiver operating characteristic for measuring sensitivity and specificity of CPS in identifying subjects with abnormal EF showed an area under the curve value of 0.974 for identifying EF <35% and 0.916 for detecting EF <50% CPS EF intraoperator and interoperator assessments demonstrated low variability. In conclusion, this technology measuring cardiac function from noninvasive biosensors and machine learning on acoustic signals provides an accurate EF measurement that is automated, real-time, and acquired rapidly by personnel with minimal training.

Relative Contribution of Atrial Fibrillation to Outcomes of Patients With Cardiomyopathy Based on Severity of Left Ventricular Dysfunction.

In patients with left ventricular (LV) dysfunction, the risk of death or heart failure hospitalizations (HFHs) increases with worsening ejection fraction (EF). Whether the relative contribution of atrial fibrillation (AF) to outcomes is more pronounced in patients with worse EF is not confirmed. The present study aimed to investigate the relative influence of AF on the outcome of cardiomyopathy patients by severity of LV dysfunction. In this observational study, data from 18,003 patients with EF ≤50% seen at a large academic institution between 2011 and 2017 were analyzed. Patients were stratified by EF quartiles (EF<25%, 25%≤EF<35%, 35%≤EF<40%, and EF≥40%, for quartiles 1, 2, 3, and 4, respectively). and followed to the end point of death or HFH. Outcomes of AF versus non-AF patients were compared within each EF quartile. During a median follow-up of 3.35 years, 8,037 patients (45%) died and 7,271 (40%) had at least 1 HFH. Rates of HFH and all-cause mortality increased as EF decreased. The hazard ratios (HRs) of death or HFH for AF versus non-AF patients increased steadily with increasing EF (HR of 1.22, 1.27, 1.45, 1.50 for quartiles 1, 2, 3, and 4, respectively, p = 0.045) driven primarily by the risk of HFH (HR of 1.26, 1.45, 1.59, 1.69 for quartiles 1, 2, 3, and 4, respectively, p = 0.045). In conclusion, in patients with LV dysfunction, the detrimental influence of AF on the risk of HFH is more pronounced in those with more preserved EF. Mitigation strategies for AF with the goal of decreasing HFH may be more impactful in patients with more preserved LV function.