Nonsustained ventricular tachycardia in heart failure with preserved ejection fraction

Impact on ventricular arrhythmic burden of SGLT2 inhibitors in patients with chronic heart failure evaluated with cardiac implantable electronic device monitoring

BACKGROUND

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have revolutionized the therapeutic scenario of heart failure, demonstrating favorable effects on mortality and quality of life. Previous studies have yielded conflicting data regarding the effects on ventricular arrhythmias.

METHODS

A prospective observational study was conducted to investigate the anti-arrhythmic properties of SGLT2 inhibitors evaluating the intra-patient difference in major adverse arrhythmic cardiac events (MAACE) over a six-month period in patients with chronic heart failure who were undergoing continuous monitoring using a cardiac implantable electronic device.

RESULTS

From January 2022 to January 2023, 82 patients [median age 63 years (IQR 15), male 87 %] were enrolled in the study, with a median follow-up of 28 weeks (IQR 5). The rate of MAACE at baseline was 11 %, without relevant differences in the follow up in terms of major and minor arrhythmic events. In patients with an arrhythmic phenotype at baseline, a mild but non statistically significant reduction of MAACE (from 36 % to 28 %, p = 0.727) was observed and a significant decrease of non-sustained ventricular tachycardia (from 68 % to 32 %, p = 0.022).

CONCLUSIONS

Our findings suggest potential anti-arrhythmic properties of SGLT2 inhibitors, evident in patients with arrhythmic events before the initiation of the drug.

Sudden Cardiac Death Risk Stratification in Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) poses a significant clinical challenge, with sudden cardiac death (SCD) emerging as one of the leading causes of mortality. Despite advancements in cardiovascular medicine, predicting and preventing SCD in HFpEF remains complex due to multifactorial pathophysiological mechanisms and patient heterogeneity. Unlike heart failure with reduced ejection fraction, where impaired contractility and ventricular remodeling predominate, HFpEF pathophysiology involves heavy burden of comorbidities such as hypertension, obesity, and diabetes. Diverse mechanisms, including diastolic dysfunction, microvascular abnormalities, and inflammation, also contribute to distinct disease and SCD risk profiles. Various parameters such as clinical factors and electrocardiogram features have been proposed in SCD risk assessment. Advanced imaging modalities and biomarkers offer promise in risk prediction, yet comprehensive risk stratification models specific to HFpEF ar0e lacking. This review offers recent evidence on SCD risk factors and discusses current therapeutic strategies aimed at reducing SCD risk in HFpEF.

Characteristics Associated with Ventricular Tachyarrhythmias and Their Prognostic Impact in Heart Failure with Mildly Reduced Ejection Fraction

Background: The occurrence of ventricular tachyarrhythmias represents an established risk factor of mortality in heart failure (HF). However, data concerning their prognostic impact in heart failure with mildly reduced ejection fraction (HFmrEF) is limited. Therefore, the present study aims to investigate patient characteristics associated with ventricular tachyarrhythmias and their prognostic impact in patients with HFmrEF. Methods: Consecutive patients hospitalized with HFmrEF (i.e., left ventricular ejection fraction 41-49% and signs and/or symptoms of HF) were retrospectively included at one institution from 2016 to 2022. The prognosis of patients with HFmrEF and different types of ventricular tachyarrhythmias (i.e., non-sustained ventricular tachycardia (nsVT), sustained VT (sVT), and ventricular fibrillation (VF) was investigated for the primary endpoint of long-term all-cause mortality at 30 months. Secondary endpoints included in-hospital all-cause mortality and long-term HF-related rehospitalization at 30 months. Results: From a total of 2184 patients with HFmrEF, 4.4% experienced ventricular tachyarrhythmias (i.e., 2.0% nsVT, 0.7% sVT, and 1.6% VF). The occurrence of nsVT was associated with higher New York Heart Association (NYHA) functional class, whereas the incidence of sVT/VF was associated with acute myocardial infarction and ischemic heart disease. However, nsVT (25.0%; HR = 0.760; 95% CI 0.419-1.380; p = 0.367) and sVT/VF (28.8%; HR = 0.928; 95% CI 0.556-1.549; p = 0.776) were not associated with a higher risk of long-term all-cause mortality compared to patients with HFmrEF without ventricular tachyarrhythmias (31.5%). In-hospital cardiovascular mortality was more frequently observed in patients with HFmrEF and sVT/VF compared to those with HFmrEF but without sustained ventricular tachyarrhythmias (7.7% vs. 1.5%; p = 0.004). Finally, the risk of rehospitalization for worsening HF was not affected by the presence of ventricular tachyarrhythmias. Conclusions: The occurrence of ventricular tachyarrhythmias in patients hospitalized with HFmrEF was low and not associated with long-term prognosis.

Differential sex-dependent susceptibility to diastolic dysfunction and arrhythmia in cardiomyocytes from obese diabetic HFpEF model

AIM

Sex-differences in heart failure with preserved ejection fraction (HFpEF) are important, but key mechanisms involved are incompletely understood. While animal models can inform about sex-dependent cellular and molecular changes, many previous preclinical HFpEF models have failed to recapitulate sex-dependent characteristics of human HFpEF. We tested for sex-differences in HFpEF using a two-hit mouse model (leptin receptor-deficient db/db mice plus aldosterone infusion for 4 weeks; db/db+Aldo).

METHODS AND RESULTS

We performed echocardiography, electrophysiology, intracellular Ca2+ imaging, and protein analysis. Female HFpEF mice exhibited more severe diastolic dysfunction in line with increased titin N2B isoform expression and PEVK element phosphorylation, and reduced troponin-I phosphorylation. Female HFpEF mice had lower BNP levels than males despite similar comorbidity burden (obesity, diabetes) and cardiac hypertrophy in both sexes. Male HFpEF mice were more susceptible to cardiac alternans. Male HFpEF cardiomyocytes (versus female) exhibited higher diastolic [Ca2+], slower Ca2+ transient decay, reduced L-type Ca2+ current, more pronounced enhancement of the late Na+ current, and increased short-term variability of action potential duration (APD). However, male and female HFpEF myocytes showed similar downregulation of inward rectifier and transient outward K+ currents, APD prolongation, and frequency of delayed afterdepolarizations. Inhibition of Ca2+/calmodulin-dependent protein kinase II (CaMKII) reversed all pathological APD changes in HFpEF in both sexes, and empagliflozin pretreatment mimicked these effects of CaMKII inhibition. Vericiguat had only slight benefits, and these effects were larger in HFpEF females.

CONCLUSION

We conclude that the db/db+Aldo preclinical HFpEF murine model recapitulates key sex-specific mechanisms in HFpEF and provides mechanistic insights into impaired excitation-contraction coupling and sex-dependent differential arrhythmia susceptibility in HFpEF with potential therapeutic implications. In male HFpEF myocytes, altered Ca2+ handling and electrophysiology aligned with diastolic dysfunction and arrhythmias, while worse diastolic dysfunction in females may depend more on altered myofilaments properties.

QT prolongation predicts all-cause mortality above and beyond a validated risk score

INTRODUCTION

QT prolongation is a risk factor for life-threatening arrhythmias and sudden cardiac death. In large cohorts, QT interval was associated with all-cause mortality, but these analyses may contain residual confounding. Whether the QT interval provides prognostic information above and beyond a validated mortality risk score is unknown. We hypothesized that QT interval on ECG will independently predict mortality after adjustment for the Care Assessment Needs (CAN) score, which was validated to predict mortality nationwide at the Veterans Administration (VA) (c-index 0.86).

METHODS

Outpatients with an ECG at the Minneapolis VA from 2012 to 2016 were included in this retrospective cohort study. ECGs with ventricular rate < 50 or > 100 beats/min and those with QRS > 120 ms were excluded. QT intervals were corrected (QTc) using the Bazett's formula. CAN score, calculated within 1-week of the ECG, was obtained from the VA Corporate Data Warehouse.

RESULTS

Of the 31,201 patients, 427 (1.4%) had QTc ≥ 500 ms, 1799 (5.8%) had QTc 470-500 ms and 28,975 (92.9%) had QTc < 470 ms. Compared to those with QTc < 470 ms, CAN-adjusted odds ratios (OR) for 1-year mortality (1.76 for QTc 470-500 and 2.70 for QTc > 500 ms; p < 0.0001 for both) and for 5-year mortality (1.75 for QTc 470-500 and 2.48 for QTc > 500 ms; p < 0.0001 for both) were significantly higher in those with longer QTc. C-index for CAN score and QTc predicting 1-year mortality was 0.837.

CONCLUSIONS

QT prolongation predicts all-cause mortality independently of a validated mortality risk prediction score.

Predictors and Outcomes of Sudden Cardiac Arrest in Heart Failure With Preserved Ejection Fraction: A Nationwide Inpatient Sample Analysis

Sudden cardiac arrest (SCA) is the leading cause of cardiovascular mortality in heart failure with preserved ejection fraction (HFpEF), contributing to around 25% of deaths observed in pivotal HFpEF trials. However, predictors and outcomes of in-hospital SCA in HFpEF have not been well characterized. We queried the Nationwide Inpatient Sample (2016 to 2017) to identify adult hospitalizations with a diagnosis of HFpEF. Patients with acute or chronic conditions associated with SCA (e.g., acute myocardial infarction, acute pulmonary embolism, sarcoidosis) were excluded. We ascertained whether SCA occurred during these hospitalizations, identified predictors of SCA using multivariate logistic regression, and determined outcomes of SCA in HFpEF. Of 2,909,134 hospitalizations, SCA occurred in 1.48% (43,105). The mean age of the SCA group was 72.3 ± 12.4 years, 55.8% were women, and 66.4% were White. Presence of third-degree atrioventricular block (odds ratio [OR] 5.95, 95% confidence interval [CI] 5.31 to 6.67), left bundle branch block (OR 1.96, 95% CI 1.72 to 2.25), and liver disease (OR 1.87, 95% CI 1.73 to 2.02) were the leading predictors of SCA in HFpEF. After excluding patients with do-not-resuscitate status, the SCA group versus those without SCA had higher mortality (25.9% vs 1.6%), major bleeding complications (4.1% vs 1.7%), increased use of percutaneous coronary intervention (2.5% vs 0.7%), and mechanical circulatory assist device (1.2% vs 0.1%). These observational inpatient data suggest identifiable risk factors for SCA in HFpEF including cardiac arrhythmias. Further research is warranted to identify the best tools to risk-stratify patients with HFpEF to implement targeted SCA prevention strategies.

Are arrhythmias the drivers of sudden cardiac death in heart failure with preserved ejection fraction? A review

In patients with heart failure with preserved ejection fraction (HFpEF), sudden cardiac death (SCD) accounts for approximately 25-30% of all-cause mortality and 40% of cardiovascular mortality in properly adjudicated large clinical trials. The mechanism of SCD in HFpEF remains unknown but thought to be driven by arrhythmic events. Apart from atrial fibrillation, which is prevalent in approximately 45% of HFpEF patients, the true burden of other cardiac arrhythmias in HFpEF remains undetermined. The incidence and risk of clinically significant advanced cardiac conduction disease with bradyarrhythmias and ventricular arrhythmias remain less known. Recommendations have been made for long-term cardiac rhythm monitoring to determine the incidence of arrhythmias and clarify mechanisms and mode of death in HFpEF patients. In animal studies, spontaneous ventricular arrhythmias and SCD are significantly elevated in HFpEF animals compared with controls without heart failure. In humans, these studies are scant, with a few published small-size studies suggesting an increased incidence of ventricular arrhythmias in HFpEF. Higher rates of clinically significant conduction disease and cardiac pacing are seen in HFpEF compared with the general population. Excepting atrial fibrillation, the predictive effect of other arrhythmias on heart failure hospitalization, all-cause mortality, and precisely SCD remains unknown. Given the high occurrence of SCD in the HFpEF population, it could potentially become a target for therapeutic interventions if driven by arrhythmias. Studies to address these knowledge gaps are urgently warranted. In this review, we have summarized data on arrhythmias and SCD in HFpEF while highlighting avenues for future research in this area.

The implantable cardiac monitor in heart failure patient: a possible new indication?

Implantable cardiac monitors (ICMs) have found increasing use in clinical practice over the years, proving, when used in high-risk populations, to facilitate the diagnosis of bradyarrhythmias and tachyarrhythmias requiring treatment. Experience with heart failure patients undergoing pacemaker (PMK) or implantable defibrillator (ICD) implantation, which allow for continuous electrocardiographic monitoring and transthoracic impedance assessment, has made it possible to identify predictors of heart failure flare-ups. In this context, the use of telemonitoring has been shown to ensure better management of patients with heart failure. These benefits cannot be assessed to date in patients with heart failure and left ventricular ejection fraction (LVEF) > 35% who have no indication for PMK or ICD implantation. This population has been shown to have a significant incidence of ventricular arrhythmias and bradyarrhythmias. In addition, a significant number of cerebrovascular events are observed in this population, largely attributable to the high incidence of atrial fibrillation (AF). In this population, the occurrence of AF has also been shown to have a negative impact on patients' prognosis; at the same time, a rhythm control strategy has been shown to be more beneficial in this area than a rate control strategy. Studies also suggest arrhythmias have a negative impact on the cognitive status and quality of life of heart failure patients. These reasons could justify the implantation of ICMs equipped with telemonitoring systems in heart failure patients. The information provided by the monitoring system, if properly managed, could bring benefits in terms of prognosis and quality of life along with a reduction in economic costs. We will try here, by answering a few questions, to assess whether there is an indication for ICM in heart failure, which patients should be candidates and how these patients should be managed.

Investigator-reported ventricular arrhythmias and mortality in heart failure with mildly reduced or preserved ejection fraction

AIMS

Few reports have examined the incidence of ventricular tachycardia (VT) and ventricular fibrillation (VF) or their relationship with mortality in patients with heart failure with mildly reduced ejection fraction (HFmrEF) or heart failure with preserved ejection fraction (HFpEF).

METHODS AND RESULTS

Data from the PARAGON-HF, TOPCAT, I-Preserve, and CHARM-Preserved trials were merged. VT/VF, reported as adverse events, were identified. Patients who experienced VT/VF were compared with patients who did not. The relationship between VT/VF and mortality was examined in time-updated Cox proportional hazard regression models. Variables associated with VT/VF were examined in Cox proportional hazard regression models. The rate of VT/VF in patients with HFmrEF compared with patients with HFpEF was examined in a Cox proportional hazards regression model. Of 13 609 patients, over a median follow-up of 1170 days (interquartile range: 966-1451), 146 (1.1%) experienced an investigator-reported VT/VF (incidence rate 0.3 per 100 person-years). Patients who experienced VT/VF were more likely to be male, have had a myocardial infarction, poorer renal function, more adverse left ventricular remodelling, and higher N-terminal pro-B-type natriuretic peptide (NT-proBNP) than patients who did not. Occurrence of VT/VF was associated with NT-proBNP, history of atrial fibrillation/flutter, male sex, lower ejection fraction, and history of hypertension. VT/VF was associated with all-cause death [adjusted hazard ratio (HR): 3.95, 95% confidence interval (CI): 2.80-5.57; P < 0.001] and cardiovascular death, driven by death from heart failure and not sudden death. Patients with HFmrEF had a higher rate of VT/VF than patients with HFpEF (adjusted HR: 2.19, 95% CI: 1.77-2.71).

CONCLUSION

VT/VF was uncommon in patients with HFmrEF and HFpEF. However, such events were strongly associated with mortality and appear to be a marker of disease severity rather than risk of sudden death.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov unique identifier: NCT01920711(PARAGON-HF); NCT00094302 (TOPCAT); NCT00095238 (I-Preserve); NCT00634712 (CHARM-Preserved).

Diabetes and Excess Aldosterone Promote Heart Failure With Preserved Ejection Fraction

Background The pathobiology of heart failure with preserved ejection fraction (HFpEF) is still poorly understood, and effective therapies remain limited. Diabetes and mineralocorticoid excess are common and important pathophysiological factors that may synergistically promote HFpEF. The authors aimed to develop a novel animal model of HFpEF that recapitulates key aspects of the complex human phenotype with multiorgan impairments. Methods and Results The authors created a novel HFpEF model combining leptin receptor-deficient db/db mice with a 4-week period of aldosterone infusion. The HFpEF phenotype was assessed using morphometry, echocardiography, Ca²⁺ handling, and electrophysiology. The sodium-glucose cotransporter-2 inhibitor empagliflozin was then tested for reversing the arrhythmogenic cardiomyocyte phenotype. Continuous aldosterone infusion for 4 weeks in db/db mice induced marked diastolic dysfunction with preserved ejection fraction, cardiac hypertrophy, high levels of B-type natriuretic peptide, and significant extracardiac comorbidities (including severe obesity, diabetes with marked hyperglycemia, pulmonary edema, and vascular dysfunction). Aldosterone or db/db alone induced only a mild diastolic dysfunction without congestion. At the cellular level, cardiomyocyte hypertrophy, prolonged Ca²⁺ transient decay, and arrhythmogenic action potential remodeling (prolongation, increased short-term variability, delayed afterdepolarizations), and enhanced late Na⁺ current were observed in aldosterone-treated db/db mice. All of these arrhythmogenic changes were reversed by empagliflozin pretreatment of HFpEF cardiomyocytes. Conclusions The authors conclude that the db/db+aldosterone model may represent a distinct clinical subgroup of HFpEF that has marked hyperglycemia, obesity, and increased arrhythmia risk. This novel HFpEF model can be useful in future therapeutic testing and should provide unique opportunities to better understand disease pathobiology.

Arrhythmic Sudden Cardiac Death in Heart Failure With Preserved Ejection Fraction: Mechanisms, Genetics, and Future Directions

Heart failure with preserved ejection fraction (HFpEF) is an increasingly recognized disorder. Many clinical trials have failed to demonstrate benefit in patients with HFpEF but have recognized alarming rates of sudden cardiac death (SCD). Genetic testing has become standard in the workup of patients with otherwise unexplained cardiac arrest, but the genetic architecture of HFpEF, and the overlap of a genetic predisposition to HFpEF and arrhythmias, is poorly understood. An understanding of the genetics of HFpEF and related SCD has the potential to redefine and generate novel diagnostic, prognostic, and therapeutic tools. In this review, we examine recent pathophysiological and clinical advancements in our understanding of HFpEF, which reinforce the heterogeneity of the condition. We also discuss data describing SCD events in patients with HFpEF and review the current literature on genetic underpinnings of HFpEF. Mechanisms of arrhythmogenesis which may lead to SCD in this population are also explored. Lastly, we outline several areas of promise for experimentation and clinical trials that have the potential to further advance our understanding of and contribute to improved clinical care of this patient population.

Exacerbation of ventricular arrhythmias by continuous positive airway pressure treatment in idiopathic dilated cardiomyopathy

Continuous positive airway pressure (CPAP) therapy can be beneficial in patients with obstructive sleep apnea (OSA) and cardiovascular diseases, reducing arrhythmia frequency and improving cardiac function. We describe a case of moderate OSA with idiopathic dilated cardiomyopathy, in which the frequency of premature ventricular contraction (PVC) and non-sustained ventricular tachycardia (NSVT) increased immediately after initiating CPAP therapy. Although PVC and NSVT are benign cardiac arrhythmias, they are associated with an increased risk of sustained lethal ventricular tachyarrhythmias. Therefore, when initiating CPAP therapy, the possibility of increased arrhythmia should be considered.

Mortality and readmission risk in relation to QRS duration among patients hospitalized for heart failure with preserved ejection fraction

BACKGROUND

In ambulatory patients with heart failure (HF) with preserved ejection fraction (HFpEF), QRS prolongation (QRS > 120 msec) and left bundle branch block (LBBB) each carry an increased risk of cardiovascular mortality and/or HF hospitalization. Less is known about implications of conduction abnormalities following an acute HF hospitalization for HFpEF.

METHODS AND RESULTS

A retrospective cohort of 1454 patients discharged from after a HF hospitalization between 2015 and 2019 with ejection fraction (EF) ≥ 45% were identified (age 75.1 ± 10.8 years, EF 58.5% ± 10.2%). All patients' electrocardiograms were classified by QRS duration (prolonged - 545 [37.5%] vs. normal [QRS ≤ 120 msec] 909 [62.5%]). QRS prolongation was comprised of: LBBB (4.2%), right bundle branch block (RBBB, 18.3%), intraventricular conduction delay (9.7%), and ventricularly paced (9.7%). Over 4.09 ± 1.00 years, 769 (52.9%) patients died. Survival was similar between normal and prolonged QRS cohorts with an age and sex adjusted hazard ratio of 1.01 (95%CI: 0.87-1.17, p = 0.16). Recurrent HF hospitalization occurred in 91 (16.7%) with QRS prolongation vs. 90 (9.9%) without (odds ratio: 1.82 [95%CI: 1.33-2.50, p < 0.001]). RBBB carried 2.26 higher odds of recurrent HF hospitalization (95%CI: 1.56-3.28).

CONCLUSIONS

Following a HF hospitalization, QRS prolongation increased the odds of re-admission for HF in patients with HFpEF without differences in overall mortality.

Deep Learning Predicts Heart Failure With Preserved, Mid-Range, and Reduced Left Ventricular Ejection Fraction From Patient Clinical Profiles

Background: Left ventricular ejection fraction (LVEF) is the gold standard for evaluating heart failure (HF) in coronary artery disease (CAD) patients. It is an essential metric in categorizing HF patients as preserved (HFpEF), mid-range (HFmEF), and reduced (HFrEF) ejection fraction but differs, depending on whether the ASE/EACVI or ESC guidelines are used to classify HF. Objectives: We sought to investigate the effectiveness of using deep learning as an automated tool to predict LVEF from patient clinical profiles using regression and classification trained models. We further investigate the effect of utilizing other LVEF-based thresholds to examine the discrimination ability of deep learning between HF categories grouped with narrower ranges. Methods: Data from 303 CAD patients were obtained from American and Greek patient databases and categorized based on the American Society of Echocardiography and the European Association of Cardiovascular Imaging (ASE/EACVI) guidelines into HFpEF (EF > 55%), HFmEF (50% ≤ EF ≤ 55%), and HFrEF (EF < 50%). Clinical profiles included 13 demographical and clinical markers grouped as cardiovascular risk factors, medication, and history. The most significant and important markers were determined using linear regression fitting and Chi-squared test combined with a novel dimensionality reduction algorithm based on arc radial visualization (ArcViz). Two deep learning-based models were then developed and trained using convolutional neural networks (CNN) to estimate LVEF levels from the clinical information and for classification into one of three LVEF-based HF categories. Results: A total of seven clinical markers were found important for discriminating between the three HF categories. Using statistical analysis, diabetes, diuretics medication, and prior myocardial infarction were found statistically significant (p < 0.001). Furthermore, age, body mass index (BMI), anti-arrhythmics medication, and previous ventricular tachycardia were found important after projections on the ArcViz convex hull with an average nearest centroid (NC) accuracy of 94%. The regression model estimated LVEF levels successfully with an overall accuracy of 90%, average root mean square error (RMSE) of 4.13, and correlation coefficient of 0.85. A significant improvement was then obtained with the classification model, which predicted HF categories with an accuracy ≥93%, sensitivity ≥89%, 1-specificity <5%, and average area under the receiver operating characteristics curve (AUROC) of 0.98. Conclusions: Our study suggests the potential of implementing deep learning-based models clinically to ensure faster, yet accurate, automatic prediction of HF based on the ASE/EACVI LVEF guidelines with only clinical profiles and corresponding information as input to the models. Invasive, expensive, and time-consuming clinical testing could thus be avoided, enabling reduced stress in patients and simpler triage for further intervention.

Clinical Predictors of Occurrence of Ventricular Tachyarrhythmias in Patients with Reduced Left Ventricle Ejection Fraction. Results of Single-Center Prospective Study

Aim      To evaluate the diagnostic significance of clinical and demographic parameters for predicting a 2-year probability of ventricular tachyarrhythmias (VT) in patients with chronic heart failure and reduced left ventricular ejection fraction (CHFrLVEF).Material and methods  This single-center, prospective cohort study included 175 patients with CHFrLVEF who were implanted with a cardioverter defibrillator (CD). The endpoint was a CD-detected episode of VT. Patients were followed up for 2 years with visits at 3, 12, and 24 months after CD implantation.Results The primary endpoint was observed in 43 (24.4 %) patients at an average of 20.9 months (95 % confidence interval (CI), 20-21.9). The 2-year risk of fatal ventricular arrhythmias increased with detection of unstable VT (one-factor analysis, odds ratio (OR), 4.2; 95 % CI, 1.1-16.5; р=0.041; multifactor analysis, OR, 6.3; 95 % CI, 1.5-26.3; р=0.012) and with ischemic CHFrLVEF origin (one-factor analysis, OR, 2.2; 95 % CI, 1.1-4.5; p=0.021; multifactor analysis, OR, 2.5; 95 % CI, 1.2-5.1; р=0.018). In the presence of any type of atrial fibrillation (AF) in patients with non-ischemic CHFrLVEF, the probability of VT increased threefold (one-factor analysis, OR, 2.97; 95 % CI, 1.02-8.8; р=0.047; multifactor analysis, OR, 3.5; 95 % CI, 1.1-10.9; р=0.032).Conclusion      The presence of ischemic heart disease and unstable VT paroxysms can be included in the number of important clinical predictors of VT in patients with CHFrLVEF. In patients with non-ischemic CHF, the presence of AF is associated with a high risk of VT.