Resource Use and Clinical Outcomes in Infants with Supraventricular Tachycardia Monitored with the Owlet Smart Sock.

OBJECTIVES: To describe the prevalence of Owlet Smart Sock (OSS) use in infants with supraventricular tachycardia (SVT) and associated demographic and clinical characteristics of users and to analyze the association of OSS use on medical resource use and clinical outcomes from emergency department (ED) encounters for SVT. STUDY DESIGN: This was a single-center, retrospective cohort study of infants with confirmed SVT from 2015 to 2022. OSS users and nonusers were compared across clinical and demographic parameters. Medical resource use (phone calls, office visits, ED visits) and outcomes (need for intensive care, length of stay, echocardiographic function, clinical appearance) were compared between OSS users and nonusers. RESULTS: Of 133 infants with SVT, OSS was used by 31 of 133 (23%), purchased before SVT diagnosis in 5 in 31 (16%) of users. No demographic difference was found between OSS users and nonusers. OSS users had more phone notes than nonusers, (P = .002) and more ED visits (P = .03), but the number of office visits and medication adjustments did not differ. During ED presentation, OSS users had better preserved left ventricular ejection fraction on echocardiogram (P = .04) and lower length of hospital stay by a mean 1.7 days (P = .02). CONCLUSIONS: OSS is used by a portion of infants with SVT. It is associated with more frequent phone calls and ED visits but lower length of stay and better-preserved cardiac function upon presentation.

Functional substrate mapping of atrium in patients with atrial scar: A novel method to predict critical isthmus of atrial tachycardia.

Atrial tachycardia (AT) is a common rhythm disorder, especially in patients with atrial structural abnormalities. Although voltage mapping can provide a general picture of structural alterations which are mainly secondary to prior ablations, surgery or pressure/volume overload, data is scarce regarding the functional characteristics of low voltage regions in the atrium to predict critical isthmus of ATs. Recently, functional substrate mapping (FSM) emerged as a potential tool to evaluate the functionality of structurally altered regions in the atrium to predict critical sites of reentry. Current evidence suggested a clear association between deceleration zones of isochronal late activation mapping (ILAM) during sinus/paced rhythm and critical isthmus of reentry in patients with left AT. Therefore, these areas seem to be potential ablation targets even not detected during AT. Furthermore, abnormal conduction detected by ILAM may also have a role to identify the potential substrate and predict atrial fibrillation outcome after pulmonary vein isolation. Despite these promising findings, the utility of such an approach needs to be evaluated in large-scale comparative studies. In this review, we aimed to share our experience and review the current literature regarding the use of FSM during sinus/paced rhythm in the prediction of re-entrant ATs and discuss future implications and potential use in patients with atrial low-voltage areas.

Comparison of initial adenosine dose conversion rate for supraventricular tachycardia in the emergency department.

OBJECTIVE: To evaluate the rate of supraventricular tachycardia (SVT) termination between 6 mg and 12 mg initial adenosine doses. METHODS: This multi-center, retrospective cohort study evaluated patients presenting to the emergency department (ED) from January 1, 2020 to June 30, 2022 in SVT and received adenosine. The primary objective of the study is to compare the rate of SVT termination between adenosine 6 mg and 12 mg as documented on a formal electrocardiogram. Secondary endpoints include termination of SVT with subsequent adenosine dose, time to ED disposition, adverse effects, and subgroup analyses of patients with a body mass index greater than or equal to 40 kg/m2 and a history of SVT. RESULTS: Of 213 patients included, a 6 mg initial adenosine dose was administered to 117 patients (54.9 %) and a 12 mg initial adenosine dose was administered to 96 patients (45.1 %). SVT termination following the initial dose of 6 mg or 12 mg was 56.4 % and 79.1 %, respectively (p < 0.001). Among the 46 patients who failed to terminate SVT with an initial 6 mg dose, 33 converted to sinus rhythm with a subsequent adenosine dose in comparison to 1 of the 7 patients receiving an initial dose of 12 mg (71.7 % vs 14.3 %, p = 0.007). Median time to ED disposition, either inpatient admission or discharge, was 209 and 161 min, respectively (p = 0.104). There was no statistical difference in either subgroup analyses. CONCLUSION: A higher rate of SVT termination was observed with an initial adenosine dose of 12 mg in the ED in comparison to the guideline recommended dose of 6 mg. There were no significant differences in adverse effects observed.

The Role of Troponin Testing in Patients with Supraventricular Tachycardia, Systematic Review and Meta-Analysis.

BACKGROUND: Supraventricular tachycardia (SVT) is commonly evaluated in the emergency department (ED). While troponin has been shown to be elevated in SVT, its usefulness for predicting coronary artery disease and future adverse cardiovascular outcomes has not been shown. OBJECTIVES: We aimed to evaluate the prognostic utility of troponin measurement as part of SVT management in the ED. METHODS: We performed a literature search in the PubMed and Scopus databases from inception to August 30, 2023, including all studies reporting troponin measurements in adult patients (age > 18 years) presenting to the ED with supraventricular tachycardia. The primary outcome of interest for this study was the prevalence of elevated troponin in patients with SVT. Secondary outcomes included the prevalence of major adverse cardiac events (MACE) and additional cardiac testing with significant findings. RESULTS: We included 7 studies (500 patients) in our analysis. Six studies reported the number of patients with SVT and elevated troponin, with a pooled prevalence of 46% (95% CI 27-66%, I2 93%). The pooled prevalence of all MACE in our study was 6% (95% CI 1-25%), while the prevalence for MACE among patients with elevated serum troponin levels was 11% (95% CI 4-27%). CONCLUSIONS: Troponin levels are frequently ordered for ED patients with SVT and are often elevated. However, this review suggests that they have low prognostic value in predicting MACE.

Successful ablation of a right epicardial accessory pathway via the right ventricular diverticulum in a patient with Wolff-Parkinson-White syndrome.

INTRODUCTION: We describe one rare case of successful ablation of a right epicardial accessory pathway (AP) via the right ventricular diverticulum in a patient with Wolff-Parkinson-White syndrome. METHODS: A 42-year-old woman was referred to the hospital for a catheter ablation of Wolf-Parkinson-White syndrome. The earliest activation was shown to be present in the region of the tricuspid annulus. However, ablation had no effect on the AP. RESULTS: We decided to do a selected angiography, in which a big diverticulum near the right tricuspid annulus was shown to be present. Ablation in this region successfully repressed the AP without any recurrences within a follow-up period of 12 months. CONCLUSION: The ventricular diverticulum-mediated AP is a novel variant of pre-excitation. It can serve as an anatomical substrate of supraventricular tachycardia, and can be ablated endocardially using an irrigation tip catheter within the diverticulum.

The effect of patient weight on the success of converting sinus rhythm in patients with PSVT treated with standard dose adenosine.

PURPOSE: The study aimed to investigate whether there is a difference in the amount of adenosine per kilogram (mg/kg) between the patient groups that can and cannot be converted to sinus rhythm (SR) with adenosine therapy in patients with supraventricular tachycardia (SVT). MATERIAL AND METHOD: This single-centered, retrospectively designed study was conducted in the ED of a training and research hospital between December 1, 2019 and December 1, 2022 on patients who were admitted to the ED with SVT diagnosis and treated with a 6-12-18 mg adenosine protocol. The main analyses were carried out in three stages. The first analysis was performed considering the first 6 mg dose of adenosine administered. The second analysis was performed by considering the 12 mg adenosine administered as the second dose because it did not respond to the first dose. Finally, the third analysis was performed by considering the 18 mg adenosine administered as the third dose because it did not respond to preciously dosages. The primary outcome variable was determined to be converting SR and created two groups according to this; the success SR group and the failure SR group. RESULTS: During the study period, 73 patients who were admitted to the ED with PSVT diagnosis and treated with intravenous adenosine were included. After the first 6 mg of adenosine treatment was administered to all 73 patients, SR was achieved in only 38% of patients. The mean adenosine dose (mg/kg) was significantly lower in the failure SR group, 0.07373 ± 0.014, compared with 0.08885 ± 0.017 mg/kg in the success SR group (mean difference with 95% CI: -0.01511 [-0.023 to -0.0071]; p < 0.001). In the second and third stage analyses, considering 12 and 18 mg adenosine doses, when the administrations with successful and failed SR were compared, no difference was found in terms of the applied adenosine doses per kilogram. CONCLUSION: This study suggest that the success of terminating SVT with the first 6 mg dose of adenosine appears to be dependent on patient weight. In patients given larger doses of adenosine, determinants of PSVT termination success may be factors other than patient weight.

Assessing the Risk of Hypoglycemia Secondary to Propranolol Therapy for the Treatment of Supraventricular Tachycardia in Infants.

Supraventricular tachycardia (SVT) is the most common arrhythmia among infants. Prevention of SVT is frequently managed through propranolol therapy. Hypoglycemia is a known adverse effect of propranolol therapy, but little research has been done on the incidence and risk of hypoglycemia in treatment of SVT in infants with propranolol. This study attempts to offer insight into the risk of hypoglycemia associated with propranolol therapy when treating infantile SVT to help inform future glucose screening guidelines. We conducted a retrospective chart review of infants treated with propranolol in our hospital system. Inclusion criteria were infants < 1 year of age who received propranolol for the treatment of SVT. A total of 63 patients were identified. Data was collected on sex, age, race, diagnosis, gestational age, nutrition source (Total Parenteral Nutrition (TPN) vs oral), weight (kg), weight for length (kg/cm), propranolol dose (mg/kg/day), comorbidities, and whether or not a hypoglycemic event was identified (< 60 mg/dL). Hypoglycemic events were identified in 9/63 (14.3%) patients. Of the patients with hypoglycemic events, 9/9 (88.9%) had comorbid conditions. Patients with hypoglycemic events had significantly lower weight and propranolol dose than those without hypoglycemic events. Weight for length also tended to increase risk for hypoglycemic events. The high incidence of comorbid conditions in the patients who had hypoglycemic events suggests that hypoglycemic monitoring may only be necessary in patients with conditions predisposing to hypoglycemia.

Rank-Adaptive Tensor Completion Based on Tucker Decomposition.

Tensor completion is a fundamental tool to estimate unknown information from observed data, which is widely used in many areas, including image and video recovery, traffic data completion and the multi-input multi-output problems in information theory. Based on Tucker decomposition, this paper proposes a new algorithm to complete tensors with missing data. In decomposition-based tensor completion methods, underestimation or overestimation of tensor ranks can lead to inaccurate results. To tackle this problem, we design an alternative iterating method that breaks the original problem into several matrix completion subproblems and adaptively adjusts the multilinear rank of the model during optimization procedures. Through numerical experiments on synthetic data and authentic images, we show that the proposed method can effectively estimate the tensor ranks and predict the missing entries.

Ripple mapping: A precise tool for atrioventricular nodal reentrant tachycardia ablation.

INTRODUCTION: Ablation for atrioventricular nodal reentrant tachycardia (AVNRT) classically utilizes evaluation of signal morphology within the anatomic region of the slow pathway (SP), which involves subjectivity. Ripple mapping (RM; CARTO-3© Biosense Webster Inc) displays each electrogram at its three-dimensional coordinate as a bar changing in length according to its voltage-time relationship. This allows prolonged, low-amplitude signals to be displayed in their entirety, helping identify propagation in low-voltage areas. We set out to evaluate the ability of RM to locate the anatomic site of the SP and assess its use in guiding ablation for AVNRT. METHODS: Patients ≤18 years with AVNRT in the EP laboratory between 2017 and 2021 were evaluated. RM was performed to define region of SP conduction in patients from 2019 to 2021, whereas standard electro-anatomical mapping was used from 2017 to 2019. All ablations were performed using cryotherapy. Demographics, outcomes, and analysis of variance in number of test lesions until success was compared between groups. RESULTS: A total of 115 patients underwent AVRNT ablation during the study; 46 patients were in the RM group and 69 were in the control group. There were no demographic differences between groups. All procedures, in both groups, were acutely successful. In RM group, 89% of first successful lesions were within 4 mm of the predicted site. There was significantly reduced variability in number of test lesions until success in the RM group (p = .01). CONCLUSION: RM is a novel technique that can help identify SP location, allowing for successful ablation of AVNRT with decreased variability.

"Forced inspiratory suction and swallow tool" a novel instrument to convert paroxysmal supraventricular tachycardia (SVT) to sinus rhythm, a case report and introduction of the device.

Paroxysmal Supraventricular Tachycardia (SVT) is an arrhythmia with sudden onset and termination, characterized by a fast heart rate and a narrow QRS complex. There are several remedies that have been described to convert the SVT, such as the Valsalva maneuver, holding the breath for a few seconds, or putting cold water on the face. Here we are presenting a case of SVT, which we converted to sinus rhythm instantly by using a novel tool that has been designed and patented at the University of Texas. This device is named "Forced Inspiratory Suction and Swallow Tool" (FISST) and is branded as "HiccAway," which is primarily designed to stop hiccups and is available as an over-the-counter tool. It works by drinking water forcibly through a pressure valve, and it follows "Bernoulli's Principle": applications of the law of conservation energy.

Empiric Slow Pathway Cryoablation in Symptomatic Children Without Documented Supraventricular Tachycardia.

In symptomatic children without documented supraventricular tachycardia (SVT) and non-inducible atrioventricular nodal reentry tachycardia (AVNRT) the benefit of empiric slow pathway (SP) ablation is unknown. We evaluated 62 symptomatic patients without documented SVT that underwent electrophysiology study (EPS). The purpose of this study was to determine if symptoms improved after empiric SP ablation in children without documented SVT and without inducible AVNRT. Sixty-two symptomatic patients without previously documented SVT underwent EPS; 31 (50%) had inducible AVNRT and underwent SP ablation, 20 (32%) were non-inducible and underwent empiric SP ablation, 11 (18%) were non-inducible and had no ablation. After a mean follow-up of 23 ± 18 months there was no significant difference in freedom from symptoms within the non-inducible cohort regardless of whether empiric SP ablation was performed (p = 0.135). There was a significant improvement in symptoms at follow-up after SP ablation when comparing inducible and non-inducible patients (p = 0.020). During follow-up no patients had documented SVT. Symptomatic children without documented SVT do not benefit from empiric SP ablation when AVNRT cannot be induced.

Gender associated disparities in atrioventricular nodal reentrant tachycardia: A review article.

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common sustained supraventricular arrhythmias. An understanding of gender-related differences in AVNRT epidemiology, diagnosis, treatment, outcome, and complications can help guide a more effective diagnosis and treatment of the condition. The study aimed to perform a review of the available literature regarding all aspects of gender-related differences of AVNRT. We focused on all aspects of gender-related differences regarding AVNRT between men and women. A literature search was performed using Google Scholar, PubMed, Springer, Ovid, and Science Direct. Many investigations have demonstrated that the prevalence of AVNRT exhibited a twofold women-to-men predominance. The potential mechanism behind this difference due to sex hormones and autonomic tone. Despite being more common in women, there is a delay in offering and performing the first-line therapy (catheter ablation) compared to men. There were no significant gender-related discrepancies in patients who underwent ablation therapy for AVNRT, regarding the acute success rate of the procedure, long-term success rate, and recurrence of AVNRT. AVNRT is more common in women due to physiological factors such as sex hormones and autonomic tone. Catheter ablation is equally safe and efficacious in men and women; however, the time between the onset of symptoms and ablation is significantly prolonged in women. It is important for the medical community to be aware of this discrepancy and to strive to eliminate such disparities that are not related to patients' choices.

A prospective evaluation of the impact of individual RF applications for slow pathway ablation for AVNRT: Markers of acute success.

BACKGROUND: Catheter ablation is highly effective for atrioventricular nodal re-entrant tachycardia (AVNRT). Generally junctional rhythm (JR) is an accepted requirement for successful ablation however there is a lack of detailed prospective studies to determine the characteristics of JR and the impact on slow pathway conduction. METHODS: Multicentre prospective observational study evaluating the impact of individual radiofrequency (RF) applications in typical AVNRT (slow/fast). Characteristics of JR during ablation were documented and detailed testing was performed after every RF application to determine outcome. Procedural success was defined as ≤1 AV nodal echo. RESULTS: Sixty-seven patients were included (mean age 53 ± 18years, 57% female and a history of SVT 2.9 ± 4.7 years). RF (50w, 60°) ablation for AVNRT was applied in 301 locations with JR in 178 (59%). Successful slow pathway modification was achieved in 66 (99%) patients with slow pathway block in 30 (46%). Success was associated with JR in all patients. Success was achieved in six patients with RF < 10 s. There was no significant difference in the CL of JR during RF between effective (587 ± 150 ms) versus ineffective (611 ± 193 ms, p = .4) applications. Inadvertent junctional beat-atrial (JA) block with immediate termination of RF was observed in 19 (28%) patients with AVNRT no longer inducible in 14 (74%). Freedom from SVT was achieved in 66 (99%) patients at a mean follow up of 15 ± 6 months. CONCLUSION: In this prospective study, JR was required during RF for acute success in AVNRT. Cycle length of JR during RF was not predictive of success. Although unintended JA block during faster JR was associated with slow pathway block, this is a precursor to fast pathway block and should not be intentionally targeted.

Challenge of managing opposing rhythms in a mother and fetus.

INTRODUCTION: We report a case of a fetus with complex congenital heart disease and supraventricular tachycardia in the setting of maternal high grade atrioventricular block at 26 weeks' gestation. METHODS AND RESULTS: Electroanatomic mapping allowed successful implantation of a permanent pacemaker to provide adequate back-up pacing in the mother with zero radiation exposure, thus allowing safe delivery of transplacental anti-arrhythmic medications to reduce the fetal arrhythmia burden and optimize the fetal ventricular rate. CONCLUSION: This is the first reported case of using electroanatomic mapping, with zero fluoroscopy use, for pacemaker lead placement and for a novel indication.

Safety, Efficacy, and Long-Term Outcomes of Anticoagulation in Cirrhotic Portal Vein Thrombosis.

BACKGROUND: The role of anticoagulation (AC) in the management of cirrhotic patients with portal vein thrombosis (PVT) remains unclear. AIMS: We conducted a retrospective study of cirrhotic patients diagnosed with PVT from 1/1/2000 through 2/1/2019, comparing those who received AC to those who did not. METHODS: Outcomes included rate of complete radiographic resolution (CRR) of PVT, recanalization of occlusive PVT (RCO), PVT extension, major bleeding, and overall survival (OS). The log-rank test was used to compare Kaplan-Meier distributions of time-to-event outcomes. Multivariable Cox-proportional-hazards modeling was used to estimate adjusted hazard ratios (HRs) with 95% confidence intervals. RESULTS: A total of 214 patients were followed for a median 27 months (IQR 12-48). Eighty-six patients (39%) received AC. AC was associated with significantly greater CRR (48% vs. 27%, p = 0.0007), (multivariable HR for CRR with AC; 2.49 (1.54-4.04, p = 0.0002)). AC was also associated with significantly greater RCO (69% vs. 28%, p = 0.0013), (multivariable HR for RCO with AC; 4.86 (1.91-12.37, p = 0.0009)). Rates of major bleeding were similar with and without AC (20% vs. 17%, p = 0.5207), multivariable HR for major bleeding with AC; 1.29 (0.68-2.46, p = 0.4423)). OS rates in the AC and no-AC groups were 83% and 70%, respectively (p = 0.1362), (HR for death with AC; 0.69 (0.38-1.28, p = 0.2441)). Among 75 patients who had CRR, 10 (13%) experienced recurrent PVT during follow-up (none were receiving AC at the time of recurrence). CONCLUSIONS: AC appears safe and effective for the treatment of cirrhotic PVT; however, prospective studies to confirm these findings and evaluate additional outcomes are needed.

Resolution of bronchoconstriction with positive airway pressure after intravenous adenosine.

Adenosine is an endogenous nucleoside that plays a major role in the pathophysiology of airway diseases, such as asthma and chronic obstructive pulmonary disease. It is also an effective drug at terminating supraventricular tachycardia and used for pharmacological stress testing with a relatively safe side effect profile. There is a contraindication for the use of adenosine in patients with asthma and a caution to use in patients with chronic obstructive pulmonary disease. We present a case of a 63-year old female patient who was treated with adenosine and subsequently went into respiratory distress. She was placed on bilevel positive airway pressure and had rapid resolution of symptoms.

Antiarrhythmic Treatment Duration and Tachycardia Recurrence in Infants with Supraventricular Tachycardia.

We sought to assess the effect of a shorter medication treatment course (up to 4-6 months of age) on the recurrence of infantile supraventricular tachycardia (SVT). This was a retrospective review of infants with SVT diagnosed at age 0-12 months at Rady Children's Hospital (2010-2017). Infants with structural congenital heart disease, automatic tachycardias, atrial flutter, or lack of follow-up data were excluded. Seventy-four infants met criteria. Median age at diagnosis was 6 days (IQR 0-21 days); 28.4% presented with fetal tachycardia. Median gestational age was 38.4 weeks (IQR 36-40), 30% were preterm. Median age at medication discontinuation was 6.7 months (IQR 4.6-9.8). Therapy was stopped at younger age in patients managed by pediatric electrophysiologist (vs. general pediatric cardiologist): 4.9 vs. 8.6 months (p = 0.03). Thirty-eight patients (51.4%) were treated for < 6 months; 32.4% for 6-12 months, and 16.2% for > 12 months. SVT recurrence was similar for these groups: 13.2% vs. 16.7%, and 33.3%, respectively, (p = 0.27). Most patients with recurrence required emergency care, though none had significant adverse outcomes. Infants with SVT and structurally normal cardiac anatomy, who remain recurrence free on a single agent, have no increased risk of recurrence with shorter treatment courses of 4-6 months, compared to traditional treatment duration of 6-12 months.

Persistence of Palpitations After Slow Pathway Modification for AVNRT in Young People.

Symptoms are the most common indication for ablation in children with atrioventricular nodal reentrant tachycardia (AVNRT). After the procedure, patients may continue to report palpitations. The objective of this study was to quantify the risk and duration of palpitations after pediatric slow pathway modification as well as demographic and technical associations. This was a retrospective review of consecutive patients at a pediatric center who underwent slow pathway modification for AVNRT from 2012 to 2018. Patients with a prior ablation attempt or congenital heart disease were excluded. Palpitations were documented in 35% of patients after ablation. Neither post-ablation echo beats nor other evidence of residual dual AV nodal physiology were associated with a higher risk of post-ablation palpitations. Of the 35 patients with post-ablation palpitations, the median time to resolution of palpitations was 48 months. Acute procedural success was achieved in all 100 cases. There were two recurrences of AVNRT during long-term follow-up and one instance of ectopic atrial tachycardia (3% SVT recurrence). Palpitations after AVNRT ablation occurred in approximately one-third of cases, despite a low recurrence of true arrhythmia. Prior to ablation, patients and families should be counseled that post-ablation palpitations are common and AVNRT recurrence is rare.

ABCDP: Approximate Bayesian Computation with Differential Privacy.

We developed a novel approximate Bayesian computation (ABC) framework, ABCDP, which produces differentially private (DP) and approximate posterior samples. Our framework takes advantage of the sparse vector technique (SVT), widely studied in the differential privacy literature. SVT incurs the privacy cost only when a condition (whether a quantity of interest is above/below a threshold) is met. If the condition is sparsely met during the repeated queries, SVT can drastically reduce the cumulative privacy loss, unlike the usual case where every query incurs the privacy loss. In ABC, the quantity of interest is the distance between observed and simulated data, and only when the distance is below a threshold can we take the corresponding prior sample as a posterior sample. Hence, applying SVT to ABC is an organic way to transform an ABC algorithm to a privacy-preserving variant with minimal modification, but yields the posterior samples with a high privacy level. We theoretically analyzed the interplay between the noise added for privacy and the accuracy of the posterior samples. We apply ABCDP to several data simulators and show the efficacy of the proposed framework.

The role and outcomes of new supraventricular tachycardia among patients with mild heart failure.

INTRODUCTION: We aimed to assess the predictors of new supraventricular tachycardia (SVT) and the association of new SVT with subsequent clinical outcomes among mild heart failure (HF) patients. METHODS AND RESULTS: The study population comprised patients enrolled in MADIT-CRT, after exclusion of patients with atrial arrhythmias before enrollment (N = 325). Multivariate analysis was used to identify predictors of new-onset SVT and the association of time-dependent development of SVT with subsequent ventricular tachyarrhythmic events (VTEs), HF-hospitalizations, and death. SVT burden was categorized into three groups based on the number of episodes per patient; (a) Low <10, (b) Intermediate ≥10 but <20, and (c) High ≥20. During mean follow up of 3.4 ± 1.1 years, 41(3%) subjects developed new SVT. African American race, diastolic blood pressure (DBP) >80 mmHg and prior non sustained ventricular arrhythmia were independent predictors for SVT. Multivariate analysis showed that the development of time-dependent SVT was associated with a >4-fold increased risk for VTEs (HR = 4.3; 95% CI: 1.6-11.7; P = .004) and with a >6-fold increased risk for all-cause mortality (HR = 6.5; 95% CI: 2.3-18.7; P < .001), but not with HF hospitalizations (HR = 2.2; 95% CI: 0.7-7.2; P = .17). Intermediate, and high SVT-burden were each independent risk factors for death when compared with Low burden (HR = 9.1; P = .03, and HR = 19.4; P < .001; respectively). CONCLUSIONS: In patients with mild HF, the development of new-onset SVT after device implantation is related to distinct baseline clinical and epidemiologic characteristics and is associated with a significant increase in subsequent adverse outcomes, including VTEs and death.