Output-dependent His bundle pacing: Unexpected His-Purkinje system pathology unmasking.

The anatomy of the His-Purkinje system has been studied, yet there remains a knowledge gap regarding the impact of His bundle pacing and its electrocardiographic implications. This case report highlights the presence of His-Purkinje system pathology without apparent clues on the surface electrocardiogram (EKG). By observing identical QRS morphology with varying HV intervals resulting from different pacing outputs, we demonstrate the presence of an electrical propagation block within the His bundle.

The impact of supraventricular arrhythmias on the outcomes of guideline-compliant implantable cardioverter defibrillator programming.

INTRODUCTION: Several implantable cardioverter defibrillators (ICD) programming strategies are applied to minimize ICD therapy, especially unnecessary therapies from supraventricular arrhythmias (SVA). However, it remains unknown whether these optimal programming recommendations only benefit those with SVAs or have any detrimental effects from delayed therapy on those without SVAs. This study aims to assess the impact of SVA on the outcomes of ICD programming based on 2015 HRS/EHRA/APHRS/SOLAECE expert consensus statement and 2019 focused update on optimal ICD programming and testing guidelines. METHODS: Consecutive patients who underwent ICD insertion for primary prevention were classified into four groups based on SVA status and ICD programming: (1) guideline-concordant group (GC) with SVA, (2) GC without SVA, (3) nonguideline concordant group (NGC) with SVA, and (4) NGC without SVA. Cox proportional hazard models were analyzed for freedom from ICD therapies, shock, and mortality. RESULTS: Seven hundred and seventy-two patients (median age, 64 years) were enrolled. ICD therapies were the most frequent in NGC with SVA (24.0%), followed by NGC without SVA (19.9%), GC without SVA (11.6%), and GC with SVA (8.1%). Guideline concordant programming was associated with 68% ICD therapy reduction (HR 0.32, p = .007) and 67% ICD shock reduction (HR 0.33, p = .030) in SVA patients and 44% ICD therapy reduction in those without SVA (HR 0.56, p = .030). CONCLUSION: Programming ICDs in primary prevention patients based on current guidelines reduces therapy burden without increasing mortality in both SVA and non-SVA patients. A greater magnitude of reduced ICD therapy was found in those with supraventricular arrhythmias.

The efficacy and safety of cryoballoon atrial fibrillation ablation in patients with heart failure: A systematic review and meta-analysis.

INTRODUCTION: While atrial fibrillation (AF) ablation has proven beneficial for heart failure (HF) patients, most reports were performed with radiofrequency ablation. We aimed to evaluate the efficacy and safety of cryoballoon AF ablation in patients with HFrEF. METHOD: We comprehensively searched the databases of MEDLINE, EMBASE, and Cochrane database from inception to December 2022. Studies that reported the outcomes of freedom from atrial arrhythmia, complications, NYHA functional class (NYHA FC), and left ventricular ejection fraction (LVEF) after Cryoballoon AF ablation in HF patients were included. Data from each study were combined with a random-effects model. RESULT: A total of 9 studies observational studies with 1414 HF patients were included. Five studies had only HF with reduced ejection fraction (HFrEF), 1 study with HF with preserved ejection fraction (HFpEF), and others with mixed HF types. Freedom from AA in HFrEF at 12 months was 64% (95% CI 56-71%, I2 58%). There was a significant improvement of LVEF in these patients with a standard mean difference of 13% (95% CI 8.6-17.5%, I2 99% P < 0.001. The complication rate in HFrEF group was 6% (95% CI 4-10%, I2 0%). The risk of recurrence of atrial arrhythmia was not significantly different between HF and no HF patients (RR 1.34, 95% CI 0.8-2.23, I2 76%). CONCLUSION: Cryoballoon AF ablation is effective in HFrEF patients comparable to radiofrequency ablation. The complication rate was low.

Efficacy and safety between radiofrequency ablation and types of cryoablation catheters for atrioventricular nodal reentrant tachycardia: A Network Meta-analysis and Systematic Review.

INTRODUCTION: Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common supraventricular tachycardia referred for ablation. Periprocedural conduction system damage was a primary concern during AVNRT ablation. This study aimed to assess the incidence of permanent atrioventricular (AV) block and the success rate associated with different types of catheters in slow pathway ablation. METHOD: A literature search was performed to identify studies that compared various techniques, including types of radiofrequency ablation (irrigated and nonirrigated) and different sizes of catheter tip cryoablation (4, 6, and 8-mm), in terms of their outcomes related to permanent atrioventricular block and success rate. To assess and rank the treatments for the different outcomes, a random-effects model of network meta-analysis, along with p-scores, was employed. RESULTS: A total of 27 studies with 5110 patients were included in the analysis. Overall success rates ranged from 89.78% to 100%. Point estimation showed 4-mm cryoablation exhibited an odds ratio of 0.649 (95%CI: 0.202-2.087) when compared to nonirrigated RFA. Similarly, 6-mm cryoablation had an odds ratio of 0.944 (95%CI: 0.307-2.905), 8-mm cryoablation had an odds ratio of 0.848 (95%CI: 0.089-8.107), and irrigated RFA had an odds ratio of 0.424 (95%CI: 0.058-3.121) compared to nonirrigated RFA. CONCLUSION: Our study found no significant difference in the incidence of permanent AV block between the types of catheters. The success rates were consistently high across all groups. These findings emphasize the potential of both RF ablation (irrigated and nonirrigated catheter) and cryoablation as viable options for the treatment of AVNRT, with similar safety and efficacy profile.

Atrial fibrillation catheter ablation in endurance athletes: systematic review and meta-analysis.

BACKGROUND: Atrial fibrillation (AF) management in endurance athletes (EA) is challenging due to the paucity of data, especially on the efficacy and safety of catheter ablation (CA). The hypothesis is that the efficacy and safety of AF CA in EA are comparable to the non-EA. METHODS: Databases from EMBASE, Medline, PubMed, and Cochrane were searched from inception through February 2023. Studies with available information on efficacy and safety profiles were included. Effect estimates from the individual studies were extracted and combined using random effect and generic inverse variance method of DerSimonian and Laird. RESULTS: Nine observational studies with a total of 1129 participants were identified, of whom 51% were EA. Our analysis found that rate of atrial arrhythmia (AA) recurrences following AF CA was not statistically different between EA and non-EA (RR 1.04, I2 = 57.6%, p = 0.54). The AA survival rates after a single ablation in EA was 60.2%, which improved up to 77% after multiple ablations during the follow-up period. Infrequent complication rates ranging from 0 to 7.6% were observed, with no mortality. CONCLUSIONS: Our meta-analysis suggests that AF CA is as effective and safe in EA as in non-EA. In the future, AF CA should be considered as a first-line therapeutic choice in this patient group.

Outcomes of cardiac resynchronization therapy in congenital heart disease: A meta-analysis and systematic review.

INTRODUCTION: Cardiac resynchronization therapy (CRT) is a standard treatment for patients with heart failure with reduced ejection fraction. However, there is still a gap of evidence in congenital heart disease (CHD) patients regarding resynchronization therapy. METHODS: We performed a meta-analysis and systematic review of CHD patients who received CRT implantation. We comprehensively searched the databases of MEDLINE, EMBASE, and Cochrane database from inception to June 2023. Studies that reported response rate to CRT, total mortality rate, change in QRS duration, change in left ventricular ejection fraction, and change in New York Heart Association functional class were included. RESULTS: A total of 14 studies were included in the study. There were 10 studies that reported response rates after implantation. The overall response rate to CRT in CHD patients was 68% (95% confidence interval [CI] 61%-75%, I2 32%). The response rates in patients with systemic right ventricle (RV), systemic left ventricle (LV), and single ventricle were 58% (95% CI 46%-70%, I2 0%), 80% (95% CI 74%-86% I2 14%), and 67% (95% CI 49%-80% I2 0%). Response to CRT in systemic RV was inferior to systemic LV with an odds ratio of 0.38 (95% CI 0.15-0.95, I2 38%). The total mortality rate from seven studies was 12% (95% CI 8%-18%, I2 55%). The parameters which represented ventricular dyssynchrony improved after CRT implantation. CONCLUSION: The overall response rate to CRT in CHD was 68%. Patients with systemic RV had a lower response rate to CRT when compared to patients with systemic LV. The total mortality rate after CRT implantation was 12%.

Challenging coronary sinus lead placement for CRT: A modified "Anchoring balloon" technique.

An 80-year-old man with a history of complete heart block underwent dual chamber pacemaker implantation about a year ago. He returned to the hospital due to de novo heart failure caused by pacing-induced cardiomyopathy; hence, we planned to upgrade his pacemaker to a biventricular device. The initial strategy was to perform left bundle branch area pacing-optimized cardiac resynchronization therapy (LOT-CRT) with left bundle branch area pacing (LBBAP) combined with a coronary sinus (CS) lead. In this challenging case, the successful placement of a CS lead was hindered by a complicated combination of a large CS body linked to the left superior vena cava and a winding CS branch. However, utilizing readily available tools, such as the coronary balloon and Guide Plus II ST catheter, proved instrumental in overcoming these obstacles. As a result, LOT-CRT provided the patient with a safe alternative to surgical LV lead placement.

Radiofrequency ablation of atrial fibrillation: A 14 years' experience at a tertiary care center in Thailand.

BACKGROUND: The result of atrial fibrillation (AF) ablation varies across centers. Most data are derived from the Western world, while data from Southeast Asian countries are lacking. We aimed to investigate the outcomes of AF ablation in Thailand. METHOD: We performed a retrospective analysis of patients who underwent AF ablation in a tertiary care center, between the years 2006-2020. Details of AF ablation, including pulmonary vein isolation (PVI), and complex fractionated atrial electrogram (CFAE) ablation, were classified. The success rate of AF ablation is determined by freedom from AF beyond 3 months blanking period. Combined success rate of AF ablation was reported along with the success rate of each technique (PVI, CFAE, and combine PVI plus CFAE). RESULT: We identified a total of 171 patients who underwent the first AF ablation. Ninety-four (55%) patients went through PVI, 55 (32%) patients for CFAE ablation, and 22 (13%) patients for PVI plus CFAE ablation. Overall freedom from AF was 73% at 12 months, 66% at 24 months, and 55% at 36 months. The success rate of PVI was 79% at 12 months, 74% at 24 months, and 59% at 36 months. The success rate of CFAE ablation was 63% at 12 months, 51% at 24 months, and 47% at 36 months. CONCLUSION: Catheter ablation of AF is proven safe and effective in Thai population.

Impact of late gadolinium-enhanced cardiac MRI on arrhythmic and mortality outcomes in nonischemic dilated cardiomyopathy: updated systematic review and meta-analysis.

Risk stratification based mainly on the impairment of left ventricular ejection fraction has limited performance in patients with nonischemic dilated cardiomyopathy (NIDCM). Evidence is rapidly growing for the impact of myocardial scar identified by late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (CMR) on cardiovascular events. We aim to assess the prognostic value of LGE on long-term arrhythmic and mortality outcomes in patients with NIDCM. PubMed, Scopus, and Cochrane databases were searched from inception to January 21, 2022. Studies that included disease-specific subpopulations of NIDCM were excluded. Data were independently extracted and combined via random-effects meta-analysis using a generic inverse-variance strategy. Data from 60 studies comprising 15,217 patients were analyzed with a 3-year median follow-up. The presence of LGE was associated with major ventricular arrhythmic events (pooled OR: 3.99; 95% CI 3.08, 5.16), all-cause mortality (pooled OR: 2.14; 95% CI 1.81, 2.52), cardiovascular mortality (pooled OR 2.83; 95% CI 2.23, 3.60), and heart failure hospitalization (pooled OR: 2.53; 95% CI 1.78, 3.59). Real-world evidence suggests that the presence of LGE on CMR was a strong predictor of adverse long-term outcomes in patients with NIDCM. Scar assessment should be incorporated as a primary determinant in the patient selection criteria for primary prophylactic implantable cardioverter-defibrillator placement.

Sex differences in clinical characteristics, management, and outcomes in patients admitted for ventricular tachycardia: 2016-2018.

INTRODUCTION: The concurrent data on sex disparities in VT management and outcomes have remained unclear. Therefore, our objective was to determine the impact of sex on ventricular tachycardia (VT) management and outcomes in patients admitted with VT, dervied from the US National Inpatient Sample database (NIS). METHODS: We used data from the US NIS to identify hospitalized adult patients who were admitted with VT between 2016 and 2018. Regression analysis was conducted to evaluate the impact of sex on VT management, in-hospital mortality, complications, length of stay, and hospitalization costs. RESULTS: Of the database, a total of 146 070 patients, who were primarily hospitalized for VT, were approximated. Among these, women comprised 25.5%; they were significantly younger and had fewer comorbidities. Of procedural aspects, women were less likely to receive an angiogram, mechanical support, implantable cardioverter-defibrillator implantation, and VT ablation compared to men. Notably, women were associated with higher do-not-resuscitate rates and in-hospital cardiac arrests than men. No differences in in-hospital mortality and cardiogenic shock were observed between men and women (p > .05). Length of stay was significantly longer for women, while no differences in hospital costs were observed in both sexes. CONCLUSION: Significant sex disparities in management and outcomes were observed in admitted patients with VT. Our results reflect the need for further studies to explore factors causing such diversities.

Syncope with autonomic dysfunction assessed with the Thai-COMPASS 31 questionnaire.

Introduction: Alteration of autonomic function is the main pathophysiology of most types of syncope, including syncope due to orthostatic hypotension and neurally mediated syncope or reflex syncope. The aim of this study was to investigate the difference in autonomic dysfunction assessed between each type of syncope and to evaluate the association between the severity of autonomic dysfunction and the recurrence of syncope. Methodology: Three hundred and six participants, including 195 syncope and 109 healthy control participants, were recruited to this retrospective cohort study. Autonomic function was initially assessed by the Thai version of the Composite Autonomic Symptom Score 31 (COMPASS 31), a self-administered questionnaire. Result: According to one hundred and ninety-five syncope participants, twenty-three participants had syncope due to orthostatic hypotension, 61 had reflex syncope, 79 had presyncope, and 32 had unclassified syncope. Participants in the syncope due to orthostatic hypotension and reflex syncope groups had significantly higher COMPASS 31 scores than the control and presyncope groups, of which the syncope due to orthostatic hypotension group had the highest score. The cutoff score of 32.9 for COMPASS 31 had a sensitivity of 50.0% and a specificity of 81.9% to predict the recurrence of syncope. Conclusion: The degree of autonomic dysfunction, which was assessed by COMPASS 31, could vary depending on the syncope type. The COMPASS 31, which is an easy-to-use self-administered questionnaire utilized for the assessment of autonomic symptoms and function, was a helpful tool for classifying some types of syncope and predicting the recurrence of syncope, which could lead to appropriate further management.

Cannabis and adverse cardiovascular events: A systematic review and meta-analysis of observational studies.

Background: Cannabis is the most used illicit drug in the world. Global trends of decriminalization and legalization of cannabis lead to various forms of cannabis use and bring great concerns over adverse events, particularly in the cardiovascular (CV) system. To date, the association between cannabis and adverse CV events is still controversial. Purpose: We aim to conduct a systematic review and meta-analysis to assess the adverse CV events from cannabis use. Patients and methods: A systematic search for publications describing the adverse CV events of cannabis use, including acute myocardial infarction (MI) and stroke, was performed via PubMed, Scopus, and Cochrane Library databases. Data on effect estimates in individual studies were extracted and combined via random-effects meta-analysis using the DerSimonian and Laird method, a generic inverse-variance strategy. Results: Twenty studies with a total of 183,410,651 patients were included. The proportion of males was 23.7%. The median age and follow-up time were 42.4 years old (IQR: 37.4, 50.0) and 6.2 years (IQR: 1.7, 27.7), respectively. The prevalence of cannabis use was 1.9%. Cannabis use was not significantly associated with acute MI (pooled odds ratio (OR): 1.29; 95%CI: 0.80, 2.08), stroke (pooled OR 1.35; 95%CI: 0.74, 2.47), and adverse CV events (pooled OR: 1.47; 95%CI: 0.98, 2.20). Conclusion: The risk of adverse CV events including acute MI and stroke does not exhibit a significant increase with cannabis exposure. However, caution should be exercised when interpreting the findings due to the heterogeneity of the studies.

Permanent pacemaker implantation in post one-and-a-half ventricle repair with tricuspid valve replacement in Ebstein anomaly: An innovative technique.

INTRODUCTION: Transvenous pacemaker implantation in patients post bidirectional Glenn anastomosis in one-and-a-half ventricle repair is usually not feasible. However, with a modified surgical technique for Glenn anastomosis and a combined interventional and electrophysiologic approach, the transvenous pacemaker was successfully implanted. FINDINGS AND CONCLUSIONS: We reported a novel technique of pacemaker implantation in a 27-year-old woman, underlying Ebstein anomaly of the tricuspid valve, who developed intermittent complete atrioventricular block at 5 years after surgical repair. The patient had a tricuspid valve replacement and a novel modified bidirectional Glenn anastomosis for one-and-a-half ventricle repair. The Glenn circuit was conducted by opening a window between the posterior wall of the superior vena cava (SVC) and the anterior wall of the right pulmonary artery (RPA), combined with putting a Goretex membrane in the SVC below the SVC-RPA window without disconnecting the SVC from the right atrium. The transvenous pacemaker was implanted by perforating the Goretex membrane, then passing the leads from the axillary vein through the perforated membrane and placing them in the coronary sinus and right atrium.

"Wearing-off" efficacy of CGRP monoclonal antibodies for migraine prevention: A meta-analysis of randomized controlled trials.

BACKGROUND: A new migraine prevention, CGRP monoclonal antibodies (mAbs), is injectable on a monthly or quarterly basis. In clinical practice, some patients reported that drug effectiveness does not last until the upcoming scheduled injection, a so-called "wearing-off" effect. We aimed to evaluate the wearing-off effect of the CGRP mAbs for migraine prevention in patients with different monthly migraine days. METHODS: We conducted a literature search for studies that reported migraine frequency after CGRP monoclonal antibody administration from MEDLINE, SCOPUS, Web of Science, and Cochrane Database from inception through February 2022. A meta-analysis, random-effects model was applied to assess the difference in migraine frequency between early and later weeks after medication to assess the presence of a wearing-off effect. Risk ratio was calculated to report the pooled treatment effect. RESULTS: Four studies were entered for the analysis, comprising 2409 patients in randomized controlled trials. There was no association between CGRP mAbs and wearing-off effect in patients with galcanezumab with a pooled risk ratio of 1.29 (95% CI 0.73 to 2.28) compared to placebo group. However, there was an association between galcanezumab and wearing-off effect in patients with chronic migraine with a pooled risk ratio of 1.91 (95% CI 1.11 to 3.28) compared to placebo group. CONCLUSION: In this meta-analysis, there was a wearing-off efficacy of galcanezumab but only in a small percentage of patients with chronic migraine in randomized controlled trials.

Proenkephalin as a Novel Prognostic Marker in Heart Failure Patients: A Systematic Review and Meta-Analysis.

Over the last several years, the use of biomarkers in the diagnosis of patients with heart failure (HF) has skyrocketed. Natriuretic peptides are currently the most widely used biomarker in the diagnosis and prognosis of individuals with HF. Proenkephalin (PENK) activates delta-opioid receptors in cardiac tissue, resulting in a decreased myocardial contractility and heart rate. However, the goal of this meta-analysis is to evaluate the association between the PENK level at the time of admission and prognosis in patients with HF, such as all-cause mortality, rehospitalization, and decreasing renal function. High PENK levels have been associated with a worsened prognosis in patients with HF.

Reverse of left ventricular remodeling in heart failure patients with left bundle branch area pacing: Systematic review and meta-analysis.

BACKGROUND: Left bundle branch area pacing (LBBAP) has recently become a promising option for the near-natural restoration of electrical activation. However, the clinical relevance of therapeutic effects in individuals with heart failure with reduced ejection fraction (HFrEF) and dyssynchrony remains unknown. METHODS: MEDLINE, EMBASE, and Cochrane databases were searched from inception until June 2022. Data from each study was combined using a random-effects model, the generic inverse variance method of DerSimonian and Laird, to calculate standard mean differences and pooled incidence ratio, with 95% confidence intervals (CIs). RESULTS: A total of 772 HFrEF patients were analyzed from 15 observational studies per protocol. The success rate of LBBAP implantation was 94.8% (95% CI 89.9-99.6, I2 = 79.4%), which was strongly correlated with shortening QRS duration after LBBAP implantation, with a mean difference of -48.10 ms (95% CI -60.16 to -36.05, I2 = 96.7%). Over a period of 6-12 months of follow-up, pacing parameters were stable over time. There were significant improvements in left ventricular ejection fraction (LVEF), left ventricular end-systolic volume (LVESV), left ventricular end-diastolic diameter (LVEDD), and left ventricular end-diastolic volume (LVEDV) with mean difference of 16.38% (95% CI 13.13-19.63, I2 = 90.2%), -46.23 ml (95% CI -63.17 to -29.29, I2 = 86.82%), -7.21 mm (95% CI -9.71 to -4.71, I2 = 84.6%), and -44.52 ml (95% CI -64.40 to -24.64, I2 = 85.9%), respectively. CONCLUSIONS: LBBAP was associated with improvements in both cardiac function and electrical synchrony. The benefits of LBBAP in individuals with HFrEF and dyssynchrony should be further validated by randomized studies.

Network meta-analysis and systematic review comparing efficacy and safety between very high power short duration, high power short duration, and conventional radiofrequency ablation of atrial fibrillation.

BACKGROUND: High-power short-duration (HPSD) atrial fibrillation (AF) ablation with a power of 40-50 W was proved to be safe and effective. Very high-power short-duration (vHPSD) AF ablation is a novel method using >50 W to obtain more durable AF ablation. This study aimed to evaluate the efficacy and safety of vHPSD ablation compared with HPSD ablation and conventional power ablation. METHODS: A literature search for studies that reported AF ablation outcomes, including short-term freedom from atrial arrhythmia, first-pass isolation (FPI) rate, procedure time, and major complications, was conducted utilizing MEDLINE, EMBASE, and Cochrane databases. All relevant studies were included in this analysis. A random-effects model of network meta-analysis and surface under cumulative ranking curve (SUCRA) were used to rank the treatment for all outcomes. RESULTS: A total of 29 studies with 9721 patients were included in the analysis. According to the SUCRA analysis, HPSD ablation had the highest probability of maintaining sinus rhythm. Point estimation showed an odds ratio of 1.5 (95% confidence interval [CI]: 1.2-1.9) between HPSD ablation and conventional power ablation and an odds ratio of 1.3 (95% CI: 0.78-2.2) between vHPSD ablation and conventional power ablation. While the odds ratio of FPI between HPSD ablation and conventional power ablation was 3.6 (95% CI: 1.5-8.9), the odds ratio between vHPSD ablation and conventional power ablation was 2.2 (95% CI: 0.61-8.6). The procedure times of vHPSD and HPSD ablations were comparable and, therefore, shorter than that of conventional power ablation. Major complications were low in all techniques. CONCLUSION: vHPSD ablation did not yield higher efficacy than HPSD ablation and conventional power ablation. With the safety concern, vHPSD ablation outcomes were comparable with those of other techniques.

Machine learning-based predictive risk models for 30-day and 1-year mortality in severe aortic stenosis patients undergoing transcatheter aortic valve implantation.

BACKGROUND: Predictive risk score for mortality plays an important role in the decision-making in patient selection and risk stratification for TAVI. Existing established predictive risk scores had poor discrimination performance in the prediction of mortality after the TAVI. OBJECTIVES: The present study aimed to develop machine learning-based predictive models for 30-day and 1-year mortality in severe aortic stenosis patients undergoing TAVI. METHODS: A total of 186 patients in a retrospective cohort study were analyzed. The models were fitted by a decision tree. Each model was tested in 100 iterations of 80:20 stratified random splitting into training/testing samples and 10-fold cross-validation. RESULTS: Variables that predict 30-day mortality are a set of factors driven mainly by height, chronic lung disease, STS score, preoperative LVEF, age, and preoperative LVOT VTI. Variables that predict 1-year mortality are a set of factors consisting of preoperative LVEF, STS score, heart rate, systolic blood pressure, home oxygen use, serum creatinine level, and preoperative LVOT Vmax. This decision tree-generated predictive models for 30-day and 1- year mortality provided the most precise accuracy of 0.97 and 0.90 with the AUC-ROC curves of 0.83 and 0.71 on 30-day and 1-year mortality on testing data and had better discrimination performance compared to the existing established TAVI predictive risk scores. CONCLUSIONS: These machine learning models show excellent accuracy and have a better prediction for 30-day and 1-year mortality than the existing established TAVI predictive risk scores. A customized predictive model deems to be properly developed for better risk discrimination among cohorts.