Left atrial strain time integral evaluated by two-dimensional speckle tracking predicts left atrial appendage dysfunction in patients with acute ischemic stroke.

Cardioembolic stroke is a serious disease with poor prognosis, whose main embolic source is the left atrial appendage (LAA). Left atrial (LA) strain evaluated by the two-dimensional (2D) speckle tracking technique has been proposed. However, the commonly used peak LA strain reflects only LA reservoir function. The LA strain also includes indicators of the other LA functions, such as booster pump function, which reflects active contraction of the LA. This study aimed to investigate whether a newly developed parameter, the left atrial strain time integral (LASTI), can evaluate LAA dysfunction more accurately in patients with acute stroke. We measured LA strain using a 2D speckle tracking method in 168 patients with acute stroke and 20 age-matched control subjects. LASTI was calculated as the area under the LA strain curve in one cardiac cycle. LAA dysfunction was defined as LAA thrombus and/or severe spontaneous echo contrast by transesophageal echocardiography. LASTI was significantly lower in patients with LAA dysfunction than those without. LASTI was a better correlation with LAA blood flow velocity measured by transesophageal echocardiography than peak LA strain. Multivariate logistic regression analysis showed that LASTI was an independent predictor of LAA dysfunction after adjustment for conventional risk factors. LASTI can be a feasible parameter for predicting LAA dysfunction in patients with acute stroke.

Improved cerebral blood flow and hippocampal blood flow in stroke-free patients after catheter ablation of atrial fibrillation.

INTRODUCTION: Atrial fibrillation (AF) is a risk factor for reduced cerebral blood flow (CBF) and cognitive dysfunction, even in stroke-free patients. We aimed to test the hypothesis that CBF and hippocampal blood flow (HBF), measured with arterial spin labeling magnetic resonance imaging (MRI), improve after catheter ablation of AF to achieve sinus rhythm (SR). METHODS: A total of 84 stroke-free patients (63.1 ± 9.1 years; paroxysmal AF, n = 50; non-paroxysmal AF, n = 34) undergoing AF catheter ablation were included. MRI studies were done before, 3 months, and 12 months after the procedure with CBF and HBF measurements. RESULTS: Baseline CBF and HBF values in 50 paroxysmal AF patients were used as controls. Baseline CBF was higher in patients with paroxysmal AF than with non-paroxysmal AF (100 ± 32% vs. 86 ± 28%, p = .04). Patients with non-paroxysmal AF had increased CBF 3 months after AF ablation (86 ± 28% to 99 ± 34%, p = .03). Differences in CBF and HBF were greater in the group with AF restored to SR (p < .01). Both CBF and HBF levels at 12 months were unchanged from the 3 months level. Successful rhythm control by catheter ablation was an independent predictor of an increase in CBF > 17.5%. The Mini-Mental State Examination score improved after ablation (p = .02). CONCLUSION: SR restoration with catheter ablation was associated with improved CBF and HBF at 3 months, maintenance of blood flow, and improved cognitive function at 12 months.

A Case of Recurrent Infective Endocarditis Caused by Streptococcus Agalactiae.

A 53-year-old man was admitted to hospital with a high fever and shivering. He had undergone aortic valve replacement 4 years previously due to infective endocarditis caused by Streptococcus agalactiae. 18F-fluorodeoxyglucose positron emission tomography/CT (18F-FDG PET/CT) showed increased uptake in the tissue surrounding the prosthetic valve. S. agalactiae was detected in blood cultures after admission. We made a diagnosis of prosthetic valve endocarditis due to an S. agalactiae infection relapse. After 6 weeks of antibacterial treatment, the inflammatory findings successfully improved. However, reexamination with 18F-FDG PET/CT suggested the possibility of persistent prosthetic valve infection. Therefore, we decided to continue the oral antibiotic treatment after discharge.

Biatrial volume, estimated using magnetic resonance imaging, predicts atrial fibrillation recurrence after ablation.

INTRODUCTION: The predictive value of left atrial volume (LAV) in atrial fibrillation (AF) is known, but the relationship of right atrial volume (RAV) and biatrial volume (BAV) with AF recurrence after pulmonary vein isolation (PVI) is not clear. Cardiac magnetic resonance (CMR) imaging allows us to more precisely quantify atrial volume. We investigated LAV, RAV, and BAV as predictors of AF recurrence following PVI in AF patients. METHODS AND RESULTS: We assessed 100 AF patients (age = 59.8 ± 9.5 years, 74 males, 26 females) who underwent nonenhanced CMR before their first PVI. LAV and RAV were measured using CMR. All patients were in sinus rhythm during CMR. BAV was calculated as the sum of LAV and RAV. During the 8-month follow-up, AF recurrence occurred in 23 patients. LAV, RAV, and BAV were significantly greater in patients with AF recurrence than in those without (LAV, 103.7 ± 25.8 vs 81.8 ± 24.2 mL, P < 0.001; RAV, 109.4 ± 27.0 vs 82.2 ± 19.6 mL, P < 0.001; BAV, 213.1 ± 46.7 vs 164.1 ± 38.7 mL, P < 0.001). Multivariate logistic regression analysis revealed that increased LAV, RAV, and BAV were significantly correlated with AF recurrence. The area under the receiver operation characteristic curve for BAV showed the largest value compared to that of LAV or RAV alone. CONCLUSIONS: LAV, RAV, and BAV were independent predictors of AF recurrence after PVI. Quantifying BAV may additionally improve prognostic stratification compared with LAV or RAV.

The Neutrophil-to-Lymphocyte Ratio Predicts All-Cause Mortality in Patients with Implantable Cardioverter Defibrillators.

BACKGROUND: The relationship between the neutrophil-to-lymphocyte ratio (NLR) and outcome in patients with implantable cardioverter-defibrillators (ICDs) is unclear. METHODS AND RESULTS: Consecutive patients with cardiomyopathy who had received an ICD (n = 120, mean age 64 ± 11 years) were prospectively enrolled. Blood samples were obtained on the morning of the day of implantation. Patients were followed for a median period of 61.2 months, to an endpoint of all-cause mortality or appropriate ICD shock, which occurred in 35 (29%) and 28 (23%) patients, respectively. Multivariate Cox analysis revealed that secondary prevention was only associated with appropriate ICD shocks. The NLR, brain natriuretic peptide level, and estimated glomerular filtration rate were independent predictors of all-cause mortality but not of appropriate ICD shocks. Subgroup analysis revealed that a high NLR (≥2.1) was valuable for anticipating all-cause mortality among patients who had received ICDs for primary or secondary prevention. A high NLR was also associated with death prior to appropriate ICD shock. CONCLUSION: Evaluating the NLR may be useful for predicting outcomes in patients with cardiomyopathy who have received ICDs.

Efficacy and safety of remote cardiac rehabilitation in the recovery phase of cardiovascular diseases (RecRCR study): A multicenter, nonrandomized, and interventional trial in Japan.

Backgrounds: Remote cardiac rehabilitation has proven useful in patients with cardiovascular disease; however, the methodology had not been fully validated. This study aimed to investigate the efficacy and safety of remote cardiac rehabilitation (RCR) with real-time monitoring and an ergometer using a bidirectional communication tool during the recovery phase of cardiovascular diseases. Methods: This multicenter, nonrandomized, interventional study was conducted at 29 institutions across Japan and enrolled patients with cardiovascular diseases who met indications for cardiac rehabilitation (CR) after receiving in-hospital treatment. The RCR group exercised at home using an ergometer and was monitored in real-time using interactive video and monitoring tools for 2-3 months. Educational instructions were provided concurrently through e-learning approaches. The safety of the RCR protocol and the improvement in peak oxygen consumption (VO2) were compared with those of the historical control group that participated in center-based CR. Results: Fifty-three patients from the RCR group were compared with 103 historical controls having similar background characteristics. No patients in RCR experienced significant cardiovascular complications while engaging in exercise sessions. After 2-3 months of RCR, the peak VO2 improved significantly, and the increases in the RCR group did not exhibit any significant differences compared to those in the historical controls. During follow-up, the proportion of patients whose exercise capacity increased by 10% or more was also evaluated; this finding did not indicate a statistically significant distinction between the groups. Conclusions: RCR during the recovery phase of cardiovascular diseases proved equally efficient and safe as center-based CR.

Anticoagulation therapy for endocardial/epicardial ablation of infarct-related ventricular tachycardia in a patient with antithrombin deficiency.

In patients with a history of antithrombin deficiency, a direct thrombin inhibitor may be considered as an alternative to intraprocedural anticoagulation. A 55-year-old woman with antithrombin deficiency and prior myocardial infarction suffered from electrical storm and appropriate defibrillator shocks. Substrate mapping guided left ventricular endocardial and epicardial ablations were successfully performed. The direct thrombin inhibitor, argatroban, was safely used as intraprocedural anticoagulation therapy with no complications. Learning objective: Optimal anticoagulation during endocardial and epicardial catheter ablation is essential to prevent thromboembolic and bleeding complications. Although patients with infarct-related electrical storm and antithrombin deficiency require unusual attention to anticoagulation, argatroban, a direct thrombin inhibitor, was safely used as intraprocedural anticoagulation therapy during catheter ablations, with no complications.

Prognostic Impact of Renal Dysfunction at 1-Year Follow-Up on Clinical Outcomes After Percutaneous Coronary Intervention.

AIMS: Renal dysfunction is an independent predictor of adverse outcomes in patients with coronary artery disease (CAD). However, the prognostic impact of mid-term changes in renal dysfunction status remains unclear. This study aimed to investigate the impact of mid-term changes in renal dysfunction status on long-term clinical outcomes in CAD patients who underwent percutaneous coronary intervention (PCI). METHODS: We enrolled 382 consecutive patients with CAD who underwent PCI. Renal dysfunction was defined as a reduced estimated glomerular filtration rate (eGFR) of ＜60 mL/min/1.73m2. Renal dysfunction status was evaluated at baseline and 1-year follow-up after PCI. We divided the study population into three groups: persistent renal dysfunction, new-onset renal dysfunction, and no or improved renal dysfunction at 1-year follow-up as compared with on baseline. The endpoints of this study were composite events, including all-cause death, acute coronary syndrome, target vessel revascularization, and stroke. RESULTS: At baseline, renal dysfunction was observed in 77 patients (20%). At the 1-year follow-up, new-onset renal dysfunction was observed in 46 patients (12%), and 59 patients (15%) had persistent renal dysfunction. Kaplan-Meier analysis revealed a significantly higher event rate in patients with persistent renal dysfunction and new-onset renal dysfunction (log-rank test, P=0.0003). In the multivariate Cox proportional hazards analysis, persistent renal dysfunction and new-onset renal dysfunction were independently associated with composite events after adjusting for confounding factors (adjusted hazard ratios 4.08 and 2.64, 95% confidence intervals 1.72-9.57 and 1.03-6.31, P=0.0016, P=0.0045, respectively). CONCLUSION: Persistent and new-onset renal dysfunction at 1-year follow-up were associated with unfavorable outcomes in patients with CAD who underwent PCI.

Prognostic impact of plasma xanthine oxidoreductase activity in patients with heart failure with atrial fibrillation.

BACKGROUND: Xanthine oxidoreductase (XOR) is a rate-limiting enzyme for uric acid (UA) production and plays an important role in generating reactive oxygen species (ROS). Overproduction of ROS is reported to contribute to the pathophysiology of atrial fibrillation (AF), however, the prognostic impact of plasma XOR activity in patients with heart failure (HF) with AF is undetermined. METHODS: We measured plasma XOR activity in 475 HF patients, including those with sinus rhythm (HF-SR, n = 211), and those with AF (HF-AF, n = 264). The type of AF included paroxysmal (n = 128) and persistent (n = 136) AF. All patients were prospectively followed up for a median period of 804 days. RESULTS: HF-AF patients had significantly higher plasma XOR activity and serum UA levels compared with HF-SR patients. Both plasma XOR activity and serum UA levels were higher in patients with persistent AF than in those with SR and with paroxysmal AF. Multivariate linear regression analysis showed that persistent AF was independently associated with increased XOR activity. During the follow-up period, there were 79 major adverse cardiovascular events (MACEs). HF-AF patients with MACEs had higher plasma XOR activity compared with those without MACEs, while there were no significant differences in serum UA levels. Multivariate Cox proportional analysis showed that high XOR activity was an independent risk factor for MACEs after adjustment for confounding factors. Kaplan-Meier analysis revealed that the high XOR activity group had a higher risk of MACEs than the low XOR activity group. The prediction model was significantly improved by the addition of XOR activity to the basic predictors. CONCLUSIONS: HF-AF patients had significantly higher plasma XOR activity compared with HF-SR patients. Plasma XOR activity proved to be a reliable indicator for MACEs in HF-AF patients.

Circulating heart-type fatty acid binding protein levels predict the occurrence of appropriate shocks and cardiac death in patients with implantable cardioverter-defibrillators.

BACKGROUND: The association between ongoing myocardial damage and outcomes in patients who have received an implantable cardioverter-defibrillator (ICD) is unclear. METHODS AND RESULTS: Consecutive patients with cardiomyopathy, who had received an ICD (n = 107, mean age 65 ± 11 years), were prospectively enrolled. Myocardial membrane injury (heart-type fatty acid binding protein [H-FABP] >4.3 ng/mL) and myofibrillar injury (troponin T >0.01 ng/mL) were defined using receiver operating characteristic curves. Patients were followed for a median of 33.6 months, to an end point of appropriate ICD shock or cardiac death. Myocardial membrane injury (45%) and myofibrillar injury (41%) were equally prevalent among patients with cardiomyopathy who had received ICDs. Appropriate ICD shocks or cardiac death occurred in 31% and 15% of patients, respectively. Multivariate Cox regression analysis showed that serum H-FABP levels >4.3 ng/mL, but not troponin T levels, were a significant independent prognostic factor for cardiac events (hazard ratio 5.502, 95% confidence interval 1.705-17.75, P = .004). Subgroup analysis revealed that measuring H-FABP levels was valuable for anticipating event-free survival among patients with ICDs who were receiving amiodarone. High H-FABP levels also predicted subsequent outcomes in patients who had received ICDs for primary or secondary prevention. CONCLUSION: Evaluating myocardial damage using H-FABP may be a promising tool for predicting outcomes in patients with cardiomyopathy who have received ICDs.

Device troubleshooting: cross connection of ventricular leads in a patient with decreased right ventricular electrical activity.

A patient with cardiac sarcoidosis showed low R-wave amplitude in the entire right ventricle (RV). To troubleshoot this, a left ventricular (LV) lead was implanted in the coronary vein. The pace/sense terminal of the defibrillation lead was connected to LV:IS-1 of the defibrillator. Conversely, the LV lead was connected to RV:IS-1. Induced ventricular fibrillation was successfully terminated without any undersensing.

Contact dermatitis associated with wearable cardioverter-defibrillator.

A 51-year-old man with dilated cardiomyopathy was resuscitated from ventricular fibrillation. Twenty-days after using a wearable cardioverter-defibrillator (WCD) contact dermatitis with itching was evident and consistent with the self-gelling defibrillation electrodes patch on the back. Itching was controlled with clobetasol propionate application. The WCD was continued until catheter ablation and device implantation. The contact dermatitis was completely recovered two weeks after discontinuing the WCD. Among 58 patients using the WCD, three (5.2%) complained about discomfort with the device, and two (3.4%) complained of itching. Only the patient presented here (1.7%) suffered from contact dermatitis with itching. Contact dermatitis is rarely observed in patients wearing a WCD but physicians should be aware of this complication to maintain WCD compliance. .

Impact of activities of daily living on percutaneous coronary intervention and acute and long-term mortality in patients with acute myocardial infarction: Yamagata AMI registry.

BACKGROUND: A decrease in the activities of daily living (ADL) is an independent risk factor for cardiovascular disease. Although percutaneous coronary intervention (PCI) is known to prevent early mortality in patients with acute myocardial infarction (AMI), the relationship between ADL prior to myocardial infarction (MI), PCI implementation, and mortality in patients with AMI remains unknown. We investigated the impact of prehospital ADL on PCI implementation and on short- and long-term mortality in patients with AMI. METHODS: We investigated the prehospital ADL in 1479 patients with AMI using data from the Yamagata AMI registry (period: 2015-2017). The patients were divided into three groups (preserved ADL, mildly impaired ADL, and severely impaired ADL) and their clinical characteristics were compared. Multivariate regression analysis was performed to elucidate the association of ADL prior to MI with the PCI implementation and mortality in patients with AMI. RESULTS: Patients with impaired ADL were older, more likely to be female, less likely to have undergone PCI, and presented with higher acute mortality compared to those with preserved ADL. The proportion of patients with impaired ADL increased with age. Multivariate regression analysis showed that the lack of PCI implementation and prehospital ADL impairment were independent risk factors for acute death in patients with AMI after adjusting for confounding factors. Furthermore, univariate and multivariate analyses revealed that impaired ADL was associated with the PCI implementation. Cox proportional hazards analysis revealed that prehospital ADL impairment was an independent risk factor for long-term mortality in patients with AMI. CONCLUSIONS: Decreased levels of prehospital ADL were associated with lower PCI implementation and higher mortality in patients-especially older patients-with AMI.

Effects of Nitric Oxide Synthase 3 Gene Polymorphisms on Cardiovascular Events in a General Japanese Population　- The Yamagata (Takahata) Study.

Background: Single nucleotide polymorphisms (SNPs) in nitric oxide synthase 3 (NOS3) are associated with cardiovascular risk factors. However, it is not clear whether the NOS3 SNP is a genetic risk factor for cardiovascular diseases. Methods and Results: This prospective cohort study included 2,726 subjects aged ≥40 years who participated in a community-based health checkup. We genotyped 639 SNPs, including 2 NOS3 SNPs (rs1799983 and rs1808593). All subjects were monitored prospectively over a median follow-up period of 16.0 years, with the endpoint being cardiovascular events, including cardiovascular death and/or non-fatal myocardial infarction. Kaplan-Meier analysis demonstrated that both rs1799983 GT/TT and rs1808593 GG carriers had a higher risk of the endpoint than non-carriers. Univariate and multivariate Cox proportional hazard regression analyses revealed that both rs1799983 GT/TT and rs1808593 GG were independently associated with cardiovascular events after adjusting for confounding risk factors. The net reclassification index and integrated discrimination index were significantly improved by the addition of NOS3 SNPs as cardiovascular risk factors. Conclusions: NOS3 gene polymorphisms could be genetic risk factors for cardiovascular events in the general Japanese population, and could be used to facilitate the early identification of individuals at high risk of cardiovascular events.

Persistent abnormal value of late potential in Brugada syndrome associated with hypokalemia.

Hypokalemia accentuates the electrocardiographic (ECG) pattern of Brugada syndrome. We report two patients with Brugada syndrome and hypokalemia-induced lethal events. Despite concealing the typical ECG pattern with normalization of serum potassium levels, late potentials were persistently detected by signal-averaged ECG, even at the 18-month follow-up. An implantable cardioverter defibrillator was inserted to prevent sudden cardiac death.

Visualization of persistent superior vena cava isolation by cryoballoon ablation.

A 54-year-old man with paroxysmal atrial fibrillation underwent pulmonary vein (PV) isolation using a 28-mm second-generation cryoballoon catheter. Unexpected electrical superior vena cava (SVC) isolation during cryoballoon application to the right superior PV was observed in the first procedure. Thirteen-months after cryoballoon-based PV isolation, sustained SVC fibrillation was confirmed irrespective of sinus rhythm. Voltage mapping visualized a low voltage area around the SVC was close to that around the right superior PV. SVC isolation was obtained by cryoballoon application to the right superior PV and persisted for over a year. .

Visualization of epicardial lead infection using 18F-FDG-PET/CT imaging.

18 F-FDG-PET/CT is promising tool to visualize not only transvenous lead infection but also epicardial lead infection.

Unmet needs for emergency care and prevention of prehospital death in acute myocardial infarction.

INTRODUCTION: Percutaneous coronary intervention (PCI) has successfully reduced the mortality of patients with acute myocardial infarction (AMI). However, patients with out-of-hospital cardiac arrest have high mortality, which is difficult to control by hospital staff. In this study, we investigated the prevalence of prehospital death (PHD) in patients with AMI. Furthermore, we investigated the risk factors associated with 30-day mortality in patients with AMI who survived PHD. METHODS: We investigated the prevalence of PHD using data from the Yamagata AMI registry and from death certification of the entire Yamagata Prefecture in Japan between 2010 and 2015. Furthermore, we investigated the risk factors for 30-day mortality in patients who survived PHD, using data from the Yamagata AMI registry from 1993 to 2015. AMI was identified by the International Classification of Diseases, 10th revision code I21. RESULTS: Out of the 6984 patients with AMI, 3771 patients had PHD. Patients with PHD were older and more likely to be women than those without PHD. More PHD occurred in winter and spring than in summer or autumn. Multivariate regression analysis showed that age, female sex, and winter onset were independently associated with PHD. We also investigated the risk factors associated with 30-day mortality in 9675 patients who survived PHD. The rate of PCI was remarkably lower in patients with acute death than in those without acute death. Multivariate regression analysis showed that age, anterior infarction, estimated glomerular filtration rate, Killip class, and PCI were independently associated with 30-day mortality after adjusting for confounding factors. CONCLUSION: Approximately half of the patients with AMI died before they could reach the destination hospital. Although emergency PCI is the most important factor in reducing 30-day mortality in patients with AMI, attempts to reduce patient delay and system delay are possibly needed to further reduce PHD.

HECT (Homologous to the E6-AP Carboxyl Terminus)-Type Ubiquitin E3 Ligase ITCH Attenuates Cardiac Hypertrophy by Suppressing the Wnt/ß-Catenin Signaling Pathway.

The HECT (homologous to the E6-AP carboxyl terminus)-type ubiquitin E3 ligase ITCH is an enzyme that plays an important role in ubiquitin-proteasomal protein degradation. Disheveled proteins (Dvl1 [disheveled protein 1], Dvl2, and Dvl3) are the main components of the Wnt/ß-catenin signaling pathway, which is involved in cardiac hypertrophy. The aim of this study was to examine the role of ITCH during development of cardiac hypertrophy. Thoracic transverse aortic constriction (TAC) was performed in transgenic mice with cardiac-specific overexpression of ITCH (ITCH-Tg) and wild-type mice. Cardiac hypertrophy after TAC was attenuated in ITCH-Tg mice, and the survival rate was higher for ITCH-Tg mice than for wild-type mice. Protein interaction between ITCH and Dvls was confirmed with immunoprecipitation in vivo and in vitro. Expression of key molecules of the Wnt/ß-catenin signaling pathway (Dvl1, Dvl2, GSK3ß [glycogen synthase kinase 3ß], and ß-catenin) was inhibited in ITCH-Tg mice compared with wild-type mice. Notably, the ubiquitination level of Dvl proteins increased in ITCH-Tg mice. Protein and mRNA expression levels of ITCH increased in response to Wnt3a stimulation in neonatal rat cardiomyocytes. Knockdown of ITCH using small-interfering RNA increased cardiomyocyte size and augmented protein expression levels of Dvl proteins, phospho-GSK3ß, and ß-catenin after Wnt3a stimulation in cardiomyocytes. Conversely, overexpression of ITCH attenuated cardiomyocyte hypertrophy and decreased protein expression levels of Dvl proteins, phospho-GSK3ß and ß-catenin. In conclusion, ITCH targets Dvl proteins for ubiquitin-proteasome degradation in cardiomyocytes and attenuates cardiac hypertrophy by suppressing the Wnt/ß-catenin signaling pathway.

The association between microRNA-21 and hypertension-induced cardiac remodeling.

Hypertension is a major public health problem among the aging population worldwide. It causes cardiac remodeling, including hypertrophy and interstitial fibrosis, which leads to development of hypertensive heart disease (HHD). Although microRNA-21 (miR-21) is associated with fibrogenesis in multiple organs, its contribution to cardiac remodeling in hypertension is poorly understood. Circulating miR-21 level was higher in patients with HHD than that in the control subjects. It also positively correlated with serum myocardial fibrotic markers. MiR-21 expression levels were significantly upregulated in the mice hearts after angiotensin II (Ang II) infusion or transverse aortic constriction (TAC) compared with control mice. Expression level of programmed cell death 4 (PDCD4), a main target of miR-21, was significantly decreased in Ang II infused mice and TAC mice compared with control mice. Expression levels of transcriptional activator protein 1 (AP-1) and transforming growth factor-ß1 (TGF-ß1), which were downstream targets of PDCD4, were increased in Ang II infused mice and TAC mice compared with control mice. In vitro, mirVana-miR-21-specific inhibitor attenuated Ang II-induced PDCD4 downregulation and contributed to subsequent deactivation of AP-1/TGF-ß1 signaling pathway in neonatal rat cardiomyocytes. Thus, suppression of miR-21 prevents hypertrophic stimulation-induced cardiac remodeling by regulating PDCD4, AP-1, and TGF-ß1 signaling pathway.