Stimulus contrast, pursuit mode, and age strongly influence tracking performance on a continuous visual tracking task.

Human observers tend to naturally track moving stimuli. This tendency may be exploited towards an intuitive means of screening visual function as an impairment induced reduction in stimulus visibility will decrease tracking performance. Yet, to be able to detect subtle impairments, stimulus contrast is critical. If too high, the decrease in performance may remain undetected. Therefore, for this approach to become reliable and sensitive, we need a detailed understanding of how age, stimulus contrast, and the type of stimulus movement affect continuous tracking performance. To do so, we evaluated how well twenty younger and twenty older participants tracked a semi-randomly moving stimulus (Goldmann size III, 0.43 degrees of visual angle), presented at five contrast levels (5%-10%-20%-40%-80%). The stimulus could move smoothly only (smooth pursuit mode) or in alternation with displacements (saccadic pursuit mode). Additionally, we assessed static foveal and peripheral contrast thresholds. For all participants, tracking performance improved with increasing contrast in both pursuit modes. To reach threshold performance levels, older participants required about twice as much contrast (20% vs. 10% and 40% vs. 20% in smooth and saccadic modes respectively). Saccadic pursuit detection thresholds correlated significantly with static peripheral contrast thresholds (rho = 0.64). Smooth pursuit detection thresholds were uncorrelated with static foveal contrast thresholds (rho = 0.29). We conclude that continuous visual stimulus tracking is strongly affected by stimulus contrast, pursuit mode, and age. This provides essential insights that can be applied towards new and intuitive approaches of screening visual function.

Final benefit of primary percutaneous coronary intervention for ST-elevation myocardial infarction in older patients: long-term results of a randomised trial.

BACKGROUND: Although the short-term benefit of primary percutaneous coronary intervention (PCI) in elderly patients with ST-elevation myocardial infarction (STEMI) has been demonstrated, the final long-term survival benefit is as yet unknown. AIM: To assess the final survival benefit of primary PCI as compared to thrombolytic therapy in patients over 75 years of age. METHODS: Patients > 75 years with STEMI were randomised to either primary PCI or thrombolysis. Long-term data on survival were available for all patients. RESULTS: A total of 46 patients were randomised to primary PCI, 41 to thrombolysis. There were no significant differences in baseline variables. After a maximum of 20 years' follow-up, all patients had passed away. The patients randomised to thrombolysis died after a mean follow-up duration of 5.2 years (SD 4.9) compared to 6.7 years (SD 4.8) in patients randomised to primary PCI (p = 0.15). Thus, the mean final survival benefit of primary PCI was 1.5 years. CONCLUSION: The final survival benefit of primary PCI as compared to thrombolysis in elderly patients with STEMI is 1.5 years and their life expectancy increases by 28.8%.

Towards individualised treatment of out-of-hospital cardiac arrest patients: an update on technical innovations in the prehospital chain of survival.

Out-of-hospital cardiac arrest (OHCA) is a major healthcare problem, with approximately 200 weekly cases in the Netherlands. Its critical, time-dependent nature makes it a unique medical situation, of which outcomes strongly rely on infrastructural factors and on-scene care by emergency medical services (EMS). Survival to hospital discharge is poor, although it has substantially improved, to roughly 25% over the last years. Recognised key factors, such as bystander resuscitation and automated external defibrillator use at the scene, have been markedly optimised with the introduction of technological innovations. In an era with ubiquitous smartphone use, the Dutch digital text message alert platform HartslagNu ( www.hartslagnu.nl ) increasingly contributes to timely care for OHCA victims. Guidelines emphasise the role of cardiac arrest recognition and early high-quality bystander resuscitation, which calls for education and improved registration at HartslagNu. As for EMS care, new technological developments with future potential are the selective use of mechanical chest compression devices and extracorporeal life support. As a future innovation, 'smart' defibrillators are under investigation, guiding resuscitative interventions based on ventricular fibrillation waveform characteristics. Taken together, optimisation of available prehospital technologies is crucial to further improve OHCA outcomes, with particular focus on more available trained volunteers in the first phase and additional research on advanced EMS care in the second phase.

Coronary angiography findings in patients with shock-resistant ventricular fibrillation cardiac arrest.

INTRODUCTION: Shock-resistant ventricular fibrillation (VF) poses a therapeutic challenge during out-of-hospital cardiac arrest (OHCA). For these patients, new treatment strategies are under active investigation, yet underlying trigger(s) and substrate(s) have been poorly characterised, and evidence on coronary angiography (CAG) data is often limited to studies without a control group. METHODS: In our OHCA-registry, we studied CAG-findings in OHCA-patients with VF who underwent CAG after hospital arrival. We compared baseline demographics, arrest characteristics, CAG-findings and outcomes between patients with VF that was shock-resistant (defined as >3 shocks) or not shock-resistant (≤3 shocks). RESULTS: Baseline demographics, arrest location, bystander resuscitation and AED-use did not differ between 105 patients with and 196 patients without shock-resistant VF. Shock-resistant VF-patients required more shocks, with higher proportions endotracheal intubation, mechanical CPR, amiodaron and epinephrine. In both groups, significant coronary artery disease (≥1 stenosis >70%) was highly prevalent (78% vs. 77%, p = 0.76). Acute coronary occlusions (ACOs) were more prevalent in shock-resistant VF-patients (41% vs. 26%, p = 0.006). Chronic total occlusions did not differ between groups (29% vs. 33%, p = 0.47). There was an association between increasing numbers of shocks and a higher likelihood of ACO. Shock-resistant VF-patients had lower proportions 24-h survival (75% vs. 93%, p < 0.001) and survival to discharge (61% vs. 78%, p = 0.002). CONCLUSION: In this cohort of OHCA-patients with VF and CAG after transport, acute coronary occlusions were more prevalent in patients with shock-resistant VF compared to VF that was not shock-resistant, and their clinical outcome was worse. Confirmative studies are warranted for this potentially reversible therapeutic target.

ST-segment elevation myocardial infarction: Historical perspective and new horizons.

After a brief history of the emergence of modern therapy for acute ST-elevation myocardial infarction, we discuss the issues that dominate ongoing studies and are the focus of intense debates. The role of angiography, pharmacotherapy, thrombus aspiration, management of multi-vessel disease, mechanical complications and cardiogenic shock and the quest for myocardial salvage are discussed.

The outcome of pulmonary hypertension and its association with pulmonary artery dilatation.

BACKGROUND: Pulmonary artery (PA) dilatation is often seen in pulmonary hypertension (PH) and is considered a long-term consequence of elevated pressure. The PA dilates over time and therefore may reflect disease severity and duration. Survival is related to the stage of the disease at the time of diagnosis and therefore PA diameter might be used to predict prognosis. This study evaluates the outcome of patients with pulmonary arterial hypertension (PAH) and chronic thrombo-embolic pulmonary hypertension (CTEPH) and investigates whether PA diameter at the time of diagnosis is associated with mortality. METHODS: Patients visiting an outpatient clinic of a tertiary centre between 2004 and 2018 with a cardiac catheterisation confirmed diagnosis of PAH or CTEPH and a CT scan available for PA diameter measurement were included. PA diameter and established predictors of survival were collected (New York Heart Association (NYHA) class, N­terminal pro-brain natriuretic peptide (NT-proBNP) level and 6­min walking distance (6MWD)). RESULTS: In total 217 patients were included (69% female, 71% NYHA class ≥III). During a median follow-up of 50 (22-92) months, 54% of the patients died. Overall survival was 87% at 1 year, 70% at 3 years and 58% at 5 years. The mean PA diameter was 34.2 ± 6.2 mm and was not significantly different among all the diagnosis groups. We found a weak correlation between PA diameter and mean PA pressure ( r = 0.23, p < 0.001). Male sex, higher age, shorter 6MWD and higher NT-proBNP level were independently associated with mortality, but PA diameter was not. CONCLUSION: The prognosis of PAH and CTEPH is still poor. Known predictors of survival were confirmed, but PA diameter at diagnosis was not associated with survival in PAH or CTEPH patients.

The ventricular fibrillation waveform in relation to shock success in early vs. late phases of out-of-hospital resuscitation.

BACKGROUND: The amplitude spectrum area (AMSA) of the ventricular fibrillation (VF) waveform predicts shock success and clinical outcome after out-of-hospital cardiac arrest (OHCA). Recently, also AMSA-changes demonstrated prognostic value. Until now, most studies focused on early shocks, while many patients require prolonged resuscitations. We studied AMSA and its changes in relation to shock success, for both the early and later phase of resuscitation. METHODS: Per-shock VF-waveform analysis of a prospective OHCA-cohort (Nijmegen, The Netherlands). The absolute AMSA and relative AMSA-changes (ΔAMSA) were calculated from three-second VF-segments prior to defibrillation. Shocks were categorised as early (#1-3) or late (#4-8). Shock success was defined as return of organised rhythm. RESULTS: Shock success was 46% for early (131/286) and 52% for late shocks (85/162), p = 0.18. Early shock success varied from 23% to 70% with increasing quartiles of AMSA (p-trend<0.001). For late shocks, there also was an association with AMSA, with a narrower range in shock success from 43% to 68% (p-trend = 0.04). Higher values of ΔAMSA were associated with shock success in the early, but not in the later phase. CONCLUSION: AMSA relates to shock success during the entire resuscitation, but associations were most apparent for early shocks. AMSA-changes were also associated with shock success, but only in the early phase of resuscitation. In an era of smart defibrillators, absolute AMSA and relative changes hold promise for studies on early guidance of resuscitation, whereas additional studies are warranted to further characterize shock prediction in the later phase.

Changes in automated external defibrillator use and survival after out-of-hospital cardiac arrest in the Nijmegen area.

PURPOSE: Out-of-hospital cardiac arrests (OHCAs) are a major healthcare problem. Over the years, several initiatives have contributed to more lay volunteers providing cardiopulmonary resuscitation (CPR) and increased use of automated external defibrillators (AEDs) in the Netherlands. As part of a quality and outcomes program, we registered bystander CPR, AED use and outcome in the Nijmegen area. METHODS: Prospective resuscitation registry with a study cohort of non-traumatic OHCA cases from 2013-2016 and historical controls from 2008-2011. In line with previous reports, we studied patients transported to the hospital (Radboudumc, Nijmegen, the Netherlands) and excluded arrests witnessed by the emergency medical service (EMS). Primary outcomes were return of spontaneous circulation (ROSC) and survival to discharge. RESULTS: In the study cohort (n = 349) the AED was attached more often than in the historical cohort (n = 180): 46% vs. 23% and the proportion of bystander CPR was higher: 78% vs. 63% (both p < 0.001). A higher proportion of patients received an AED shock (39% vs. 15%, p < 0.001) and the number of required shocks by the EMS was lower (2 vs. 4, p = 0.004). Survival to discharge was higher (47% vs. 33%, p = 0.002) without differences in ROSC. The survival benefit was restricted to patients with a shockable initial rhythm. In both cohorts, bystander CPR and AED use were independently associated with survival. CONCLUSION: In patients admitted after OHCA, survival to discharge has markedly improved to 40-50%, comparable with other Dutch registries. As increased bystander CPR and the doubled use of AEDs seem to have contributed, all civilian-based resuscitation initiatives should be encouraged.

Appropriate use criteria for optical coherence tomography guidance in percutaneous coronary interventions : Recommendations of the working group of interventional cardiology of the Netherlands Society of Cardiology.

INTRODUCTION: Optical coherence tomography (OCT) enables detailed imaging of the coronary wall, lumen and intracoronary implanted devices. Responding to the lack of specific appropriate use criteria (AUC) for this technique, we conducted a literature review and a procedure for appropriate use criteria. METHODS: Twenty-one of all 184 members of the Dutch Working Group on Interventional Cardiology agreed to evaluate 49 pre-specified cases. During a meeting, factual indications were established whereupon members individually rated indications on a 9-point scale, with the opportunity to substantiate their scoring. RESULTS: Twenty-six indications were rated 'Appropriate', eighteen indications 'May be appropriate', and five 'Rarely appropriate'. Use of OCT was unanimously considered 'Appropriate' in stent thrombosis, and 'Appropriate' for guidance in PCI, especially in distal left main coronary artery and proximal left anterior descending coronary artery, unexplained angiographic abnormalities, and use of bioresorbable vascular scaffold (BVS). OCT was considered 'Rarely Appropriate' on top of fractional flow reserve (FFR) for treatment indication, assessment of strut coverage, bypass anastomoses or assessment of proximal left main coronary artery. CONCLUSIONS: The use of OCT in stent thrombosis is unanimously considered 'Appropriate' by these experts. Varying degrees of consensus exists on the appropriate use of OCT in other settings.

Predictors of severe stenosis at invasive coronary angiography in patients with normal myocardial perfusion imaging.

PURPOSE: Normal myocardial perfusion imaging (MPI) is associated with excellent prognosis. However, in patients with persisting symptoms, it may be difficult to determine the patients in whom invasive angiography is justified to rule out false negative MPI. We evaluated predictors for severe stenosis at invasive angiography in patients with persisting symptoms after normal MPI. METHODS: 229 consecutive patients with normal MPI, without previous bypass surgery, underwent invasive angiography within 6 months. Older age was defined as >65 years. Multivariable analyses were performed to adjust for differences in baseline variables. RESULTS: Mean age was 62 ± 11 years, 48% were women. Severe stenosis was observed in 34%, and of these patients 60% had single-vessel disease (not left main coronary artery disease). After adjusting for several variables, including diabetes, smoking status, hypertension and hypercholesterolaemia, predictors of severe stenosis were male gender, odds ratio (OR) 2.7 (95% confidence interval (CI) 1.5-4.9), older age, OR 1.9 (95% CI 1.02-3.54) previous PCI, OR 2.0 (95% CI 1.0-4.3) and typical angina, OR 2.5 (95% CI 1.4-4.6). CONCLUSIONS: Increasing age, male gender, previous PCI and typical symptoms are predictors of severe stenosis at invasive coronary angiography in patients with normal MPI. The majority of these patients have single-vessel disease.

Diagnosis of takotsubo cardiomyopathy is increasing over time in patients presenting as ST-elevation myocardial infarction.

BACKGROUND: Takotsubo cardiomyopathy often presents with the clinical signs of ST-elevation myocardial infarction (STEMI). The increase in scientific publications addressing this relatively rare condition may result in higher awareness and diagnosis of takotsubo cardiomyopathy. AIM: To assess the observed prevalence per year of takotsubo cardiomyopathy in a large registry of patients with STEMI, during a 12-year inclusion period. METHOD: All patients presenting with STEMI at a large regional cardiology clinic were entered into a database (n = 8,413, mean age 63 ± 13 years). Takotsubo cardiomyopathy was diagnosed in 42 patients (0.5 %). Years of evaluation were defined as 'early years' (January 2002 to December 2007; n = 4350) and 'later years' (January 2008 to December 2013). Multivariable analyses were performed to adjust for differences in demographical and clinical variables. RESULTS: In later years, the age of STEMI patients was slightly higher (64 ± 13 vs. 63 ± 13 years, p < 0.001), with more patients with clinical symptoms of shock (10 vs. 7 %, p < 0.001) or a history of percutaneous coronary intervention or hypertension (10 vs. 8 %, p = 0.001 and 37 vs. 34 %, p < 0.001). Smoking and a positive family history were less often observed during later years (39 vs. 46 %, p < 0.001 and 37 vs. 42 % p < 0.001). Patients with takotsubo cardiomyopathy were more often female (81 vs. 27 %, p = 0.001). Takotsubo cardiomyopathy was more often diagnosed in the later period (0.7 vs. 0.3 %, OR 2.4, 95 % CI 1.2-4.6, p = 0.009). The higher prevalence of takotsubo cardiomyopathy in recent years remained significant after adjustment for differences in patient characteristics (OR 2.1, 95 % CI 1.1-4.3). CONCLUSION: Takotsubo cardiomyopathy is currently more often diagnosed in patients with STEMI compared with in earlier years. This is probably due to the increased scientific and clinical awareness among doctors, but the prevalence is still low.

Novel X-ray image noise reduction technology reduces patient radiation dose while maintaining image quality in coronary angiography.

AIMS: The consequences of high radiation dose for patient and staff demand constant improvements in X-ray dose reduction technology. This study assessed non-inferiority of image quality and quantified patient dose reduction in interventional cardiology for an anatomy-specific optimised cine acquisition chain combined with advanced real-time image noise reduction algorithms referred to as 'study cine', compared with conventional angiography. METHODS: Fifty patients underwent two coronary angiographic acquisitions: one with advanced image processing and optimised exposure system settings to enable dose reduction (study cine) and one with standard image processing and exposure settings (reference cine). The image sets of 39 patients (18 females, 21 males) were rated by six experienced independent reviewers, blinded to the patient and image characteristics. The image pairs were randomly presented. Overall 85 % of the study cine images were rated as better or equal quality compared with the reference cine (95 % CI 0.81-0.90). The median dose area product per frame decreased from 55 to 26 mGy.cm(2)/frame (53 % reduction, p < 0.001). CONCLUSION: This study demonstrates that the novel X-ray imaging technology provides non-inferior image quality compared with conventional angiographic systems for interventional cardiology with a 53 % patient dose reduction.

STEMI time delays: a clinical perspective : Editorial comment on the article by Verweij et al.

STEMI time delays have been introduced as a performance indicator or marker of quality of care. As they are only one part of a very complex medical process, one should be aware of concomitant issues that may be overlooked or even be more important with regard to clinical outcome of STEMI patients. In this overview we try to summarise the most important ones.

The influence of residential distance on time to treatment in ST-elevation myocardial infarction patients.

AIMS: To evaluate the relation between residential distance and total ischaemic time in patients with acute ST-elevation myocardial infarction (STEMI). METHODS: STEMI patients were transported to the Isala Hospital Zwolle with the intention to perform primary percutaneous coronary intervention PCI (pPCI) from 2004 until 2010 (n = 4149). Of these, 1424 patients (34 %) were referred via a non-PCI 'spoke' centre ('spoke' patients) and 2725 patients (66 %) were referred via field triage in the ambulance (ambulance patients). RESULTS: A longer residential distance increased median total ischaemic time in 'spoke' patients (0-30 km: 228 min, >30-60 km: 235 min, >60-90 km: 264 min, p < 0.001), however not in ambulance patients (0-30 km: 179 min, >30-60 km: 175 min, >60-90 km: 186 min, p = 0.225). After multivariable linear regression analysis, in 'spoke' patients residential distance of >30-60 km compared with 0-30 km was not independently associated with ischaemic time; however, a residential distance of >60-90 km (exp (B) = 1.11, 95 % CI 1.01-1.12) compared with 0-30 km was independently related with ischaemic time. In ambulance patients, residential distance of >30-60 and >60-90 km compared with 0-30 km was not independently associated with ischaemic time. CONCLUSION: A longer distance from the patient's residence to a PCI centre was associated with a small but significant increase in time to treatment in 'spoke' patients, however not in ambulance patients. Therefore, referral via field triage in the ambulance did not lead to a significant increase in time to treatment, especially at long distances (up to 90 km).

Towards a biomimetic gyroscope inspired by the fly's haltere using microelectromechanical systems technology.

Flies use so-called halteres to sense body rotation based on Coriolis forces for supporting equilibrium reflexes. Inspired by these halteres, a biomimetic gimbal-suspended gyroscope has been developed using microelectromechanical systems (MEMS) technology. Design rules for this type of gyroscope are derived, in which the haltere-inspired MEMS gyroscope is geared towards a large measurement bandwidth and a fast response, rather than towards a high responsivity. Measurements for the biomimetic gyroscope indicate a (drive mode) resonance frequency of about 550 Hz and a damping ratio of 0.9. Further, the theoretical performance of the fly's gyroscopic system and the developed MEMS haltere-based gyroscope is assessed and the potential of this MEMS gyroscope is discussed.