Electromechanical Delay Research Articles

Neuromusculoskeletal model calibration accounts for differences in electromechanical delay and maximum isometric muscle force

Electromechanical delay (EMD) and maximum isometric muscle force (FoM) are important parameters for joint contact force calculation with EMG-informed neuromusculoskeletal (NMS) models. These parameters can vary between tasks (EMD) and individuals (EMD and FoM), making it challenging to establish representative values. One promising approach is to personalise candidate parameters to the participant (e.g., FoM by regression equation) and then adjust all parameters within a calibration (i.e., numerical optimisation) to minimise error between corresponding pairs of experimental measures and model-predicted values. The purpose of this study was to determine whether calibration of an NMS model resulted in consistent joint contact forces, regardless of EMD value or personalisation of FoM. Hip, knee, and ankle contact forces were predicted for 28 participants using EMG-informed NMS models. Differences in joint contact forces with EMD were examined in six models, calibrated with EMD from 15 to 110 ms. Differences in joint contact forces with personalisation of FoM were examined in two models, both calibrated with the same initial EMD (50 ms), one with generic and one with personalised values for FoM. For all models, joint contact force peaks during the first and second halves of stance were extracted and compared using a repeated-measures analysis of variance. Calibrated models with EMD set between 35 and 70 ms produced similar magnitude and timing of peak joint contact forces. Compared with generic values, personalising and then calibrating FoM resulted in comparable peak contact forces at hip, but not knee or ankle, while also producing muscle-specific tensions similar to reported literature. Overall, EMD between 35 and 70 ms and personalised initial values of FoM before calibration are advised for EMG-informed NMS modelling.

Assessment of atrial conduction times in patients with frequent premature ventricular complex.

Premature ventricular complex (PVC) is a frequent finding in the general population. The atrial conduction time (ACT) is the period between the electrocardiographic P wave and the atrial mechanical contraction, and its prolongation indicates an atrial electromechanical delay (EMD). In our study, we compared atrial conduction parameters by echocardiographic methods between patients with frequent PVC and healthy control subjects. The study included 54 patients with PVC and 54 healthy volunteers. Atrial conduction parameters were measured with echocardiographic examination. The time difference between the p wave and the Am wave was measured in the septal, lateral, and tricuspid annulus regions. The interatrial EMD, left atrial intra-atrial delay, and the right atrial intra-atrial delay were calculated from these measurements. The groups were compared for demographic and electrocardiographic features and echocardiographic parameters. Left intra-atrial EMD, right intra-atrial EMD, and interatrial EMD were significantly longer in the patient group (p=.001, p < .001, p < .001, respectively). PA lateral, PA septal, and PA tricuspid durations were significantly prolonged in the patient group (all p < .001). All ACT parameters were significantly prolonged in patients with PVC QRS duration of 150 ms and above (all p < .001). All ACT parameters were prolonged in PVCs of right ventricular origin than those of left ventricular origin (all p < .001). ACT parameters were prolonged in patients with a coupling interval time below 485 ms (all p < .001). Atrial conduction times are prolonged in patients with frequent PVC.

Continuous Switching Control of an Input-Delayed Antagonistic Muscle Pair During Functional Electrical Stimulation

Existing controllers for functional electrical stimulation (FES) of upper limb muscles were initially designed to assist unilateral movements and may not be readily applicable to assist antagonistic muscle movements. Furthermore, it is yet unclear if electromechanical delays (EMDs) are present during the coactivation of muscles. In this article, a robust controller is designed to facilitate the FES of an antagonistic muscle pair during elbow flexion and extension. The controller uses a continuous switching law that maps a joint angle error to control the antagonistic muscle pair. Furthermore, the controller compensates for EMDs in the antagonistic muscle pair. A Lyapunov stability analysis yields uniformly ultimately bounded (UUB) tracking for the human limb joint. The experimental results on four participants without disabilities indicate that the controller is robust and effective in switching between antagonistic muscles. A separate set of experiments also showed that EMDs are indeed present in the coactivated muscle pair. The designed controller compensates for the EMDs and statistically improves root mean square error (RMSE) compared to a traditional linear controller with no EMD compensation. The proposed controller can be generalized to assist FES-elicited tasks that involve a weak antagonistic muscle pair.

A human motion angle prediction method using a neural network and feature-extraction-processed sEMG obtained in real time to utilize mechanical delay of sEMG

Surface electromyogram (sEMG) has been used to estimate human motions. Feature extraction (FE) has been proposed as a process to decrease noise and extract information about muscle activities from measured raw sEMG signals. Electromechanical delay (EMD) is a time delay between a generation of sEMG and subsequent occurrence of human motions, and sEMG can be obtained in advance of motions occurrence by using this time delay. The purpose of this study is to propose a real time human motion prediction method using a neural network model and FE-processed sEMG signals utilizing EMD. Experimental results show that the proposed method has better prediction results among other methods.

Robust Cadence and Power Tracking on a Switched FES Cycle With an Unknown Electromechanical Delay

Functional electrical stimulation (FES) is commonly used to facilitate cycling tasks for people with lower-limb movement disorders. In this work, FES and motor controllers are designed to track a desired power and cadence, respectively, and a Lyapunov-based switched systems analysis is performed to guarantee uniformly ultimately bounded power tracking and global exponential cadence tracking for a switched, delayed, nonlinear, and uncertain FES-cycling system. A unique challenge in this problem is that there is an unknown time-varying input delay to produce force, and a different unknown time-varying residual input delay where force is still produced after stimulation is removed. These delays impact the dwell-time conditions that dictate stimulation timing, and if not properly accounted for can lead to undesired effects such as antagonistic muscles exerting force at the same time or potential instabilities. The proposed controllers were validated by experimental analysis of four participants with neurological conditions (NCs) and five able-bodied participants, and yielded average power and cadence tracking errors of 0.01 ± 0.09 W and −0.05 ± 0.65 revolutions per minute (RPM), respectively, for the able-bodied participants and 0.01 ± 1.11 W and −0.07 ± 1.17 RPM, respectively, for the participants with NCs.

Effects of Blood Flow Restricted Exercise on Electromechanical Delay and Time to Peak Force after Task Failure: A Randomized Crossover Trial

Introduction: Electromechanical delay (ED) and time to peak force (TPF) could be used to investigate the central or peripheral sources of performance decline in fatiguing tasks. Exercise with partial blood flow restriction (BFR) has been shown to induce fatigue, but the repercussions of exercise with partial BFR on ED and TPF are unclear. The present study aimed to compare the ED and TPF after an intermittent isometric task until failure with BFR and free blood flow (FBF). Methods: In this crossover randomized clinical trial, 15 healthy and physically active men volunteered in this study. Volunteers performed two intermittent isometric handgrip exercise (IIHE) to failure (72 h apart), combined with either BFR or FBF. Maximum voluntary isometric force (MVIF) concomitant with the electromyographic activity of the wrist and finger flexor muscles were assessed before (PRE) and one minute after (POST) the task failure. Within (PRE vs. POST) and between comparisons (eFBF vs. eBFR) of peak force, time to peak force, rate of force development (RFDpeak) and ED were carried out. Results: No significant between-intervention differences were identified pre- or post-exercise. Peak force and RFDpeak reduced significantly after both blood flow conditions (p &lt; 0.05), but without between-condition difference. TPF was statistically higher after exercise only in the FBF intervention (p &lt; 0.05). None of the interventions induced a significant change in the ED after IIHE. Conclusion: ED and TPF were similar after BFR and FBF, indicating both conditions induce similar acute performance impairments after IIHE, which seems not to be caused by local (i.e., muscular) factors, but probably by central (i.e., neural) factors.

Evaluation of Atrial Electromechanical Delay and Left Atrial Phasic Function in Individuals with Electrocardiographic Early Repolarization Pattern.

Atrial electromechanical delay (EMD) and left atrial (LA) phasic function have been demonstrated to be predictors for the development of atrial fibrillation (AF). In the present study, we aimed to evaluate atrial EMD and LA phasic function in individuals with electrocardiographic early repolarization pattern (ERP). Eighty consecutive individuals with ERP and 40 age- and gender-matched control subjects without ERP were compared in this cross-sectional study. Atrial electromechanical coupling (Pa') was measured from lateral mitral annulus (Pa'lateral), septal mitral annulus (Pa'septal), and lateral tricuspid annulus (Pa'tricuspid) using tissue Doppler echocardiography to calculate intra- and inter-atrial EMD. LA maximal volume, LA minimal volume, and LA volume before atrial contraction were calculated using the biplane area-length method to assess LA phasic function. LA diameter, LA volume index, Pa'lateral, Pa'septal, Pa'tricuspid electrical activity and intra-left atrial EMD were significantly increased in the ERP patients. Mitral lateral, septal, tricuspid lateral annular tissue Doppler s' and e' waves were significantly decreased in the ERP patients. There were no significant difference between the groups in terms of interatrial EMD, intra-right atrial EMD, LA total emptying volume and LA total emptying fraction indicating LA reservoir function, LA passive emptying volume and LA passive emptying fraction indicating LA conduit function, LA active emptying volume and LA active emptying fraction indicating LA pump function. Left atrial EMD parameters are affected in individuals with ERP, but LA phasic functions are not affected. Further prospective studies are needed to clarify whether individuals with ERP have an increased susceptibility to AF.

Impact of empagliflozin on left atrial mechanical and conduction functions in patients with type 2 diabetes mellitus.

Empagliflozin, an oral anti-diabetic drug that inhibits the sodium-dependent glucose co-transporter 2 (SGLT2), has pleiotropic effects on the myocardium. The aim of the study is to investigate the effect of empagliflozin on atrial electromechanical delay (AEMD) and the left atrial (LA) mechanical functions in patients with type 2 diabetes mellitus (DM). In total 62 patients (40.3% female, mean age 50.5 ± 8.6 years old) with type 2 DM were enrolled to the study. Participants were used a SGLT2 inhibitor (empagliflozin 10-25 mg/daily) for 6months. Patients were examined initially and after 6 months with echocardiography. LA volume was recorded, atrial conduction times were measured using tissue Doppler imaging (TDI). No significant change was observed in LA volumes (maximal, minimal, and presystolic), total emptying and passive emptying volume at the end of 6months; however, there was a significant decrease in active emptying volume (8.3 ± 2.9ml/m2 vs. 7.9 ± 2.9ml/m2 , p=0.04). The posteroanterior lateral, septal, and tricuspid conduction times significantly decreased after the empagliflozin treatment. The decrease in right inter-AEMD was statistically significant (13.25 ± 10.21 ms vs. 10.85 ± 9.14 ms, p=0.011). The changes in inter-AEMD were found to be correlated with the changes in LA active emptying volume (r=0.408). Empagliflozin may enhance the structure and electrical conductions of the atrium and may prevent DM patients from DM-2-related functional disorder and arrhythmia.

The effect of fatigue on electromechanical response times in basketball players with and without persistent low back pain

Typically, athletes alter movement mechanics in the presence of back pain, but the effect of these changes on lower extremity injury risk is not well understood. This study aimed to compare the effect of fatigue on electromechanical response times during a choice reaction task in basketball players with and without persistent low back pain. Twenty-four male basketball players participated. Total reaction time (TRT), premotor time (PMT), and electromechanical delay (EMD data were recorded before and after fatigue. The chronic low back pain (CLBP) group had significantly longer EMD in Med gastrocnemius (p = 0.001) and Tibialis anterior (p = 0.001), and shorter EMD in Vastus Lateralis (p = 0.001), Vastus Medialis Oblique (p = 0.003), and Semitendinosus (p = 0.025) muscles after fatigue. PMT in the CLBP group had longer than the Non-CLBP in Vastus Lateralis (p = 0.010), Vastus Medialis Oblique (p = 0.017), Semitendinosus (p = 0.002). Also, TRT was longer in knee flexion (p = 0.001) and ankle plantarflexion (p = 0.001) muscle groups. The different effects of fatigue on electromechanical response times of the knee and ankle in people with CLBP may represent the effect of an axial injury on lower extremity injury risk factors in situations of higher cognitive load, similar to competitive play.

Plantarflexor neuromuscular performance in Insertional Achilles tendinopathy

BackgroundInsertional Achilles tendinopathy (IAT) is a common and painful musculoskeletal condition. The management of IAT commonly involves strengthening of the plantarflexors, although there is currently a paucity of research investigating plantarflexor neuromuscular performance specific to people with IAT. ObjectivesTo compare plantarflexor neuromuscular performance between men with IAT and controls, and to investigate the relationship between plantarflexor neuromuscular performance and patient reported outcome measures for men with IAT. DesignCase control. Method34 men with IAT (age 43.7 years [SD 10.02], weight 89.6 kg [16.3]) were matched with 34 healthy men (age 42.8 years [SD 8.9], weight 87.2 kg [9.7]). Participants underwent a plantarflexion maximal voluntary isometric contraction (MVIC) task, and a target force matching task. Neuromuscular variables from these tasks include; MVIC, rate of torque development (RTD), electromechanical delay (EMD), and muscle force steadiness. Participants also completed questionnaires regarding; pain and function, and psychological factors. ResultsThe IAT group had reduced MVIC (p < 0.01) and RTD, (p < 0.01) compared to controls, however no significant difference in plantarflexor force steadiness (p = 0.08), or EMD (p = 0.71) was observed. Low strength correlations were detected between the VISA-A and RTD (r = 0.37, p = 0.04), kinesiophobia and EMD (r = 0.45, p = 0.03). ConclusionsThis study established impairments in plantarflexor strength and RTD among people with IAT. Plantarflexor force steadiness and EMD is not altered in IAT, which is in contrast to evidence from mid-portion Achilles tendinopathy. Plantarflexor RTD was the only neuromuscular outcome measure linked to symptom severity, which may indicate it is an important rehabilitation finding.

Assessment of atrial conduction times in patients with frequent premature venticular complex

Abstract Background Premature ventricular complex (PVC) is common in general population. The atrial conduction time (ACT) represents the interval between electrocardiographic P wave and atrial mechanical contraction, and the prolongation of ACT called atrial electromechanical delay (EMD). In the present study, we investigated atrial conduction parameters through echocardiography in patients with frequent PVC. Methods The study involved 54 patients with PVC and 54 healthy volunteers as a control group. A comprehensive echocardiographic examination was done. The time difference between the onset of the p wave and septal Am wave was the PA septal, the time difference between the onset of the p wave and the lateral Am wave was the PA lateral, and the time difference between the onset of the p wave and the tricuspid annulus Am wave was the PA tricuspid. The interatrial EMD was the time difference between the PA lateral and the PA tricuspid, the left atrial (LA) intraatrial delay was the time difference between the PA lateral and the PA septal and the right atrial (RA) intraatrial delay was the time difference between the PA septal and the PA tricuspid. Results LA anterior-posterior dimension and LA maximum volume were significantly larger in the patient group. Left intraatrial EMD, right intraatrial EMD, and interatrial EMD were significantly longer in the patient group. PA lateral, PA septal, PA tricuspid durations were significantly prolonged in the patient group. Conclusions Atrial conduction times were prolonged in patients with frequent PVC. Funding Acknowledgement Type of funding sources: None.

Prevalence of atrial myopathy among hypertrophic cardiomyopathy patients without atrial fibrillation

Abstract Background Atrial myopathy (AM) is an entity reflecting left atrial (LA) structural and electrical remodeling, connected to atrial fibrillation (AF) development and heart failure progression in various substrates. In hypertrophic cardiomyopathy (HCM), prevalence of AM beyond AF and its correlations are not fully investigated. Purpose Aim of this study was to estimate the prevalence of AM in a cohort of HCM patients without AF history through assessment of LA volume index (LAVI), LA reservoir strain (LARS) and total atrial conduction time (TACT) (estimated by tissue Doppler imaging). Additionally, to investigate AM indices' correlation with other phenotypic and functional characteristics of HCM. Methods We included 50 HCM patients (60±16 years, 80% male, maximum wall thickness 18.6±4.1mm) without history of AF who have consecutively undergone 2D-speckle tracking echocardiography and cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE). TACT and LARS measurement is shown on left panel. Burden of fibrosis (percentage of LV mass) was defined by LGE extent (&amp;gt;5 standard deviations compared to nulled myocardium) in CMR slices. Cut-off points for TACT, LAVI and LARS were adopted by literature (≥115 msec, ≥34 mL/m2 and &amp;lt;21.3% respectively). Results All HCM patients had preserved EF (61.8±8%), while 13 (26%) presented outflow tract obstruction and 4 (8%) diastolic dysfunction stage≥2. LGE was observed in 32 patients (64%) occupying 7.2±5% of left ventricular (LV) mass. Mean TACT was 139.9±22 msec, with LAVI being 30.8±16.1 mL/m2 and LARS 27.6±13.9%. After assessing prevalence of AM parameters, 41 patients (82%) presented a prolonged (≥115 msec) TACT with only 13 of them having also a significantly dilated LA (≥34 mL/m2) and 16 an impaired LARS. Among HCM demographic, phenotypic and functional characteristics tested, age and LV mass index were found to be the only independent regressors of TACT (r=0.54, p&amp;lt;0.0005 and r=0.44, p=0.002 respectively, right panels), while E/E' (r=−0.44, p=0.003) and fibrosis extent (r=0.36, p=0.02) were the strongest predictors of LARS and LAVI values respectively. Conclusions Atrial electro-mechanical delay assessed through TDI based TACT, is the most frequent AM parameter among HCM patients irrespective of AF and even before LA dilatation and LA strain impairment. AM parameters seem to correlate with various morphological and functional characteristics of HCM, their significance, however, in predicting progression towards AF development or HF presentation remains to be elucidated. Funding Acknowledgement Type of funding sources: None.

Evaluation of strain echocardiography and atrial electromechanical delay in patients with idiopathic carpal tunnel syndrome

Aim: Carpal tunnel syndrome (CTS) could be an early marker for amyloidosis before developing of overt symptoms of cardiac amyloidosis (CA). CA characterized with left ventricular (LV) diastolic dysfunction and impairment of LV deformation-based parameters. There is limited data about echocardiographic parameters such as strain value of LV, diastolic parameters and atrial EMD in patients with idiopathic CTS. In this study, we investigated LV strain values, diastolic parameters of LV and atrial EMD in patients with idiopathic CTS. Then, we compared these parameters in CTS patients to control group. Material and Method: Thirty-four patients with idiopathic CTS and twenty-four aged and sex matched volunteers were enrolled to study. Patients with known amyloidosis, heart failure, diabetes mellitus and secondary etiologic states for CTS such as trauma or rheumatologic disease were excluded from the study. ECG and echocardiographic examination of each patient were performed and recorded by cardiology specialist. Conventional and strain imaging echocardiography were performed. Atrial electromechanical delays (EMD) were measured. Results: Baseline characteristics features were not different in groups. Mitral inflow velocities (mitral E and A wave), mitral E wave deceleration time, tissue Doppler velocities (lateral annular E’ and A wave), E/A and E/E’ ratios were similar in two groups. Septal basal strain values increased in CTS group (-21.3±4.83% vs -25.7±2.96%, p&amp;lt;0.001). Septal apical to base ratio (SAB) and relative apical sparing (RELAPS) were increased in CTS group compared to control group (0.94±0.43 vs 0.66±0.12, 0.90±0.31 vs 0.73±0.08, p=0.004, p=0.013, respectively). PA lateral, PA septal, inter-atrial EMD and intra-atrial EMD were significantly higher in CTS group compared to control group (78.2±12.3 ms vs 70.6±9.9 ms, 64.1±8.42 ms vs 58.3±10.1 ms, 25.8±9.09 ms vs 20.7±5.31 ms, 11.68±5.11 ms vs 8.46±3.02 ms, p=0.015, p=0.023, p=0.009 and p=.008, respectively). Conclusion: In CTS group, mean basal strain decreased compared to control group. SAB and RELAPS which associate with CA, decreased in CTS group. Atrial EMD prolonged in CTS group. These changes may associate with increased risk of CA and AF in patients with CTS.

SAĞLIKLI BİREYLERDE SİMÜLE OBSTRÜKTİF APNEDE ATRİYAL ELEKTROMEKANİK GECİKMENİN DEĞERLENDİRİLMESİ

Amaç: Çalışmalar, obstrüktif uyku apnesinin, atriyal fibrilasyon gibi artmış disritmi riskine işaret ettiğini ileri sürmektedir. Atriyal elektriksel aktivitenin başlangıcı ile atriyal kontraksiyonun başlangıcı arasındaki zaman aralığı, atriyal elektromekanik gecikme olarak tanımlanmış ve uzamış atriyal elektromekanik gecikme, atriyal fibrilasyonun bir prediktörü olarak önerilmiştir. Bu çalışmanın amacı, solunum manevraları yoluyla obstrüktif uyku apnesini simüle ederek atriyal elektromekanik gecikme üzerindeki akut etkilerini değerlendirmektir.Gereç ve Yöntemler: Çalışmaya toplam 50 sağlıklı birey dahil edildi ve simüle edilmiş obstrüktif apne (Mueller manevrası), istemli ekspirasyon sonu santral apne ve normal solunum esnasında doku Doppler görüntüleri kaydedildi. Bu kayıtlardan intra-atriyal ve interatriyal elektromekanik gecikme ölçüldü.Bulgular: Tüm sağlıklı deneklerde Mueller manevrası ve istemli ekspirasyon sonu santral apne sırasında interatriyal elektromekanik gecikme (Mueller Manevrası sırasında + 10.1ms; istemli ekspirasyon sonu santral apne sırasında + 8.7ms; p &amp;lt;0.001) ve sol intra-atriyal elektromekanik gecikme (Mueller Manevrası sırasında +7.3 ms; istemli ekspirasyon sonu santral apne sırasında + 6.7ms; p &amp;lt;0.001) normal solunumla karşılaştırıldığında arttı.Sonuç: Simüle edilmiş obstrüktif uyku apnesi, sağlıklı deneklerde intra-atriyal ve interatriyal elektromekanik gecikmeyi artırdı. Bu bulgular, obstrüktif uyku apnesindeki akut intratorasik basınç değişikliğinin atriyal fibrilasyonun bağımsız bir tetikleyicisi olabileceğini gösterebilir.

Preliminary Validation of Proportional Myoelectric Control of A Commercially Available Robotic Ankle Exoskeleton.

Proportional myoelectric control of robotic lower limb exoskeletons can increase the variability and adaptability of biomechanical behaviors for assisting human movement compared to traditional state-based control. Previous exoskeletons using proportional myoelectric control have relied on pneumatic actuators and been limited to laboratory use. We applied proportional myoelectric control to a robotic ankle exoskeleton using a brushless DC motor (Dephy) and enabled it to work in community settings. Benchtop testing verified electromechanical responses similar to biological values (electromechanical delay of 22 ms and time to peak activation of 123 ms). Four healthy participants trained for thirty minutes each using bilateral ankle exoskeletons. From minute one of powered walking to minute 30 of powered walking, peak soleus EMG reduced by 17.9% as they learned to walk with exoskeleton assistance. Our future work will extend the powered walking period, measure metabolic cost, and measure gait variability between participants using proportional myoelectric control on fully portable, electromechanical ankle exoskeletons.

Atrial electromechanical delay is impaired in patients with COVID-19

Background: COVID-19 infection has the potential to affect the cardiovascular system. Intra/ interatrial electromechanical delay (EMD) demonstrated by P wave dispersion (PD) and tissue doppler echocardiography (TDE) is related to the development of atrial fibrillation. This study aimed to investigate atrial conduction time by PD and TDE in patients with COVID-19.&#x0D; Material and Method: A total of 143 participants were selected in the current study. The COVID-19 group included 90 subjects and the control group included 53 individuals. Two groups were compared with each other, in terms of electrocardiographic P wave measurements, and atrial electromechanical coupling (AEC) parameters by TDE.&#x0D; Results: Maximum P-wave duration (Pmax) and PD were significantly higher in COVID-19 patients compared to the control group (p

Robust cadence tracking for switched FES-cycling using a time-varying estimate of the electromechanical delay

To combat the severity of neurological conditions (NCs), limit the complications, and reduce the cost of treatment, researchers have turned to hybrid exoskeletons such as functional electrical stimulation (FES) cycling. In this work, closed-loop FES/motor controllers are developed that compensate for time-varying, nonlinear, and uncertain dynamics, unknown disturbances, switching between actuators (e.g., between muscle groups and the motor), fatigue, and the unknown time-varying muscle delay between stimulation application and the production of muscle force, called the electromechanical delay (EMD). Control authority is maintained and efficient muscle contractions are produced through the development of FES/motor switching conditions that are both EMD and state dependent. Contributions are that the controllers implement a modular time-varying estimate of the EMD and yield exponential cadence tracking as verified by a Lyapunov-like stability analysis. An example EMD estimate is presented that varies with cycling time to account for fatigue. Furthermore, experiments were conducted to validate the developed control system, which produced an average cadence error of -0.01 ± 1.35 revolutions per minute (RPM) across five able-bodied participants and -0.05 ± 1.38 RPM across four participants with NCs.

Polycystic Ovary Syndrome Triggers Atrial Conduction Disorders: A Systematic Review and Meta-Analysis.

Background: Polycystic ovary syndrome (PCOS) is closely related to various adverse cardiovascular manifestations and increased cardiovascular risk. However, atrial fibrillation (AF) development and atrial conduction abnormalities have not been thoroughly studied in patients with PCOS. Methods: This meta-analysis (CRD42021261375) was conducted in accordance with the PRISMA guidelines. Our aim was to investigate associations between PCOS and disorders in atrial conduction parameters linked with an increased risk for AF occurrence. Results: Five cohort studies with aggregate data on 406 adult women (229 with PCOS and 177 age-matched without PCOS) were included in this analysis. Our results showed a significantly increased mean difference in P-wave maximum duration (+7.63 ± 7.07 msec; p < 0.01) and P-wave dispersion (+11.42 ± 5.22 msec; p = 0.03) of patients with PCOS compared to healthy women. The mean difference in P-wave minimum duration (−2.22 ± 2.68 msec; p = 0.11) did not reach the statistical threshold between the compared groups. Echocardiographic measurements of atrial electromechanical delay (AED) also indicated a statistically significant mean difference in favour of the PCOS group in all assessed parameters, except for atrial electromechanical coupling (PA) in the tricuspid annulus. Particularly, PCOS was associated with increased lateral PA, septal PA, inter- and intra-AED durations (mean difference: +17.31 ± 9.02 msec; p < 0.01, +11.63 ± 7.42 msec; p < 0.01, +15.31 ± 9.18 msec; p < 0.01, +9.31 ± 6.85 msec; p < 0.01, respectively). Conclusions: PCOS is strongly associated with alterations in several electrocardiographic and echocardiographic parameters indicating abnormal atrial conduction. Therefore, PCOS could be considered as a causal or triggering factor of AF. Larger studies are needed to confirm these results and investigate direct associations between PCOS and AF.

Left atrial and ventricular longitudinal strain in embolic stroke of undetermined source

Objective: Left atrial (LA) and left ventricular (LV) remodelling may lead to stroke. The aim of this study was to analyze LA function and LV strain in patients with embolic stroke of undetermined source (ESUS). Materials and Methods: This prospective study included 35 ESUS patients and 37 age and sex-matched controls. All participants underwent brain computed tomography (CT), conventional and diffusion-weighted magnetic resonance imaging (MRI), CT or MR angiography, 12 lead ECG, transthoracic echocardiography, and 48 hour Holter ECG monitoring. LA volume and function were determined by echocardiography. LA reservoir and LV strains were measured longitudinally by speckle-tracking method. CHA2DS2-VASc, The National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS) scores were calculated. Results: Major cardiovascular risk factors were similar between thetwogroups. The mean CHA2DS2-VASc score was 2.6 ± 1.2. NIHSS was 3.9 ± 3.0 and mRS was 1.3 ± 0.8. Atrial electromechanical coupling intervals and delays, LA emptying fraction and volumes were similar between the two groups. LA reservoir strain was lower than controls (25.2 ± 7.2% vs. 29.7 ± 8.8%, p=0.019). LV global longitudinal strain was lower than controls (-14.7 ± 4.2% vs -16.4 ± 3.9%, p=0.031). There was no correlation between LA, LV strains and the scores (CHA2DS2-VASc, NIHSS, mRS). Conclusions: ESUS patients had lower LA reservoir and LV longitudinal global strains than controls. Left atrial volume index, LA emptying fraction did not differ between the two groups. Echocardiographic quantification of LA and LV remodelling has great potential for secondary prevention from ESUS. Further studies are needed to confirm our findings.

Exploratory insights into novel prehabilitative neuromuscular exercise-conditioning in total knee arthroplasty

BackgroundContemporary strategies for prehabilitation and rehabilitation associated with total knee arthroplasty (TKA) surgery have focused on improving joint range-of-motion and function with less emphasis on neuromuscular performance beneficially affecting joint stability. Furthermore, prehabilitation protocols have been found to be too long and generic-in-effect to be considered suitable for routine clinical practice.MethodsA pragmatic exploratory controlled trial was designed to investigate the efficacy of a novel, acute prehabilitative neuromuscular exercise-conditioning (APNEC) in patients electing TKA. Adults electing unilateral TKA were assessed and randomly allocated to exercise-conditioning (APNEC, n = 15) and usual care (Control, n = 14) from a specialised orthopaedic hospital, in the United Kingdom. APNEC prescribed nine stressful exercise-conditioning sessions for the knee extensors of the surgery leg, accrued over one week (3 sessions·week−1; 36 exercise repetitions in total; machine, gravity-loaded) and directly compared with usual care (no exercise). Prescribed exercise stress ranged between 60%—100% of participant’s daily voluntary strength capacity, encompassing purposefully brief muscular activations (≤ 1.5 s). Baseline and follow-up indices of neuromuscular performance focusing on muscle activation capacity (electromechanical delay [EMD], rate of force development [RFD] and peak force [PF]) were measured ipsilaterally using dynamometry and concomitant surface electromyography (m. rectus femoris[RF] and m. vastus lateralis[VL]).ResultsGroup mean ipsilateral knee extensor muscular activation capacity (EMDRF [F(3,57) = 53.5; p < 0.001]; EMDVL [F(3,57) = 50.0; p < 0.001]; RFD [F(3,57) = 10.5; p < 0.001]) and strength (PF [F(3,57) = 16.4; p < 0.001]) were significantly increased following APNEC (Cohen’s d, 0.5—1.8; 15% to 36% vs. baseline), but unchanged following no exercise control (per protocol, group by time interaction, factorial ANOVA, with repeated measures), with significant retention of gains at 1-week follow-up (p < 0.001).ConclusionsThe exploratory APNEC protocol elicited significant and clinically-relevant improvement and its retention in neuromuscular performance in patients awaiting TKA.Trial registration(date and number): clinicaltrial.gov: NCT03113032 (4/04/2017) and ISRCTN75779521 (3/5/2017).