Optimal Heart Rate and Prognosis in Patients with Cardiac Amyloidosis

Background: Optimal heart rate (HR) that associates with higher cardiac output and greater clinical outcomes in patients with cardiac amyloidosis remains unknown. Methods: Consecutive patients with sinus rhythm who were diagnosed with cardiac amyloidosis at our institute between February 2015 and February 2021 were retrospectively included. Ideal HR, at which E-wave and A-wave stand adjacent without any overlaps in the trans-mitral flow echocardiography, was calculated by the formula: 86.8−0.08 × deceleration time (msec). The association between optimal HR and cardiac death or heart failure readmission was investigated. Results: Ten patients (median 74 years old, 8 men) were included. On median, actual HR was 64 bpm and ideal HR was 69 bpm. An incidence rate of the primary endpoint in the sub-optimal HR group tended to be higher than optimal HR group: one of the four patients in optimal HR group had events (25%); two of the two patients in higher HR group had events (100%); two of the four patients in lower HR group had events (50%). Conclusions: The optimal HR was associated with greater clinical outcomes in patients with cardiac amyloidosis. The clinical impact of aggressive HR optimization in this cohort remains the next concern.

Umbilical artery pulsatility index and half-peak systolic velocity in second- and third-trimester fetuses with trisomy 18 and 13

Objectives To analyze umbilical artery (UA) Doppler velocimetry and its possible role in placenta-mediated fetal growth restriction (FGR) in second- and third-trimester fetuses with trisomy 18 and 13. Methods UA pulsatility index (PI) and half-peak systolic velocity deceleration time (hPSV-DT) were measured in fetuses with trisomy 18 and 13. Correlation with gestational age, birthweight, and perinatal outcome was analyzed. Results A total of 80 measurements were taken from 33 fetuses with trisomy 18 and 19 with trisomy 13. Overall, there was a high prevalence of abnormal UA Doppler velocimetry. In fetuses with trisomy 18, 54% (27/50) of the UA PI values and 58% (29/50) of the UA hPSV-DT values were abnormal. In fetuses with trisomy 13, 80% (24/30) of the UA PI values and 87% (26/30) of the UA hPSV-DT values were abnormal. The prevalence of abnormal UA Doppler velocimetry increased with gestational age in both types of aneuploidy. However, this trend was only significant for trisomy 13 (p<0.05). All fetuses with trisomy 18 and 86% of fetuses with trisomy 13 were classified at birth as FGR. There were no perinatal survivors in this series. Conclusions A high prevalence of abnormal UA Doppler velocimetry was found in second- and third-trimester fetuses with trisomy 18 and 13, which further increased with gestational age. These results may well correlate with alterations described previously in the placenta, suggesting placental insufficiency has an important role in the development of FGR in these autosomal aneuploid fetuses.

613 Fontan associated nephropathy: does diastolic function play a role?

Aims In Fontan patients, the pathophysiology of diastolic function and its relationship with systemic complications are still not well understood. Methods and results This is a prospective study including patients who underwent Fontan completion in our centre between 1993 and 2016. We excluded patients with major congenital renal anomalies, those who underwent cardiac transplantation and redo-Fontan patients. All the subjects underwent clinical evaluation, laboratory exams with complete renal and hepatic function, transient hepatic elastography, and complete cardiac evaluation. We used Schwartz equation for estimating glomerular filtration rate in patients younger than 18 years, and CDK-EPI equation for adult patients. We enrolled 35 patients, 46% female (N = 16), and 54% male (N = 19). Medium age was 17 years old (range: 10–31 years old). Medium time from Fontan completion was 160 months (range: 57–340 months). Ten patients had a functional single left ventricle (FSLV, 28.5%) and 21 a functional single right ventricle (FSRV, 60%); four patients had an undetermined single ventricle (11.5%). Data from renal function assessment showed a prevalence of stage 2 chronic kidney disease (eGFR: 60–89 ml/min 1.73 mq). Of those, 11% with creatinine-based equation and 26% (N = 9) when using cystatin C-based equation, with one patients showing a moderate reduced loss of kidney function (eGFR: 40–59 ml/min/1.73 mq). Most of the patients with reduced eGFR measured with cystatin C were FSRV (89%). None had laboratory markers of acute tubular damage, but four patients had signs of chronic tubular dysfunction with elevation of beta 2 microglobulin (13%). Echocardiographic evaluation of diastolic function showed two patients with baseline E/A &lt; 1 (6%, tot N = 33) and 11/33 (33%) pts with abnormal E/E′ (&gt;12). All of them were FSRV patients (100%). Interestingly, statistical correlation between diastolic parameters and renal function showed a significant association between tubular damage parameters, such as alfa1microglobulin and beta2microglobulin, and E/E′ (Pearson’s R 0.4 and 0.48, respectively, P &lt; 0.05), both for FSLV and FSRV patients. Diastolic function appeared to be associated also with glomerular filtration: we found a statistically significant direct correlation between diastolic pulmonary wave deceleration time (dt D wave) and creatinine value (Pearson’s R 0.49, P &lt; 0.05). Supporting the role of diastolic function in Fontan systemic complications is the linear correlation we found with hepatic tests: higher values of aspartate aminotransferase and of gamma-glutamyltransferase were associated with worse diastolic ventricular filling (longer dt D wave and E wave deceleration time, lower TDI early diastolic wave; Pearson’s R 0.45, 0.5, and −0.41, respectively, P &lt; 0.05). Conclusions Fontan-related nephropathy is associated with worsening diastolic function, which was more represented in FSRV patients. Diastolic function is also associated with liver disease in Fontan patients. Those data suggest renal and liver function should be closely monitored in patients with impaired diastolic function.

Risk Evaluation for Conflicts between Crossing Pedestrians and Right-Turning Vehicles at Intersections

In recent years, conflicts between crossing pedestrians and right-turning vehicles have become more severe at intersections in China, where right-turning vehicles are usually not controlled by traffic signals. This study proposes a quantitative method for evaluating the conflict risk between pedestrians and right-turning vehicles at intersections based on micro-level behavioral data obtained from video detection. A typical intersection in Shanghai was selected as the study site. In total, 670 min of video were recorded during the peak hours from 7:30 a.m. to 9:30 p.m on one day. After processing the video information, vehicle and pedestrian tracking data were obtained, including the velocity, acceleration, deceleration, time, and location coordinates. Based on these data, several conflict indicators were proposed and these indicators were extracted automatically using MATLAB to identify pedestrian–right-turning vehicle conflicts and to determine the severity of the conflicts identified. This process identified 93 examples of such conflicts. The conflict risks were quantitatively classified using the K-means fuzzy clustering method and all of the conflicts were assigned to five grades. The characteristics of the conflict distribution and the severity of different types of conflict were also analyzed, which showed that conflicts on different areas on the crosswalk differed in their severity. Based on the conclusions, practical traffic management and control measures are proposed to reduce the risk on pedestrian crossings.

EXPRESS: Right Ventricular Function as Assessed by Cardiac Magnetic Resonance Imaging-Derived Strain Parameters compared to High-Fidelity Micromanometer Catheter Measurements

Right ventricular (RV) function has prognostic significance in patients with pulmonary hypertension (PH). We evaluated whether cardiac magnetic resonance (CMR)-derived strain and strain rate (SR) parameters could reliably reflect RV systolic and diastolic function in precapillary PH. End-systolic elastance (Ees) and the time constant of RV relaxation tau, both derived from invasive high-fidelity micromanometer catheter measurements, were used as gold standards for assessing systolic and diastolic RV function, respectively. Nineteen consecutive precapillary PH patients underwent CMR and right heart catheterization prospectively. CMR data were compared with those of 19 control subjects. In PH patients, associations between strain- and SR-related parameters and invasive hemodynamic parameters were evaluated. Longitudinal peak systolic strain, SR, and early diastolic SR were lower in PAH patients than in controls; peak atrial-diastolic SR was higher in PH patients. Similarly, circumferential peak systolic SR was lower and peak atrial-diastolic SR was higher in PH. In PH, no correlations existed between CMR-derived and hemodynamically-derived measures of systolic RV function. Regarding diastolic parameters, tau was significantly correlated with peak longitudinal atrial-diastolic SR (r = -0.61), deceleration time (r = 0.75), longitudinal systolic to diastolic time ratio (r = 0.59), early diastolic SR (r = -0.5), circumferential peak atrial-diastolic SR (r = -0.52), and deceleration time (r = 0.62). Strain analysis of the RV diastolic phase is a reliable non-invasive method for detecting RV diastolic dysfunction in PAH.

Efficiency Assessment of Tai Chi Exercises in Physical Rehabilitation of Knee Joint in Young Rhythmic Gymnasts and Choreography Students

Various types of physical activity, including tai chi exercises, have become part of physical rehabilitation of young athletes after knee joint injury. However, many physiological mechanisms of the restorative effect of traditional systems still need to be clarified. We recruited 38 girls aged 10–16 years (mean age 12.5 years, interquartile range [10.8; 13.2] years) involved in different types of physical activity (rhythmic gymnastics and choreography) needing to recover their knee joint function after overuse injury. The subjects were divided into two groups: the main group (physical rehabilitation using a specially developed set of tai chi movements) and the control group (standard course of physical rehabilitation taking place in a physical therapy room). After 2 weeks of rehabilitation, the participants underwent isokinetic testing of the knee joint using the Biodex System 4 Pro (USA). The test results obtained by cluster analysis were typified into three characteristic patterns (χ2 test, p = 0.004): 1) insufficiency of strength parameters (peak torque (PT), peak torque to body mass (PT/BM)) at high speed and insufficiency of functional parameters (PT angle, deceleration time) at high speed; 2) insufficiency of functional parameters (time to PT, deceleration time); 3) insufficiency of strength parameters (PT, PT/BM). It was shown that while the classical means of physical rehabilitation are good for restoring the dynamic muscle parameters (PT), tai chi exercises optimally restore the functional parameters of muscle activation (TP angle and deceleration time). For citation: Vasil’ev O.S., Levushkin S.P., Achkasov E.E., Lyakh V.I., Sharapov A.N. Efficiency Assessment of Tai Chi Exercises in Physical Rehabilitation of Knee Joint in Young Rhythmic Gymnasts and Choreography Students. Journal of Medical and Biological Research, 2021, vol. 9, no. 2, pp. 115–125. DOI: 10.37482/2687-1491-Z049

Abstract P711: Factors Affecting Intracranial Aneurysm Incidence and Phenotypes at Risk of Rupture in Autosomal Dominant Polycystic Kidney Disease

Background: Autosomal dominant polycystic kidney disease (ADPKD) is an autosomal dominant genetic disorder in which cysts of various sizes invade the renal parenchyma. Intracranial aneurysms occur in 8-12% of ADPKD patients, which is approximately 3-4 times the rate of the healthy population. However, research on factors related to aneurysm incidence and rupture in patients with ADPKD is insufficient. Objective: We analyzed the factors associated with risk of aneurysm incidence and phenotype in ADPKD patients. Methods: From the ADPKD registry in the tertiary hospital, we screened patients with cerebral angiography enrolled between January 2007 and May 2017. Then, 926 enrolled patients were classified into three groups according to the intracranial aneurysm incidence and phenotype (multiplicity, size, location): no intracranial aneurysm (Group 1); low-risk intracranial aneurysm (Group 2); high-risk intracranial aneurysm (Group 3). We analyzed the difference of patients’ demographic factors, cardiovascular risk factors, laboratory data, echocardiographic data, and imaging data between groups. Results: The prevalence [C1] of intracranial aneurysm in ADPKD patients was 16.0%. Aneury[C2] sm-positive group (Group 2 and 3, n=148) was significantly older (p<0.001) and had a greater proportion of females (p<0.001) than patients in the aneurysm-negative group (Group 1, n=778). Compared to Group 1, Group 3 was significantly associated with age (odds ratio (OR) 1.027, p=0.007), female sex (OR 3.184, p<0.001), dyslipidemia (OR 0.460, P=0.001), basilar artery dolichoectasia (OR 8.443, p=0.016), and mitral inflow deceleration time (OR 1.005, p=0.039). Conclusion: Factors associated with a high-risk aneurysms were age, sex, dolichoectasia, dyslipidemia, and mitral inflow deceleration time in ADPKD patients. Identification of these factors would help detect high risk aneurysms and manage the aneurysms in ADPKD patients.

Adaptive cruise control system based on improved variable time headway spacing strategy

In the following process, in order to improve the driving safety and road utilization of the adaptive cruise control (ACC) system, a variable time headway spacing strategy was studied. In view of the fact that the variable spacing strategy cannot adapt to the complex and variable deceleration conditions, an improved variable time headway strategy is proposed, which changes with the deceleration time and deceleration of the preceding vehicle. Based on this, the upper controller of adaptive cruise control based on model predictive control is designed, and numerical simulation of the variable time headway spacing strategy is performed, which verifies the effectiveness of the improved variable time headway strategy. The results show that the spacing strategy proposed in this paper can more smoothly keep up with the preceding vehicle, and improve driving safety, comfort and road utilization.

Evaluation of Left Ventricular Outflow Gradients During Staged Exercise Stress Echocardiography Helps Differentiate Pediatric Patients With Hypertrophic Cardiomyopathy From Athletes and Normal Subjects

Background: Elevated left ventricular outflow tract (LVOT) gradients during exercise can occur in patients with hypertrophic cardiomyopathy (HCM) as well as in athletes and normal controls. The authors’ staged exercise protocol calls for imaging at rest and during each stage of exercise to evaluate the mechanism of LVOT obstruction at each stage. They investigated whether this staged approach helps differentiate HCM from athletes and normal controls. Methods: They reviewed pediatric exercise stress echocardiograms completed between January 2009 and October 2017 at their center and identified those with gene-positive HCM, athlete’s heart, and normal controls. Children with inducible obstruction (those with no LVOT gradient at rest who developed a LVOT peak gradient > 25 mm Hg during exercise) were included. LVOT peak gradient, velocity time integral, acceleration time, and deceleration time were measured at rest, submaximal stages, and peak exercise. Results: Compared with athletes, HCM patients had significantly higher LVOT peak gradients at rest (P = .019), stage 1 of exercise (P = .002), and peak exercise (P = .051), as well as a significantly higher change in LVOT peak gradient from rest to stage 1 (P = .016) and from rest to peak (P = .038). The acceleration time/deceleration time ratio of the LVOT Doppler was significantly lower in HCM patients compared with normal controls at peak exercise. Conclusions: The HCM patients who develop elevated LVOT gradients at peak exercise typically manifest early obstruction in the submaximal stages of exercise, which helps to differentiate them from athletes and normal controls.

E-wave asymmetry elucidates diastolic ventricular stiffness-relaxation coupling: model-based prediction with in vivo validation

Although diastolic stiffness and relaxation are considered independent chamber properties, the cardio-hemic inertial oscillation that generates E-waves obeys Newton’s law. E-waves vary with heart rate requiring simultaneous change in stiffness and relaxation. By retrospective analysis of human heart-rate varying transmitral Doppler-data, we show that diastolic stiffness and relaxation are coupled and that the coupling manifests through E-wave asymmetry, quantified through a parametrized diastolic filling model-derived dimensionless parameter, which only depends on deceleration time and acceleration time, readily obtainable via standard echocardiography.