Cardiorespiratory function of patients undergoing surgical correction of Scheuermann's hyperkyphosis

The aim of this study was to analyze the impact of surgical correction of the thoracic deformity on the cardiorespiratory function of patients with moderate-severe Scheuermann’s hyperkyphosis (SK). A series of 23 adolescents with SK who underwent surgery through an only posterior approach using all pedicle screw constructs were included in the study. Cardiorespiratory parameters were measured during a maximal exercise tolerance test before and 2 years after surgery. Heart rate, oxygen saturation (SatO2), maximum oxygen uptake (VO2 max), ventilatory capacity at maximal exercise (VEmax), and energy costs were recorded. There were statistically significant differences in the forced vital capacity (FVC) (P < 0.05), total VO2max (ml/min) (P < 0.01), maximum expired volume (VEmax) per minute (P < 0.01) and cardiovascular efficiency (HR/VO2 ratio) (P < 0.05). None of these changes were clinically relevant. There were no changes in the VO2max per kg of body mass. The magnitude of the kyphosis correction did not correlate with the change in normalized VO2max or VEmax. In conclusion, patients with moderate-severe SK improve their baseline respiratory limitations and the tolerance to maximum exercise 2 years after surgery. However, the slight cardiorespiratory functional improvements should not necessarily be attributed to the surgery, and could also be caused solely by the residual growth of the lungs and thorax. Furthermore, respiratory functional changes are under thresholds considered as clinically relevant.

Aerobic exercise training prevents skeletal myopathy by myomiRs regulation in heart failure

Introduction Heart failure (HF) is the endpoint of systemic arterial hypertension. Exercise intolerance is a common symptom, partly due, to changes in the skeletal muscle mass (SM) and fiber type profile. Otherwise, aerobic exercise training (ET) has been used as an important non-pharmacological therapy in HF. MyomiRs are a muscle-specific class of miRNAs, which regulate genes that inhibiting the expression of proteins in pathological and physiological conditions controlling phenotypic changes in the SM, however little is known about these changes in ET-induced HF Purpose To elucidate the molecular mechanisms of ET involved in the metabolic alterations of SM in HF rats of hypertensive etiology. Methods The study was approved by the animal ethics committee (USP-No. 2020/01). 20 male rats, spontaneously hypertensive (SHR), and 10 Wistar Kyoto rats (WKY), SHR controls, nine-months-old, were divided into three groups: sedentary WKY (WKY-S), sedentary SHR (SHR-S), and trained (SHR-T). The ET consisted of swimming sessions with 60 minutes, 1x/day, 5x/week, for 10 weeks, with 5% of body overload. After ET protocol, blood pressure (BP), cardiac morphology and function (Echocardiography), exercise tolerance test, maximal oxygen uptake (VO2 peak), mitochondrial oxygen consumption (Oroboros), immunohistochemistry of the SM, expression of miRNAs (RT-qPCR) were evaluated. Statistical analyzes were performed by one-way ANOVA followed by the Tukey test. The results were expressed as mean ± standard error. Results ET reduced blood pressure levels and cardiac dysfunction in SHR-T compared to SHR-S. The SHR-S group covered smaller distance in the exercise tolerance test (255±22 meters) compared to the WKY-S (419±19 meters, p&lt;0.0001), however ET reestablished the exercise tolerance (SHR-T: 365±20 meters; SHR-S: p&lt;0.001 and WKY-S: p&gt;0.05). The HF induced changes in type I and II fibers composition (I: 73±0.6% and II: 24±0.9%), VO2 peak (50±1.5 mL kg–1 min–1), mitochondrial oxygen consumption (State 3: 3.0±0.2 nmol O2 min–1 mg protein–1) and myomiRs expression (miRNA-208b: 65±4%, -499: 73±5%, -1: 153±10%) in the soleus muscle of SHR-S compared to WKY-S (I: 94±0.6%, II: 6±0.6%, p&lt;0.001; VO2 peak: 59±2.3 mL kg–1 min–1, p&lt;0.01; State 3: 4.0±0.2 nmol O2 min–1 mg protein–1, p&lt;0.05; miRNAs: p&lt;0.01). ET minimized changes in metabolic profile by counteract the muscle fiber type switching, and the oxygen consumption impairment, and myomiRs expression dysregulation (I: 90±0.5%, II: 9±0.6%, SHR-S p&lt;0.01; VO2 peak: 79±2.4 mL kg–1 min–1, SHR-S: p&lt;0.0001; State 3: 5.45±0.32 nmol O2 min–1 mg protein–1, SHR-S: p&lt;0.0001; miRNA-208b: 91±5%, -499: 106±8%, -1: 100±9%; SHR-S: p&lt;0.01). Conclusions ET reestablished structural and metabolic changes in SM, resulting from the progression of HF, through the regulation of myomiRs, improving exercise tolerance. FUNDunding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): The Coordination for the Improvement of Higher Education Personnel (CAPES): Academic Excellence Program (Proex).

Development of a Wearable Mouth Guard Device for Monitoring Teeth Clenching during Exercise

Teeth clenching during exercise is important for sports performance and health. Recently, several mouth guard (MG)-type wearable devices for exercise were studied because they do not disrupt the exercise. In this study, we developed a wearable MG device with force sensors on both sides of the maxillary first molars to monitor teeth clenching. The force sensor output increased linearly up to 70 N. In four simple occlusion tests, the trends exhibited by the outputs of the MG sensor were consistent with those of an electromyogram (EMG), and the MG device featured sufficient temporal resolution to measure the timing of teeth clenching. When the jaw moved, the MG sensor outputs depended on the sensor position. The MG sensor output from the teeth-grinding test agreed with the video-motion analysis results. It was comparatively difficult to use the EMG because it contained a significant noise level. Finally, the usefulness of the MG sensor was confirmed through an exercise tolerance test. This study indicated that the developed wearable MG device is useful for monitoring clenching timing and duration, and the degree of clenching during exercise, which can contribute to explaining the relationship between teeth clenching and sports performance.

EXERCISE TOLERANCE TESTS IN THE DIAGNOSIS OF CORONARY HEART DISEASE, TESTING OF PATIENTS WITH MYOCARDIAL INFARCTION AND REVASCULARIZATION

Exercise tolerance test is one of the most commonly used non-invasive cardiac tests used to diagnose coronary heart disease, determine prognosis, and evaluate treatment. Treadmill test or bicycle ergometry allows determining how much more expensive and complex follow-up examination is necessary for the patient: myocardial perfusion scintigraphy with stress, stress echocardiography, multispiral computed tomography, as well as defining more clearly the indications for coronary angiography. The article presents modern ideas about a differentiated approach to performing exercise tolerance tests in patients with coronary heart disease, myocardial infarction, and revascularization.

P1502 A clinical case of mitral annulus disjunction syndrome revealed by cardiac MRI

A 39year old female patient with a family history of probable sudden cardiac death/long QT syndrome (sister died aged 36) was referred to our Arrhythmia/inherited cardiac conditions clinic. Patient was fit and well. She described occasional postural presyncope and some chest pain with stress. Not on any medication that could prolong QT. On examination she appeared well with normal heart sounds and no clinical signs of heart failure. Her ECG in clinic confirmed sinus rhythm with normal QTc at 418msec. There were U waves which may reflect late repolarisation of His Purkinje system. Diagnostic techniques and findings A 24-hour ECG tape to look at the average QT interval, an exercise tolerance test to look for appropriate shortening of QT interval with exercise and an echocardiogram to exclude significant structural abnormality were requested. The 24-hour ECG tape confirmed underlying sinus rhythm with multi-focal aberrant beats &lt;1% of total. One symptom demonstrated short run of ventricular bigeminy. During the exercise tolerance test, QT interval was not obviously prolonged. There were frequent bifocal ventricular ectopic beats in recovery. The echocardiogram showed minor abnormality with mild left ventricular dilatation, otherwise normal findings. Patient referred for cardiac MRI In order to rule out any cardiomyopathy. Cardiac MRI did not show any prolapse on the 3 chamber cine. In addition, the inferior and inferolateral annulus showed thinning passing into the LV, which is a feature of some patients with mitral annulus disjunction syndrome. We went through the echocardiogram and in one single frame images are suspicious of focal P2 prolapse. Learning points: Mitral annulus disjunction (MAD) is an abnormal atrial displacement of the mitral valve leaflet hinge point. It has been associated with mitral valve prolapse and sudden cardiac death. MAD is usually revealed with echocardiogram. In this case report we showed that CMR revealed a MAD previously missed by echo. Abstract P1502 Figure.