Exercise Training Induces Left- but not Right-sided Cardiac Remodelling in Olympic Rowers

Whilst the athlete’s heart has been extensively described, less work has focused on the potential for elite athletes to demonstrate further cardiac remodelling upon an increase in training volume. Moreover, little work explored potential side-specific cardiac remodelling. Therefore, we examined the impact of an increase in training volume across 9-months in elite rowers on left- and right-sided cardiac structure, function and mechanics (i. e. longitudinal, radial and circumferential strain, twist and strain-volume loops). As part of the preparations to the 2012 Olympic Games, twenty-seven elite rowers (26.4±3.7years, 19 male) underwent echocardiography prior to and post (9 months) an increase in training volume (24 to 30–35 h weekly). Training increased left ventricular structure, including wall thickness, diameter, volume, mass and LV twist (all p<0.05). Female rowers demonstrated larger adaptation in left ventricular diameter and mass compared to male rowers (both p<0.05). No changes were observed in other measures of left ventricular function in both sexes (all p>0.05). The 9-month intervention showed no change in right ventricular/atrial structure, function or mechanics (all p>0.05). In conclusion, our data revealed that 9-month increased training volume in elite rowers induced left-sided (but not right-sided) structural remodelling, concomitant with an increase in left ventricular twist, with some changes larger in women.

Assessment of left ventricular twist by 3D ballistocardiography and seismocardiography compared with 2D STI echocardiography in a context of enhanced inotropism in healthy subjects

Ballistocardiography (BCG) and Seismocardiography (SCG) assess the vibrations produced by cardiac contraction and blood flow, respectively, by means of micro-accelerometers and micro-gyroscopes. From the BCG and SCG signals, maximal velocities (VMax), integral of kinetic energy (iK), and maximal power (PMax) can be computed as scalar parameters, both in linear and rotational dimensions. Standard echocardiography and 2-dimensional speckle tracking imaging echocardiography were performed on 34 healthy volunteers who were infused with increasing doses of dobutamine (5–10–20 μg/kg/min). Linear VMax of BCG predicts the rates of left ventricular (LV) twisting and untwisting (both p < 0.0001). The linear PMax of both SCG and BCG and the linear iK of BCG are the best predictors of the LV ejection fraction (LVEF) (p < 0.0001). This result is further confirmed by mathematical models combining the metrics from SCG and BCG signals with heart rate, in which both linear PMax and iK strongly correlate with LVEF (R = 0.7, p < 0.0001). In this setting of enhanced inotropism, the linear VMax of BCG, rather than the VMax of SCG, is the metric which best explains the LV twist mechanics, in particular the rates of twisting and untwisting. PMax and iK metrics are strongly associated with the LVEF and account for 50% of the variance of the LVEF.

Механика левого желудочка у детей в возрасте от 1 до 5 лет, рожденных с очень низкой и экстремально низкой массой тела

Цель исследования - изучение механики левого желудочка у детей, рожденных недоношенными с низкой и экстремально низкой массой тела, в период постнатального онтогенеза. Материал и методы исследования: в работу включено 88 детей в возрасте от 1 года до 5 лет, рожденных глубоконедоношенными с очень низкой и экстремально низкой массой тела. Группу сравнения составили 46 здоровых детей аналогичного возраста, рожденных доношенными. Меха ника левого желудочка изучена путем оценки вращения левого желудочка на уровне базальных сегментов, папиллярных мышц, верхушки и скручивания с помощью технологии двухмерной спекл-трекинг эхокардиографии. Результаты исследования: выделено четыре типа скручивания левого желудочка как у здоровых доношенных детей, так и у детей, рожденных глубоконедоношенными. Распределение типов скручивания левого желудочка у детей в возрасте от 1 года до 5 лет, рожденных с низкой, очень низкой и экстремально низкой массой тела, отличалось от детей, рожденных доношенными. Первый (“взрослый”) тип скручивания левого желудочка выявлен у 46,59% детей, рожденных глубоконедоношенными, и у 67,39% здоровых доношенных детей. “Детские” (второй и третий) типы по час тоте не различались между детьми обеих групп (11,36 и 15,91% против 13,04 и 15,22% соответственно). Четвертый тип (отрицательная апикальная ротация) значительно чаще обнаружен у детей, рожденных глу боконедоношенными (26,14 против 4,37%, P = 0,01). Не выявлено различий в час тоте выявленных типов скручивания левого желудочка в зависимости от пола ребенка среди детей, рожденных глубоконедоношенными. Выявлена связь скручивания левого желудочка с массой тела при рождении (r = 0,53, P = 0,003) у детей, рожденных глубоконедоношенными, в возрасте от 1 года до 3 лет. Ключевые слова: двухмерная спеклтрекинг эхокардиография, ротация левого желудочка, скручивание левого желудочка, механика левого желудочка, недоношенные дети, дети, рожденные с очень низкой массой тела, дети, рожденные с экстремально низкой массой тела, 2D speckle tracking echocardiography (imaging), left ventricular rotation, left ventricular twist, left ventricular mechanics, premature infants, children with

Cardiac Helical Function

Background. The aim of this study was to investigate: a) the starts and ends of the myocardial band; b) the slippage between the band segments, when performing both torsion and ventricular detorsion, implies that there should be an antifriction mechanism that avoids dissipating the energy; c) the electrical activation of the endocardial and epicardial bands and secondarily understand ventricular twist and the mechanism of active suction during the diastolic isovolumic phase. Methods. They were used: a) Ten young-bovine hearts (800-1000 g) and seven human hearts (one embrión, 4 g; one 10 years, 250 g and five adult, 300 g/average); b) five patients with no structural cardiac abnormalities and normal QRS complexes underwent three-dimensional endoepicardial electroanatomic mapping. Results. We have found in all the bovine and human hearts studied a nucleus (fulcrum) underlying the right trigone, whose osseus, chondroid or tendinous histological structure depends on the specimen analyzed. All the hearts studied presented myocardial attachment to the rigid structure of the fulcrum. Hyaluronic acid was found in the cleavage planes between the myocardial bundles.Endo-epicardial mapping demonstrates an electrical activation sequence in the area of the apex loop in agreement with the synchronic contraction of the descending and ascending band segments, consistent with the mechanism of ventricular twist. The late activation of the ascending band segment is consistent with its persistent contraction during the initial period of the isovolumic diastolic phase (the basis of the suction mechanism). Conclusions. The finding of the fulcrum gives support to the spiral myocardial band being the point of fixation that allows the helicoidal torsion. The hyaluronic acid would act as a lubricant and provide great resistance to mechanical pressures. This study explains the ventricular twist and the active suction mechanism during the isovolumic diastolic and early ventricular filling phases.Trial. This work does not correspond to a trial