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.

Left ventricular twist predicts mortality in severe aortic stenosis

ObjectiveLeft ventricular (LV) twist is a major component of ventricular mechanics reflecting the helical orientation of cardiac fibres and compensating for afterload mismatch. However, it is not known whether it determines outcome after transcatheter aortic valve implantation (TAVI). This study sought to investigate TAVI-induced short-term changes of LV twist and to define its role in outcome prediction.MethodsA total of 146 patients (median age 81.78 years, 50.7% male) undergoing TAVI for severe aortic stenosis were included. LV rotation and twist were determined by speckle tracking echocardiography within 3 months before and 2 weeks after TAVI. All-cause mortality at 2 years was defined as primary end point.ResultsPatients who survived exhibited a higher apical peak systolic rotation (APSR) (p<0.001), twist (p=0.003) and torsion (p=0.019) pre-TAVI compared with those who died (n=22). Within 2 weeks after TAVI, APSR, twist and torsion decreased in patients who survived (all p<0.001), while no change occurred in those who died. Cox regression analysis showed an association of pre-TAVI APSR (HR 0.92, p=0.010), twist (HR 0.93, p=0.018) and torsion (HR 0.68, p=0.040) with all-cause mortality and an even stronger association of the respective changes after TAVI (∆APSR: HR 1.15, p<0.001; ∆twist: HR 1.14, p<0.001; ∆torsion: HR 2.53, p<0.001). All the parameters determined outcome independently of global longitudinal strain (GLS) and LV ejection fraction (LVEF).ConclusionAPSR, twist and torsion pre-TAVI as well as their change within 2 weeks after TAVI predict 2-year all-cause mortality after TAVI, adding incremental prognostic value to LVEF and GLS.

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

Simulating the effect of sodium channel blockage on cardiac electromechanics

There is growing interest to better understand drug-induced cardiovascular complications and to predict undesirable side effects at as early a stage in the drug development process as possible. The purpose of this paper is to investigate computationally the influence of sodium ion channel blockage on cardiac electromechanics. To do so, we implement a myofiber orientation dependent passive stress model (Holzapfel-Ogden) in the multiphysics solver Chaste to simulate an imaged physiological model of the human ventricles. A dosage of a sodium channel blocker was then applied and its inhibitory effects on the electrical propagation across ventricles were modeled. We employ the Kerckhoffs active stress model to generate electrically excited contractile behavior of myofibers. Our predictions indicate that a delay in the electrical activation of ventricular tissue caused by the sodium channel blockage translates to a delay in the mechanical biomarkers that were investigated. Moreover, sodium channel blockage was found to increase left ventricular twist. A multiphysics computational framework from the cell level to the organ level was thus used to predict the effect of sodium channel blocking drugs on cardiac electromechanics.