Echocardiographic deformation imaging reveals preserved regional systolic function in endurance athletes with left ventricular hypertrophy

Molecular Mechanisms Underlying Cardiac Adaptation to Exercise

Exercise elicits coordinated multi-organ responses including skeletal muscle, vasculature, heart, and lung. In the short term, the output of the heart increases to meet the demand of strenuous exercise. Long-term exercise instigates remodeling of the heart including growth and adaptive molecular and cellular re-programming. Signaling pathways such as the insulin-like growth factor 1/PI3K/Akt pathway mediate many of these responses. Exercise-induced, or physiologic, cardiac growth contrasts with growth elicited by pathological stimuli such as hypertension. Comparing the molecular and cellular underpinnings of physiologic and pathologic cardiac growth has unveiled phenotype-specific signaling pathways and transcriptional regulatory programs. Studies suggest that exercise pathways likely antagonize pathological pathways, and exercise training is often recommended for patients with chronic stable heart failure or following myocardial infarction. Herein, we summarize the current understanding of the structural and functional cardiac responses to exercise as well as signaling pathways and downstream effector molecules responsible for these adaptations.

Integrated Imaging in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HC) has a very heterogeneous clinical spectrum and lends itself to multimodality imaging for evaluation and management. This review addresses clinical applications of cardiac imaging in patients with HC. Integrating various techniques of echocardiography and cardiac magnetic resonance (CMR) is discussed in the clinical context such as diagnosis, evaluation, management, risk stratification, and family screening of patients with HC. The utility of periprocedural imaging techniques is highlighted for guiding surgical and transcatheter septal reduction procedures. More limited roles of invasive or computed tomography coronary angiography are discussed for patients with HC with chest pain and risk factors for coronary artery disease. Nuclear techniques although available for decades play a more limited role in contemporary routine management but may assist in risk assessment. Newer CMR and echo imaging techniques are discussed in their emerging roles for further characterization of patients with HC and family members with prospects of preclinical diagnosis. The strengths of the different imaging modalities are presented as well as a flow diagram summarizing integrated imaging in this disease. In conclusion, integrated imaging using the various imaging techniques predominantly echocardiography and CMR based on the clinical picture plays an essential role in the management of patients with HC.

Cardiac function following prolonged exercise: influence of age

This study sought to determine the influence of age on the left ventricular (LV) response to prolonged exercise (PE; 150 min). LV systolic and diastolic performance was assessed using echocardiography (ECHO) before (pre) and 60 min following (post) exercise performed at 80% maximal aerobic power in young (28 ± 4.5 years; n = 18; mean ± SD) and middle-aged (52 ± 3.9 years; n = 18) participants. LV performance was assessed using two-dimensional ECHO, including speckle-tracking imaging, to determine LV strain (LV S) and LV S rate (LV SR), in addition to Doppler measures of diastolic function. We observed a postexercise elevation in LV S (young: −19.5 ± 2.1% vs. −21.6 ± 2.1%; middle-aged: −19.9 ± 2.3% vs. −20.8 ± 2.1%; P < 0.05) and LV SR (young: −1.19 ± 0.1 vs. −1.37 ± 0.2; middle-aged: −1.20 ± 0.2 vs. −1.38 ± 0.2; P < 0.05) during recovery in both groups. Diastolic function was reduced during recovery, including the LV SR ratio of early-to-late atrial diastolic filling (SRe/a), in young (2.35 ± 0.7 vs. 1.89 ± 0.5; P < 0.01) and middle-aged (1.51 ± 0.5 vs. 1.05 ± 0.2; P < 0.01) participants, as were conventional indices including the E/A ratio. Dobutamine stress ECHO revealed a postexercise depression in LV S in response to increasing dobutamine dose, which was similar in both young (pre-exercise dobutamine 0 vs. 20 μg·kg−1·min−1: −19.5 ± 2.1 vs. −27.2 ± 2.2%; postexercise dobutamine 0 vs. 20 μg·kg−1·min−1: −21.6 ± 2.1 vs. −23.7 ± 2.2%; P < 0.05) and middle-aged participants (pre: −19.9 ± 2.3 vs. −25.3 ± 2.7%; post: −20.8 ± 2.1 vs. −23.5 ± 2.7; P < 0.05). This was despite higher noradrenaline concentrations immediately postexercise in the middle-aged participants compared with young (4.26 ± 2.7 nmol/L vs. 3.00 ± 1.4 nmol/L; P = 0.12). These data indicate that LV dysfunction is observed following PE and that advancing age does not increase the magnitude of this response.

Effect of long term and intensive endurance training in athletes on the age related decline in left and right ventricular diastolic function as assessed by Doppler echocardiography

The aim of this study was to evaluate (1) the effect of endurance training on left ventricular and right ventricular diastolic function and (2) whether the normal aging effect on left ventricular and right ventricular diastolic function is slowed by endurance training. A total of 269 healthy subjects were prospectively enrolled for echocardiographic evaluation. Five groups were defined on the basis of age and athletic activities: (1) young (18 to 39 years) nonathletes (n = 62), (2) veteran (>or=40 years) nonathletes (n = 33), (3) young regular athletes (9 to 18 hours of sports/week; n = 58), (4) young elite athletes (>18 hours of sports/week; n = 63), and (5) veteran athletes (>or=40 years and >or=9 hours of sports/week; n = 53). Pulsed-wave Doppler indexes for diastolic function in the left and right ventricles were obtained at rest. No significant differences were found among the young controls, regular athletes, and elite athletes in left ventricular and right ventricular pulsed-wave and tissue Doppler diastolic parameters. These were also comparable between the veteran athletes and controls. In athletes and controls, similar and significant correlations were found between age and diastolic parameters. Age was the most important determinant in almost all parameters in multivariate analysis, while the influence of the amount of training did not account for >2% of the observed variance in any of these parameters. In conclusion, the amount of endurance training did not alter diastolic parameters in either ventricle in the young. Furthermore, the biventricular decreases in diastolic function observed in healthy, nonathletic subjects with age was also observed in aging athletes' hearts.