Changes in Right Ventricular Function with Exercise in Healthy Subjects: Optimal Parameters and Effects of Gender and Age

The athlete's heart: insights from echocardiography

The manifestations of the athlete's heart can create diagnostic challenges during an echocardiographic assessment. The classifications of the morphological and functional changes induced by sport participation are often beyond 'normal limits' making it imperative to identify any overlap between pathology and normal physiology. The phenotype of the athlete's heart is not exclusive to one chamber or function. Therefore, in this narrative review, we consider the effects of sporting discipline and training volume on the holistic athlete's heart, as well as demographic factors including ethnicity, body size, sex, and age.

Systematic Review and Regression Modeling of the Effects of Age, Body Size, and Exercise on Cardiovascular Parameters in Healthy Adults

PURPOSE

Blood pressure, cardiac output, and ventricular volumes correlate to various subject features such as age, body size, and exercise intensity. The purpose of this study is to quantify this correlation through regression modeling.

METHODS

We conducted a systematic review to compile reference data of healthy subjects for several cardiovascular parameters and subject features. Regression algorithms used these aggregate data to formulate predictive models for the outputs-systolic and diastolic blood pressure, ventricular volumes, cardiac output, and heart rate-against the features-age, height, weight, and exercise intensity. A simulation-based procedure generated data of virtual subjects to test whether these regression models built using aggregate data can perform well for subject-level predictions and to provide an estimate for the expected error. The blood pressure and heart rate models were also validated using real-world subject-level data.

RESULTS

The direction of trends between model outputs and the input subject features in our study agree with those in current literature.

CONCLUSION

Although other studies observe exponential predictor-output relations, the linear regression algorithms performed the best for the data in this study. The use of subject-level data and more predictors may provide regression models with higher fidelity.

SIGNIFICANCE

Models developed in this study can be useful to clinicians for personalized patient assessment and to researchers for tuning computational models.

Biventricular function in exercise during autonomic (thoracic epidural) block

BACKGROUND

Blockade of cardiac sympathetic fibers by thoracic epidural anesthesia (TEA) was previously shown to reduce right and left ventricular systolic function and effective pulmonary arterial elastance. At conditions of constant paced heart rate, cardiac output and systemic hemodynamics were unchanged. In this study, we further investigated the effect of cardiac sympathicolysis during physical stress and increased oxygen demand.

METHODS

In a cross-over design, 12 patients scheduled to undergo thoracic surgery performed dynamic ergometric exercise tests with and without TEA. Hemodynamics were monitored and biventricular function was measured by transthoracic two-dimensional and M-mode echocardiography, pulsed wave Doppler and tissue Doppler imaging.

RESULTS

TEA attenuated systolic RV function (TV S': - 21%, P < 0.001) and LV function (MV S': - 14%, P = 0.025), but biventricular diastolic function was not affected. HR (- 11%, P < 0.001), SVI (- 15%, P = 0.006), CI (- 21%, P < 0.001) and MAP (- 12%, P < 0.001) were decreased during TEA, but SVR was not affected. Exercise resulted in significant augmentation of systolic and diastolic biventricular function. During exercise HR, SVI, CI and MAP increased (respectively, + 86%, + 19%, + 124% and + 17%, all P < 0.001), whereas SVR decreased (- 49%, P < 0.001). No significant interactions between exercise and TEA were found, except for RPP (P = 0.024) and MV E DT (P = 0.035).

CONCLUSION

Cardiac sympathetic blockade by TEA reduced LV and RV systolic function but did not significantly blunt exercise-induced increases in LV and RV function. These data indicate that additional mechanisms besides those controlled by the cardiac sympathetic nervous system are involved in the regulation of cardiac function during dynamic exercise. Trial registration Clinical trial registration: Nederlands Trial Register, NTR 4880 http://www.trialregister.nl/trialreg/admin/rctview.asp?TC=4880 .

Right Ventricle Mechanics and Function during Stress in Patients with Asymptomatic Primary Moderate to Severe Mitral Regurgitation and Preserved Left Ventricular Ejection Fraction

Background and objectives. Mitral regurgitation (MR) is usually dynamic and increasing with exertion. Stress may provoke symptoms, cause the progression of pulmonary hypertension (PH) and unmask subclinical changes of the left and right ventricle function. The aim of this study was to evaluate changes of right ventricle (RV) functional parameters during stress and to find out determinants of RV function in patients with MR. Materials and methods. We performed a prospective study that included patients with asymptomatic primary moderate to severe MR and preserved left ventricular (LV) ejection fraction (EF) at rest (≥60%). Conventional 2D echocardiography at rest and during stress (bicycle ergometry) and offline speckle tracking analysis were performed. Results. 80 patients were included as MR (50) and control (30) groups. Conventional functional and myocardial deformation parameters of RV were similar in both groups at all stages of exercise (p > 0.05). The grade of MR (p = 0.004) and higher LV global longitudinal strain (p = 0.037) contributed significantly to the changes of tricuspid annular plane systolic excursion (TAPSE) from rest to peak stress. Changes of MR ERA from the rest to peak stress were related to RV free wall longitudinal strain (FWLS) and four chambers longitudinal stain (4CLS) at rest (p = 0.011; r = −0.459 and p = 0.001; r = −0.572, respectively). Significant correlations between LV EF, stroke volume, cardiac output and RV fractional area change, S′, TAPSE, FWLS, 4CLS were obtained. However, systolic pulmonary artery pressure and RV functional, deformation parameters were not related (p > 0.05). Conclusions. Functional parameters of LV during exercise and severity of MR were significant determinants of RV function while PH has no correlation with it in patients with primary asymptomatic moderate to severe MR.

Endurance exercise in seniors: Tonic, toxin or neither?

INTRODUCTION

Cardiac adaptation to sustained exercise in the athletes is established. However, exercise-associated effect on the cardiac function of the elderly has to be elucidated. The aim of this study was to analyse left (LV) and right ventricular (RV) characteristics at different levels of chronic exercise in the senior heart.

MATERIALS AND METHODS

We studied 178 participants in the World Senior Games (mean age 68 ± 8 years, 86 were men; 48%). Three groups were defined based on the type and intensity of sports: low-, moderate- and high-intensity level. Exclusion criteria were coronary artery disease, atrial fibrillation, valvular heart disease or uncontrolled hypertension. LV and RV size and function were evaluated with an echocardiogram.

RESULTS

LV trans-mitral inflow deceleration time decreased in parallel to the intensity of chronic exercise: 242 ± 54 ms in low-, 221 ± 52 ms in moderate- and 215 ± 58 ms in high-intensity level, p = .03. Left atrial volume index (LAVI) was larger in high-intensity group, p = .001. The LAVI remained significantly larger when adjusting for age, gender, heart rate, hypertension and diabetes (p = .002). LV and RV sizes were larger in the high-intensity group. LV ejection fraction and RV systolic function evaluated by tissue Doppler velocity, atrioventricular plane displacement and strain did not differ between groups.

CONCLUSION

Left ventricular diastolic filling is not only preserved, but may also be enhanced in long-term, top-level senior athletes. Moreover, LV and RV systolic function remain unchanged at different levels of exercise. This supports the beneficial effects of endurance exercise participation in senior hearts.

Right Ventricular Contractile Reserve Is Impaired in Children and Adolescents With Repaired Tetralogy of Fallot: An Exercise Strain Imaging Study

BACKGROUND

Pulmonary insufficiency (PI) and right ventricular (RV) dysfunction are long-term complications in patients with repaired tetralogy of Fallot (rTOF). The aim of this study was to investigate RV contractile reserve and changes in PI that occur during exercise in patients with rTOF and the associations of these changes with exercise performance using stress echocardiography.

METHODS

Subjects with rTOF (n = 32) and healthy control subjects (n = 10) were prospectively enrolled and underwent rest and peak exercise echocardiography during standard cardiopulmonary exercise test protocol on a cycle ergometer or treadmill. RV contractile reserve was defined as the change in RV global longitudinal strain from rest to peak exercise. PI was assessed with the diastolic-to-systolic time-velocity integral ratio and diastolic/systolic velocity ratio from pulmonary artery Doppler interrogation. Exercise measures included heart rate reserve, percentage predicted maximum oxygen consumption, percentage predicted maximum work, and oxygen pulse.

RESULTS

RV contractile reserve was impaired in patients with rTOF compared with control subjects, with a significant drop in the absolute value of RV global longitudinal strain from 17% (range, 8%-27%) at rest to 13% (range, 5%-28%) at peak exercise. Similarly, PI decreased at peak exercise, with decreases in diastolic-to-systolic time-velocity integral and diastolic/systolic velocity ratios. Reduction in PI was directly associated with percentage predicted maximum oxygen consumption, percentage predicted maximum work, and greater oxygen pulse. Heart rate reserve was directly associated with percentage predicted maximum oxygen consumption and percentage predicted maximum work. RV contractile reserve was not associated with any exercise parameters.

CONCLUSIONS

Patients with rTOF have an abnormal myocardial response to exercise with impaired RV contractile reserve compared with control subjects. Heart rate reserve and reduction in PI at peak exercise are associated with better exercise performance and appear to be significant contributors to exercise performance in rTOF. Measures to improve chronotropic health in rTOF should be explored.

Non-invasive imaging of global and regional cardiac function in pulmonary hypertension

Pulmonary hypertension (PH) is a progressive illness characterized by elevated pulmonary artery pressure; however, the main cause of mortality in PH patients is right ventricular (RV) failure. Historically, improving the hemodynamics of pulmonary circulation was the focus of treatment; however, it is now evident that cardiac response to a given level of pulmonary hemodynamic overload is variable but plays an important role in the subsequent prognosis. Non-invasive tests of RV function to determine prognosis and response to treatment in patients with PH is essential. Although the right ventricle is the focus of attention, it is clear that cardiac interaction can cause left ventricular dysfunction, thus biventricular assessment is paramount. There is also focus on the atrial chambers in their contribution to cardiac function in PH. Furthermore, there is evidence of regional dysfunction of the two ventricles in PH, so it would be useful to understand both global and regional components of dysfunction. In order to understand global and regional cardiac function in PH, the most obvious non-invasive imaging techniques are echocardiography and cardiac magnetic resonance imaging (CMRI). Both techniques have their advantages and disadvantages. Echocardiography is widely available, relatively inexpensive, provides information regarding RV function, and can be used to estimate RV pressures. CMRI, although expensive and less accessible, is the gold standard of biventricular functional measurements. The advent of 3D echocardiography and techniques including strain analysis and stress echocardiography have improved the usefulness of echocardiography while new CMRI technology allows the measurement of strain and measuring cardiac function during stress including exercise. In this review, we have analyzed the advantages and disadvantages of the two techniques and discuss pre-existing and novel forms of analysis where echocardiography and CMRI can be used to examine atrial, ventricular, and interventricular function in patients with PH at rest and under stress.

The Complex Phenotype of the Athlete's Heart: Implications for Preparticipation Screening

Preparticipation screening is vital to exclude inherited cardiac conditions that have the potential to cause sudden cardiac death in seemingly healthy athletes. Recent research has questioned traditional theories of load-induced, dichotomous cardiac adaptation. We therefore considered whether a one-size-fits-all approach to screening can account for interindividual differences brought about by sporting discipline, training volume, ethnicity, body size, sex, and age.

The association between right ventricular free wall strain and exercise capacity for health check-up subjects

BACKGROUND

Right ventricular (RV) function has been found to be a major factor of exercise capacity in patients with heart failure. However, the role of RV function in exercise capacity in healthy subjects has not been well studied. This study aims to validate the role of RV strain derived from speckle tracking echocardiography for exercise capacity for health check-up subjects.

METHODS

This study prospectively recruited subjects from a routine health examination. All of them were symptom free. RV function represented by RV strain was derived from speckle tracking echocardiography in addition to traditional echocardiography parameters. Functional capacity was determined by a symptom limited treadmill exercise test with the Bruce protocol.

RESULTS

Among 164 recruited subjects (age 52.2 ±9.2 years, 66.4% male), 32 subjects represented impaired functional capacity (MET<8), which was significantly correlated with age, left ventricular mass index, left ventricular filling pressure (E/e'), global longitudinal strain of the left ventricle (LVGLS) (-16.0±2.5% vs. -18.9±3.8%, p < 0.001) and RV free wall strain (RVLS_FW) (-17.0±4.9% vs. -21.9±3.2%, p <0.001). After multivariate logistic regression, RVS_FW was an independent predictor for impaired functional capacity (OR 1.62, CI 1.32-1.98; p <0.001).

CONCLUSIONS

In conclusion, RV strain is independently associated with exercise capacity for health check-up subjects. RV function is an important factor for functional capacity.

Exercise testing can unmask right ventricular dysfunction in systemic sclerosis patients with normal resting pulmonary artery pressure

BACKGROUND

Pulmonary arterial hypertension (PAH) is a frequent complication of systemic sclerosis (SSc). Diagnosis usually occurs late and often after the development of irreversible right heart dysfunction. Exercise testing is increasingly used for assessing right ventricular (RV) function when resting hemodynamics do not account for symptoms. We hypothesized that SSc patients without resting pulmonary hypertension could have impaired exercise capacity and RV contractile reserve with exercise thus unmasking early RV dysfunction and pulmonary vascular disease.

METHODS

Treadmill exercise stress echocardiography with concurrent expired gas analysis was performed in 25 SSc patients with normal resting pulmonary arterial pressure (PAP) and healthy controls (n = 50). Additionally, controls and SSc patients were compared to those with established PAH (n = 23). Parameters of RV systolic function (RV fractional area change (FAC), Doppler tissue (DTI) s' velocity, systolic strain and strain rate (S-Sr)) were evaluated at baseline and post-exercise with the difference (Δ) being contractile reserve.

RESULTS

RV contractile reserve was reduced in the SSc group with normal resting PAP, compared with healthy controls (Δs': 6.1 ± 2.3 vs 8.0 ± 2.2 cm s(-1), p < 0.001; and ΔS-Sr: 2.3 ± 0.5 vs 2.6 ± 0.2s(-1), p = 0.02) in association with a significantly higher mean PAP with exercise (25.5 ± 6.6 vs 19.9 ± 7.2 mmHg, p < 0.001). PAH patients demonstrated the lowest levels of contractile reserve (Δs', Δ strain, ΔS-Sr and ΔFAC, all p < 0.05).

CONCLUSION

Exercise stress testing unmasks reduced RV contractile reserve in SSc patients with normal resting PAP. Subclinical RV dysfunction during exercise may be a surrogate for early pulmonary vascular disease in SSc patients.