The role of exercise echocardiography in the diagnostics of heart failure with normal left ventricular ejection fraction

A Contemporary Review of the Effects of Exercise Training on Cardiac Structure and Function and Cardiovascular Risk Profile: Insights From Imaging

Exercise is a commonly prescribed therapy for patients with established cardiovascular disease or those at high risk for de novo disease. Exercise-based, multidisciplinary programs have been associated with improved clinical outcomes post myocardial infarction and is now recommended for patients with cancer at elevated risk for cardiovascular complications. Imaging studies have documented numerous beneficial effects of exercise on cardiac structure and function, vascular function and more recently on the cardiovascular risk profile. In this contemporary review, we will discuss the effects of exercise training on imaging-derived cardiovascular outcomes. For cardiac imaging via echocardiography or magnetic resonance, we will review the effects of exercise on left ventricular function and remodeling in patients with established or at risk for cardiac disease (myocardial infarction, heart failure, cancer survivors), and the potential utility of exercise stress to assess cardiac reserve. Exercise training also has salient effects on vascular function and health including the attenuation of age-associated arterial stiffness and thickening as assessed by Doppler ultrasound. Finally, we will review recent data on the relationship between exercise training and regional adipose tissue deposition, an emerging marker of cardiovascular risk. Imaging provides comprehensive and accurate quantification of cardiac, vascular and cardiometabolic health, and may allow refinement of risk stratification in select patient populations. Future studies are needed to evaluate the clinical utility of novel imaging metrics following exercise training.

Diastolic stress test echocardiography in patients with suspected heart failure with preserved ejection fraction: a pilot study

AIMS

The purpose of this pilot study was to assess the potential usefulness of diastolic stress test (DST) echocardiography in patients with suspected heart failure with preserved ejection fraction (HFpEF).

METHODS AND RESULTS

Patients with suspected HFpEF (left ventricular ejection fraction ≥ 50%, exertional dyspnoea, septal E/e' at rest 9-14, and N-terminal pro-B-type natriuretic peptide (NT-proBNP) at rest < 220 pg/mL; n = 13) and a control group constituted from asymptomatic patients with arterial hypertension (n = 19) and healthy subjects (n = 18) were included. All patients were analysed by two-dimensional and Doppler echocardiography at rest and during exercise (DST) and underwent cardiopulmonary exercise testing and NT-proBNP analysis during exercise. HFpEF during exercise was defined as exertional dyspnoea and peak VO₂  ≤ 20.0 mL/min/kg. In patients with suspected HFpEF at rest, 84.6% of these patients developed HFpEF during exercise, whereas in the group of asymptomatic patients with hypertension and healthy subjects, the rate of developed HFpEF during exercise was 0%. Regarding the diagnostic performance of DST to detect HFpEF during exercise, an E/e' ratio >15 during exercise was the most accurate parameter to detect HFpEF (accuracy 86%), albeit a low sensitivity (45.5%). Nonetheless, combining E/e' with tricuspid regurgitation (TR) velocity > 2.8 m/s during exercise provided a significant increase in the sensitivity to detect patients with HFpEF during exercise (sensitivity 72.7%, specificity 79.5%, and accuracy 78%). Consistent with these findings, an increase of E/e' was significantly linked to worse peak VO₂ , and the combination of an increase of both E/e' and TR velocity was associated with elevated NT-proBNP values during exercise.

CONCLUSIONS

The findings of this pilot study suggest that DST using E/e' ratio and TR velocity could be of potential usefulness to diagnose HFpEF during exercise in patients with suspected HFpEF at rest.

Cardiopulmonary Exercise Testing: What Is its Value?

Compared with traditional exercise tests, cardiopulmonary exercise testing (CPET) provides a thorough assessment of exercise integrative physiology involving the pulmonary, cardiovascular, muscular, and cellular oxidative systems. Due to the prognostic ability of key variables, CPET applications in cardiology have grown impressively to include all forms of exercise intolerance, with a predominant focus on heart failure with reduced or with preserved ejection fraction. As impaired cardiac output and peripheral oxygen diffusion are the main determinants of the abnormal functional response in cardiac patients, invasive CPET has gained new popularity, especially for diagnosing early heart failure with preserved ejection fraction and exercise-induced pulmonary hypertension. The most impactful advance has recently come from the introduction of CPET combined with echocardiography or CPET imaging, which provides basic information regarding cardiac and valve morphology and function. This review highlights modern CPET use as a single or combined test that allows the pathophysiological bases of exercise limitation to be translated, quite easily, into clinical practice.

New echocardiographic parameters in the diagnosis of heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is a serious clinical disease. The pathophysiology of HFpEF is complex, and specific diagnostic criteria have evolved over time. Limited data are available on the quantification of diastolic function using two-dimensional real-time echocardiography, and a simple parameter has not yet been established. The aim of this work is to evaluate new echocardiographic parameters-the diastolic wall strain of the posterior wall (DWS PW) and the vortex formation time (VFT). Echocardiographic data from 111 subjects with exertional dyspnea and normal left ejection fraction (Group A) and 20 healthy volunteers (Group B) were retrospectively evaluated. In addition to the standard parameters used in the diagnosis of HFpEF, DWS PW and VFT were assessed in all patients. HFpEF was diagnosed in 38 patients with dyspnea (Group A1). The remaining 73 patients did not meet the established criteria for a positive diagnosis of HFpEF (Group A2). We discovered that both observed parameters were significantly lower in patients with HFpEF than in other groups. Multivariate analysis revealed that both DWS PW and VFT independently predicted the presence of HFpEF. DWS PW and VFT are simple parameters in the evaluation of diastolic function and may play a potential role as a part of an integrated approach to the assessment of HFpEF.

How to diagnose heart failure with preserved ejection fraction: the value of invasive stress testing

Heart failure with preserved ejection fraction (HFpEF) is a growing healthcare burden worldwide and its prevalence is increasing. Diagnosing HFpEF is challenging and relies upon the presence of symptoms and/or signs of heart failure, preserved left ventricular systolic function, and evidence of diastolic dysfunction. Current diagnostic algorithms mainly rely on echocardiography (E/e’) and biomarkers (NT-proBNP). However, only a minority of patients with HFpEF are identified, and especially HFpEF patients at an early stage of the disease are easily missed. We propose to incorporate invasive stress testing, by means of right heart catheterisation at rest and during exercise, and accurate assessment of right ventricular function, by means of cardiac magnetic resonance imaging. These additions to the current diagnostic work-up will improve diagnostic sensitivity and accurate staging of HFpEF patients.

Longitudinal, circumferential and radial systolic left ventricular function in patients with heart failure and preserved ejection fraction

INTRODUCTION

Heart failure with preserved left ventricular ejection fraction (HFPEF) is an epidemiologically serious disease. Noninvasive diagnosis of HFPEF remains challenging. The current diagnosis is based on evidence of diastolic dysfunction, albeit systolic dysfunction is also present but not included in the diagnostic algorithm. The aim of this study was to analyze the longitudinal (long), circumferential (circ) and radial (rad) component of systolic left ventricular (LV) function in patients with exertional dyspnea of unexplained etiology and normal left ventricular ejection fraction (LVEF).

METHODS

One hundred and twenty-two patients with exertional dyspnea of unexplained etiology and normal LVEF and 21 healthy controls, underwent echocardiography examination at rest and at the end of symptom-limited exercise. We analysed the longitudinal, circumferential and radial deformation of myocardium using two dimensional speckle tracking echocardiography in all subjects.

RESULTS

Patients with exertional dyspnea and preserved LVEF were divided into group A1 (46 patients meeting the criteria for the diagnosis HFPEF) and group A2 (76 patients without HFPEF). Group A1 had significantly worse longitudinal and circumferential systolic LV function than group A2. Subjects in group A1 compared to group A2 showed significantly different strain rates during atrial contraction (SR A), circ and ratio of peak early trans-mitral flow velocity (E) and strain rate E wave (E / SR E) circ. Multivariate logistic regression analysis showed that the SR parameter A circ is an independent predictor of HFPEF (odds ratio 0.550, 95% confidence interval: 0.370 - 0.817, P value 0.003).

CONCLUSION

Longitudinal and circumferential LV deformation was significantly more impaired in patients with HFPEF than in patients with exertional dyspnea without HFPEF. In patients with exertional dyspnea and normal LVEF, the value of SRA circ appears to be a significant and independent predictor of HFPEF. This parameter may, in the future complement the diagnostic algorithm for HFPEF.

Value of exercise echocardiography in heart failure with preserved ejection fraction: a substudy from the KaRen study

BACKGROUND

KaRen is a multicentre study designed to characterize and follow patients with heart failure and preserved ejection fraction (HFpEF). In a subgroup of patients with clinical signs of congestion but left ventricular ejection fraction (LVEF) >45%, we sought to describe and analyse the potential prognostic value of echocardiographic parameters recorded not only at rest but also during a submaximal exercise stress echocardiography. Exercise-induced changes in echo parameters might improve our ability to characterize HFpEF patients.

METHOD AND RESULTS

Patients were prospectively recruited in a single tertiary centre following an acute HF episode with NT-pro-BNP >300 pg/mL (BNP > 100 pg/mL) and LVEF > 45% and reassessed by exercise echo-Doppler after 4-8 weeks of dedicated treatment. Image acquisitions were standardized, and analysis made at end of follow-up blinded to patients' clinical status and outcome. In total, 60 patients having standardized echocardiographic acquisitions were included in the analysis. Twenty-six patients (43%) died or were hospitalized for HF (primary outcome). The mean ± SD workload was 45 ± 14 watts (W). Mean ± SD resting LVEF and LV global longitudinal strain was 57.6 ± 9.5% and -14.5 ± 4.2%, respectively. Mean ± SD resting E/e' was 11.3 ± 4.7 and 13.1 ± 5.3 in those patients who did not and those who did experience the primary outcome, respectively (P = 0.03). Tricuspid regurgitation (TR) peak velocity during exercise were 3.3 ± 0.5 and 3.7 ± 0.5 m/s (P = 0.01). Exercise TR was independently associated with HF-hospitalization or death after adjustment on baseline clinical and biological characteristics.

CONCLUSION

Exercise echocardiography may contribute to identify HFpEF patients and especially high-risk ones. Our study suggested a prognostic value of TR recorded during an exercise. That was demonstrated independently of the value of resting E/e'.

Can we diagnose isolated, exercise-induced heart failure with normal ejection fraction?

BACKGROUND

A significant proportion of patients with exertional dyspnea require exercise to diagnose heart failure with normal ejection fraction (HFNEF).

METHODS AND RESULTS

In this review article, we evaluate current data on the prevalence, clinical significance and specifically the establishment of a diagnosis of isolated, exercise-induced HFNEF. Despite the unquestioned clinical importance and high prevalence of exercise-induced HFNEF, there are limited and conflicting data on making a diagnosis of exercise-induced HFNEF. This mostly relies on the evidence of exercise-induced elevation in left ventricular filling pressure (LVFP). At present, there is no agreement on the ability of exercise echocardiographic parameteres to predict exercise-induced LVFP elevation. In addition, even invasively measured exercise LVFP faces the problem of defining normal exercise LVFP values. More data and probably new diagnostic approaches are necessary to reliably diagnose exercise HFNEF.

CONCLUSIONS

There are conflicting results and significant problems associated with the diagnosis of exercise HFNEF. This review hopefully will encourage further research in this difficult but clinically important area of heart failure.

Can biomarkers help to diagnose early heart failure with preserved ejection fraction?

Early heart failure with preserved ejection fraction (HFpEF) is a frequent disease, but its diagnosis is difficult and relies mostly on the evidence of left ventricular filling pressure (LVFP) elevation during exercise. Several reports have suggested that natriuretic peptides plasma levels reflect exercise-induced increase in LVFP, but they still have significant limitations. In this context, any new laboratory biomarker that can accurately reflect LVFP elevation during exercise is desirable. Recently, cardiotrophin-1, soluble endoglin, ST2, growth differentiation factor 15, galectin-3, and other new laboratory markers associated with LVFP have emerged. However, the current data on the relationship of these biomarkers and diastolic dysfunction are limited to resting conditions. Therefore, their secretion deserves to be tested under the exercise to determine their potential role in making a diagnosis of early HFpEF.

A systematic review of diastolic stress tests in heart failure with preserved ejection fraction, with proposals from the EU-FP7 MEDIA study group

AIMS

Cardiac function should be assessed during stress in patients with suspected heart failure with preserved ejection fraction (HFPEF), but it is unclear how to define impaired diastolic reserve.

METHODS AND RESULTS

We conducted a systematic review to identify which pathophysiological changes serve as appropriate targets for diagnostic imaging. We identified 38 studies of 1111 patients with HFPEF (mean age 65 years), 744 control patients without HFPEF, and 458 healthy subjects. Qualifying EF was >45-55%; diastolic dysfunction at rest was a required criterion in 45% of studies. The initial workload during bicycle exercise (25 studies) varied from 12.5 to 30 W (mean 23.1 ± 4.6), with increments of 10-25 W (mean 19.9 ± 6) and stage duration 1-5 min (mean 2.5 ± 1); targets were submaximal (n = 8) or maximal (n = 17). Other protocols used treadmill exercise, handgrip, dobutamine, lower body negative pressure, nitroprusside, fluid challenge, leg raising, or atrial pacing. Reproducibility of echocardiographic variables during stress and validation against independent reference criteria were assessed in few studies. Change in E/e' was the most frequent measurement, but there is insufficient evidence to establish this or other tests for routine use when evaluating patients with HFPEF.

CONCLUSIONS

To meet the clinical requirements of performing stress testing in elderly subjects, we propose a ramped exercise protocol on a semi-supine bicycle, starting at 15 W, with increments of 5 W/min to a submaximal target (heart rate 100-110 b.p.m., or symptoms). Measurements during submaximal and recovery stages should include changes from baseline in LV long-axis function and indirect echocardiographic indices of LV diastolic pressure.

The effect of age on right ventricular diastolic function in healthy subjects undergoing treadmill exercise test

OBJECTIVE

There is an increasing interest for the value of right ventricle (RV) in predicting exercise tolerance and prognosis in cardiovascular disease. However, there is relatively few data evaluating the effect of age on RV diastolic filling velocities during rest or exercise in healthy subjects.

METHODS

A total of 54 healthy subjects were enrolled in this study. Patients were divided into 2 groups according to their age: Group 1 (≤45-years-old) and Group 2 (>45-years-old). A treadmill exercise test was performed using modified Bruce protocol. Conventional pulsed-wave Doppler and tissue Doppler velocities were obtained both at rest and immediately after the end of exercise, respectively.

RESULTS

In the overall analysis, tricuspid flow Doppler analysis showed a significant increase in A-wave velocity, less marked rise in E-wave velocity, decreased E/A ratio and decreased E-wave deceleration time (EDT) with exercise. Tissue Doppler analysis revealed increased Aa velocity, decreased in Ea/Aa ratio and IVRT. No significant change was observed in Ea velocity and E/Ea ratio with exercise. Although diastolic velocities changed significantly with exercise, systolic velocities did not. Cardiac response to exercise differed slightly in the older subjects compared to younger ones. The older subjects were more likely to have a reduced mean rate of RV filling for the second half of diastole from baseline to peak exercise.

CONCLUSION

To distinguish normal physiological changes due to aging from those of pathologic conditions may provide benefits while evaluating patients with known or suspected cardiovascular disease.

Update on cardiac imaging techniques 2012

Cardiac imaging is one of the basic pillars of modern cardiology. The potential list of scenarios where cardiac imaging techniques can provide relevant information is simply endless so it is impossible to include all relevant new features of cardiac imaging published in the literature in 2012 in the limited format of a single article. We summarize the year's most relevant news on cardiac imaging, highlighting the ongoing development of myocardial deformation and 3-dimensional echocardiography techniques and the increasing use of magnetic resonance imaging and computed tomography in daily clinical practice.

Integration of exercise evaluation into the algorithm for evaluation of patients with suspected heart failure with preserved ejection fraction

Approximately half of all patients with heart failure (HF) have a preserved left ventricular ejection fraction (HFPEF) and the prevalence of this form of HF is increasing. Although dyspnoea on exertion and diminished functional capacity is the key symptom of patients with HFPEF, current diagnostic criteria focus on resting indices of ventricular function. Specifically, current proposed criteria for the diagnosis of HFPEF, include clinical signs of HF; normal left ventricular systolic function; and evidence of abnormal diastolic performance and/or altered natriuretic peptides. By contrast, recent studies demonstrate that the key pathophysiologic features of HFPEF may not be evident at rest, and can only be detected during exertion. This review addresses the potential role of exercise testing using invasive haemodynamic or echocardiographic assessment in patients with suspected HFPEF in which current diagnostic criteria are not met.

Variability of post-exercise pulmonary capillary wedge pressure recovery. Implications for noninvasive echocardiographic diagnostics

AIM

The aim of our study was to assess the course of immediate post-exercise pulmonary capillary wedge pressure (PCWP) changes to identify the optimal time window for the noninvasive diagnostics of exercise-induced PCWP elevation.

METHODS AND RESULTS

Seventy-one patients at risk of heart failure with normal left ventricular ejection fraction underwent simultaneous exercise echocardiography and right heart catheterization. The ratio of early left ventricular filling velocity (E) to early diastolic mitral annular velocity (e') was used to predict noninvasively exercise-induced PCWP elevation. Fifty-one patients had exercise-induced PCWP elevation ≥ 8 mmHg and reached peak exercise PCWP ≥ 20 mmHg. Rapid post-exercise recovery of PCWP within 2 min was achieved in 18 (35.3%) patients. Intermediate post-exercise PCWP recovery at 3 and 4 min was found in 16 (31.4%) patients while late post-exercise PCWP recovery (≥ 5 min) was achieved in 17 (33.3%) patients.

CONCLUSION

The course of post-exercise PCWP recovery is highly variable, and a significant proportion of patients have only a brief period (≤ 2 min) of exercise-induced PCWP elevation. This fact should be taken into account in noninvasive assessment of exercise-induced PCWP.