Exercise stress echocardiography (ESE) is a widely used diagnostic test in cardiology departments. ESE is mainly used to study patients with coronary artery disease; however, it has increasingly been used in other clinical scenarios including valve pathology, congenital heart disease, hypertrophic and dilated cardiomyopathies, athlete evaluations, diastolic function evaluation, and pulmonary circulation study. In our laboratories, we use an established methodology in which cardiac function is evaluated while exercising on a treadmill. After completing the exercise regimen, patients remain in a standing position or lie down on the left lateral decubitus, depending on the clinical questions to be answered for further evaluation. This method increases the quality and quantity of information obtained. Here, we present the various methods of exercise stress echocardiography and our experience in many clinical arenas in detail. We also present alternatives to ESE that may be used and their advantages and disadvantages. We review recent advances in ESE and future directions for this established method in the study of cardiac patients and underline the advantage of using a diagnostic tool that is radiation-free.

Background Dynamic left ventricular outflow obstruction (LVOTO) during exercise stress echocardiography (ESE) is recommended in hypertrophic cardiomyopathy (HCM) to identify the obstructive phenotype. Aim To assess left ventricular outflow gradient (LVOTG) during ESE in different conditions. Methods In a single-group, prospective, observational study, we performed peak and/or post-treadmill ESE with systematic assessment of LVOTG in the orthostatic position by continuous-wave Doppler in 1333 subjects (837 males, mean age 38,2±20 ranging from 6 to 87 years) recruited over a period of twenty years, from 2001 to 2021. Peak LVOTG ≥30 mm Hg was considered abnormal for LVOTO during ESE. We enrolled 7 different populations: asymptomatic healthy controls (n=35); HCM (n=81); genotype-positive, phenotype negative asymptomatic HCM (n=6); patients with chest pain symptoms, suspected myocardial ischemia and either normal coronary arteries (INOCA, n=131,or with very low pre-test probability of coronary artery disease (probable INOCA, n=416) and; fatigue and suspected heart failure with preserved ejection fraction (HFpEF, n=206); amateur athletes with ischemia-like ECG changes during exercise-test or symptoms such as near syncope or chest pain or dizziness (n=457); aborted sudden death and with negative screening (n=1). Results Technical success rate of LVOTG assessment was 1333/1333 at rest and at peak stress (feasibility 100%). Imaging and analysis time were <1 minute. LVOTG at rest was present in 25 pts (2.8%) of the overall population: 23 HCM, 1 INOCA, and 1 HFpEF. Overall prevalence during ESE was 432/1333 (32%). During ESE, LVOTO (see Figure 1 and 2) was 0% (0/35) in normals, 58% (47/81) in HCM (23 with obstruction at rest), 33% (2/6) in genotype-positive, phenotype negative HCM, 37% (33/131) in INOCA, 40% (135/416) in athletes and 1/1 in the patient with aborted sudden death on strenuous exercise. Conclusion LVOTO in orthostatic position is detectable during treadmill ESE in several cardiovascular conditions associated with symptoms such as dyspnea, chest pain or near syncope, and even in asymptomatic patients with genotype-positive, phenotype-negative HCM. The identification of the obstructive phenotype is easy to capture during ESE without any significant additional imaging and analysis burden and can be important also outside HCM. FUNDunding Acknowledgement Type of funding sources: None. Figure 1 Figure 2

A 16-year-old boy reported an episode of dizziness related to intense training six months before an episode of aborted sudden death. The screening required for competitive sports practice was normal. There were no personal or familial antecedents of sudden death or heart disease. After winning a triathlon competition, he experienced a cardiac arrest episode. He received defibrillation with the return of spontaneous circulation. A medical evaluation that included electrocardiogram (ECG) and echocardiogram had normal results. A complete study including cardiac MRI, coronary CT angiography, a genetic study for heart disease, the flecainide test, and a stress echocardiogram with ergometrine was done, and all results were normal. During a Holter ECG and exercise stress echo, isolated premature ventricular complexes were detected. During the effort treadmill stress echocardiogram, the athlete developed a significant intraventricular obstruction with an end-systolic peak, without systolic anterior movement of the mitral valve, which disappeared in the first minute of the recovery. We highlight the possible cause-effect relation between the events.

Funding Acknowledgements Type of funding sources: None. Introduction 3D left ventricular ejection fraction (LVEF) quantification methods are more accurate and reproducible than 2D echocardiography, however, conventional 3D is time consuming and requires extensive user expertise, thus hindering its routine implementation in busy echocardiography laboratories and its use by inexperienced physicians. HeartModel A.I. (HM) is a simple, fast, recently validated 3D automated analysis software that detects LV endocardial surfaces and calculates LVEF. The aim of this work is to evaluate the performance of HM with experienced and inexperienced physicians, its time saving potential and to assess whether this software can be a better alternative to 2D measurements in routine echocardiography. Methods Prospective analysis of 30 nonconsecutive patients referred for transthoracic echocardiogram in a university hospital echocardiography lab, from 1st February 2021 to 31st March 2021. 2D biplane LVEF was measured by an experienced and inexperienced physician (less than 250 echocardiograms performed), then the same physicians used the automated analysis software to assess LVEF (blinded for each other results). The time to make the measurements was registered. Comparisons of agreement between LVEF measurements (experienced versus inexperienced physicians) included linear regression with Pearson correlation coefficients and Bland-Altman analyses to assess the bias and limits of agreement (defined as 2SD around the mean). Results A total of 30 patients were included, mean age of 68.6 ± 20.1 years and 60% male. HM showed significantly lower acquisition times in both inexperienced (72±17s versus 173± 44s, P<0.01) and experienced (56±12s versus 126±29s, P<0.01) physicians. The difference in time of acquisition between 2D and HM was approximately 101s for inexperienced users and around 70s for experienced users. Regarding LVEF assessment, HM acquisitions compared to 2D measurements showed stronger correlations between experienced and inexperienced physicians (r= 0,98, P<0,01 versus r= 0,92, P<0,01) with minimal bias (−0,5 versus −0,6) and stronger agreement (HM limits of agreement: ± 5,8% versus 2D limits of agreement: ± 12,5%) Conclusion 3D LVEF assessment by HM significantly reduced acquisition times and exhibited higher interobserver agreement than 2D Simpson’s biplane method. These results suggest that automated 3D algorithms, such as HM, may play a key role in implementing 3D measurements in routine practice in busy echocardiography laboratories and allow the use of 3D echocardiography at early stages of physicians training.

Increased intraventricular pressure gradients due to dynamic left ventricular outflow tract obstruction during exercise have long been known to cause different symptoms. Exercise stress echocardiography is fundamental in the diagnostic approach of symptoms presenting during exercise. We hypothesize on the possible pathophysiological mechanisms responsible for our patient's syncopal episodes.