Upright exercise stress echocardiography may unmask dynamic left ventricular obstruction also beyond hypertrophic cardiomyopathy

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.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

P794 Treadmill exercise stress echocardiography in children; our experience

Background

Exercise stress echocardiography (ESE) is routinely used in adults but its role in children (C) is less established

Purpose

To assess the feasibility and clinical value of ESE in outpatient children

Methods

We enrolled 309 consecutive C (mean age = 14,1 ± 2,6 years, range 6-17 yrs) who underwent treadmill ESE between 2002 and 2019: One group (Group I) of 258 C including: 237 with exercise related symptoms (chest pain and/or dyspnea and/ or lypotimia-syncope), 15 with resting ECG alterations, 6 with positive ECG stress test and other group of C (Group II) including: 10 asymptomatic for screening requested by parents, 11 with symptoms unrelated to exercise, 12 with antecedents of sudden death in the family, and 17 with known pathology - 10 with hypertrophic cardiomyopathy, 2 with aortic coarctation, 1 each with Cortriatriatum sinister, pulmonary stenosis, subaortic stenosis, bicuspid aortic valve, left ventricular hypertrophy related to arterial hypertension, aortic switch operation. Regional wall motion abnormalities (RWMA) by 2-D and continuous wave Doppler (transvalvular or transaortic or intraventricular (IVG) gradients were assessed in all.

Results

The success rate was 309/309 (100%). Only one complication (allowing asthma diagnosis by serendipity) occurred: a severe asthmatic crisis in one girl studied because of chest pain with exercise (with ESE negativity), Stress-induced RWMA occurred in 2 pts (one with HCM, the other with normal coronary arteries). A significant orthostatic exercise induced IVG (> 30 mmHg) was present in 101 of the 258 C (39%) studied due to symptoms, ECG alterations or positive stress ECG.

In group II the C with induced IVG attained

greater heart rate (HR) 184 ± 12 vs 174 ± 16 (p < 0,001); greater blood pressure (BP) 150 ± 19 mmHg vs 136 ± 23 mmHg (p < 0,001). The OR to the reproduced symptoms that motivated the exam during the SE comparing the 101 C with IVG with the 158 without IVG was 8,22 (4,83-13,99) p < 0,001 (95% CI).

Conclusions

Treadmill ESE is feasible and safe in young people. RWMA are of limited usefulness in our outpatient C group. Doppler often documents significant exercise induced IVG, occult at rest that associate with symptoms.

Abstract P794 Figure. ESE Induced IVG in a C with chest pain

P945 Should children, with exercise induced intra-ventricular gradients, be treated with beta blockers?

Background

In our experience, treadmill exercise echocardiography (SE) is feasible and safe in children (C). Regional wall motion abnormalities (RWMA) are of limited usefulness, but Doppler often - (in 39% from 258 previously studied C) - documents significant intraventricular gradients (IVG), occult at rest, and allowing to document a possible explanation for exercise related symptoms, or abnormal resting or stress-ECG findings.

Purpose - To assess the effect of ß blockers on the occurrence of IVG, in C, with symptoms or abnormal resting or stress-ECG findings.

Methods – We repeated SE in 66 of the 101 C – (with normal echocardiogram at rest) - that developed IVG on exertion, under treatment with ß blockers. These 66 C who repeated the SE under treatment with ß blockers are the study group. 15 (23%) of them were female and the mean age of the group was 14,6 ± 1,7 years old (11 to 17).

They all underwent SE with 2D and Doppler echocardiographic evaluation of, and during treatment with ß blockers.

Results

Mean IVG in those 66 C submitted to SE was 105 ± 38 mmHg in the first SE evaluation. In SE evaluation performed under ß blockers, 37 of them didn’t develop IVG and in 29 of them IVG was significantly reduced to a mean IVG of 58 ± 32 mmHg (p< 0,0001). The mean heart rate attained at peak exercise was 178 ± 15 bpm in the first SE evaluation and 157 ± 9 bpm in the evaluation performed under treatment with ß blockers (p < 0, 0001). 47 of these C reproduced clinical symptoms (that were indication to SE) of beta-blockers, and only 7 reproduced the symptoms under treatment with beta blockers (p< 0,0001).

Conclusions

In C with symptoms, abnormal rest or exercise ECG on medical evaluation and IVG on exertion, treatment with oral ß blockers prevented the occurrence of IVG or significantly reduced its magnitude. These changes were associated to significant clinical improvement in 85 % of the symptomatic population.

Abstract P945 Figure. SE without and with beta-blockers

P918 Screening protocol of patent foramen ovale in cryptogenic stroke

Introduction

Cryptogenic stroke reaches a prevalence of 30% and entails a significant risk of recurrence. Transesophageal echocardiography is the gold standard in identifying potential proximal embolic sources, including patent foramen ovale (PFO). Based on recent evidence, PFO percutaneous closure is recommended in selected cases of cryptogenic stroke, especially if associated with high risk features. Since PFO is present in up to 27% of the general population, the real challenge is to define which patients have a pathogenic PFO.

Purpose

To develop a pathogenic PFO screening protocol in patients with cryptogenic stroke, aimed at secondary prevention.

Methods

We revised the literature, analysing published articles in PubMed in the last 5 years, with the keywords "patent foramen ovale and cryptogenic stroke". Subsequently, we produced a screening algorithm based on cryptogenic stroke definition, on RoPE (Risk of Paradoxical Embolism) Score and on the inclusion and exclusion criteria of the CLOSE, REDUCE and RESPECT studies, which showed promising results of PFO closure in this context.

Results

Our protocol establishes that patients who present with ischemic stroke should be evaluated for risk factors and undergo a detailed etiological study. When the study is inconclusive, the RoPE score is applied to determine the probability of finding a pathogenic or an incidental PFO. If equal or greater than 7 points, in the absence of predefined exclusion criteria, a transesophageal echocardiogram is performed. If the screening is positive, the patient will be referred to the Cardiology Department for therapeutic guidance. If negative, alternative complementary diagnostic methods may be considered.

Conclusion

Through the application of this protocol, patients with high probability of having a pathogenic PFO and, consequently, those who may benefit from percutaneous closure, will be selected to undergo a screening transesophageal echocardiogram. The implementation of a PFO screening protocol in patients who present with cryptogenic stroke is relevant, by proposing to reduce its recurrence rate through the early referral of young patients with indication for an invasive strategy.