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

Abstract 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