Predictors and prognostic impact of dynamic left ventricular outflow tract obstruction during dobutamine stress echocardiography.

BACKGROUND: Dynamic left ventricular outflow tract obstruction (DLVOTO) is a recognized phenomenon during dobutamine stress echocardiography (DSE), but its predictors and long-term prognostic significance remain uncertain.

OBJECTIVES: To identify clinical and echocardiographic predictors of DLVOTO during DSE and to assess the association between DLVOTO and major adverse cardiovascular events (MACE).

METHODS: We conducted a retrospective, single-center study included 355 consecutive patients undergoing DSE for ischemia assessment. DLVOTO was defined as a peak left ventricular outflow tract gradient ≥ 30 mmHg on continuous-wave Doppler. Clinical, echocardiographic, and stress-related variables were analyzed. The primary outcome was 3-point MACE (cardiovascular death, non-fatal myocardial infarction, or hospitalization for heart failure) during two-year follow-up. Multivariable logistic regression was used to identify independent predictors of DLVOTO and MACE.

RESULTS: DLVOTO occurred in 48 patients (13.5%). Compared with patients without DLVOTO, those with DLVOTO were more frequently female and had higher baseline left ventricular ejection fraction and less frequent beta-blocker use and known coronary artery disease. During stress, they experienced more symptoms and arrhythmias but fewer positive ischemia tests. Female sex, higher baseline left ventricular ejection fraction, increased basal septal thickness, and absence of beta-blocker therapy were independent predictors of DLVOTO. During follow-up, DLVOTO was not independently associated with MACE, whereas chronic kidney disease and a positive ischemia test predicted adverse events.

CONCLUSIONS: DLVOTO during DSE is relatively frequent and associated with identifiable clinical and echocardiographic predictors but does not confer an increased risk of major adverse cardiovascular events at two years.