Usefulness of Stress Echocardiography in Assessment of Dynamic Left Ventricular Obstructions: Case Series and Review of the Literature

Abstract

Dynamic left ventricular outflow tract obstruction (DLVOTO) or midcavity obstruction in patients with structurally normal hearts is not uncommon in routine clinical practice and can cause significant symptoms mimicking coronary artery disease or heart failure. Although exercise echocardiography is the gold standard for assessing DLVOTO, dobutamine stress echocardiography (DSE) may be valuable diagnostic modality in patients who are unable to exercise or have an uninterpretable 12-lead electrocardiogram. We provide an updated overview of the relevant literature regarding prevalence, pathophysiology, clinical significance, and prognostic impact of DLVOTO and midcavity obstruction in structurally normal hearts. We also present a clinical series of 4 cases of DLVOTO and midcavity obstruction documented by DSE and discuss the value of different kinds of modern stress imaging modalities involving: (1) contrast-enhanced DSE to assess myocardial perfusion and inducible ischemia; (2) adenosine stress echocardiography to assess coronary flow reserve/microvascular dysfunction; and (3) functional imaging with deformation echocardiography to assess subclinical myocardial dysfunction in patients with structurally normal heart and without significant coronary disease. Based upon our own experiences and a critical review of the current literature, we will then present a practical guidance for management of DLVOTO and midcavity obstruction.

Tissue tracking of segmental strain as a predictor of provoked dynamic left ventricular outflow tract obstruction

“… Although exercise echocardiography is the gold standard for assessing DLVOTO, we used DSE which could be a valuable diagnostic modality for DLVOTO. 3 Provoked DLVOTO based on diverse LV geometric changes as anterior mitral leaflet length and thickness, and aorto-septal angel, have been identified in earlier research, 4 therefore it appeared fair to study another parameter as basal septum contractility in the current study. We only used LS rather than radial and circumferential strain.…”

“…Although exercise echocardiography is the gold standard for assessing DLVOTO, we used DSE which could be a valuable diagnostic modality for DLVOTO. 3 …”

“…Exercise or DSE are reliable screening modalities for DLVOTO diagnosis. 3 DLVOTO can develop due to various geometric changes. 4 However, the increased contractility of the basal-septal segment is probably an essential factor in the provoked obstruction and therefore may be used to identify subgroups of patients at increased risk of provoked DLVOTO.…”

Intraventricular gradients—When we have to “exercise” our minds: A case report

“… 13 , 14 Betablocker therapy was used in this patient, following the rationale that it has a negative inotropic and chronotropic effect, and hence antagonizes LVOT and midcavity obstructions. 13 , 15 …”

“…The DLVOTO is associated with an increase in myocardial work and demand for oxygen supply causing angina secondary to enhanced demand-supply mismatch with subsequent subendocardial ischemia, which, ultimately, is manifested as ST segment depression on surface ECG. 13,14 Betablocker therapy was used in this patient, following the rationale that it has a negative inotropic and chronotropic effect, and hence antagonizes LVOT and midcavity obstructions. 13,15 In our opinion, the case described, in which significant abnormalities in cardiac function were found only during and after exercise, suggests that exercise stress echocardiography should be applied to other patients that have dizziness or syncope related to exercise but no structural abnormalities.…”