Tilting of the Cardiac Axis During Dobutamine Stress Echocardiography: Potential Marker for Ischemia

Abstract

Stress echocardiography is a tool for assessing the extent and severity of coronary artery disease (CAD) during physical or pharmacological stress. Transient worsening of regional left ventricular (LV) function during stress is a well-recognized abnormality of inducible ischemia. We present the case of a 57-year-old female with risk factors for CAD who was referred for a dobutamine stress echocardiogram for complaints of typical angina. It was interpreted as positive for inducible ischemia, but using unconventional criteria. Unfortunately, this study had reduced sensitivity due to LV hypertrophy. All LV wall segments were not clearly seen to comment on regional contractility, and an abnormal cardiac tilt from its axis was noted, suggestive of ischemia along the anteroseptal, anterior and lateral walls. Following this, a coronary angiogram showed diffuse CAD. The cardiac axis with the presence of a tilt as a potential measure of ischemia is previously unrecognized. The idea invokes a mathematical principle based on the direction and the magnitude of the vector of opposing walls during contractility. Simply implying that ischemic segments might contract in the same direction, vector magnitude will be less prominent; hence, “axial tilt” will occur. Prospective studies are needed to validate the feasibility and reproducibility of this abnormality in the assessment of ischemia and its viability in clinical practice.