Dynamic left ventricular outflow tract obstruction induced by dobutamine stress echocardiography leading to myocardial ischemia and infarction

Takotsubo cardiomyopathy--a clinical review

Stress cardiomyopathy is characterised by reversible left ventricular dysfunction. It simulates an acute coronary syndrome (ACS), presenting with precordial pain or dyspnoea, changes of the ST segment, T wave, or QTc interval on electrocardiogram, and raised cardiac enzymes. Typical findings are disturbances of segmental contractility (apical hypokinesia or akinesia), with normal epicardial coronary arteries. The true prevalence is unknown, as the syndrome may be under-diagnosed; it is more common in postmenopausal women. There is usually a trigger in the form of physical or psychological stress. The electrocardiographic, echocardiographic, and ventriculographic changes resolve spontaneously over a variable period of time (from days to months). There are a number of pathophysiological theories, none of which has been shown to be definitive, suggesting that all of them may be involved to some extent. The prognosis is generally favourable, and recurrence is very rare.

Left ventricular outflow tract and mid-cavity obstruction may cause false-positive dobutamine stress echocardiograms

Left ventricular (LV) outflow tract obstruction (LVOTO) occurs in up to 20% of patients undergoing dobutamine stress echocardiography (DSE). Mid-cavity LV obstruction occurs less commonly during DSE. LV regional wall motion abnormalities during DSE may occur despite normal coronaries due to hypertensive blood pressure response and takotsubo stress cardiomyopathy. We describe herein two cases of LVOTO and one case of mid-cavity LV obstruction during DSE associated with transient apical hypokinesis.