A 53 year old male hypertensive patient with no history of previous myocardial infarction presented with exertional dyspnoea and fatigue. The ECG revealed complete left bundle branch block (LBBB), and echocardiography demonstrated moderately reduced left ventricular function (ejection fraction 36%) with anteroseptal and anteroapical located severe hypokinesia and akinesia. Assessment of myocardial viability using ^18F-fluoro-deoxyglucose (FDG) positron emission tomography (PET) (left panels showing a midventriclar short axis view (top) as well as a horizontal (middle) and a vertical (bottom) long axis view) revealed a severe defect of the septum from base to apex extending to the anterior and inferior wall (white arrowheads) suggesting scar tissue. Contrast enhanced cardiac magnetic resonance imaging (MRI) 15 minutes after gadolinium–DTPA administration using a T1 weighted gradient echo sequence optimised for the detection of scar tissue (which presents as bright myocardial enhancement as opposed to normal black myocardium) revealed complete absence of scar (right panels showing corresponding short axis and long axis views). Atherosclerotic coronary artery disease was excluded at coronary angiography.

The finding of a reduced tracer uptake on FDG-PET images in the septal region of patients with LBBB is not uncommon, leaving uncertainty about the viability status. In this patient with LBBB and severely abnormal FDG-PET scan, absence of scar tissue in the septal region and hence myocardial viability could be confirmed using contrast enhanced MRI. Thus, contrast enhanced MRI may be a valuable adjunct for the assessment of myocardial viability in patients with regional severe wall motion abnormalities and LBBB.