Reversible Wall Thinning in Hibernation Predicted by Cardiovascular Magnetic Resonance
An 82-year-old woman was admitted with shortness of breath and chest pain. She was found to have pulmonary edema, and an ECG showed ischemic ST changes. Coronary angiography revealed severe left main stem disease and an occluded right coronary artery, and her left ventricular ejection fraction (LVEF) was estimated at 10% to 20%. She was referred for urgent cardiovascular magnetic resonance (CMR).
CMR was performed on a Siemens Sonata 1.5-T scanner with standard trueFISP cine sequences in 2-chamber, 4-chamber, and short-axis views. Late gadolinium enhancement viability studies were performed after injection of 0.1 mmol/kg gadolinium diethylene triamine pentaacetic acid (Schering) with a standard FLASH inversion recovery sequence in the same slice orientations. CMR demonstrated a globally dilated LV with poor systolic function and an EF of 28%. Marked thinning of the anterior wall, apex, septum, and inferior wall (Figure; Movies I and II) was noted. Gadolinium enhancement revealed partial thickness infarction (<50% transmural thickness) of the basal inferoseptal wall. Near-transmural infarction of the mid-inferior septum was also noted. One segment was classified via the standard 17-segment model as nonviable and 16 were classified as viable despite the extensive severe wall motion abnormalities and wall thinning. On the basis of the results of the CMR scan, surgical revascularization was performed the following day (radial grafts to the left anterior descending and first obtuse marginal arteries), and the patient’s postoperative course was uneventful. CMR was performed 2 months after the bypass operation (Figure; Movies III and IV) and showed a normal-size LV with normal systolic function (Table). LVEF increased to 68%, and the LV showed significantly increased thickness of previously thinned segments.
To our knowledge, this reversal of myocardial thinning in hibernation has not been described previously. Of interest is that the thinned myocardium was correctly identified as hibernating by CMR. Nuclear techniques were not performed because of the clinical scenario, but identification of viability in such thinned segments may well have been problematic because of lower resolution and partial volume effects. In conclusion, although thinned myocardium is usually interpreted as indicating nonviability, this case suggests that such an assumption may not be warranted in the absence of gadolinium enhancement.
Movies I through IV are available in the online-only Data Supplement linked to this article at http://www.circulationaha.org.