Читать книгу Interventional Cardiology - Группа авторов - Страница 273

The combination of CMR stress perfusion, function, and LGE allows the use of CMR as a primary form of testing for: (i) diagnosing IHD, (ii) determining which patients are candidates for revascularization; and (iii) defining the distribution of CAD prior to revascularization [53].

Figure 10.3 (a) Early and (b) delayed contrast‐enhanced images of the left atrial appendage for evaluation prior to pulmonary vein ablation. There appears to be a filling defect in the early images concerning for thrombus but delayed images confirm that there is no LAA thrombus. Images (c) and (d) delineate the anatomy of the left atrium and the pulmonary veins.

Dobutamine stress CMR relies on wall motion evaluation with increasing doses of dobutamine and vasodilator perfusion stress CMR relies on the perfusion of gadolinium at stress compared to rest for evaluation of ischemia. A recent study [76] evaluated 2349 patients who underwent stress CMR perfusion imaging after presenting with chest pain over a period of 5.4 years and found that patients without ischemia and LGE had a low incidence of cardiac events, need for revascularization and subsequent ischemia testing. This adds to the growing body of evidence that in intermediate‐risk patients with IHD, a normal perfusion stress CMR perfusion can serve as an excellent initial screening test.

LV systolic function measured on CMR can be used to determine a patient’s eligibility for cardiac resynchronization therapy or for a defibrillator. CMR also plays an important role in evaluating myocardial viability which is defined as transmural scar of 50% or less as characterized by LGE. It has the unique advantage of directly visualizing scar and normal myocardium in the same image and is more sensitive for subendocardial scar than SPECT imaging [77]. Myocardial viability testing is currently recommended as a part of revascularization planning in patients with heart failure [78].