Читать книгу Practical Cardiovascular Medicine - Elias B. Hanna - Страница 143

Dyskinesis signifies that a non-contractile myocardial segment moves out during myocardial contraction and moves in during relaxation (paradoxical motion). LV aneurysm is an extreme form of dyskinesis and consists of a thin area of infarcted, dyskinetic myocardium that forms a myocardial pocket. Dyskinesis without an aneurysm implies that the myocardium protrudes only during systole, whereas an aneu- rysm protrudes in both systole and diastole, forming a separate chamber, and always has thin walls. LV aneurysm usually reflects the presence of extensive transmural necrosis; contrarily, dyskinesis may be seen with acute reversible ischemia, post-ischemic stunning, or takotsubo cardiomyopahty without any necrosis, in which case the myocardial wall is not thin (it may appear thin in systole from the lack of thickening, but it is not thin in diastole). Dyskinesis without an aneurysm is much more common than a true aneurysm.

LV aneurysm is a form of adverse LV remodeling and dilatation of the necrotic area. ~50% develop acutely in the first 48 hours, from early dilatation of the necrotic, expansile myocardium, and the remainder usually appear within 2 weeks.¹⁵⁷ The mature, thick scar appears several weeks later, followed by calcifications. The early use of ACE-I, β-blocker, and aggressive blood pressure control prevents LV aneurysm from appearing or expanding.

An aneurysm leads to increased preload and afterload, and a double mortality for the same EF.¹⁵⁸ LV aneurysm occurs in 5% of STEMI cases, mainly anteroapical STEMI (80% of LV aneurysms are anteroapical; the rest are inferoposterior). LV aneurysm may initiate or worsen: (i) HF, (ii) angina (from the adverse loading conditions), (iii) VT, and (iv) mural thrombosis.

The diagnosis is made by echo. ST elevation that persists >3 weeks suggests LV aneurysm, but may also be seen with a dyskinetic, often non-viable wall.

Treatment consists of standard HF therapy which aims to reverse LV remodeling. Aneurysmectomy is indicated for refractory HF or refractory VT, mainly in conjunction with CABG. Operative mortality is <10%.