Definition of Left Ventricular Aneurysm: well-demarcated and thin/fibrotic/scarred ventricular wall (usually the result of a prior trans-mural myocardial infarction with healing)
Aneurysm is Devoid of Muscle or Contains Necrotic Muscle
Aneurysmal Wall is Usually Thin and Consists of White, Fibrous Scar Tissue: endocardial surface is usually smooth and trabeculated
Aneurysm Contains Organized Thrombus in 50% of Cases: due to flow stasis within the aneurysm or contact of blood with procoagulant fibrous tissue within the aneurysm
Mural thrombus and/or aneurysmal wall may calcify over time
Dense Adhesions Commonly Develop Between the Aneurysmal Wall and the Adjacent Overlying Pericardium
Aneurysmal Wall is Either Akinetic (Lacking Movement) or Dyskinetic (with Paradoxical Ballooning) During Systole
Aneurysmal Wall Usually Collapses Inward with Venting During Surgery
Location of Left Ventricular Aneurysm
Location
Apical/Anterior Walls: 70-85% of cases (due to left anterior descending arterial occlusion)
Inferior/Basal Walls: 10-15% of cases (due to right coronary artery occlusion)
Lateral Wall: rare (due to left circumflex artery occlusion)
Left Ventricular Aneurysm in the Presence of Multi-Vessel Coronary Artery Disease: left ventricular aneurysm is uncommon if there is extensive collateralization or if the left anterior descending artery is patent
Size of Left Ventricular Aneurysm
Range: 1-8 cm
Risk of Left Ventricular Aneurysmal Rupture
Low: although left ventricular aneurysms may enlarge over time, they rarely rupture, due to the presence of dense fibrotic tissue within the aneurysmal wall
In contrast, left ventricular pseudoaneurysms (see Left Ventricular Pseudoaneurysm, [[Left Ventricular Pseudoaneurysm]]) have a high risk of rupture (30-45% of cases rupture)
Angina/Chest Pain (see Chest Pain, [[Chest Pain]]): due to increased left ventricular oxygen demand (which may result in myocardial ischemia, particularly in the setting of coronary artery disease)
Physiology: systolic paradoxical bulging of the aneurysmal segment -> “loss” of part of the stroke volume, effectively decreasing cardiac output and causing left ventricular volume overload -> left ventricular dilates and wall stiffens -> increase in left ventricular end-diastolic pressure
Increased left ventricular size results in increased left ventricular wall tension -> increased left ventricular oxygen demand (which may result in myocardial ischemia, particularly in the setting of coronary artery disease)
Findings Related to the Left Ventricular Aneurysm Itself
Diffuse Apical Impulse with Displacement to the Left of the Mid-Clavicular Line
Palpable Dyskinesis Over Apex or Left Lateral Chest Wall in Region of the Left Ventricle Anterior Wall
Third/Fourth Heart Sound: often heard (due to blood flow into a dilated, stiff left ventricular chamber
Mitral Regurgitation Murmur (see Mitral Regurgitation, [[Mitral Regurgitation]]): due to distortion of left ventricular geometry with resulting absence of mitral valve leaflet apposition, papillary muscle dysfunction, and/or mitral annular dilatation
Ventricular Tachyarrhythmias: may result in sudden cardiac death
General Comments
Due to myocardial ischemia and increased myocardial stretch -> increased automaticity or triggered activity
Due to occurrence at reentrant tachycardia at the border zone in the myocardium (which consists of a mix of fibrotic tissue, inflammatory cells, damaged/disorganized muscle fibers): reentry may occur when two electrically heterogeneous pathways with distinct conduction velocities/refractoriness are adjacent to each other
Anticoagulation: indicated for significant left ventricular dysfunction or with evidence of thrombus within the aneurysm or left ventricle (see Intracardiac Thrombus, [[Intracardiac Thrombus]])
Risk of Embolization Decreases with Chronicity of Left Ventricular Aneurysm: risk of embolization is low with aneurysms diagnosed at least a month after myocardial infarction (presumably due to endothelialization or organization of the thrombus), even though mural thrombus is frequently observed
Therefore, anticoagulation may not be required in these cases
Surgical Therapy
Indications for Surgical Repair
Congestive Heart Failure Unresponsive to Medical Therapy
Intractable Ventricular Arrhythmias Unresponsive to Catheter-Based Therapy
Progressive Increase in Left Ventricular Diameter and/or Decrease in Left Ventricular Ejection Fraction: even before the development of overt congestive heart failure
Refractory Angina
Symptomatic Patients with Akinetic/Dyskinetic Segments
Systemic Embolization in Patient with a Contraindication for Anticoagulation
Technique
Median Sternotomy
Left Lateral Thoracotomy
Prognosis
Coronary Artery Surgery Study (CASS) (1982): 71% 5-year survival
However, this and other studies of the long-term outcome of left ventricular aneurysm were performed prior to the modern era of acute myocardial infarction management and the results are likely not applicable to modern outcomes
