Left Ventricular Pseudoaneurysm

Left ventricular pseudoaneurysm (false aneurysm) is a contained rupture of the left ventricular free wall. The wall of the sac is formed by pericardium, thrombus and fibrous tissue, with no myocardium. It communicates with the ventricle through a narrow neck and has a high risk of rupture.

It follows myocardial infarction (about 0.1% of infarcts, mainly inferior, posterior and lateral walls), cardiac surgery (especially mitral valve replacement), trauma, endocarditis and, rarely, percutaneous procedures. Late presentation, absence of reperfusion, corticosteroid or NSAID use after infarction, and pericardial adhesions favour containment.

Presentation is from days to years after the insult. Untreated, rupture risk is as high as 30 to 45%, and surgery carries an operative mortality of about 10 to 30%.

Pathophysiology.

Myocardial rupture occurs where necrotic wall is thin. Adhesive pericardium (from earlier inflammation, surgery or infarct related pericarditis) limits bleeding and forms a sac that is continuous with the ventricular cavity.

The sac expands under systolic pressure. Thrombus lines the cavity, and embolism and arrhythmia may result. The narrow neck (neck width under 50% of the maximum sac diameter) helps distinguish it from a true aneurysm, which has a wide neck and contains myocardium.

Many patients are asymptomatic and are found on imaging. Others have dyspnoea, chest pain, syncope, palpitations, embolic events, or heart failure. Examination may reveal a to-and-fro murmur, a new systolic murmur, persistent ST elevation after infarction, or an abnormal cardiac silhouette.

• Echocardiography with contrast: a sac outside the expected ventricular contour, narrow neck (ratio of neck to sac diameter of 0.5 or less), turbulent to-and-fro flow across the neck, and a pericardial effusion in many.
• Cardiac CT or MRI: define neck, sac size, thrombus, relation to coronary arteries and the pericardium; MRI shows lack of myocardium and pericardial enhancement.
• Left ventriculography and coronary angiography before surgery.
• ECG: persistent ST elevation, or new changes. Troponin if acute.
• Blood cultures and inflammatory markers if infection is suspected.

Differential diagnosis.

• True left ventricular aneurysm (wide neck, preserved myocardium, usually anterior or apical).
• Loculated pericardial effusion or haematoma, pericardial cyst and cardiac tumour.
• Ventricular diverticulum and ventricular septal rupture.
• Free wall rupture in progress.

Definitive treatment is surgical. Repair is advised once diagnosed, including in most asymptomatic patients, because rupture is unpredictable.

• Surgical repair: patch closure of the neck with prosthetic or pericardial material, with concomitant coronary bypass where indicated.
• Selected small, stable, asymptomatic chronic pseudoaneurysms found incidentally years after the event (neck narrow, sac under about 3 cm, no growth) may be observed with imaging every 3 to 6 months.
• Transcatheter closure with a septal occluder device is an option for high risk surgical candidates in specialist centres.

Bridging medical care.

• Strict control of blood pressure and heart rate: target systolic 100 to 120 mmHg and heart rate 60 to 80 beats/min with esmolol 500 microgram/kg intravenous bolus over 1 minute, then 50 microgram/kg/min, increased by 50 microgram/kg/min every 4 minutes to a maximum of 200 microgram/kg/min (reduce in heart failure; avoid in bradycardia or conduction block; hypotension monitored); change to oral metoprolol tartrate 25 to 50 mg twice daily when stable (maximum 200 mg daily; reduce in severe hepatic impairment).
• Avoid thrombolysis, strenuous activity, and excessive anticoagulation unless thrombus or embolism requires it (unfractionated heparin by aPTT 1.5 to 2.5 times control).
• Heart failure treatment as indicated; avoid raising cardiac output.
• Tamponade: pericardiocentesis is hazardous because it can release the tamponade effect of the sac and precipitate rupture. Perform only as a bridge with surgery immediately available, removing only enough fluid to restore perfusion.
• Infected pseudoaneurysm: intravenous antibiotics by culture with urgent surgery.

Monitoring. After repair, echocardiography before discharge, at 3 months and then annually. For observed lesions, imaging every 3 to 6 months, with prompt reassessment for symptoms.

Referral and escalation. Refer all patients immediately to a cardiothoracic surgical centre. Chest pain, hypotension or syncope with a pericardial effusion (impending rupture or tamponade), rapid growth in sac size, new haemopericardium, and embolic stroke or limb ischaemia are emergencies.

Special groups.

• Older adults and frail patients: heart team decision on transcatheter closure or conservative care.
• Pregnancy: rare; manage in a tertiary centre with surgical standby.
• Kidney impairment: contrast imaging with hydration and minimal contrast volume.