A heart aneurysm after a heart attack

Patients with acute myocardial infarction are at risk for a number of survival-reducing complications, one of which is a post-infarction cardiac aneurysm - a bulge in the weakened muscle wall of the heart.

Epidemiology

According to studies, left ventricular aneurysm formation occurs in 30-35% of cases of acute transmural myocardial infarction. Almost 90% of such aneurysms affect the ventricular apex, but usually extend to the anterior wall of the ventricle.

Very rarely, left ventricular aneurysm after infarction affects the posterior wall of the left ventricle, and only in isolated cases there is a submithral (subvalvular) postinfarction aneurysm leading to left ventricular dysfunction.

Causes of the cardiac aneurysms after a heart attack.

The main causes of cardiac aneurysm after myocardial infarction are prolonged ischemia developing due to insufficient blood supply and then focal tissue necrosis. As a rule, it is a transmural (full-layer) infarction that affects the muscular layer of the heart wall - myocardium, as well as its epicardium and endocardium. Such an infarction develops with obstruction of the left anterior descending or right coronary artery.

Ischemic necrosis due to inadequate tissue blood supply leads to postinfarction cardiosclerosis - with replacement of muscle tissue by fibrous tissue and partial hypokinesia of the heart.

Within three months after myocardial infarction, a postinfarction left ventricular aneurysm may form in the anterior wall of the left ventricle of the heart (ventriculus sinister cordis), where the pressure of pumped blood is higher than in the right ventricle (ventriculus dexter). [1]

Acute cardiac aneurysm formation is noted in the acute period of infarction (after 48 hours or a few days), and chronic aneurysm formation is noted in the subacute period.

Aneurysm after extensive infarction involving significant areas of cardiac muscle tissue, extending to the interventricular septum as well as the lateral walls, occurs along with other complications including supraventricular arrhythmias, atrial rupture, cardiogenic shock, and vascular thromboembolism.

Useful information in the materials: Myocardial infarction: complications

Risk factors

Patients with cardiovascular atherosclerosis (including coronary atherosclerosis) and various cardiomyopathies including, CHD, myocardial dystrophy of various etiologies, unstable angina pectoris, and coronary circulatory insufficiency are at increased risk of postinfarction aneurysm formation.

Clinical practice supports a higher likelihood of left ventricular aneurysm formation within hours of infarction:

• at high blood pressure - due to excessive systolic tension of the ventricular wall;
• in case of preservation of contractility of myocardium surrounding the focus of ischemic necrosis;
• If ventricular dilatation (enlargement of the ventricles of the heart) is present.

Pathogenesis

How does an acute cardiac aneurysm form during a heart attack? Postinfarction heart aneurysm is formed when the part of the heart muscle affected by sclerosis expands, is replaced by fibrous (scar) tissue - due to apoptosis of its cells (cardiomyocytes), and the collagen extracellular matrix undergoes remodeling. This causes the formation of a pathologic area with an increased tendency of myocardium to stretch.

Although the affected area cannot participate in the contraction phase of the cardiac cycle (systole), blood pressure continues to act on it, resulting in limited bulging of the wall.

The pathogenesis of left ventricular aneurysm is similar: within a few days or weeks after the infarction, the pressure inside the ventricle created by heartbeats stretches the damaged area, where the structure of its wall tissue has changed due to the loss of muscle cells. And such an aneurysm is most often formed in the form of a thin-walled "pocket", which communicates with the rest of the ventricle with a wide neck. [2]

Also read - Acute and chronic cardiac aneurysms

Symptoms of the cardiac aneurysms after a heart attack.

The first signs of a postinfarction left ventricular aneurysm of significant size are a feeling of weakness and shortness of breath during exercise or while lying down.

Other symptoms are manifested by increased heart rate - ventricular tachycardia, disturbance of their rhythmicity - arrhythmia, as well as swelling of the ankles, feet and lower legs. [3]

On auscultation, breath sounds at the base of the lungs (due to pericardial friction) and an amplified third heart tone (S3) known as a "ventricular gallop" are heard. And an ECG over several weeks often shows persistent ST segment elevation.

In addition to the feeling of squeezing in the heart area, patients are bothered by attacks of left-sided chest pains that subside at rest.

Complications and consequences

Answering the question, what is the danger of a cardiac aneurysm after a heart attack, cardiologists list such its most frequent clinical consequences and complications as:

• congestive heart failure of a chronic nature;
• blood clots due to blood stasis at the site of the aneurysm, which can lead to stroke or other embolic complications;
• severe ventricular tachyarrhythmias that can cause cardiac arrest;
• Extravascular hemorrhage and backflow of blood through the mitral valve during systole - mitral regurgitation;
• ventricular rupture, cardiac tamponade and shock.

Diagnostics of the cardiac aneurysms after a heart attack.

The detection of cardiac aneurysms is carried out in much the same way as the diagnosis of the heart attack itself. See - Myocardial infarction: diagnosis

Laboratory tests include blood tests: general and biochemical, blood coagulation (coagulogram), creatine kinase and its MB fraction, myoglobin, lactate dehydrogenase 1(LDH1) and troponin T in blood. [4]

Instrumental diagnosis utilizes: electrocardiography (ECG), transthoracic echocardiography (echocardiography), chest x-ray, myocardial scintigraphy, coronary arteriography, left ventriculography.

Differential diagnosis

The differential diagnosis is between coronary artery aneurysm, myocardial rupture, pseudoaneurysm (fused to the pericardium), cardiac or ventricular diverticulum, and pulmonary embolism and acute aortic dissection.

Treatment of the cardiac aneurysms after a heart attack.

In symptomatic cardiac aneurysm after infarction, treatment aimed at limiting/eliminating the various clinical manifestations is mandatory. [5]

Medications used include:

• Cardiac glycoside Digoxin;
• potassium-saving diuretics (Hydrochlorothiazide or Hypothiazide);
• anticoagulants, specifically Warfarin;
• thrombolytic agents or antiaggregants: Aspirin, Clopidogrel, Medogrel, Diloxol and others;
• arrhythmia medications, which include beta-adrenoblockers: Vasocardin (Corvitol, Metoprolol, and other trade names), Propranolol, Carvedilol (Carvidox, Medocardil), and others;
• ACE (angiotensin-converting enzyme) inhibitors: Captopril, Berlipril (Enalapril, Renitec), Ramipril, Lisinopril (Zonixem), etc.

Read also - Drugs to prevent and correct heart failure

If the left ventricular aneurysm is large and dilated, as well as in cases of progressive complications (thromboembolism) and heart valve dysfunction (mitral regurgitation), surgical treatment may be performed.

Most often resort to open-heart surgery - surgical resection of a large aneurysm (aneurysmectomy) with removal of scar tissue, followed by reconstruction of the left ventricle - endoventricular circular plastic or artificial patch.

When indicated, aortocoronary bypass surgery may be performed in addition to this procedure - to improve the oxygen supply to the heart muscle. [6]

Prevention

Left ventricular aneurysm is one of the most severe complications of acute myocardial infarction. Therefore, prevention of its formation consists of strict compliance with the treatment plan for infarction, adherence to the medication regimen and observation by a cardiologist, as well as cardiac rehabilitation and lifestyle changes.

Forecast

In each case, the prognosis of this complication of myocardial infarction depends on many factors, including the patient's general history, the severity and area of cardiac muscle damage, the presence of symptoms and their intensity. Thus, for asymptomatic patients, the 10-year survival rate is 90%, while in the presence of symptoms it does not exceed 50%.

Left ventricular aneurysm after infarction is associated with high cardiac mortality, with some reports as high as 65% within three months and 80% within a year.