Disease Description (Causes and Symptoms)
Old myocardial infarction (chronic myocardial infarction) refers to a condition in which necrosis occurred in a specific area of the myocardium in the past due to coronary artery occlusion, and that area has become scarred and fibrotic. The main causes and pathophysiology are as follows.
- Cause: The main cause is acute coronary artery occlusion (acute myocardial infarction) due to coronary artery stenosis and thrombosis resulting from atherosclerosis. Risk factors include hyperlipidemia, smoking, diabetes, hypertension, abdominal obesity, lack of exercise, and stress.
- Pathophysiology: After an acute infarction, necrotic myocardium is replaced by scar tissue and loses its contractile function. As a result, the risk increases for localized or generalized reduction in myocardial contractility, left ventricular enlargement (remodeling), regional wall-motion abnormalities, hemodynamic changes, and arrhythmias.
- Main symptoms: During the chronic phase, symptoms may include chest pain (in the form of angina), chest tightness, a history of chest pain that persisted even without exertion, shortness of breath (during exercise or at rest), fatigue, arrhythmias (palpitations, syncope), and referred pain (to the jaw, neck, left arm, etc.). People with diabetes and others may not experience chest pain (silent myocardial infarction).
Treatment Methods and Precautions
- Drug therapy (standard treatment)
- Antiplatelet agents: Aspirin (usually maintained long term) ± P2Y12 inhibitors (such as clopidogrel and ticagrelor; the duration is determined according to guidelines after revascularization or during the acute phase).
- Hyperlipidemia treatment: High-intensity statins (e.g., atorvastatin and rosuvastatin). Ezetimibe or PCSK9 inhibitors may be considered if necessary.
- Beta-blockers: Used to improve ischemic symptoms, heart rate, and left ventricular ejection fraction.
- ACE inhibitors or ARBs: Used to suppress left ventricular remodeling and prevent heart failure and recurrence (particularly when LVEF is reduced).
- Diuretics and MRAs (such as spironolactone): Used to control symptoms of left-sided heart failure and improve prognosis (when indicated).
- Antianginal agents: Nitroglycerin (for relief of acute symptoms) and calcium channel blockers (if necessary).
- Anticoagulation (selective): Indicated when left ventricular thrombus is present or in certain cases of atrial fibrillation.
- Procedures/Surgery
- Percutaneous coronary intervention (PCI, stent placement): Used when restenosis or symptoms of the coronary arteries persist or revascularization is needed.
- Coronary artery bypass grafting (CABG): Used for multivessel disease, left main coronary artery disease, complex lesions, or when PCI is inappropriate.
- Other: Removal of left ventricular thrombus and pacemaker/implantable cardioverter-defibrillator (ICD) placement (when ventricular function is severely reduced and there is a risk of recurrent life-threatening arrhythmias).
- Nonpharmacological treatment and rehabilitation
- Cardiac rehabilitation (exercise therapy, education, and risk-factor management): Important for reducing the risk of recurrence and restoring function.
- Lifestyle management: Smoking cessation, weight loss, and a low-sodium, low-fat, Mediterranean-style diet are recommended; regular aerobic exercise (beginning after consultation with a doctor); and achieving target blood pressure, blood glucose, and lipid levels.
- Precautions (self-management and risks)
- NSAIDs (nonsteroidal anti-inflammatory drugs) may increase cardiovascular risk, so consult a doctor if they are needed.
- Do not stop taking medications without a doctor's instructions, as discontinuation may increase the risk of acute worsening or recurrence.
- If heart failure or reduced cardiac output is present, caution is needed when using certain medications (e.g., some antiarrhythmic drugs).
- Infections (such as influenza) increase the burden on the cardiovascular system, so vaccinations are recommended (including influenza and pneumococcal vaccines).
Checklist Before an Outpatient Visit (Including Examples of Items to Prepare and Questions)
Items to prepare
- A list of all currently used medications (including doses and administration times), including supplements, herbal medicines, and OTC medications
- Previous test results: electrocardiogram (ECG), echocardiogram (Echo), coronary angiography (Angiogram), recent blood tests (lipids, blood glucose, kidney function), and records of surgeries/procedures
- Symptom diary: when symptoms began, frequency, triggers, duration, relieving factors (including whether nitroglycerin was used)
- Lifestyle information: smoking status, amount of alcohol consumed, amount of exercise, and eating habits
- Allergies and past medical history (especially bleeding disorders, asthma, kidney failure, etc.)
- Records of blood pressure, weight, and heart rate (the most recent measurements available)
Information that is helpful to provide to the doctor during an outpatient visit (checklist)
- When the previous acute myocardial infarction occurred (the date/year, if possible)
- Whether and when a procedure (PCI/stent) or surgery (CABG) was performed
- Whether there have been changes in shortness of breath, syncope, dizziness, or chest pain
- Symptoms suspected to be medication side effects (dizziness, cough, muscle pain, etc.)
Emergency symptoms (immediate emergency room visit recommended)
- Newly occurring or worsening chest pain that lasts for more than 10–20 minutes and does not improve with rest or nitroglycerin
- Loss of consciousness or repeated syncope, severe shortness of breath, cyanosis, or markedly low blood pressure
Examples of General Questions to Ask the Doctor
- What are the main side effects of this medication (or combination), and how should I respond if they occur?
- What should my target LDL, blood pressure, and blood glucose levels be?
- Given my current condition, do I need revascularization (PCI or CABG)?
- Where and how can I start a cardiac rehabilitation program?
- When will it be safe to resume exercise, driving, sexual activity, and work?
Examples of Disease-Specific Questions
- What is my left ventricular ejection fraction (LVEF) on my most recent echocardiogram, and is it at a level that requires ICD placement (e.g., is LVEF ≤35%)?
- Were there signs of a thrombus in the left ventricle or findings suggesting thrombus formation? Do I need anticoagulant treatment?
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