Myocardial Infraction and its Management

A heart attack or myocardial infarction (MI) is the permanent necrosis of the heart muscle brought on by persistent ischemia. MI typically results from an imbalance between oxygen supply and demand, which is most frequently brought on by plaque rupture with thrombus formation in a coronary vessel. This causes a portion of the myocardium to experience an acute reduction in blood supply as a result of being abruptly and severely oxygen-deprived.

Risk Factor

Pathophysiology

• Changes in the condition of plaque in the coronary artery
• Activates the platelets
• Formation of thrombus
• Coronary arteries occlusion
• Myocardial ischemia
• Decreased coronary artery blood supply than demand
• Myocardial cell death → Anaerobic glycolysis →lactic acid production →severe chest pain.
• Myocardial irritability → dysrhythmia →alter repolarization of myocardium→↑ST
• Decreased myocardial contractility →stimulation of CNS →↑`HR→ ↑oxygen demand → ↑afterload
• Decreased left ventricular function
• Decreased cardiac output
• Shock
• Death

Signs and Symptoms

The degree of symptoms might range from a diabetic patient who is asymptomatic to a cardiac arrest. Despite the wide range of presentations, the bulk of the symptoms and indicators are as follows:

• Pain usually substernal with radiation to the arm, jaw or back, severe, crushing, viselike w sudden onset, unrelieved by rest or nitrates
• Nausea and vomiting
• Skin-cool, clammy ashen, pallor, cyanosis
• Dysrhythmias, dyspnea, fever, diaphoresis
• Apprehension; fear of death and restlessness
• Initial increase in BP and pulse, with gradual drop BP
• Occasional findings; rales and crackles, pericard friction rubs

Dysrhythmias, heart failure, pulmonary edema, thrombophlebitis, cardiogenic shock, pericarditis, post-infarction angina from mitral valve insufficiency, ventricular rupture, and Dressler syndrome are among the complications of MI.

Diagnosis

MI diagnosis standards usual signs such as abnormal Q waves, ST elevation, or depression, together with an increase in cardiac troponin

• History:
  • Chest discomfort, types, nature of chest pain, aggravating and alleviating factors of pain, associated symptoms, prior episodes of angina, myocardial ischemia hypertension, diabetes mellitus etc
• Physical examination:
  • Vital signs, heart sound, lung sound, JVP, skin condition etc
• ECG to detect myocardial ischemia
• Cardiac enzyme:
  • CK-MB level rises within 3-12 hours of the onset of chest pain, reach peak values within 24 hours, and return to baseline after 48-72 hours (50-325 unit/L
  • Troponin levels increase within 3-12 hours from the onset of chest pain, peak at 24-48 hours, and return to baseline over 5-14 days.
  • LDH level rises 24 hrs after MI, peaks between 48- 72 hours and falls to normal in 7 days (normal value- troponin 1 < 0.6ng / m * l >1.5 ng/ml consistent MI), (troponin T > 0.1 - 0.2ng / m * l consis aMI)
  • Myoglobin level rises within 1 hour after cell death, peaks in 4-6 hours and return to normal within 24-36 hours
• Lipid profile, TC, DC, ESR
• Cardiac catheterization or angiogram: To confirm or rule out anatomy and degree of myocardial perfusion abnormalities
• Echocardiogram: To evaluate ventricular function and wall-motion abnormalities

Management

Goals: 

• Recovery of the oxygen supply-demand equilibrium in order to stop additional ischemia.
• Pain management.
• Prevention and care for side effects.
• Rest: Lowers the oxygen demand on the myocardium.
• 02 treatment: Keeping SPO2 above 90%.
• Usually, morphine (an opioid) is administered intravenously (I/V) to treat pain and anxiety. Monitoring breathing is necessary because morphine may depress the respiratory center.
• Nitroglycerine Isordil, GTN, and mononitrate are examples of nitrates (nitroglycerine); they have vasodilator effects.
• Aspirin: 75–150 mg of a maintenance dose and 150–325 mg of a loading dose (chewed).
• High-potency statins that need to be constantly used to lower cholesterol include atorvastatin 80 mg and rosuvastatin 40 mg.
• Propanol, inderal, and atenolol are examples of beta blockers that reduce myocardial oxygen consumption by lowering heart rate, blood pressure, and myocardial contraction force. Keep an eye on your blood pressure, heart rate, and other vital signs.
• Heparin or small molecule 1 mg/kg body weight of heparin.
• Enalapril and captopril are angiotensin converting enzyme (ACE) inhibitors, which are used to stop the conversion of angiotensin I to angiotensin II. They lower blood pressure and cause the kidneys to eliminate Na+ H2O, which reduces the heart's need for oxygen. It guards against cardiac failure.
• After nitrates and beta blockers, calcium channel blockers may be employed. Inotropes and antiarrhythmics may be utilized in accordance with the ECG, BP, and pulse.
• If a patient experiences arrhythmias, a defibrillator may be used to restore a normal rhythm.A temporary pacemaker may be required if medicinal therapy is insufficient to control an arrhythmia.
• Fibrinolytic/thrombolytic therapy: Most commonly, streptokinase (1500,000 IU) is utilized, and 1000 ml of NS is dissolved in it over the course of 30 to 60 minutes. It dissolves the thrombus in a coronary artery and restores blood flow to the area, making it useful for chest pain that has lasted less than 12 hours. Keep a close eye out for bleeding.
• H2 antagonist.
• Stool softeners, which lessen the strain on the heart during feces.
• At night, sedative, anxiolytic, and hypnotic medications.
• Diuretics: can aid in eliminating extra fluids that occasionally build up when the heart is not working efficiently. They are often ingested, causing the body to eliminate fluids through urination.
• Antidiabetics to lower fever.

If ST elevation is detected on the ECG, urgent IV thrombolysis or primary PCI should be performed.

Medicines: 

The" MONABHAI" principle

• M-Morphine
• O-Oxygen
• N-Nitrate
• A- Antiplatelets
• B-Beta blockers
• H-Heparin
• A- Atorvastatin
• I- Inotropes (dopamine, dobutamine)

Surgical Management

• Percutaneous coronary intervention/ percutaneous transluminal coronary angioplasty (PCI/PTCA).
• Coronary artery bypass graft (CABG)

Nursing Management

The focus of the plan of care for MI patient includes:

• Recognize and address dysrhythmias that could be fatal.
• Keep an eye out for issues caused by lower productivity.
• Maintain a therapeutic environment for essential care.
• Determine how the MI affected the client's and their close relationships on a psychological level.
• Inform the patient about adjusting their lifestyle and receiving post-MI care.

Assessment

• History of chest pain, discomfort, difficulty in breathing, palpitation, faintness etc.
• Physical examination- position of the patient, sweating, BP, pulse, temperature, heart sound
• ECG, Cardiac enzyme

Nursing diagnosis

• Acute pain (chest) from myocardial ischemia due to coronary artery obstruction is characterized by loss or restriction of blood supply to a portion of the myocardium and necrosis; symptoms include diaphoresis, nausea, vomiting, palpitations, and pain that radiates to the arms.
• Reduced cardiac output due to myocardial damage, as evidenced by changes in LOC, weakness, numbness in the extremities, and other symptoms.
• Reduced Pa02, altered heart rate, blood pressure, temperature, skin color change, dyspnea, and impaired capillary refill are all signs of poor gas exchange and cardiac output.
• Unsuccessful RT of planned lifestyle change.
• Hospitalization-related anxiety and mortality fears.
• High chance of intolerance to activities Disproportion between supply and demand, RT.
• High risk of bowel elimination changes (constipation) Rest in bed, medicines, NPO, and soft food.
• Health maintenance changes RT MI and the effects of a lifestyle change.
• Lack of expertise in RT diagnosis, treatment, etc.

Nursing Interventions

• The creation of a patent IV line Provide morphine sulfate IV as prescribed for pain treatment.
• Give 02 as directed to treat dyspnea and stop dysrhythmias. Reduce heart workload by providing bed rest in the semi-Fowler position.
• Track hemodynamic and ECG procedures Use antiarrhythmic medications as directed.
• Conduct the evaluation and finish the pulmonary/cardiovascula.
• Observe your urine discharge.
• Keep up a complete liquid diet while gradually increasing your sodium intake.
• Maintain a calm atmosphere.
• Use stool softeners as directed to promote bowel movement and avoid straining. alleviate apprehension related to the CCU atmosphere.
• Administer thrombolytics (streptokinase) as directed and administer anticoagulants as directed.
• Provide teaching on:
  • MI effects and healing protocol treatment.
  • Medication schedule, including brand name, dose, and side effects.
  • Low salt, low cholesterol, and no caffeine are allowed on the diet.
  • Importance of taking part in a program of progressive exercise.
  • Returning to sexual activity as directed by a doctor (usually 4-6 weeks).
  • The following symptoms must be reported: intensified, ongoing chest discomfort; dyspnea; weakness; exhaustion; palpitations; and lightheadedness.
  • Enrollment in a cardiac rehabilitation program for the patient.