posteroinferior myocardial infarction

Posteroinferior Myocardial Infarction (MI)

A posteroinferior MI occurs when the posterior and inferior walls of the left ventricle are affected, usually due to the occlusion of the right coronary artery (RCA) or left circumflex artery (LCX). This type of infarction is relatively rare compared to anterior and inferior infarctions.

Causes

The posteroinferior MI is often caused by the blockage of one of the two main arteries that supply blood to the heart, specifically:

• The right coronary artery (RCA)
• The left circumflex artery (LCX)

Characteristics

A posteroinferior MI can be identified by several characteristic features, including:

• Electrocardiogram (ECG) changes: Tall anterior R waves and loss of electrical forces in a dorsal direction.
• Physical findings: A sudden appearance of a pansystolic or early systolic murmur radiating to the left axilla or to the base or both.

Complications

A posteroinferior MI can lead to complications such as:

• Left ventricular dysfunction: Due to the larger area of myocardial damage.
• Increased risk of heart failure: As a result of the infarction and subsequent left ventricular dysfunction.

References

• [5] Acute posterior-inferior myocardial infarction (MI) is usually due to the occlusion of the right coronary artery (RCA) or left circumflex artery (LCX).
• [9] Posterior wall ST-elevation myocardial infarction commonly occurs as a complication (or extension) of acute inferior wall STEMI.
• [3] Posterior myocardial infarction (PMI) is relatively rare compared with anterior and inferior infarction and is usually associated with infarction of other areas.

Posterior-inferior Myocardial Infarction (MI) Signs and Symptoms

A posterior-inferior myocardial infarction is a type of heart attack that affects the back and lower part of the heart. The symptoms can be different from those experienced in other types of MI.

• Chest Pain: Severe and prolonged chest pain is a common symptom, often located in the middle or lower part of the chest and radiating to the back, jaw, or left arm [15].
• Pain around the Shoulder Blades: Some people may experience pain or pressure around their shoulder blades, which can be a sign of posterior MI [9].
• ST Depression: On an electrocardiogram (ECG), ST depression in the right precordial leads is often seen in posterior MI [7].
• Tall Anterior R Waves: A tall anterior R wave on an ECG can indicate posterior MI, especially if it's new and not secondary to other conditions [8].
• Reciprocal Depression of the ST Segment: There may be reciprocal depression of the ST segment, although this is often very slight or absent [2].

Other Possible Symptoms

In addition to these specific signs and symptoms, patients with posterior-inferior MI may also experience:

• Shortness of Breath: Some people may feel short of breath due to fluid buildup in the lungs.
• Lightheadedness or Dizziness: A decrease in blood pressure can cause lightheadedness or dizziness.
• Rapid or Irregular Heartbeat: An abnormal heart rhythm can be a sign of posterior MI.

Important Note

Posterior-inferior MI often co-occurs with inferior or inferolateral MI, making diagnosis challenging. If you suspect someone is experiencing a heart attack, call emergency services immediately.

Treatment of Posteroinferior Myocardial Infarction

The treatment of posteroinferior myocardial infarction (MI) is similar to that of other types of heart attacks and focuses on restoring blood flow to the affected area of the heart. According to various medical sources [10, 11], early and efficient coronary reperfusion is the main therapeutic goal in acute MI, especially in ST-segment elevation MI (STEMI).

Reperfusion Treatment

The first randomized control trial demonstrated the superiority of primary percutaneous coronary intervention (PCI) over fibrinolysis [10]. Fibrinolysis had been established as the mainstay in reperfusion treatment until this study. Primary PCI is now considered the preferred method for restoring blood flow to the heart muscle.

Pharmacological Therapy

In addition to reperfusion treatment, pharmacological therapy plays a crucial role in managing posteroinferior MI. Blood tests, such as troponin levels, are essential in confirming the diagnosis of myocardial infarction and evaluating the extent of heart muscle damage [10]. Cardiac enzymes and biomarkers help guide treatment decisions.

Treatment Goals

The primary goals of treatment for posteroinferior MI include:

• Restoring blood flow to the affected area of the heart
• Reducing the size of the infarcted area
• Preventing further cardiac damage
• Improving left ventricular (LV) systolic function and survival [11]

References

[10] Cardiac enzymes and biomarkers: Blood tests, such as troponin levels, are essential in confirming the diagnosis of myocardial infarction and evaluating the extent of heart muscle damage. Treatment: The treatment of PMI is similar to that of other types of heart attacks and focuses on restoring blood flow to the affected area of the heart.

[11] Most of these deaths are arrhythmic in etiology. Because early reperfusion treatment of patients with acute MI improves LV systolic function and survival, every effort must be made to minimize prehospital delay.