Myocardial bridging

Myocardial bridging is a congenital condition characterized by a segment of a coronary artery that goes intramurally through the myocardium rather than resting on its surface. This condition is significant because it can lead to various clinical manifestations, including angina pectoris, myocardial infarction, arrhythmias, and even sudden cardiac death, particularly under conditions of increased heart rate which compresses the bridged segment of the artery, potentially leading to myocardial ischemia.

Etiology and Pathophysiology

Myocardial bridging typically involves the left anterior descending (LAD) artery, although it can affect any coronary artery. During systole, the myocardial muscle over the bridged segment contracts, potentially compressing the artery and obstructing blood flow. This compression is usually relieved during diastole, but in some cases, it can lead to compromised blood flow to the myocardium, resulting in ischemia.

Clinical Presentation

Patients with myocardial bridging may be asymptomatic or present with symptoms ranging from chest pain to severe cardiac events. Symptoms often mimic those of coronary artery disease and may include:

• Angina pectoris
• Palpitations
• Dyspnea on exertion
• Syncope

Diagnosis

Diagnosis of myocardial bridging is challenging due to its asymptomatic nature in many individuals. It is often discovered incidentally during coronary angiography, which remains the gold standard for diagnosis. Other diagnostic tools include:

• Computed tomography coronary angiography (CTCA)
• Magnetic resonance imaging (MRI)
• Intravascular ultrasound (IVUS)

Management

Management of myocardial bridging focuses on symptom relief and prevention of complications. Treatment options vary based on the severity of symptoms and may include:

• Medical therapy with beta-blockers or calcium channel blockers
• Percutaneous coronary intervention (PCI) with stenting in severe cases
• Surgical myotomy in refractory cases

Prognosis

The prognosis for individuals with myocardial bridging is generally favorable, especially for those who are asymptomatic or have mild symptoms. However, patients with significant obstruction and symptoms may have a higher risk of adverse cardiac events.

Epidemiology

Myocardial bridging is present in a significant portion of the population, with autopsy studies revealing a prevalence of up to 25%. However, the majority of these cases are asymptomatic and do not require treatment.

Conclusion

Myocardial bridging is a congenital anomaly of the coronary arteries that can lead to significant cardiac events in a subset of patients. While many individuals remain asymptomatic, those with symptoms require careful evaluation and management to prevent complications.