What are three board-style questions related to mechanical complications of myocardial infarction (heart attack)?

From the Guidelines

Mechanical complications of myocardial infarction are life-threatening and require prompt detection and management, with the most recent guidelines emphasizing the importance of immediate echocardiographic assessment when mechanical complications are suspected 1. Here are three board-style questions addressing mechanical complications of myocardial infarction:

• Question 1: A 68-year-old man presents with sudden onset severe dyspnea and hypotension 5 days after an inferior wall myocardial infarction. Physical examination reveals a new harsh holosystolic murmur at the left sternal border that increases with inspiration. What is the most likely diagnosis? Answer: Ventricular septal rupture. This complication typically occurs 3-5 days post-MI and presents with sudden hemodynamic compromise and a new holosystolic murmur. The murmur of ventricular septal rupture increases with inspiration, distinguishing it from mitral regurgitation. Urgent echocardiography confirms the diagnosis, showing a defect in the interventricular septum with left-to-right shunting. Management includes immediate stabilization with inotropes, vasodilators, and intra-aortic balloon pump, followed by surgical repair, as recommended by the 2014 ESC/EACTS guidelines on myocardial revascularization 1.
• Question 2: A 72-year-old woman develops cardiogenic shock and pulmonary edema 2 days after an anterolateral myocardial infarction. Examination reveals a new holosystolic murmur at the apex radiating to the axilla. What is the most likely diagnosis? Answer: Papillary muscle rupture causing acute mitral regurgitation. This serious complication typically occurs 2-7 days post-MI and presents with sudden heart failure and a new apical holosystolic murmur radiating to the axilla. Posteromedial papillary muscle rupture is more common due to its single blood supply from the right coronary artery. Management includes stabilization with afterload reduction, inotropic support, and mechanical ventilation if needed, followed by urgent surgical mitral valve repair or replacement, as recommended by the 2011 ACCF/AHA guideline for coronary artery bypass graft surgery 1.
• Question 3: A 65-year-old man presents with persistent chest pain, jugular venous distention, and pulsus paradoxus 3 days after a large anterior wall myocardial infarction. Echocardiography shows a pericardial effusion with right ventricular diastolic collapse. What is the most likely diagnosis? Answer: Left ventricular free wall rupture with contained cardiac tamponade. This fatal complication typically occurs 1-5 days post-MI and presents with persistent chest pain, hypotension, and signs of tamponade including jugular venous distention and pulsus paradoxus. It most commonly affects the anterior or lateral wall following transmural infarction. Management includes immediate pericardiocentesis for stabilization followed by emergency surgery with patch repair of the ventricular wall, as emphasized by the 2021 ACC/AHA/SCAI guideline for coronary artery revascularization 1. The key to managing these complications is prompt recognition and intervention, with a focus on stabilizing the patient and addressing the underlying mechanical issue, as highlighted by the 2017 ESC guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation 1.

From the Research

Mechanical Complications of Myocardial Infarction

The following are three board-style questions related to mechanical complications of myocardial infarction (heart attack):

• What is the role of intra-aortic balloon support in managing mechanical complications of acute myocardial infarction, such as papillary muscle avulsion and free wall rupture 2?
• How do the predictors, clinical features, diagnostic, and management strategies differ for various mechanical complications of myocardial infarction, including rupture of a papillary muscle, ventricular septum, and free wall 3?
• What are the long-term outcomes of surgical management for postinfarction mechanical complications, such as free wall rupture, ventricular septal defect, papillary muscle rupture, and pseudoaneurysm, and how do they compare to outcomes with mechanical circulatory support devices 4, 5?

Diagnostic and Management Strategies

Diagnostic investigations, such as echocardiography, play a crucial role in evaluating mechanical complications of myocardial infarction 3.

• Urgent surgical repair is often required for mechanical complications, although mechanical circulatory support devices can provide a bridge to definitive therapy 3, 5, 6.
• The use of mechanical circulatory support devices has increased over time, but in-hospital mortality rates remain high even among patients who receive these devices 5.

Interventional Management

Interventional management of mechanical complications in acute myocardial infarction, including transcatheter interventions for ventricular septal rupture or acute mitral regurgitation, has improved patient outcomes 6.

• Mechanical circulatory support devices, especially those with minimally invasive implantation, can provide stability until definitive treatment can be applied 6.