WBR0460
| Author | [[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Anatomy |
| Sub Category | SubCategory::Cardiology |
| Prompt | [[Prompt::A 56-year-old male presents to the emergency room with complaints of chest pain and shortness of breath. Blood work-up reveals elevated levels of Troponin and an electrocardiogram (ECG) demonstrates ST-segment elevation in more than one lead, leading you to diagnose him with ST-elevation myocardial infarction (STEMI). Cardiac catheterization displays occlusion of the right coronary artery (RCA). Which of the following components of the heart is most likely affected as a result of the patient’s STEMI?]] |
| Answer A | AnswerA::Anterior interventricular septum |
| Answer A Explanation | AnswerAExp::The LAD usually provides the blood supply to the anterior interventricular septum. |
| Answer B | AnswerB::Left atrium |
| Answer B Explanation | AnswerBExp::The left main coronary artery usually provides the blood supply to the left atrium. |
| Answer C | AnswerC::Anterolateral papillary muscle |
| Answer C Explanation | AnswerCExp::The anterior papillary muscle most commonly receives a dual blood supply from the LAD and the LCx. |
| Answer D | AnswerD::Sinoatrial (SA) node |
| Answer D Explanation | AnswerDExp::The RCA usually provides the blood supply to the SA node. |
| Answer E | AnswerE::Apex |
| Answer E Explanation | AnswerEExp::The apex of the heart receives a dual blood supply from the LAD and the PDA. The LDA provides the majority of the blood supply to the apex. |
| Right Answer | RightAnswer::D |
| Explanation | [[Explanation::The cardiac circulation is characterized by two main arteries, containing several branches as they descend from their sinuses at the base of the aorta, which are the left main artery and the right coronary artery (RCA). The left main artery is divided into the left anterior descending (LAD) artery, also called the “widow maker” because it is the most common artery to be occluded in myocardial infarction and subsequent death, and the Left circumflex (LCx) artery. The LCx gives rise to the posterior descending artery (PDA) in approximately 35% of cases.
The RCA, which supplies the SA node, gives rise to the PDA in more than 65% of the cases. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::coronary artery, WBRKeyword::sinoatrial node, WBRKeyword::SA, WBRKeyword::blood supply, WBRKeyword::cardiovascular system, WBRKeyword::cardiology |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |