A 20-year-old man develops substernal chest pain and palpitations, followed by brief syncope while playing soccer. The patient is rushed to the emergency department where he reports feeling fine. He describes previous episodes of "chest pressure" while overexerting himself, after which he needs to stop and rest. He has had no previous episodes of syncope. Medical history is unremarkable. The patient does not use tobacco, alcohol, or illicit drugs. There is no family history of coronary heart disease or sudden death. Blood pressure is 122/78 mm Hg and pulse is 78/min. Cardiac examination reveals no murmurs in both the supine and standing positions. ECG shows normal sinus rhythm with a rate of 72/min. No ST-segment or T-wave abnormalities are present. The QTc interval is 410 msec. The patient is recommended to avoid exercise until he can undergo further workup, but 2 days later he collapses and dies while jogging. Which of the following is the most likely diagnosis?

Question

A 20-year-old man develops substernal chest pain and palpitations, followed by brief syncope while playing soccer.  The patient is rushed to the emergency department where he reports feeling fine.  He describes previous episodes of "chest pressure" while overexerting himself, after which he needs to stop and rest.  He has had no previous episodes of syncope.  Medical history is unremarkable.  The patient does not use tobacco, alcohol, or illicit drugs.  There is no family history of coronary heart disease or sudden death.  Blood pressure is 122/78 mm Hg and pulse is 78/min.  Cardiac examination reveals no murmurs in both the supine and standing positions.  ECG shows normal sinus rhythm with a rate of 72/min.  No ST-segment or T-wave abnormalities are present.  The QTc interval is 410 msec.  The patient is recommended to avoid exercise until he can undergo further workup, but 2 days later he collapses and dies while jogging.  Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

Explanation: 11ec2b69_c111_758a_8f63_d3f6591fbd7b_MD0005_00 This patient experienced sudden cardiac death (SCD) most likely due to anomalous aortic origin of a coronary artery (AAOCA). In younger patients (age <35), SCD is usually due to underlying structural heart disease, with ventricular tachyarrhythmia as the most common terminal event. The high-risk types of AAOCA are among the most common causes of SCD in young athletes; in one study, autopsies on military recruits with SCD revealed AAOCA to be the cause in about one-third of cases. Two types of AAOCA commonly associated with SCD are the left main coronary artery originating from the right aortic sinus and the right coronary artery originating from the left aortic sinus. These defects create sharp curvature of the anomalous artery, making it less amenable to high-volume flow. In addition, the anomalous artery passes between the aorta and the pulmonary artery, making it susceptible to external compression during exercise. Patients with AAOCA may experience exertional angina, lightheadedness, or syncope; however, some patients experience SCD without any premonitory symptoms. Resting ECG is typically unremarkable. Transthoracic echocardiography can sometimes make the diagnosis, but it can also miss or inaccurately characterize AAOCA. CT coronary angiography or coronary magnetic resonance angiography provide the best visualization of coronary anatomy, and are the diagnostic tests of choice in patients with suspected AAOCA. (Choices B and C) Brugada syndrome and long QT syndrome are associated with an increased risk of SCD; however, the lack of characteristic ECG findings for Brugada syndrome (right bundle branch block and ST-segment elevation in leads V1-V3) or long QT syndrome (QTc >450 msec in men or >470 msec in women) makes these diagnoses less likely. (Choice D) Hypertrophic cardiomyopathy is the most common cause of SCD in young athletes in the United States; however, it is unlikely in the absence of a systolic murmur that increases in intensity with standing. increases in intensity (Choice E) Wolff-Parkinson-White syndrome is an uncommon cause of SCD. Resting ECG typically shows a short PR interval with slurred upstroke and widening of the QRS complex. Educational objective: Anomalous aortic origin of a coronary artery is a common cause of sudden cardiac death in young athletes. Patients may have premonitory symptoms of exertional angina, lightheadedness, or syncope. ECG is typically unremarkable and transthoracic echocardiography or coronary angiographic imaging is required for diagnosis. References: Sudden cardiac death in athletes. (http://www.ncbi.nlm.nih.gov/pubmed/24350833) Sudden death in young adults: a 25-year review of autopsies in military recruits. (http://www.ncbi.nlm.nih.gov/pubmed/15583223)

A 20-Year-Old Man Develops Substernal Chest Pain and Palpitations, Followed