A 65-year-old man is brought to the emergency department after a syncopal episode. He was sitting at the kitchen table when his wife saw him suddenly slump over. She estimates he was unresponsive for 30 seconds. He felt "completely fine" after the incident and was not confused. The patient sustained no trauma and does not remember any symptoms prior to the event. He has a history of benign prostate hyperplasia, hypertension, and a myocardial infarction requiring stent placement 3 years ago. He takes aspirin, carvedilol, atorvastatin, ramipril, and tamsulosin. Temperature is 36.7 C (98 F), blood pressure is 130/80 mm Hg, pulse is 60/min, and respirations are 14/min. Pulse oximetry shows 96% on room air. Physical examination reveals moist mucous membranes, normal jugular venous pressure, clear lung fields, and normal first and second heart sounds. There is trace edema of the lower extremities bilaterally. Neurologic examination is within normal limits. Complete blood count, basic metabolic panel, troponin, and chest x-ray are normal. ECG reveals normal sinus rhythm, Q waves in leads V2 to V4, normal QRS complex duration, and normal QTc interval. Transthoracic echocardiogram shows an apical wall motion abnormality with ejection fraction of 40%. Which of the following is the most likely cause of this patient's syncope?

Question

A 65-year-old man is brought to the emergency department after a syncopal episode.  He was sitting at the kitchen table when his wife saw him suddenly slump over.  She estimates he was unresponsive for 30 seconds.  He felt "completely fine" after the incident and was not confused.  The patient sustained no trauma and does not remember any symptoms prior to the event.  He has a history of benign prostate hyperplasia, hypertension, and a myocardial infarction requiring stent placement 3 years ago.  He takes aspirin, carvedilol, atorvastatin, ramipril, and tamsulosin.  Temperature is 36.7 C (98 F), blood pressure is 130/80 mm Hg, pulse is 60/min, and respirations are 14/min.  Pulse oximetry shows 96% on room air.  Physical examination reveals moist mucous membranes, normal jugular venous pressure, clear lung fields, and normal first and second heart sounds.  There is trace edema of the lower extremities bilaterally.  Neurologic examination is within normal limits.  Complete blood count, basic metabolic panel, troponin, and chest x-ray are normal.  ECG reveals normal sinus rhythm, Q waves in leads V2 to V4, normal QRS complex duration, and normal QTc interval.  Transthoracic echocardiogram shows an apical wall motion abnormality with ejection fraction of 40%.  Which of the following is the most likely cause of this patient's syncope?

Quizplus · Accepted Answer

Explanation: 11ec2b69_be66_799b_8f63_1d6eabccd79e_MD0005_00 This patient most likely experienced cardiac syncope due to ventricular tachycardia (VT); scarring from previous myocardial infarction (evidenced by Q waves on ECG and wall motion abnormality on echocardiogram) increases the risk of ventricular arrhythmia. Syncope due to VT usually has no warning symptoms (other than palpitations in some patients). The arrhythmia spontaneously terminates within 1-2 minutes, resulting in restoration of cardiac output and rapid patient recovery with no residual symptoms. The recognition of cardiac syncope is crucial because these patients are often at high risk of sudden cardiac death. Absence of autonomic prodromal symptoms (eg, nausea, pallor, diaphoresis, feeling of warmth), which are usually present prior to a benign syncope event, suggests cardiac syncope. The presence of underlying structural heart disease (eg, ischemic scarring, cardiomyopathy with low ejection fraction) specifically suggests cardiac syncope due to VT. This patient warrants further evaluation with electrophysiology testing, likely followed by placement of an implantable cardiac defibrillator. (Choice A) Acute pulmonary embolism presents with syncope in approximately 15% of cases. However, absence of jugular venous distension, significant hypoxemia, and findings of right ventricular strain on echocardiogram makes the diagnosis less likely. (Choice B) Carotid sinus hypersensitivity refers to recurrent episodes of syncope triggered by pressure on the carotid sinuses (eg, due to a tight collar). The syncope is reflex mediated and often preceded by autonomic prodromal symptoms. (Choice C) Syncope due to orthostatic hypotension can result from medication adverse effects (eg, tamsulosin, an alpha-1 antagonist). It usually occurs with a change in position from supine or sitting to standing. Syncope that occurs after going from standing to sitting position is not consistent with orthostatic syncope. (Choice D) Vasovagal syncope is commonly triggered by prolonged standing, emotional stress, or painful stimuli, and is usually accompanied by an autonomic prodrome. This patient's history of ischemic heart disease and absence of a prodrome make cardiogenic syncope more likely. Educational objective: Cardiac syncope due to ventricular tachycardia is suggested by the presence of underlying structural heart disease and the abrupt onset of syncope without prodrome. Patients with cardiac syncope are at risk of sudden cardiac death and require definitive evaluation and management. References: Guidelines for the diagnosis and management of syncope. (http://www.ncbi.nlm.nih.gov/pubmed/19713422) Evaluation and management of syncope. (http://www.ncbi.nlm.nih.gov/pubmed/21135810) Syncope: a review of emergency department management and disposition. (http://www.ncbi.nlm.nih.gov/pubmed/27752576)

A 65-Year-Old Man Is Brought to the Emergency Department After