A hospitalized patient in their 80s became tachycardic. The patient initially presented with changes in mental status and generalized weakness, which were attributed to urinary tract infection. An electrocardiogram (ECG) showed a narrow-complex tachycardia with nonspecific ST-T wave changes (Figure, A). The patient was asymptomatic and denied having palpitations, chest pain, and shortness of breath; blood pressure was normal. The patient had a remote history of coronary artery disease. A left carotid sinus massage (CSM) was performed at the bedside (Figure, B).
Please finish quiz first before checking answer.
Read the answer below and download your certificate.
Read the discussion below and retake the quiz.
Carotid sinus massage was mentioned by Parry6 in 1799 as producing dizziness and slowing of the heart. The carotid sinus contains baroreceptors innervated by the carotid sinus nerve, a branch of the glossopharyngeal nerve. Increased pressure on the baroreceptors sends a signal to the solitary nucleus in the medulla of brainstem, which modulates the activity of the sympathetic and parasympathetic neurons in the medulla and pons. The end result is a reduction in blood pressure and slowing of the heart rate.
The ECG effects include sinus slowing; atrial conduction defects with changes in amplitude, duration, and morphology of the P wave; various degrees of AVB; asystole; and rarely, premature ventricular contractions. It is thought that right-sided CSM exerts more inhibitory effects on the sinus node compared with left-sided CSM, which slows conduction more so in the atrioventricular node.
Sign in to take quiz and track your certificates
JN Learning™ is the home for CME and MOC from the JAMA Network. Search by specialty or US state and earn AMA PRA Category 1 Credit(s)™ from articles, audio, Clinical Challenges and more. Learn more about CME/MOC
CME Disclosure Statement: Unless noted, all individuals in control of content reported no relevant financial relationships. If applicable, all relevant financial relationships have been mitigated.
Corresponding Author: Mazen M. Kawji, MD, Saint Margaret’s Health–Peru, 925 West St, Peru, IL 61354 (email@example.com).
Published Online: June 21, 2022. doi:10.1001/jamainternmed.2022.2078
Conflict of Interest Disclosures: None reported.
You currently have no searches saved.
You currently have no courses saved.