Name:
A 43-Year-Old with Palpitations
Description:
A 43-Year-Old with Palpitations
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Duration:
T00H04M14S
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Content URL:
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Upload Date:
2022-02-28T00:00:00.0000000
Transcript:
Language: EN.
Segment:0 .
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CATHY: Hi. Welcome to Harrison's Podclass where we discuss important concepts in internal medicine. I'm Cathy Handy. And I'm Charlie Wiener and we're coming to you from the Johns Hopkins School of Medicine. Welcome to Harrison's Podclass. This is Episode 10: A 43-year-old with Palpitations. I'll read the question. A 43-year-old woman is seen in the emergency department after sudden onset of palpitations, 30 minutes prior to her visit. She was seated at her work computer when the symptoms began.
CATHY: Aside from low back pain, she's otherwise healthy. In triage, her heart rate is 178 beats per minute and her blood pressure is 98/56 with normal oxygen saturation. On physical examination, she has a frog sign in her neck in tachycardia but is otherwise normal. ECG shows a narrow complex tachycardia without identifiable P waves. Which of the following is the most appropriate first step to manage her tachycardia? Option A: 5mg of metoprolol IV; Option B: 6mg of adenosine IV; Option C: 10mg of verapamil IV; Option D: Carotid sinus massage; Option E: DC cardioversion using 100 Joules.
CATHY: So Cathy, first of all, what is the frog sign and what does it signify?
CATHY: The frog sign is seen during your neck vein examination, and it appears as if the veins in the neck are flapping or bulging like you would see in a frog. These are due to accentuated or cannon A waves that occur during simultaneous atrial and ventricular contraction against the closed tricuspid valve.
CHARLIE: Okay, so what do you make from this case?
CATHY: She's mildly symptomatic from her palpitations and she has a borderline blood pressure. Her EKG shows a regular narrow complex tachycardia without P waves, and that's crucial to understanding the diagnosis and what the therapeutic plan would be in this patient.
CHARLIE: So, what dysrhythmia do you think she has?
CATHY: This patient has classic signs and symptoms of an AV nodal reentry tachycardia. She's not hemodynamically unstable, so the first-line therapy would be to do maneuvers to increase her vagal tone. Often, this is all that's required to return the patient to normal sinus rhythm. Because the increased vagal tone will slow the sinus and AV nodal conduction and will lower the heart rate and atrial arrhythmias. It doesn't work for ventricular dysrhythmias. So, the best answer in this case is D, carotid sinus massage which is one way to increase the vagal tone.
CHARLIE: What if that simple intervention does not work in a patient such as this?
CATHY: Again, if the patient's hemodynamically stable, you have more choices. So, you can use an IV, short acting medication would be really my first step. Adenosine 6 to 12mg is usually the first choice. If adenosine fails, IV beta-blockers such as metoprolol or you could use calcium channel blockers such as verapamil, as well. These often will convert the patient to sinus rhythm, but at least will slow the heart rate.
CHARLIE: What about if the patient is hemodynamically unstable?
CATHY: So, if the patient has a dangerously low blood pressure or any mental status changes or other systemic effects, you'd wanna do synchronized cardioversion with 100 to 200 Joules. Sometimes, when the sinus massage or IV medications haven't worked, she may need to do this anyways, but you can usually do it in a more elective setting.
CHARLIE: Great, so the teaching point here is that the physical examination can once again give a good clue to the etiology of a paroxysmal tachycardia and the treatment really depends on the likely etiology and the patient's clinical condition. In a later episode, we will review the approach to wide-QRS complex tachyarrhythmias.
CATHY: For more information refer to Harrison's chapter on Disorders of the Cardiovascular System. And also for your reference, there's a great video on New England Journal of Medicine, Images in Clinical Medicine from April 14, 2016 that shows a video of the frog sign in a patient with AV nodal reentry tachycardia.