Master the board step 3

Master the Boards: USMLE Step 3
Beta Blockers (Metoprolol)
• Ischemic heart disease
• Migraines
• Graves disease
• Pheochromocytoma
Calcium Channel Blockers
(Diltiazem)
• Asthma
• Migraine
Digoxin
• Borderline hypotension
Give oxygen first for MAT.
Multifocal Atrial Tachycardia (MAT)
This condition presents like an atrial arrhythmia in association with COPD/
emphysema. EKG will show polymorphic P waves, revealing different atrial
foci for the QRS complexes. As the name implies, patients with MAT have
tachycardia (heart rate > 100). MAT manifests as an irregular chaotic rhythm
on EKG. Do not use beta blockers. Give oxygen first, then diltiazem.
Supraventricular Tachycardia (SVT)
SVT presents with palpitations and tachycardia and occasionally syncope. It
is not associated with ischemic heart disease. SVT has a regular rhythm with
a ventricular rate of 160–180.
Diagnostic Testing
If the EKG does not show SVT, order Holter monitor or telemetry to increase
the sensitivity of detection.
CCS Tip: On CCS, all cases of dysrhythmia should undergo transthoracic echocardiography
(TTE) after the initial set of orders.
Treatment
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Best initial management for unstable patients: Synchronized cardioversion
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Best initial management for stable patients: Vagal maneuvers (carotid sinus
massage, ice immersion of the face, Valsalva)
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Next best step in management if vagal maneuvers do not work: Intravenous
adenosine (Note: This is the most frequently asked SVT question.)
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Best long-term management: Radiofrequency catheter ablation
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