Study 3 Cardiac Arrhythmias with 12 free online flashcards. Review key terms, definitions, and concepts with this interactive flashcard deck.
What should be assessed before treating an ECG rhythm?
Assess responsiveness, pulse, airway, breathing, blood pressure, oxygenation, and perfusion. Cardiopulmonary compromise includes hypotension, acutely altered mental status, shock, ischemic chest discomfort, or acute heart failure.
Which features should be checked in a systematic rhythm reading?
Assess rate, regularity, P waves, PR interval, QRS width, and the atrial–ventricular relationship. A usual PR interval is 0.12–0.20 seconds; a QRS of 0.12 seconds or longer is wide.
What ECG pattern characterizes sinus bradycardia?
Sinus bradycardia is regular, with a sinus P wave before each QRS and a slow rate. It can be normal during sleep or in a well-trained athlete; treat the cause and symptoms, not the number alone.
What defines first-degree AV block?
Every P wave conducts to a QRS, but the PR interval is prolonged and constant. It is a conduction delay, not a dropped beat.
What pattern identifies Mobitz I AV block?
The PR interval progressively lengthens until a P wave is not followed by a QRS.
What distinguishes third-degree AV block?
There is no consistent relationship between P waves and QRS complexes: the atria and ventricles beat independently. The escape rhythm may be narrow or wide.
What is the initial medication pathway for compromised bradycardia?
For bradycardia causing compromise, the AHA algorithm recommends atropine 1 mg IV every 3–5 minutes, up to 3 mg total. If ineffective, use transcutaneous pacing and/or an epinephrine or dopamine infusion.
What is the usual approach to sinus tachycardia?
It is usually a regular narrow-complex rhythm with a sinus P wave before each QRS. Common causes include fever, pain, hypovolemia, hypoxia, or infection, so treat the underlying problem.
How is stable regular narrow-complex SVT initially managed?
In a stable patient, vagal maneuvers are appropriate. For a regular narrow-complex tachycardia, adenosine may be given as a 6 mg rapid IV push followed by a saline flush; if needed, give 12 mg.
How do atrial fibrillation and atrial flutter typically differ on ECG?
Atrial fibrillation is irregularly irregular with no consistent discrete P waves. Atrial flutter often has repetitive flutter waves; its ventricular rhythm can be regular or irregular depending on AV conduction.
What is recommended for unstable AF or flutter with a rapid ventricular response?
Immediate synchronized cardioversion is recommended when atrial fibrillation or flutter with a rapid ventricular response causes hemodynamic instability.
How should an uncertain wide-complex tachycardia be approached?
VT is generally a wide-complex tachycardia; monomorphic VT has a consistent QRS shape, while polymorphic VT varies. If a wide-complex tachycardia's cause is uncertain, treat it as potentially ventricular and seek expert help.