Bradycardia and Tachycardia Management - NREMT Paramedic Level

1. Which AV block shows constant PR intervals with intermittent nonconducted P waves?

   Second-degree AV block type II (Mobitz II). Constant PR with sudden drops indicates infranodal block, more serious than type I.

2. Which AV block is characterized by progressive PR prolongation until a QRS is dropped?

   Second-degree AV block type I (Wenckebach). Progressive PR interval reflects delayed AV node conduction leading to dropped beats in this block type.

3. Which rhythm is defined by AV dissociation with independent atrial and ventricular rates?

   Third-degree (complete) AV block. Complete block results in no AV conduction, causing independent atrial and ventricular rhythms.

4. Which rhythm is described as polymorphic VT with a twisting QRS axis around baseline?

   Torsades de pointes. Torsades features varying QRS amplitude and axis due to prolonged QT interval.

5. What is the recommended dopamine infusion range for refractory symptomatic bradycardia?

   Dopamine $5$–$20\ \text{mcg}/\text{kg}/\text{min}$ IV infusion. Dopamine acts as a vasopressor and chronotrope at this dose range to support heart rate and blood pressure.

6. Which option best describes the immediate priority for symptomatic bradycardia with poor perfusion?

   Atropine, then TCP without delay if ineffective. Prompt escalation to pacing ensures rapid heart rate support if atropine fails.

7. Which findings define an unstable tachycardia in ACLS?

   Hypotension, shock, ischemic discomfort, AMS, or acute HF. These signs indicate the tachycardia is causing life-threatening hemodynamic compromise.

8. What is the atropine repeat interval and maximum total dose for adult bradycardia?

   Repeat every $3$–$5$ min; max $3\ \text{mg}$. Dosing protocol ensures cumulative effect while preventing excessive anticholinergic toxicity.

9. Which action is appropriate for stable, regular, monomorphic wide-complex tachycardia?

   Consider adenosine; then antiarrhythmic infusion. Adenosine diagnoses SVT with aberrancy; antiarrhythmics like procainamide treat confirmed VT.

10. Which step is prioritized for any unstable tachycardia with a pulse in ACLS?

    Immediate synchronized cardioversion. Unstable tachycardias require immediate restoration of sinus rhythm to stabilize hemodynamics.

11. Which initial maneuver is recommended for stable, regular, narrow-complex SVT?

    Vagal maneuvers. Vagal maneuvers increase parasympathetic tone to interrupt reentrant SVT circuits.

12. What is the recommended epinephrine infusion range for refractory symptomatic bradycardia?

    Epinephrine $2$–$10\ \text{mcg}/\text{min}$ IV infusion. Epinephrine infusion offers adrenergic stimulation for heart rate support in refractory bradycardia.

13. What QRS duration cutoff distinguishes narrow from wide complex tachycardia in ACLS?

    Narrow $< 0.12\ \text{s}$; wide $\geq 0.12\ \text{s}$. QRS width helps differentiate supraventricular from ventricular origins in tachycardia management.

14. What is the first-line medication and initial dose for symptomatic adult bradycardia?

    Atropine $1\ \text{mg}$ IV/IO bolus. Atropine blocks vagal tone to increase heart rate in symptomatic bradycardia as the initial pharmacologic option.

15. Which intervention is recommended if atropine is ineffective for symptomatic bradycardia?

    Transcutaneous pacing (TCP). TCP provides electrical stimulation to increase heart rate when medications fail in symptomatic cases.

16. Which tachycardia must NOT be treated with adenosine, even if narrow-complex?

    Irregular tachycardia (suspected atrial fibrillation/flutter with variable block). Adenosine can worsen irregularity or cause complications in atrial fibrillation or flutter.

17. What is the second adenosine dose if SVT persists after the first dose?

    Adenosine $12\ \text{mg}$ rapid IV push, then flush. Higher dose is used if initial fails, maximizing chance of terminating the arrhythmia.

18. Which bradycardia rhythms commonly require pacing rather than relying on atropine?

    Mobitz II and third-degree AV block. These blocks are often infranodal, where atropine is less effective, necessitating pacing.

19. Which therapy is first-line for torsades de pointes in the field?

    Magnesium sulfate IV/IO. Magnesium suppresses early afterdepolarizations to stabilize membrane in torsades.

20. Which clinical finding determines whether bradycardia requires treatment in ACLS?

    Persistent symptoms with hypotension, shock, ischemia, or AMS. Treatment is indicated only if bradycardia causes hemodynamic instability, as asymptomatic cases may not require intervention.

21. What heart rate threshold defines adult bradycardia in the ACLS bradycardia algorithm?

    Heart rate $< 50$ beats/min. ACLS uses this threshold to identify bradycardia requiring assessment for symptoms and potential intervention in adults.

22. Identify the correct shock type for atrial fibrillation with RVR causing hypotension.

    Synchronized cardioversion. Synchronized shock avoids R-on-T phenomenon in rhythms with organized QRS complexes.

23. What is the first adenosine dose for stable, regular, narrow-complex SVT?

    Adenosine $6\ \text{mg}$ rapid IV push, then flush. Adenosine briefly blocks AV node conduction to terminate reentrant tachycardias.

24. Identify the correct shock type for pulseless ventricular tachycardia on the monitor.

    Defibrillation (unsynchronized shock). Pulseless VT is treated as VF with high-energy unsynchronized shocks for defibrillation.

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