Narrow Complex Tachycardias Flashcards
What is this defined as?
HR > 100 bpm. Here, the QRS is < 120ms (3 small squares).
Management:
What is the first thing to do?
What are the signs if the pt becomes unstable?
→ What should be done in this case?
What should be done if the pt is stable?
How does Adenosine work?
➊ A-E assessment
➋ Shock, Syncope, Heart failure, Myocardial ischaemia
→ Synchronised DC cardioversion
➌ Find out if the rhythm is regular or irregular
* Regular (SVT) - Try vagal manouveres (valsalva or carotid sinus stimulation) first. If no improvement, give IV Adenosine 6mg rapid blous (try 12mg, then 18mg if not helping).
* Irregular (AF) - If < 48 hrs, pharmacological cardioversion (flecanide, amiodarone). If > 48 hrs, rate control (Metoprolol/Bisoprolol, Verapamil) and anticoagulate.
N.B. Carotid sinus stimulation tends not to be that helpful, so valsalva is more commonly used (blowing into an empty syringe).
N.B. Bisoprolol is the best cardio-specific BB, but it takes around 24 hrs for its effect to clear, therefore it can’t be easily reversed if it brings the HR and BP down too much. Therefore, Metoprolol tends to be the better option initially as it can more easily be stopped.
➍ Adenosine causes transient, complete blockage of the AV node
N.B. Adenosine is contraindicated in poorly controlled asthmatics as it can cause bronchospasm.
What are the 2 types of shocks that can be given?
→ How do they differ?
Unsynchronised and Synchronised
→ * Unsynchronised is another word for defibrillation. It’s a high-energy shock delivered at any random phase of the cardiac cycle.
* Synchronised shock is a lower-energy shock that’s delivered in time with an R-wave to reset the heart’s rhythmn.
