Supraventricular arrhythmias Flashcards
1
Q
What is a supra ventricular tachycardia (SVT)
A
- an abnormally fast heart rhythm arising from improper electrical activity in the atria
2
Q
List the different types of SVT
A
- Sinus tachycardia
- Innapropriate sinus tachycardia
- Sinus nodal re-entrat tachycardia
- Atrial tachycardia
- A flutter
- Paroxysmal Supraventricular Tachycardia (PSVT)
- A-fib
- WPW syndrome
3
Q
Sinus tachycardia: HR, types
A
- when there’s a sinus rhythm with an elevated rate of impulses, defined as a rate greater than 100 beats/min (bpm)
- 2 types:
.Physiologic: during exercise
.Pathologic: anaemia, drugs, hyperthyroidism, hypoxia, hypovolemia, pheochromocytoma
4
Q
Inappropriate sinus tachycardia
A
- the underlying cause is not found, give BB
5
Q
Sinus nodal re-entrant tachycardia: def, ECG, T
A
- narrow complex tachycardia due to micro re-entrant circuit in SA
- ECG: normal p waves
- T: BB and Calcium Channel Blockers are the first line treatment. Radiofrequency ablation is second
6
Q
Atrial tachycardia: HR, ECG, T
A
- regular rhythm > 100 bpm
- ECG: different P wave morphology
- found in normal as well as cardiac diseases (metabolic disarray, digitalis toxicity, pulmonary disease), short PR
- T: BB, Calcium channel blocker, propafenone, amiodarone, stall, IV adenosine
7
Q
Atrial flutter: what is it
A
- a supraventricular arrhythmia, that results from a re-entrant mechanism, from either the right or left atrium
- re-entrant signals loop back on themselves, overriding the sinus node and making an endless cycle, causing the atria to contract again and again at a very fast rate
- > 300bpm
8
Q
What are the different types of A-flutter
A
- type 1
- type 2
9
Q
A-flutter: type 1
A
- caused by a single reentrant circuit that moves around the annulus: the ring of the tricuspid valve of the right atrium
10
Q
A-flutter: type 2
A
- a re-entrant circuit develops in the right or left atrium, but the exact location is not known
11
Q
A-flutter: Causes
A
- everyone has a cavotricuspid isthmus, but not everyone has a-flutter causing a re-entrant circuit, so an underlying cause must create it
- Ischemia: makes the heart cells more irritable
12
Q
A-flutter: ECG
A
- ECG: toothed like shape, + narrowed QRS complexes
Ratio of Atrial contractions : Ventricular contractions will depend on the delay at the AV node
13
Q
A-flutter: symptoms
A
- shortness of breath
- nausea
- chest pain
- dizziness
14
Q
A-flutter: complications
A
- overtime, the ventricles can tire out and decompensated and people can develop HF
- Blood clot formation in the atrium -> stroke. Because the blood stagnate/ pool in the atrium
15
Q
A-flutter: T
A
- anticoagulants/ blood thinners: to reduce chances of clot formation
- BB, CCB to control HR
- Cardioversion, to stop the episode of flutter: it depolarizes all the atrial tissue at once and let the sinus node take control again
- Radiofrequency catheter ablation: depending on which type of A-flutter it is
16
Q
What happens in AVRT and AVNRT
A
- Atrioventricular Reentrant Tachycardia
- the electrical signal uses a separate accessory pathway to get back up from the ventricles to the atria, causing the atria to contract before the SA node sends out another signal
- signal moves back down the AV node to the ventricles and contracts the ventricles, and goes back up the accessory pathway -> cycle repeats
- HR: 200-300 bpm
17
Q
What is the most common type of AVRT
A
- Woll-Parkinson-white syndrome
- uses the bundle of Kent as accessory pathway
- this type of re-entry is known as an anatomical re-entrant circuit, because the accessory pathway is a fixed anatomically defined pathway
18
Q
AVNRT- what happens there, what’s the difference with AVRT
A
- AVNRT: Atrioventricular nodal re-entrant tachycardia
- here, the accessory pathway is located in or near the AV node, whereas for AVRT, it was located in the ventricles. Both going to the atria.
19
Q
AVRT and AVNRT symptoms
A
- usually doesn’t last long
- both rarely life-threatening
- Palpitations, shortness of breath, feeling of dizziness, syncope or fainting in rare cases
20
Q
AVRT: ECG
A
- tachycardia
- P wave might or might not be buried, depending on where the accessory pathway is located
21
Q
AVNRT: ECG
A
- tachycardia
- P mostly not visible. Because the signal’s getting to the atria and ventricles at almost the same time, so the P wave starts essentially where the QRS starts and when you add them together
22
Q
AVRT and AVNRT Treatment
A
- Radio catheter ablation: to destroy the accessory pathways
- Vagal maneuvers for AVNRT, to activate the vagus nerve, which tends to block the AV node temporarily, and potentially stopping the episode
- Carotid sinus massage
- Valsalva maneuver
- medications to slow AV node conduction
- Cardioversion: when other treatments are not effective
