Supraventricular Tachycardias

Question 1

What are SVTs?

Answer 1

A blanket term for a group of tachycardia who’s origin lie above the ventricles

Question 2

What are the two general types?

Answer 2

Focal and re-entrance SVTs - the latter is considerably more common

Question 3

What are the 4 main types of re-entrance SVTs?

Answer 3

Atrial flutter
AF
AVRT
AVNRT

Question 4

Explain the pathophysiology of Atrial flutter

Answer 4

A tachycardia originating from a loop circuit around the tricuspid valve. It has a fixed rate of 300bpm - the type of atrial flutter clinically present and the HR of the patient depends on the ratio of these electrical excitations from getting through. For example 1:2 has a HR of 150bpm, and 1:3 has a HR of 100bpm

Question 5

What are the typical ECG characteristics of atrial flutter?

Answer 5

P waves are present and slightly more regular than AF
Saw-tooth pattern p waves
Tachycardia

Question 6

What is an AVRT? What is the most common example?

Answer 6

Presence of an accessory pathway that allows electrical signals to bypass the AVN.
Signals can be orthodromic and travel down the AVN and up the pathway, or antidromic and travel back up the AVN.
The most common example is Wolf Parkinson White Syndrome

Question 7

What is an AVNRT?

Answer 7

Within the AVN, there is a fast and slow pathway that can conduct signals. These form a circuit with rapid conduction that produces a regular tachycardia

Question 8

What is SAN disease?

Answer 8

Disease of the SAN where it causes atrial tachycarrhythmias.
It is associated with periods of flatline where no impulses are sent out before resuming function

Question 9

What is the ECG presentation of LBBB?

Answer 9

WilliaM
R wave is negative, S is positive, T is negative in V1
R wave is positive, S is negative, T is positive in V6

Question 10

What is the ECG presentation of RBBB?

Answer 10

MarroW
R wave is positive, S is negative and T is positive in V1
R wave is negative, S is positive and T is negative in V6