Narrow complex tachycardias

Question 1

Give the ECG features of atrial fibrillation

Answer 1

irregularly irregular
NO P waves
lack of an isoelectric baseline
variable ventricular rate
QRS <120

Question 2

what does the QRS complex represent

Answer 2

ventricular depolarisation

Question 3

what is a normal QRS value, and when is it considered prolonged

Answer 3

between 0.08s and 0.10s

prolonged = >0.12s

Question 4

give the causes of atrial fibrillation

Answer 4

Alcohol and caffeine, acid-base disturbance
Thyrotoxicosis
Rheumatic fever and mitral valve pathologies
IHD
Atrial myxoma
Lungs (pulmonary HTN, PE, pneumonia)

Pharmacological
Iatrogenic
Blood pressure

Question 5

what are the three most common causes of atrial fibrillation

Answer 5

IHD
HTN
Mitral valve pathologies

Question 6

describe the general rule of thumb for management of AF

Answer 6

asymptomatic or mild symptomatic patients = RATE control

Symptomatic patients, age >65 or concominant HF = RHYTHM control

Question 7

how do you assess the need for anticoagulation in AF

Answer 7

CHADs VASC score -

Question 8

how do you RATE control in AF

Answer 8

monotherapy with either a beta-blocker or a calcium channel blocker

second line: combination therapy with Digoxin + CCB or BB

Question 9

how do you RHYTHM control in chronic AF

Answer 9

give a beta blocker

+ if ventricular impairment, amiodarone

or

if no ventricular impairment, dronedarone

Question 10

how do you RHYTHM control in chronic paroxysmal AD

Answer 10

flecanide

Question 11

how do you RHYTHM control in acute AF

Answer 11

if symptomatic for <48hr IMMEDIATE CARDIOVERSION

if no structural HD use IV flecanide or amiodarone

if structural HD use amiodarone

If symptomatic for >48h do DELAYED CARDIOVERSION
with TTE guided cardiovesion

Question 12

what is atrial flutter

Answer 12

a supraventricular tachycardia caused by a re-entry circuit within the right atrium

Question 13

how does atrial flutter normally present

Answer 13

breathlessness and palpitations

syncope and severe dyspnoea

Question 14

what is the commonest cause of palpitations in patients with no structural heart anomalies

Answer 14

atrioventricular nodal re-entrant tachycardia

Question 15

what with the ECG show in AVNRT

Answer 15

tachycardia of 140-280 bpm with normal and regular QRS complexes. There will be either

No visible P-waves (hidden within the QRS complex) or
P-waves immediately before the QRS or
P-waves immediately after the QRS complex

Question 16

how does AVNRT usually present

Answer 16

sudden onset palpitations
dizziness
breathlessness

Question 17

how do you manage AVNRT

Answer 17

vagal manouvers
IV adenosine or CCBs
in emergencies with haemodynamic compromise, DC cardioversion is indicated

Question 18

what is Wolf-Parkinson White syndrome

Answer 18

a combination of the presence of a congenital accessory pathway and episodes of tachyarrhythmia

it is a pre-excitation syndrome which can often lead to atrioventricular re-entrant tachycardia

Question 19

what are the ECG features of WPW

Answer 19

short PR interval <120s
delta wave - slow rising initial segment of QRS
prolonged QRS

Question 20

what is the definitive treatment of WPW

Answer 20

catheter ablation of the accessory pathway

Question 21

how do you manage WPW

Answer 21

vagal manouvers
IV adenosine and procainment
DC cardioversion