Tachycardias and Tachyarrhythmias

Question 1

What are the clinical feature of tachycardias

Answer 1

Adverse features

• shock - hypotension, pallor, increased cap refill time
• syncope
• myocardial ischaemia
• cardiac failure - PND, Orthropneoa, bibasal crepitations, raised JVP

Non Adverse features

• Palpitations
• dyspneoa
• Anxiety

Question 2

How would you initially investigate and manage a tachycardia

Answer 2

A-E assessment 
Maintain a patent airway
Controlled oxygen to maintain sats 
Bedside obs: HR, RR, BP, sats, temp
ECG 
IV access and take bloods 
- FBC 
- U+Es 
- magnesium 
- Bone profile - calcium and phosphate
- TFTs
- LFTs
- clotting 
Fluids if appropiate
CXR

Question 3

How do you differentiate between narrow complex and a broad complex tachycardia

Answer 3

Narrow complex QRS interval of <120ms

Broad complex QRS interval >120ms

Question 4

How are regular SVTs managed?

Answer 4

A-E, Oxygen, ECG, IV access
Vagal manoeuvres - valsalva and carotid massage
IV adenosine 6mg ->12mg -> 12mg
monitor ECG
SEEK HELP
Electro cardioversion if haemodynamically unstable

Question 5

In which conditions is adenosine contraindicated in and what should be used instead

Answer 5

Avoided in patients with asthma
Use verapamil instead
Avoid in WPW and patients with denervated hearts also

Question 6

What are the features of WPW on ECG

Answer 6

Short PR interval
Wide QRS with slurred upstroke ‘delta wave’
Left axis deviation - if right sided accessory pathway
Right axis deviation - if left sided accessory pathway

Question 7

How is WPW treated

Answer 7

Radiofrequency ablation of pathway

Medical: flecanide, amiodarone

Question 8

What is wolff parkinson white syndrome

Answer 8

Syndrome caused by a congenital accessory pathway down the bundle of kent between the atria and the ventricles leading to an atrioventicular re-entry tachycardia

Question 9

How is monomorphic VT managed?

Answer 9

High flow O2
IV access
12 lead ECG
Bloods - FBC,, U+Es, Mg, Ca, cardiac enzymes
ABG - if evidence of pulmonary oedema, reduced conscious level, sepsis
Amiodarone 300mg IV

Question 10

How is polymorphic VT (torsades de pointes) managed

Answer 10

Magnesium 2g IV over 10 mins
Stop any meds that may prolong the QT interval
Correct electrolyte imbalances

Question 11

Which drugs may prolong the QT interval

Answer 11

Antipsychotics - chlorpromazine, haloperidol, quetiapine, olanzapine
Antidepressants - Citalopram, Escitalopram, TCA, venlafaxcine
Antibiotics - macrolides (erthromycin and clarithromycin)
Type 1A antiarrhythmics - procainimide
Type 1C - flecainide
Class 3 - sotalol and amiodarone

Question 12

In ventricular tachycardia when should cardioversion be considered

Answer 12

If adverse signs are present it should be considered before pharmacological intervention
(shock, hypotension, pallor, increased cap refill time, chest pain, syncope, heat failure)
or if amiodarone fails

Question 13

How are irregular SVT managed

Answer 13

If onset <48hrs - amiodarone 300mg IV over 20-60mins
otherwise control rate with
IV Beta blockers
IV Digoxin

Question 14

What can precipitate a VT

Answer 14

Metabolic - hypokalaemia, hypomagnesium
Cardiac - IHD, Cardiomyopathy, MI
Drugs - Cocaine

Question 15

What can precipitate an SVT

Answer 15

Cardiac - IHD
Metabolic - thyrotoxicosis
Drugs - caffeine, alcohol, smoking

Question 16

What can precipitate an episode of AF

Answer 16

Cardiac - IHD, HTN, mitral valve disease, pericardial disease, Cardiomyopathy
Resp - lung disease
Post operatively

Question 17

What is the MOA of amiodarone

Answer 17

Blocks potassium channels which inhibits repolarisation and prolongs the action potential
Class 3 antiarrhythmic

Question 18

What is the CHA2DS2 VASC score and what does it stand for

Answer 18

It is a score predicting whether a patient with AF needs anticoagulation
C - congenital heart failure 
H - hypertension 
A2 - Age >75 (2points)
Age 65-74 (1 point)
D - Diabetes mellitus 
S2 - Prior stroke or TIA (2 points)

Vascular disease
S- Sex - Female

Question 19

Which scoring system is used to risk assess patients who need anticoagulation

Answer 19

HAS-BLED
H - hypertension - uncontrolled
A - Abnormal renal of liver function
S - Stroke - hx of

B - bleeding, hx of bleeding, tendency to bleed
L - Labile INRs (high, unstable INRs time in therapeutic range <60%)
E - elderly >65years old
D - Drugs that may predispose to bleeding (antiplatelet agents/NSAIDs)
Alcohol use >8 units per week

A score of 3 or more is considere=d high risk

Question 20

What should be done in ventricular fibrillation or pulseless or unstable VT

Answer 20

asychronised DC shock

Question 21

What is a common complication of using amiodarone through a peripheral line

Answer 21

Phlebitis

especially if conc is over 2mg/ml

Question 22

What is a fusion beat

Answer 22

when a normal beat fuses with a VT complex to create an unusual complex

Question 23

What is a capture beat

Answer 23

a normal QRS between abnormal beats

Question 24

What is the most common post-MI arrhythmia and what do they suggest

Answer 24

Ventricular ectopics
They suggest electrical instability
Risk if VF if ‘R on T’ pattern is seen (no gap before the T wave)