Approach to Tachycardia Flashcards
1st step in approaching patient with tachycardia?
ABCDE to determine if they are stable or unstable.
What are some signs of an unstable patient with tachycardia?
1) Shock: hypotension (<90 mmHg), pallor, sweating, cold, clammy extremeties, confusion or impaired conciousness.
2) Syncope
3) Myocardial ischaemia
4) HF
If any adverse signs are present in a patient with tachycardia, what is the next step?
Synchronised DC shocks.
Up to 3 shocks can be given –> then seek expert help.
How many synchronised DC shocks can be given in unstable patients with tachycardia?
Up to 3 - then seek expert help
What history may be present in patients with tachycardia?
- palpitations
- exercise intolerance
- lightheadedness
- syncope
Key investigation in tachycardia?
ECG –> assess regular or irregular, broad or narrow complex.
If patient with tachycardia is stable, what is next step?
Get an ECG –> determine if the QRS if narrow or broad.
What is a narrow QRS?
<120ms
What is a broad QRS?
> 120ms
What does a narrow complex tachycardia indicate?
That the pacing originates above the ventricles –> suggests you are dealing with SVT (if regular).
Stepwise mx of regular narrow complex tachycardia? (4)
1) Vagal manoeuvres
2) IV adenosine (monitor ECG continuously):
- 6mg rapid IV bolus
- 12mg
- 18mg
3) Verapamil or beta blocker
4) Synchronised DC shock up to 3 atttempts (sedation or anaesthesia if conscious)
Mx of sinus tachycardia?
Treat cause e.g. fever, anxiety, pain, exercise, hyperthyroidism, pregnancy, anaemia.
What are some vagal manoeuvres used in narrow complex regular tachycardia? (3)
1) valsalva manoeuvre
2) applying a cold stimulus to the face e.g. application of a bag filled with ice and cold water over the face for 15-30 secs
3) carotid sinus massage
What do Valsalva manoeuvres commonly used include?
1) forceful exhalation against a closed airway for approximately 15-20 seconds
2) blowing into an occluded straw
3) adopting a head-down position for approximately 15-20 seconds
When is a carotid sinus massage contraindicated?
If any history of carotid artery disease
If adenosine is contra-indicated or fails in the management of SVT, what is the 2nd line medication?
Verapamil –> given IV over a two-minute period
What is an irregular narrow-complex tachycardia most likely to be?
Atrial fibrillation (or less commonly atrial flutter with a variable atrio-ventricular block)
Mx of AF with duration of <48 hours?
Can be offered rhythm control or rate control.
Note –> rhythm control is recommended in most patients with a new onset of AF presenting at this time.
What are the options for rhythm control in AF <48 hours?
1) DC Cardioversion,
2) Chemical cardioversion:
- flecainide
- propafenone
- amiodarone
When can flecainide & propafenone not be used in rhythm control of AF?
What can be used instead?
If evidence of structural heart disease or HF.
Use amidarone or digoxin instead.
Mx of AF >48 hours?
Do not treat with cardioversion until they have been anti-coagulated for at least 3 weeks, to reduce the risk of dislodging an atrial thrombus.
If a patient with AF >48 hours BUT is unstable and requires urgent cardioversion, what do you do?
Give LMWH or UH first
Heparin treatment as well as oral anti-coagulation should be commenced after cardioversion (whether successful or not)
What is aim of rate control of AF?
To decrease the heart rate at rest and during exertion
Symptoms are normally associated with high heart rates.
What medications can be used for rate control of AF?
1) Beta blockers
2) Non-dihydropyridine calcium channel blockers e.g. verapamil and diltiazem
3) Digoxin (but not recommended outside of sedentary patients with non-paroxysmal AF)
Which beta blocker is NOT used for rate control in AF?
Sotalol –> used for rhythm control
When is long term management of SVT indicated?
If the frequency and severity of SVT episodes significantly impacts on the patients quality of life and functioning:
Indications for definitive or long-term treatment include:
1) Recurrent symptomatic SVT episodes affecting quality of life
2) Evidence of Wolff-Parkinson-White on ECG and symptoms of SVT episodes
3) Infrequent SVT episodes but in a profession or sport which puts themselves or others at risk (e.g. drivers, pilots, surgeons)
What are some options for long term mangement of SVT?
1) Radio-frequency ablation is often preferred due to the low risk of complications and high success rate (>95%)
2) Pharmacological treatment usually involves beta blockers or calcium-channel blockers as a first-line option (if ablation declined)
3) Second-line medication options include flecainide and sotalol
What is broad complex regular tachycardia caused by?
Assume ventricular tachycardia (VT) - unless previously confirmed SVT with bundle branch block.
Mx of VT?
1) Loading dose of amiodarone 300mg IV over 10-60 mins. Followed by 24 hour infusion.
2) Synchronised DC shock up to 3 times
What is the loading dose of amiodarone given in VT?
300mg IV over 10-60 mins
Mx of broad complex regular tachycardia with previously confirmed SVT with BBB?
Treat as for regular narrow complex tachycardia
Causes of broad complex irregular tachycardia?
1) AF with BBB (most common)
2) Polymorphic VT e.g. torsades de pointes
Mx of AF with BBB?
Seek expert help
Treat as for irregular narrow complex tachycardia
Mx of polymorphic VT (e.g. torsades de pointes)?
Magnesium 2g over 10 mins
