Cardiology: Tachycardia Flashcards
1
Q
What happens in atrial fibrillation?
A
1) Factors that cause dilation of the atria through inflammation and fibrosis result in discrepancies in the refractory periods within the atrial tissue (left atrium loses refractoriness before the end of atrial systole)
2) This causes electrical re-entrant pathways within the atria and recurrent uncoordinated atrial contraction, typically at 300-600 bpm
3) Delay at the AV node means that only some of the atrial impulses are conducted to the ventricles, resulting in an irregular ventricular response
2
Q
What is the most common sustained cardiac arrhythmia?
A
AF
3
Q
What are cardiac causes of AF?
A
1) Ischaemic heart disease (most common)
2) HTN
3) Rheumatic heart disease
4) Pericarditis/myocarditis
4
Q
What are non-cardiac causes of AF?
A
1) Dehydration
2) Endocrine e.g. hyperthyroidism
3) Infective e.g. sepsis
4) Pulmonary e.g. pneumonia or PE
5) Environmental toxins e.g. alcohol abuse
6) Electrolyte disturbances e.g. hypokalaemia, hypomagnesaemia
5
Q
What are the 4 classifications of AF?
A
1) Acute - lasts < 48h
2) Paroxysmal - lasts < 7 days and is intermittent
3) Persistent - lasts > 7 days but is amenable to cardioversion
4) Permanent - lasts > 7 days and is not amenable to cardioversion
6
Q
What are symptoms of AF?
A
1) Palpitations
2) Chest pain
3) Shortness of breath
4) Dizziness
7
Q
What are signs of AF?
A
1) Irregularly irregular pulse with variable volume
2) Single waveform on the JVP (due to loss of a wave)
3) Apical to radial pulse deficit
4) Variable intensity first heart sound
5) Features suggestive of underlying cause or complications e.g. HF
8
Q
What does an ECG show in AF?
A
Irregularly irregular HR + absent p waves
9
Q
What is fast AF?
A
When the ventricular rate > 100 bpm (requires immediate treatment)
10
Q
How do you assess a patient with fast AF?
A
Assess for haemodynamic stability using an ABCDE approach - shock, syncope, chest pain, pulmonary oedema
11
Q
How do you treat a patient with fast AF who is haemodynamically unstable?
A
DC cardioversion
12
Q
What are the principles of management in AF?
A
1) Consider reversible causes e.g. infection, dehydration, abnormal electrolytes
2) If AF persists or reversible causes are not present then decisions should be made about rate control, rhythm control or electrical cardioversion
13
Q
What is the first line strategy for managing AF?
A
Rate control
14
Q
When do you not offer rate control as the first line strategy to people with AF?
A
1) AF has a reversible cause
2) Heart failure thought to be primarily caused by AF
3) New-onset AF
4) When rhythm control would be more suitable based on clinical judgement
15
Q
What is the first line initial monotherapy rate control for AF?
A
Beta blocker e.g. bisoprolol or rate-limiting CCB e.g. diltiazem
16
Q
When would you consider digoxin monotherapy for rate control in AF?
A
For people with non-paroxysmal AF only if they are sedentary
17
Q
What is the most commonly used beta-blocker in AF?
A
Bisoprolol
18
Q
When can beta blockers not be used for AF?
A
Hypotension - bisoprolol will drop BP
19
Q
Which beta blocker cannot be used as a rate control agent in AF?
A
Sotalol - bc of its rhythm control action
20
Q
Which non-dihydropyridine CCBs are used in AF for rate control?
A
Diltiazem or verapamil
21
Q
Why are non-dihydropyridine CCBs not frequently used in hospital settings for AF?
A
Bc they are negatively ionotropic - therefore CI in HF
22
Q
How is digoxin used in AF for rate control?
A
1) Usual for patients who are hypotensive or have co-existent HF
2) Often used second line in conjunction with beta blockers if fast AF remains refractory
3) Avoid in younger patients - increases cardiac mortality
23
Q
How can rhythm control be achieved in AF?
A
1) Electrical cardioversion
2) Pharmacological cardioversion
24
Q
Why is cardioversion/rhythm control not considered in most cases of chronic AF or those who have failed cardioversion before?
A
Bc they are unlikely to be successfully cardioverted
25
How do you rhythm control new acute AF (onset < 48h) ?
DC cardioversion with sedation
26
How do you rhythm control AF with onset > 48h or uncertain onset?
Patient must be anticoagulated for at least 3 weeks before DC cardioversion can take place
(OR patient can have TOE to rule out a thrombus in the left atrial appendage before cardioversion)
27
Which drugs are used for pharmacological cardioversion/rhythm control in AF?
1) Flecainide
2) Amiodarone
3) Sotalol
28
When and how is flecainide used for pharmacological cardioversion/rhythm control in AF?
1) Preferred in young patients with structurally normal hearts (can induce fatal arrhythmias in structurally abnormal hearts)
2) Given regularly or when symptoms come on
29
When and how is amiodarone used for pharmacological cardioversion/rhythm control in AF?
1) V effective drug in controlling rate + rhythm
2) But massive list of significant side effects so should normally only be given to older, sedentary patients
30
When and how is sotalol used for pharmacological cardioversion/rhythm control in AF?
1) Beta blocker with additional K channel blocker action
2) Used for those that don't meed the demographics for either flecainide or amiodarone
31
What is the main complication of AF?
Embolic stroke - long term anticoagulation reduces this risk
32
Which score stratifies risk of embolic stroke and thromboembolism for AF patients with non-valvular AF?
CHADS2VASc score
33
What are the components of the CHADS2VASc score?
1) Congestive heart failure - 1 point
2) Hypertension - 1 point
3) Age > 75 - 2 points
4) Diabetes - 1 point
5) Stroke/TIA previously - 2 points
6) Vascular disease known - 1 point
7) Age 65-74 - 1 point
8) Sc - Female - 1 point
34
When should patients be anticoagulated according to the CHADS2VASc score?
Males scoring 1 or more, females scoring 2 or more
(max score = 9 = 15% annual stroke risk)
35
Which score stratifies bleeding risk?
HASBLED (considered as a risk of anticoagulation)
36
What are the components of the HASBLED score?
1) Hypertension - 1 point
2) Abnormal renal or liver function - 2 points if both
3) Stroke previous - 1 point
4) Bleed - major, previous - 1 point
5) Labile INR - 1 point
6) Elderly > 65 - 1 point
7) Drugs/alcohol - 1 point for drug or alcohol use (2 if both)
37
Which score is recommended by 2021 NICE AF guidelines to assess bleeding risk when deciding whether to anticoagulate a patient?
ORBIT score
38
What are the components of the ORBIT score?
1) Sex
2) Low Hb - 2 points
3) Age > 74 - 1 point
4) Bleeding history - 2 points
5) eGFR < 60 - 1 point
6) Concomitant use of anti-platelets - 1 point
39
What is currently considered to be the anticoagulation treatment of choice in AF?
DOACs e.g. edoxaban, apixaban, rivaroxaban, dabigatran
40
What are the benefits of DOACs for AF?
1) Do not require monitoring
2) Generally associated with less bleeding risks than warfarin
41
What is the con of DOACs for AF?
Most have approximately 12 hour half-lives therefore if patients miss doses they are not covered
42
Which is the only oral anticoagulant licensed for valvular AF?
Warfarin
43
How does warfarin need to be prescribed?
1) Requires cover with LMWH for 5 days when initiating treatment (because warfarin is initially prothrombotic)
2) Requires regular INR monitoring - INR can be affected by many drugs and foods
44
What is the half life of warfarin?
40 hours - anticoagulant effects lasts days
45
When is LMWH e.g. enoxaparin used for AF?
Rarely for patients who cannot tolerate oral treatment - involves daily treatment dose injections
46
When is atrial ablation an option for AF treatment?
For some patients who have uncontrolled symptoms and have an identifiable locus in their left atrium
47
What are complications of AF (from uncontrolled HR, embolism or anticoagulation)?
1) HF
2) Systemic emboli - ischaemic stroke, mesenteric ischaemia, acute limb ischaemia
3) Bleeding - GI, intracranial
48
What defines a narrow complex tachycardia?
QRS complex < 120ms (three small squares on ECG)
49
How do you assess a patient with narrow complex tachycardia?
ABCDE
50
How do you manage a narrow complex tachycardia (incl. AF) in a patient that shows adverse features (shock, syncope, acute pulmonary oedema or myocardial ischaemia (chest pain)?
Synchronised DC cardioversion
(Emergency/immediate synchronised direct current cardioversion/shock)
51
How is a broad complex tachycardia defined?
QRS complex > 120ms
52
What are adverse features in a patient with narrow complex tachycardia?
1) Shock
2) Syncope
3) Acute pulmonary oedema
4) Myocardial ischaemia - chest pain
53
What do you need to know to determine management in a haemodynamically stable patient with narrow complex tachycardia?
Whether it is regular or irregular
54
How do you manage regular narrow complex tachycardia (SVT) in a haemodynamically stable patient?
1) Vagal manoeuvres - carotid sinus massage or valsalva manoeuvres
2) Then IV adenosine 6mg
3) Then IV adenosine 12mg
4) then IV adenosine 18mg
55
What is the first line management of a regular narrow complex tachycardia in a haemodynamically stable patient?
Vagal manoeuvres - carotid sinus massage or valsalva manoeuvres
56
What is second line management of regular narrow complex tachycardia in a haemodynamically stable patient if vagal manoeuvres fail?
IV adenosine 6mg
57
What is third line management of regular narrow complex tachycardia in a haemodynamically stable patient?
IV adenosine 12mg
58
What is fourth line management of regular narrow complex tachycardia in a haemodynamically stable patient?
IV adenosine 18mg
59
What is the most likely diagnosis in irregular narrow complex tachycardia?
Atrial fibrillation
60
What condition do you manage irregular narrow complex tachycardia?
AF
61
What is another name for regular narrow complex tachycardias?
Supraventricular tachycardias (SVT)
62
What are the two types/causes of narrow complex tachycardias?
1) SVT (regular)
2) AF (irregular)
63
How do you manage acute AF (irregular narrow complex tachycardia) in a haemodynamically stable patient with onset < 48h?
Rhythm control
1) LMWH followed by flecainide (if no heart disease)
2) LMWH followed by amiodarone (if heart disease)
64
In which patients can you use flecainide to rhythm control acute AF with onset < 48h?
Healthy - NO heart disease
65
How do you manage acute AF (irregular narrow complex tachycardia) in a haemodynamically stable patient with onset > 48h?
Rate control
1) Metoprolol or bisoprolol or verapamil
2) Digoxin if signs of heart failure
3) Anticoagulation
66
How do you manage acute narrow complex tachycardia in a patient who is not haemodynamically stable?
Synchronised DC shock
67
What condition is an irregular broad complex tachycardia presumed to be?
VF
68
Is VF pulse or pulseless?
Always pulseless
69
What do the QRS complexes look like in VF?
Polymorphic + irregular
70
Which guidelines dictate VF management
ALS
71
What are the initial priorities in VF?
BLS
1) Ensure airway is patent
2) Check for signs of life (pulse and breathing)
3) Commence CPR
72
Is VF shockable?
Yes
73
What is first line management of VF?
Defibrillation - unsynchronised cardioversion using 200J biphasic shock
74
What type of shock do you give in VF?
200J biphasic shock
75
How do you manage VF?
1) Check airway, signs of life + commence CPR
2) Defibrillation - unsynchronised cardioversion using 200J biphasic shock
3) Resume chest compressions (CPR) for 2 mins before re-checking rhythm
4) After the 3rd shock - 1mg adrenaline IV (10ml 1:10,000) + 300mg amiodarone IV
5) Continue to administer adrenaline every 3-5 mins after every alternate shock
76
What is the medical management of VF/pulseless VT?
After 3rd shock
1) IV adrenaline 1mg (10ml 1:10,000) + IV amiodarone 300mg
Every 3-5 mins after every alternate shock:
2) IV adrenaline 1mg (10ml 1:10,000)
77
What are the features of ventricular tachycardia on ECG?
Absent P waves + monomorphic regular broad QRS complexes
78
What is the rhythm in VF?
Irregular
79
What is the rhythm in VT?
Regular
80
How do you manage pulseless VT?
Same as VF
1) Check airway, signs of life + commence CPR
2) Defibrillation - unsynchronised cardioversion using 200J biphasic shock
3) Resume chest compressions (CPR) for 2 mins before re-checking rhythm
4) After the 3rd shock - 1mg adrenaline IV (10ml 1:10,000) + 300mg amiodarone IV
5) Continue to administer adrenaline every 3-5 mins after every alternate shock
81
How long do you carry out CPR for after unsynchronised shock (defibrillation) before re-checking the rhythm?
2 minutes
82
How do you manage VT or torsades de pointes with a pulse and adverse features (shock, syncope, myocardial ischaemia (chest pain) or heart failure (acute pulmonary oedema)?
1) Synchronised DC shock - up to 3 attempts
2) Seek expert help
3) IV amiodarone 300mg over 10-20 mins
4) IV amiodarone 900mg over 24h
83
What is the first line management of VT with pulse and adverse features?
Synchronised DC shock
84
What is medical management of VT or torsades de pointes with pulse and adverse features?
After 3 attempts of synchronised DC shock + seeking expert help:
1) IV amiodarone 300mg over 10-20 mins
2) IV amiodarone 900mg over 24h
85
How do you manage VT with pulse and NO adverse features?
AMIODARONE
1) IV amiodarone 300mg over 20-60 mins
2) IV amiodarone 900mg over 24h
86
What is Torsades de Pointes (TdP)?
A form of polymorphic VT caused by QT prolongation
87
Is torsades de pointes regular or irregular?
Can be either
88
What does torsades de pointes look like on ECG?
QRS complexes twisting around the isoelectric line
89
What are causes of torsades de pointes?
1) Congenital long QT syndromes e.g. Romano Ward syndrome, Jervell and Lange-Neilsen syndrome
2) Medication - antiarrhythmics, erythromycin/clarithromycin, TCAs, antipsychotics, ketoconazole
3) MI
4) Renal/liver failure
5) Hypothyroidism
6) AV block
7) Toxins
90
What medications can cause torsades de pointes?
1) Antiarrhythmics
2) Antibiotics e.g. erythromycin/clarithromycin
3) TCAs
4) Antipsychotics
5) Ketoconazole
91
What are cardiac causes of torsades de pointes?
1) Congenital long QT syndromes e.g. Romano Ward syndrome, Jervell and Lange-Neilsen syndrome
2) MI
3) AV/heart block
92
What are other causes of torsades de pointes?
1) Renal/liver failure
2) Hypothyroidism
3) Toxins
93
How do you manage torsades de pointes in haemodynamically unstable patients?
Same as VT - synchronised DC shock + IV amiodarone
94
How do you manage torsades de pointes in haemodynamically stable patients?
1) IV magnesium sulphate - 2g over 10 mins
2) Stop offending drugs that prolong the QT interval
3) Correct electrolyte abnormalities esp. hypokalaemia and hypomagnesaemia
4) Consider isoprenaline infusion and temporary/permanent pacing
95
What is the most important first line treatment in torsades de points in haemodynamically stable patients?
IV magnesium sulphate (2g over 10 mins)
96
What can be used in patients with recurrent torsades de pointes despite initial therapy with magnesium sulphate?
Isoprenaline infusion + temporary/permanent pacing
97
Which electrolyte abnormalities are especially important to correct in torsades de pointes?
Hypokalaemia + hypomagnesaemia
98
Which part of the heart is affected in narrow complex tachycardia?
Atria
99
Which part of the heart is affected in broad complex tachycardia?
Ventricles
100
What are indications for transcutaneous pacing in tachyarrhythmias?
Patients unresponsive to medical management e.g. patients with SVT failing to respond to vagal manoeuvres and adenosine
101
Which tachyarrhythmias require pacemakers?
Those that are resistant to pharmacological therapy
102
What type of permanent pacemakers are used in tachyarrhythmias resistant to pharmacological therapy?
1) These forms of permanent pacing are typically dual chamber (with one lead in the right atrium and one lead in the right ventricle)
2) Bi-ventricular pacemaker (in which a 3rd wire is placed in a branch of the coronary sinus, to allow left ventricular pacing and ventricular synchronisation) is an option if the left ventricular ejection fraction is <35%
103
What type of arrhythmia does Wolff Parkinson White syndrome (WPW) lead to?
Supraventricular tachycardia (SVT)
104
What causes WPW?
1) A congenital accessory electrical pathway connects the atria to the ventricles bypassing the AV node
2) The accessory pathway leads to the potential for re-entrant circuits to form leading to SVTs
105
Who is more affected by WPW?
Men (2:1)
106
How does WPW present?
Asymptomatic OR
1) Palpitations
2) Dizziness
3) Syncope
107
What do you see on an ECG in WPW?
1) Delta waves - slurred upstroke in QRS
2) Short PR interval < 120ms
3) Broad QRS
4) OR narrow complex tachycardia if a re-entrant circuit has developed
108
What investigations are done for WPW?
1) ECG
2) 24h ECG monitoring - if paroxysmal symptoms
3) Routine bloods - incl. TFTs if non-cardiac causes of tachycardia are suspected
4) Echo - to assess ventricular function
5) Intracardiac electrophysiological studies to map the location of the accessory pathway
109
What investigation is done in WPW if patients have paroxysmal symptoms?
24h ECG
110
Why is an echo done in WPW?
To assess ventricular function
111
What investigation can be done in WPW to map the location of the accessory pathway?
Intracardiac electrophysiological studies
112
How do you treat WPW?
1) Radiofrequency ablation of the accessory pathway
2) Drug treatment e.g. amiodarone or sotalol to avoid further tachyarrhythmias (CI in heart disease)
3) Surgical (open heart) ablation - rarely done, only used in complex cases
113
How do you definitively treat WPW?
Radiofrequency ablation of the accessory pathway
114
How can you try and avoid further tachyarrhythmias in WPW?
Drug treatment - e.g. amiodarone or sotalol (CI in structural heart disease)
115
Which two drugs are contraindicated in WPW for long term use and why?
Digoxin and NDP-CCBs e.g. verapamil - they may precipitate VF
116
How do you manage an SVT in an unstable patient with WPW?
Urgent DC cardioversion (regardless of rhythm)
117
What are signs of an unstable WPW patient with SVT?
1) BP < 90/60
2) Signs of systemic hypoperfusion
3) Fast AF
118
What is an orthodromic AV reciprocating tachycardia?
Narrow QRS complex + short PR interval (in WPW)
119
In which condition is a orthodromic and antidromic AV reciprocating tachycardia seen?
WPW
120
How do you manage a WPW stable patient with orthodromic AV reciprocating tachycardia (narrow QRS + short PR)?
Like SVT
1) Vagal manoeuvres (carotid sinus massage or valsalva manoeuvre)
2) IV adenosine
121
What happens in orthodromic AV reciprocating tachycardia in WPW?
1) One limb of the aberrant circuit involves the AV node
2) So slowing conduction through the AV node helps terminate the tachycardia
122
What is antidromic AV reciprocating tachycardia?
Wide QRS complex
123
How do you treat stable WPW patients with antidromic AV reciprocating tachycardia, AF or atrial flutter?
IV procainamide or flecainide (antiarrhythmics) - help prevent rapid conduction through the accessory pathway
124
What can be used in stable WPW patients with ortho/antidromic AV reciprocating tachycardia, AF or atrial flutter if symptoms persist?
DC cardioversion
125
What is Brugada syndrome?
Genetic condition caused by sodium channelopathies
126
Where is the mutation in Brugada syndrome?
Sodium channels
127
In which patients is incidence of Brugada syndrome high?
Southeast Asian males
128
What is Brugada syndrome a common cause of?
Sudden cardiac death
129
How does Brugada syndrome present?
Asymptomatic OR
1) Palpitations
2) Syncope
Due to AV nodal re-entrant tachycardias (AVNRTs), VT or VF
130
What arrhythmias can Brugada syndrome cause?
AV nodal re-entrant tachycardias (AVNRTs), VT or VF
131
How is Brugada syndrome diagnosed?
Characteristic ECG changes + at least one clinical criterion:
1) VF or polymorphic VT
2) Family history of sudden cardiac death under the age of 45
3) Syncope or ECG signs in the family
4) Inducible VT
5) Nocturnal agonal breathing
132
What is a key clinical sign in Brugada syndrome?
Nocturnal agonal breathing
133
What investigations are used for diagnosis of Brugada syndrome?
1) ECG
2) Genetic testing
3) Family history
4) Special provocation tests e.g. ajmaline
134
What risk factors can increase the risk of arrhythmia in Brugada syndrome?
1) Fever
2) Excess alcohol intake
3) Dehydration
4) Medication
5) Electrolyte abnormalities
135
What advice should patients with Brugada syndrome be given?
To avoid risk factors for arrhythmia (e.g. excess alcohol) or take prompt action e.g. taking paracetamol if they have any fever
136
Which medications can increase the risk of arrhythmia in Brugada syndrome?
1) Antiarrhythmics e.g. flecainide
2) Verapamil
3) Antidepressants e.g. amitriptyline
137
What is definitive management of Brugada syndrome?
ICD - to reduce the risk of sudden death from arrhythmias e.g. VT or VF
