54. Palpitation/arrhythmia Flashcards
Define palpitation
The sensation of an abnormally perceived heartbeat (may be abnormally fast, slow, irregular, forceful)
Causes of palpitations (cardiac and non-cardiac).
a) Most common
b) Others
a) - Cardiac: Atrial fibrillation, Sinus tachycardia, Ventricular ectopics
- Non-cardiac: Panic attack/ anxiety, drug-induced (B2-agonists, caffeine, alcohol, stimulants)
b) - Cardiac: bradyarrhythmias (e.g. heart block), tachyarrhythmias (e.g. atrial flutter, SVT, VT), Long QT (and Torsades de Pointes), Aberrant pathways (e.g. WPW),
- Non-cardiac: thyroid, adrenal, anaemia, fever, etc.
Workup for palpitations.
a) History
b) Exam
c) Ix
a) HPC - onset, duration, triggers/relieving factors, associated symptoms (SOB, CP, anxiety, syncope, endocrine symptoms, etc.)
PMHx - cardiac disease, systemic illness
DHx - stimulants (e.g. beta-agonists)
FHx - sudden cardiac death
b) CV, pulse and BP, general health
c) - 12 lead ECG (ambulatory ECG / cardiac monitoring if non-conclusive)
- Bloods: FBC, UEs, TFTs, LFTs, glucose, calcium, magnesium. toxicology
- Special tests (if required): ECHO, exercise ECG, implantable loop recorder
Palpitations - red flags (urgent admission/ referral)
- Cardiac sx: CP, SOB, syncope or near-syncope, onset precipitated by exercise
- Focal neurology
- Family history of sudden cardiac death < 40 years.
- Cardiac history - eg, coronary heart disease, heart failure, cardiomyopathy, valve disease.
- Examination - Haemodynamically unstable (HR/ BP)
- ECG - suggestive of serious pathology (e.g. VT/VF, fast AF or SVT not responsive to vagal manoeuvres)
Tachycardias.
a) Narrow complex - define. Examples
b) Broad complex - define. Examples
c) Which is worse?
a) Tachy (>100 bpm) + QRS < 120 ms (< 3 small squares). Impulse is conducted normally via the AVN.
- DDx: sinus tachy (physiological - fever, pain, anaemia, exercise, stress), AF (irregular), flutter, SVT, AVRT (e.g. WPW), drug-induced
b) Tachy (>100 bpm) + QRS > 120 ms (> 3 small squares). Impulse does not conduct via the AVN properly.
- DDx: VTs, VF, any SVT with aberrant conduction like a bundle branch block (inc SVT, AF, flutter, WPW)
c) Broad complex usually a sign of ischaemic damage and confer worse prognosis. Also can degenerate into VF and more commonly haemodynamically unstable
Acute management of tachyarrhythmias.
a) Initial
b) If haemodynamically unstable - ?
c) If stable (dependent on cause - SVT, AF, flutter)
a) A-E (oxygen, IV access)
- monitor, ECG, bloods, etc
b) - VF/Pulseless VT: CPR + defibrillation
- Others: cardioversion (DC or amiodarone), or specific treatments (e.g. adenosine for SVT)
c) Establish cause and treat reversible causes (e.g. electrolyte abnormalities, thyroid disease)
- SVT: vagal manoeuvres (note - do not affect VT), Adenosine 6mg, then 12mg x2
- AF/flutter: <48h (DC/amiodarone), >48h (rate control with IV beta-blocker or digoxin)
- VT (pulse present): A-E approach (CPR if required), DC cardioversion or IV antiarrythmic (e.g. lidocaine)
- Pulseless VT/VF: ALS (CPR + defibrillation)
Long-term management of tachyarrhythmias
a) SVT
b) AF / flutter
c) WPW
d) VT
a) Rate control: BB/verapamil
b) - Rate control: BB/verapamil (+ digoxin)
- If this fails, rhythm control
- Anticoagulate (based on CHADSVASc)
- If required, cardioversion after 4 weeks anticoagulation
- Radio-ablation (AF - pulmonary veins; flutter - focal ablation of re-entry circuit)
c) Radiofrequency ablation of aberrant pathway
- If unsuccessful - rate control with BB/verapamil
d) ICD if sustained VT with complications (e.g. previous arrest or syncope, reduced ejection fraction, etc.)
Bradycardia.
a) Causes (cardiac and non-cardiac)
b) AV nodal blocking agents (ABCD)
c) Differentiating physiological from pathological
d) Investigations
a) - Non-cardiac: Physiological (e.g. athletes), drug induced, hypoxia, hypothyroid, hypothermia, Cushing’s reflex (HTN, low HR, abnormal resps)
- Cardiac: sick sinus syndrome, heart block
b) Adenosine, amiodarone
Beta blockers
Calcium channel blockers (verapamil / diltiazem)
Digoxin
c) - Exercise testing - if physiological should have good exercise tolerance with appropriate increase in HR
- Associated symptoms - e.g syncope/ near-syncope, systemic symptoms, hypotension, heart failure
d) - 12-lead ECG (ambulatory if non-conclusive)
- Bloods: FBC, UEs, TFTs, glucose, cardiac enzymes, calcium, magnesium. toxicology
Types of VT
Monomorphic
Polymorphic (e.g. Torsades)
Management of bradycardia
a) Initial
b) Drug management
a) - 12 lead ECG and bloods
- Identify any underlying cause and treat any reversible causes (e.g. remove offending medications, correct electrolyte abnormality)
- A-E assessment (including oxygen and IV access; resuscitate if required)
b) - IV atropine (alternatives: glycopyrrolate, dopamine)
- If persistent: cardiac pacing
Sick sinus syndrome.
a) Types
b) Causes
c) Presentation
d) Management
a) Alternating tachycardia and bradycardia (tachy-brady syndrome), bradyarrhythmias (e.g. heart block) or tachyarrhythmias (e.g. AF)
b) Intrinsic SA node disease: idiopathic, amyloidosis, ischaemia, cardiomyopathy
- Extrinsic causes: electrolyte, hypothermia, sepsis, thyroid disease
c) Asymptomatic, fatigue, dizziness, syncope, palpitations
d) - Identify and treat any causes (12-lead ECG, bloods)
- Pacemaker
Antiarrhythmics - side effects
a) Amiodarone
b) Fleicainide
c) Sotalol
a) Arrhythmias; hepatic disorders; hyper/hypothyroidism; nausea; respiratory disorders (eg fibrosis); skin reactions (eg blue discolouration) and photosensitivity; corneal deposits
b)
c)
Indications for ICD
a) Primary prevention
b) Secondary prevention
a) Familial conditions associated with sudden cardiac death, for example:
- Long QT syndrome
- Hypertrophic cardiomyopathy
- Brugada’s syndrome
- Arrhythmogenic right ventricular dysplasia.
b) - Sustained VT causing syncope.
- Sustained VT with ejection fraction < 35%.
- Previous cardiac arrest due to VT or VF.
- Myocardial infarction complicated by non-sustained VT, or inducible VT on electrophysiological testing
Sepsis and arrhythmias
Sepsis (particularly if feverish) can lead to sinus tachycardia, but also arrhythmias like AF
Resolution of the infection should lead to restoration of sinus rhythm
