Palpitations/ECG Flashcards
Questions to ask to clarify palpitations?
Onset:
- When and how did it start?
- Sudden vs gradual onset?
- Dehydration, fear, food
Character:
- Fast, slow, or irregular?
- Did you check your pulse at the time?
Timecourse:
- Precipitating/relieving factors (exercise is a red flag)
- Duration
- Resolution - fast/slow, confusion?
- Previous episodes/FHx (e.g. sudden death)
Associated symptoms of palpitations
Dyspnoea
Syncope -> seizures/witnesses
Dizziness/light-headedness
Chest pain
Differential for irregular fast palpitations
Atrial flutter, atrial fibrillation
Important PMHx for palpitations
Rheumatic fever
Angina/IHD
Previous ECG monitoring/angiograms
Diabetes
HTN
Operations (e.g. CABG)
Thyroid function
Valvular heart disease
Differential for slow palpitations
Drug-related bradycardias, ventricular bigeminy, heart block
Differential for regular fast palpitations
SVTs:
AVNRT (young women, 70% of SVTs)
AVRT: Assoc w/ WPW syndrome
Differential for ‘missed beats’
Atrial, ventricular ectopics
What is atrial fibrillation?
Irregular atrial rhythm from extranodal depolarisation –> variable conduction through AVN leads to irregular ventricular rhythm
What is the main risk/complication of AF?
Embolic stroke
Causes of AF?
IHD
Mitral valve disease/rheumatic heart disease
Hypertension
Thyrotoxicosis
Precipitants:
- Pneumonia/endocarditis
- PE
- Caffeine, alcohol, post-op
- Hypokalaemia/Hypomagnasaemia
Management of acute AF in unstable patient
DC cardioversion
Management of acute AF in stable patient within 48h of onset
Rate OR rhythm control (DC cardioversion or flecainide)
Give heparin if DC cardioversion delayed
Correct underlying
Management of acute AF in stable patient >48h from onset
Rate control only!
Need >3wks anticoagulation before rhythm control
Pharmacological rate control in AF
Ca channel blockers (non-dihydropiridine, e.g. verapamil/diltiazem not amlodipine)
Beta blockers (e.g. bisoprolol)
Digoxin
Rhythm control for AF
Beta blocker
Sotalol
Amiodarone
Flecainide
Electricity
Contraindications for flecainide
Structural heart disease (e.g. previous MI)
Ischaemic heart disease
Management of chronic AF
Anticoagulate with DOAC (e.g. apixaban) or warfarin
Management of atrial flutter
Same as atrial fibrillation!
DC cardioversion preferred
Lifestyle risk factors for atrial flutters/arrhythmias
Stress
Caffeine
Alcohol
Nicotine
Contraindications of atropine for bradycardia
Mobitz Type II/complete heart block (only affects SAN not AVN)
Long Q-T –> increase risk of ectopics –> torsades de pointes
Differential for narrow-complex tachycardia
Atrial flutter, atrial tachycardia
AV nodal reentrant tachycardia (75% of SVTs, younger women)
AV reentrant tachycardia (associated with WPW)
Which tachycardia is treated with adenosine
AVNRT (adenosine blocks AVN only!)
ECG features of WPW
Short PR interval
Delta wave (slurred upstroke of QRS)
Differential of broad-complex tachycardia
Ventricular tachycardia (80% of broad-complex tachys, 95% of those w/ pre-existing heart disease)
SVT + WPW/BBB
Initial treatment of broad-complex tachycardia
Lidocaine
Differentiating VT from SVT + BBB
LAD, regularity, QRS >160ms –> Suggest VT
T-wave inversion + palpitations DDx
LV hypertrophy/LBBB: Aortic stenosis, HTN
RV hypertrophy: Pulmonary HTN
Hypertrophic cardiomyopathy (young patients)
What is pre-excited AF?
AF + re-entry circuit (e.g. WPW) –> Fast + irregular QRS (>200) –> predispose to VT/VF
Causes of prolonged Q-T syndrome
Anti-arrhythmic drugs: e.g. amiodarone, sotalol
Psychiatric drugs: Tricyclic antidepressants, antipsychotics
Antimicrobial drugs: macrolides, antimalarials
5 hypos: Hypothyroid, hypothermia, hypokalaemia, hypocalcaemia, hypomagnasaemia
What causes torsades de pointes
QRS ectopic landing on T-wave
How do you calculate corrected Q-T interval (should be <450)
QT/sqrt(RR interval)
Management of VT
DC cardioversion
Correct K+ and Mg2+ via central line
Amiodarone via central line if refractory
Prolonged PR interval
First degree heart block
Mobitz Type II block
Form of second degree heart block
Some P waves not followed by QRS complexes
Leads where T-wave inversion is normal
VR
III
V1-V2
(V3-V4 in black people)
Normal septal Q waves
I, VL, V6
<1x2mm
Causes of LBBB
MI
Myocardial fibrosis: HTN/AS/HCM –> LV hypertrophy
Peaked P waves
P Pulmonale
RA hypertrophy: Tricuspid stenosis, pulmonary HTN
Bifid P waves
M-shaped –> P mitrale
LA hypertrophy (mitral stenosis)
ECG changes RV hypertrophy
Dominant R wave in V1, deep S wave in V6
RAD
Peaked P waves
?T-wave inversion in V1-V2
Posterior MI
Dominant R wave in V1
T-wave inversion differential
STEMI (if Q waves or ST changes)
NSTEMI: no Q-waves/ST changes
Ventricularl hypertrophy
BBB
Digoxin treatment (reverse tick)
ECG effects of hypokalaemia/hypomagnasaemia
Flattened T wave
Presence of U wave
Prolonged PR interval
Increased P-wave amplitude
ECG effects of hyperkalaemia/hypermagnasaemia
Peaked T waves
Prolonged PR interval
Flattened P waves
Broad QRS complexes
Symmetric T-wave inversion in non-coronary distribution
HOCM
Causes of raised troponin
MI
Myocarditis
SVT
HF
PE
Renal failure
severe sepsis
