Arrhythmias Flashcards
Associated risk factors of AF
Increasing AGE greatest risk factor
M > F
HTN, Valvular HD - MS+++, HOCM, Hyperthyroidism, Obesity, DM
What is the associated increased in all cause mortality from AF. Why?
1.5-2x increase in mortality
Due to stroke and other thromboembolic disease, heart failure
Pathogenesis of AF
Left atrial stretch
Increase risk with family history
Inflammation
Metabolic syndrome
AF mechanisms
1st stage: Arrhythmic foci extending into the pulmonary veins –> recurrent paroxysmal AF lasting <24hrs
2nd stage: Arrhythmic burden +/- other cardiac factors –> remodeling –> persistent AF
3rd stage: Gross electrical and structural remodeling –> permanent AF
Management of new onset AF <48hrs
REVERT!!!
TTE, Renal functions and TFTs should be done
Anticoagulate as per CHAD2S
Management of AF >48hrs/???
TOE, revert and anticoagulate for at least 6 weeks
Anticoagulate for 4-6 weeks then revert
? Urgent Cardioversion?
Unstable patient haemodynamics
Sinus rhythm maintenance for paroxysmal AF?
Sotalol - MAINTENANCE NOT REVERSION. Causes fatigue
Amiodarone - Effective BUT SIDE EFFECTS = Thyroid, pulmonary, hepatic and occular
Flecainide - Very effective at reverting. Can’t use in pts with structural heart disease. Side effects of GIT and dysthesias, and can cause A flutter
Rate Vs. Rhythm control
Not relevant to recent AF
Not relevant to symptomatic AF
Not relevant to anticoagulation
PERSISTENT ASYMPTOMATIC AF- AFFIRM trial
AF Rate control agents?
Beta blockers
Calcium calcium blocker- NOT IN HF
Digoxin
Aim <110 bpm
AF Ablation?
For symptomatic AF refractory to meds
60-70% successful
Does not improve outcomes
Mechanism of atrial flutter
Macro re-entrant circuit in the RA between the IVC and tricuspid valve
Counterclockwise motion –> downward p waves in ii, iii and aVF
Treatment for Atrial Flutter?
Ablation
Success in 90%
Anticoagulate as per AF
Risk stratification for anti-thromboembolism therapy?
CHADS2 CCF =1 HTN =1 Age >75yrs =1 DM =1 Previous stroke =2
Score of 0 = nothing
Scores 1-2 = 2% risk = anticoagulate
Scores 3+ = 4% risk = anticoagulate
Anticoagulate with what?
NOAC or Warfarin
Not aspirin
No NOAC for valvular heart disease
AV nodal reentry tachycardia
2 conduction pathways in the AV node with the slow pathway blocked by the refractory period
When a premature complex occurs –> conduction through the slow pathway –> retrograde p wave –> tachycardia
Prevention of AVNRT
Verapamil
EPS
Treatment of AVNRT
Vagal maneuvres
Adenosine
CCBs
B blockers
Different manifestations of WPW
- Accessory pathway
- Orthodromic tachycardia - long QRSP. Down slow and up fast
- Antidromic Tachycardia = wide complex tachycardia - looks like VT. Down fast pathway and up slow pathway –> Torsades
Investigation of WPW
Exercise test to assess pathway conduction. Loss of delta wave <130bpm is predictor of low risk
Different kinds of VT
- Associated with structural HD - post MI, ischaemic and non-ischaemic cardiomyopathy, myocarditis and infiltrative cardiac diseases
- Not ass. with structural heart disease
Treatment of VT with structural heart disease
= AICD!!!
Primary prophylaxis with IHD
Post AMI = beta blockers –> reduction by 30%
AICD for EF <35% >40 days post AMI.
Primary prevention in non-ischaemic cardiomyopathy
Optimise medical therapy
Beta blockers
CRT for QRS >120ms
CRT for class 4 heart failure
Commonest cause of SCD <35yrs
HOCM
Diagnosis of HOCM
ECG !!! Inverted T waves V4-V6. Still negative in 10%
Genetic tests - genes found in 60% of cases = used to screen other family members
? AICD for HOCM
Average risk .05% but range from 0-10%
Family hx of SCD Unexplained syncope nsVT on monitoring IVS> 30mm Abnormal BP during exercise
Arrhythmogenic RV cardiomyopathy genetics
Mutations in genes coding desmosomal proteins
Identified in 40-60%
Not diagnostic - incomplete penetrance
Diagnosis of Cardiac Sarcoidosis
Cardiac MRI
Aneurysms and enhancements
Genetics of long QT syndrome
LQTS1 = KCNQ1 LQTS2= KCNQ2 LQTS3 = SCN5A
Autosomal dominant
70-80% positive gene test
When do events occur in LQTS?
LQTS1 - events in exercise
LQTS2- load noise
LQTS3- events during sleep or rest
BIGGEST RISK WHEN QT >500
Management of LQTS
Beta blockers for all
AICD for high risk and previous events
Brugada Syndrome
Diagnosis on ECG - downsloping ST segment
Peak prevalence of SCD in 4th decade
Elicit with flecainide challenge
Other Syndromes
Catecholaminergic polymorphic VT
Short QT syndrome
Idiopathic VT
1st degree heart block
PR >0.2 secs
Benign
Unless bifascicular block –> advanced block
2nd degree heart block
Type 1:
- Increasing PR interval –> dropped QRS
- No indication for PPM
Type 2:
- No variation in PR interval - non conducted P waves
- PPM if very bradycardic
3rd degree heart block
PPM unless asymptomatic and rate >40
Pacing in heart failure
LVEF <50% = bi-ventricluar pacing
Results in less death and heart failure hospitalisations
How do you distinguish between constrictive pericarditis and restrictive cardiomyopathy?
Tissue Doppler imaging
Constrictive PC = fast and large E wave
Restrictive CM = slow and small E wave
