atrial fibrillation and flutter

Question 1

supra ventricular tachycardia?

Answer 1

AV node re-entry (AVNRT) • Accessory pathway re-entry (AVRT) • Atrial tachycardia (AT)
result from…
“AV node dependent”
Generally narrow QRS (≤ 120 ms).

Question 2

avnrt?

Answer 2

V1 - p wave right after QRS III - Inverted p wave right after QRS; pseudo s wave

Question 3

re entrant arrythmia pathway?

Answer 3

1. orthodromic ap to avn to hb to ap 2. antidromic ap to hb to avn to ap

Question 4

ecg of orthodromic AVRT?

Answer 4

retrograde P waves some distance after QRS

Question 5

node dependent re entrant tachycardias; management?

Answer 5

vagotonic manoeuvres: 1. carotid massage, 2. cough, 3. valsava. drugs: 1. adenosine, 2. verapamil, 3. beta blockers

Question 6

adenosine?

Answer 6

Induces transient block in AV node
- stops SVT that is node-dependent
- unmasks atrial activity in AT (& sometimes terminates it)
• Contraindicated in asthmatics

Question 7

management of node dependent SVT?

Answer 7

Reassure – Benign (unless underlying coronary disease or LV failure)
treatment: • Do nothing – PRN A&E visit for Adenosine • Drug therapy - ⅓ chance of being both effective and well-tolerated • Catheter ablation - > 95% cure rate - 1% - 2% complication rate - Now offered as 1st line therapy

Question 8

wolff parkinson white syndrome?

Answer 8

short PR interval, delta wave, increase QRSd pre excited ECG=accessory pathway; pre excited ECG + symptoms = WPW syndrome

Question 9

problem with antegrade ap conduction: VF/SCD from AF?

Answer 9

Risk of VF / SCD depends on antegrade RP of AP
A long antegrade RP does not preclude AVRT, but patient won’t be at risk of SCD during AF

Question 10

accessory pathway?

Answer 10

Antegrade Conduction • Pre-excited ECG  •  + symptoms = WPW
 Retrograde Conduction (Concealed AP) •  Normal ECG  •  Potential for AVRT  •  No risk of VF / SCD

Question 11

add focal at pic

Question 12

atrial fib and flutter?

Answer 12

Confirm with ECG • 1st priority: control heart rate & provide adequate antithrombotic Rx • Elucidate cause • For AF, long term, decide rate vs rhythm control • For AFL, almost always ablate

Question 13

af why bother?

Answer 13

Commonest sustained arrhythmia (0.7% in 55-59 yr; 18% in those >85yr); prevalence to double next 50 yrs
Overall risk of thromboembolism : 5% / yr; majority are embolic strokes
1/3 of strokes in > 80‘s is due to AF
Stroke risk can be ameliorated
Only 25% of AF patients admitted with stroke are anticoagulated Hospitalisation cost : US$5 billion in 2008/9

Question 14

af venus triggers?

Answer 14

Pulmonary Veins (top cause) • Superior vena cava • Coronary sinus • Ligament of Marshall

Question 15

add peri atrial ganglia

Question 16

af predisposing factors?

Answer 16

Age • Hypertension • Valvular heart disease • Cardiomyopathy • ASD • Congenital heart disease • IHD • Pericarditis
• Thyroid dysfunction • Lung disease e.g. COPD / PE / Pneumonia • DM • Alcoholism • Sleep Apnoea • Obesity • Chronic Renal disease

Question 17

af types?

Answer 17

1. first detected: only one diagnosed episode, 2. paroxysmal: recurrent episodes that self terminate in less than 7 days, 3. persistent: recurrent episodes that last moee than 7 days, 3. permanent: an ongoing lomg tterm episode

Question 18

af clinical manifestation?

Answer 18

Silent (e.g. detected by practice nurse measuring BP) Palpitations Fatigue Effort intolerance / dyspnoea Dizziness TIA / Stroke Acutely ischaemic limb or bowel
Paroxysmal Recurrent AF - self terminate in < 7 days, & usu within 48 h Persistent Recurrent episodes, ea ≥ 7 days (Long-standing Persistent) Persistent for > 1 yr Permanent When SR is no longer deemed possible
Paroxysmal AF carries the same stroke risk as persistent or permanent AF

Question 19

af management plan?

Answer 19

add poc

Question 20

af basic evaluation?

Answer 20

Symptoms? Severity? Date of onset, duration, frequency Co-morbid disease (?DM ?prev CVA ?alcohol abuse ?thyroid) Previous Rx BP (? HT; ? haemodynamic instability) HR (? tachycardia) Heart murmurs / signs of heart failure (? valve or structural disease) Goitre / signs of lung disease 1st line Ix : ECG / TFT / biochemistry / Echo 2nd line Ix : Ambulatory rhythm recording, CXR, ETT, etc

Question 21

af stroke risk

Answer 21

add chad pic

Question 22

af: aspirin or warfarin?

Answer 22

20% RRR of stroke with Aspirin • 70% RRR of stroke with Warfarin (INR 2 -3)
• Balance between stroke risk vs bleeding risk
• Stroke risk: CHADS • Bleeding risk: HAS-BLED

Question 23

bleeding risk?

Answer 23

has bled Hypertension (>160 mmHg systolic) 1 • Abnormal liver or renal function (Cr >200) (1 pt each) 1 or 2 • Stroke (esp lacunar stroke) 1 • Bleeding Hx or predisposition (e.g. anaemia) 1 • Labile INR 1 • Elderly (> 65 yr) 1 • Drugs (NSAID) / alcohol x‘s (>8u / wk) (1pt each) 1 or 2 (Max 9 points)

Question 24

how to treat?

Answer 24

Maintaining sinus rhythm with AAD has no mortality benefit over simple rate-control of the arrhythmia.
• Decision to restore sinus rhythm, or just manage ventricular rate, is dictated by severity of AF symptoms & QoL.

Question 25

stratergy for management of sr?

Answer 25

add pic

Question 26

who should be selected?

Answer 26

add pic

Question 27

drugs for rate control?

Answer 27

β-blockers (Atenolol, Bisoprolol, Metoprolol) avoid in acute decompensated heart failure; AFFIRM study
• Calcium antagonists (Diltiazem, Verapamil) avoid in acute decompensated heart failure
• Digoxin (often used in combination with above; caution in renal failure, elderly)
AF: target H

Question 28

what to do in the middle of the night?

Answer 28

If AF < 48 hr, give LMWH, rate-limit or cardiovert (DC or drug).
If AF > 48 hr or unsure, give LMWH, then either rate-limit or cardiovert (after TOE). Then reassess.
If plan to cardiovert electively, therapeutic INR for at least 3 weeks pre- and then for 4 weeks post-cardioversion.
Regardless of AF duration, if presentation with acute heart failure / shock, give LWMH, urgent rate-control, urgent Echo, and often cardioversion (after TOE).

Question 29

atrial flutter?

Answer 29

Less common than AF, but frequently co-exists with AF, and may be more troublesome
Shares same pre-disposing factors as AF, but particularly after atrial surgery
2 types: (1) CTI-dependent (A) Counterclockwise / Typical (B) Clockwise (2) Non-CTI dependent
Managed as per AF: i.e. thrombophylaxis + rate / rhythm-control (DC cardioversion, ablation, drugs).
Generally drug-resistant, but exquisitely sensitive to DC cardioversion.
Tends to recur, so ablation is 1st line Rx if uncompromised (esp if CCW CTI- dependent).