| Atrial Fibrillation: Definition & symptoms | - DEF: rapid, irregularly irregular atrial rhythm
- Symptoms: often asymptomatic; palpitations or HF (weakness, light-headedness
+ dyspnea)
- HR: 400-600bpm |
| Atrial Fibrillation: Classification | 1- Paroxysmal - self-limiting within 7 days (usually 48 hours) + sinus rhythm resolves spontaneously
2- Persistent - continuous, lasts >7 days, needs therapy to restore to sinus rhythm
3- Longstanding Persistent - lasts >1 year, possibility of restoring sinus rhythm
4- Permanent - cannot be converted back to Normal sinus rhythm
5- Lone - w/o identifiable cause for ages <60 |
| Atrial Fibrillation: ECG diagnostic criteria | - Absent P waves
- Irregular/narrow QRS <120 ms
- Irregular f waves (<0.1mv = fine, >0.1mv= coarse)
- Irregularly irregular R-R intervals
- LV hypertrophy (Axis deviation, high QRS voltage >15) |
| Atrial Flutter: Definition & Symptoms | - DEF: regular atrial tachycardia
- HR: >250bpm
- Symptoms: dependent of ventricular rate
if VR <120bpm: few/no symptoms
if VR >150bpm: palpitations, reduced cardiac output, chest discomfort, dyspnea, weakness, syncope |
| Atrial flutter: Classification | - Type 1: Typical - Macroreentrant tachycardia (2:1 AV block, 250-350 bpm) involves idioventricular rhythm & tricuspid isthmus in reentry circuit:
a) Anticlockwise flutter: -ve F waves in Inf. leads( II, III, avF)
b) Clockwise +ve F waves in Inf. leads
- Type 2 - Atypical: (3:1 or 4:1 blocks, 350-450 bpm):
* mostly for people with previous heart surgery or catheter ablasion |
| Atrial Flutter: ECG diagnostic criteria | - 'sawtooth' shape of P waves: Inf. leads (-) II, III avF +V6 & (+)V1
- No isoelectric line
- Always Regular
- Narrow QRS <120 ms
NB:Adenosine slows the ventricular rate (doesn't for Afib/AVNRT) |
| A.fib/A. flutter: Anticoagulants indications + contraindications | Indications: recommended for all patients unless:
- specifically contraindicated
- at slow risk of stroke ( CHA₂DS₂-VASc score <2)
AIM: to prevent thromboembolisms & stroke |
| A.fib/A. flutter: CHA₂DS₂-VASc score | - Congestive HF : 1 point
- Hypertension: 1 point
- Age >75: 2 points
- Diabetes: 1 point
- Stroke/ TIA : 2 points
- Vascular disease: 1point
- Age 65-74: 1point
- Sex: 1 point |
| A.fib/A. flutter: Anticoagulation principles | - 0 score = Low risk: no anticoagulants
- 1 score = low-moderate risk: anti-platelet (aspirin OR combination therapy: aspirin + clopidogrel & warfarin INR 2-3
- >2 score = moderate-high risk :oral anticoagulation (warfarin INR 2-3, dabigatran, rivaroxaban, apixaban, edoxaban)
- Use long-term anticoagulation for patients with persistent or paroxysmal AFib/AF
- Persists for longer than 48 hours / Post-cardioversion = 4 weeks of adequate anticoagulation |
| A.fib/A.flutter: Antiarrhythmic treatment | Rate control: can completely resolve symptoms
- 1st line : Beta-blockers (metoprolol) & CCBs ( verapamil, diltiazem)
- 2nd line: Digoxin if HF present
- if ineffective: Amiodarone (and cannot tolerate first line)
Rhythm control: to restore sinus rhythm / if rate control unsuccessful
- Cardioversion: electrical or chemical by anti-arrhythmic drugs
eg Class 1a /9quinidine, procainamide), Class 1b( flecainamide) Class III (Amiodarone/sotalol ) |
| A.Fib/ A.flutter: Anti-arrhythmic treatment (procedures) | Nonsurgical :
- For A.fib: after anti-arrhythmic drugs: Pulmonary vein isolation ablation (Cryoablation or RDA)+ Pacemaker
- A. flutter: AV node ablation (RDA or Isthmus block) - initially before drugs
Surgical: Pacemaker, Open-heart maze procedure |
| First Degree AV block | - AV conduction delay but w/out skipped beats
- 1:1 (every P is followed by QRS)
- Consistently prolonged PR >200ms
- Rate 79bpm
- BENIGN: young w/ high vagal tone
- Causes: idiopathic conduction, tissue disease, ischemia, drugs (digoxin, B-blockers, Calcium antagonists) |
| Type 1 Second Degree AV block | I Type (Wenckebach):
- Progressive prolongation of the PR interval until a ventricular beat is dropped, repeats in clusters.
- Associated with AV node disease
- Usually BENIGN if associated w/ high vagal tone OR pacemaker needed |
| Type 2 Second Degree AV block | II Type (Mobitz) :
- Regularly dropped ventriicular beats (2:1) with no lengthening of PR interval
- Associated w/disease in His-Purkinje system
- can progress to complete heart block
-Pacemaker required |
| Type 3 Second Degree AV block | III Type (advanced/high grade) :
- Several consequent P waves are blocked in the AV node
- before every QRS, P wave is "tied" to the QRS
- PR interval constant
(looks like complete heart block)
- If HR is low, after progression to complete AV block, it can be followed by asystole |
| Third Degree AV block | Third Degree (complete block):
- No impulse conduction from atria to ventricles,
- hence independent atrial and ventricular rates
- AV dissociation: no relationship between A-V complexes
-QRS: If Narrow- indicates ventricular pacemaker at that level of AV node / If Broad (>120ms)- pacemaker below AV node
- PERMANENT PACEMAKER to prevent mortality & reduce morbidity from Morgangni-Adams-Stokes attacks |
| Modes of Permanent Pacemaker | Designated by 3-5 letters representing:
I - Chambers placed: O (None), A (atrial), V (ventricle), D (dual)
II - Chambers sensed: O (None), A (atrial), V (ventricle), D (dual)
III - Response to sensing: O (None), T (trigger), I (inhibit), D (dual)
IV - Rate modulation: O (none), R (rate modulating)
V- whether pacemaker is multisite: in both atria, both ventricles or >1 pacing lead in a single chamber |
| Pacemaker: Principles | 1st class indications: Sinus node dysfunction, AV blocks, chronic bifascicular blocks, after acute phase of MI, after cardiac transplantation & pacing to prevent tachycardia)
1- Indications for single chamber pacemakers - permanent A. fib (VVI: a.fib w/ bradycardia, AAI: sinus bradycardia, sinus arrest)
2- Indications for dual chamber pacemakers - Sick sinus syndrome caused by sinus node dysfunction, AV blocks |
