AF

Question 1

Definition

Answer 1

SV tachyarrhythmia. disorganised rapid atrial activation and uncoordinated atrial contraction.
structural or electrophysiological abnormality promotes abnormal impulse formation or propagation. Normal regular SAN impulses overwhelmed by disorganised impulses usually originating in PV roots. Irregular ventricular conduction.
Paroxysmal- more than one episode terminate spontaneously or with intervention in 7 days.
Persistent- episodes last over 7 days.
Long standing persistent- for over 1 year. Cardioversion failed or not tried.
Permanent- stop pursuing SR.

Question 2

Aetiology

Answer 2

Loss atrial muscle mass and atrial fibrosis.
Re entrant and focal mechanisms cause multiple wandering waves usually originating from PVs. 
Cardiomyopathy, CHF, HTN (most common)
Peri and myocarditis.
Atrial tachy and flutter, WPW. 
HypoK and Mg.
Obesity
Drugs. 
MITRAL HH-
MVD
IHD
Thyrotoxicosis, phaeochromocytoma
Rheumatic fever
Alcohol, caffeine
Lung- PE, COPD, apnoea, CO, CA
Hypertension
HypoK
Exercise of alcohol can trigger

Question 3

Differentials

Answer 3

Multifocal atrial tachy, Flutter, WPW, MI
Alcohol
Rheumatic HD
Hyperthyroid 
PE, COPD
Pericarditis
Anxiety
Systemic HTN
MVD
ASD

Question 4

Symptoms

Answer 4

Often none
CP
Palpitations
Dyspnoea
Faint

Question 5

Signs

Answer 5

Irregularly irregular pulse
Apical pulse rate greater than radial
1st heart sound variable intensity
LVF signs

Question 6

Management

Answer 6

Heparin acute, warfarin long term (inhibits vit K reductase preventing CF activation in liver).
Rate control- BB eg atenolol, CCB eg varapimil, digoxin.
Rhythm control- amiodarone, flecainide.
Cardioversion.

Question 7

Complications

Answer 7

Stroke due to turbulence= clot, to brain.
HF
Dilated cardiomyopathy

Question 8

Diagnosis

Answer 8

Absent P
Irregular QRS
Echocardiogram for cause
Bloods- UE, cardiac enzymes, TFTs.

Question 9

Class 2 BB

Answer 9

Inhibit heart beta 1 Rs. Less Ca IN.
Slow ventricular rate in AF and flutter.
AE- bronchospasm, hypotension.
DONT use in partial AV block or acute V failure unless pm in situ.

Question 10

Class 3 K blocker eg amiodarone.

Answer 10

Increase ARP
Lot AE- proarrhythmic, pulmonary fibrosis, hepatic injury, increase LDL, thyroid disease, photosensitivity, optic neuritis.
Require high loading dose as long t1/2.
Give to central V to avoid thrombophlebitis.
DDI- digoxin, class 1’s, warfarin.

Question 11

Class 1c eg flecainide

Answer 11

VGNa blocker, use dependant. Slower binding offset than other class 1's. 
AE- pro arrhythmic, sudden death chronic use, CNS, GI, metallic taste, headache. Increase ventricular response to SV arrhythmia.

Question 12

Class 1a eg quinidine, procainamide.

Answer 12

Intermediate binding offset.

AE- hypotension, low CO, torsades increase QT. Dizzy, confusion, insomnia, seizure. GI. Lupus like syndrome.

Question 13

Class 4 CCB eg verapimil, diltiazem

Answer 13

Decrease force and rate, some peripheral vasodilation.
Diltiazem for AF
Caution if partial AV block AND on BB- can=asystole.
Caution in hypotension as reduce CO.
Constipation.

Question 14

Adenosine no class

Answer 14

Activates K current in nodes. Blocks conduction then restarts SR.
V short t1/2 (seconds)

Question 15

Cardiac glycoside eg digoxin

Answer 15

Positive ionotrope
Blocks Na/K ATPase, reverses NCX, more Ca IN.
Also increases vagal activity (increase K current, decrease Ca=slows AV conduction and HR).

Question 16

Explanation

Answer 16

• the heart normally beats in a systematic rhythmic way because an impulse start at the top and follows a set path. In AF the impulse starts from different places on the upper chamber walls and spreads to the lower chambers at all difffereent times. This means that the pumping action is not strong and regular like it should be. And your heart beats very fast.
• so the heart does not pump enough blood around the body which can cause dizziness and shortness of breath. Also because pumping is not normal, blood doesnt flow smoothly and quickly out the heart which can lead to clots. If these spreads to the brain they can cause strokes. Also the heart os working abnormally hard which in the long term can cause HF.
• lifestyle
• tx includes drugs to stop the blood clotting so easily to reduce the risk of stroke. Also drugs to slow the heart rate as well as to correct the abnormal rhythm. If that doesnt work we can reset the rhythm by applying electrical stimulation from the outside.