Week 5/6 - B -Atrial Fibrillation, Atrial Flutter - symptoms, types, management Cardiac Arrest - management, reversible causes COPY

Question 1

Atrial fibrillation is an important cause of cardiovascular morbidity and mortality. What is atrial fibrillation and what are the different types?

Answer 1

Atrial fibrillation is chaotic and disorganized electrical activity resulting in an irregular heartbeat It can be paroxysmal, persistent or permanent (chronic)

Question 2

What is the mechanism of atrial fibrillation?

Answer 2

The mechanism of atrial fibrillation is due to ectopic foci in muscle sleeves in the ostia of the pulmonary veins These triggers may lead to re-entrant circuits forming in abnormal atrial myocardium preventing the atria from organizing hence the irregular rhythm.

Question 3

Describe the 3 different forms of atrial fibrillation

Answer 3

Paroxysmal AF - * episodes last less than 7 days (often less than 48 hours), self terminating, recurrent Persistent * episodes last greater than 7 days - * unlikely to spontaneously terminate to NSR and requires pharmacological or DC cardioversion Permanent (chronic) * Inability of pharmacological or non pharmacological methods to restore NSR

Question 4

What are the symptoms of AF?

Answer 4

Palpitations Pre-syncope Syncope Chest pain Dyspnoea Sweatiness Irregular pulse

Question 5

When should paroxysmal AF be suspected? How is a diagnosis of AF confirmed?

Answer 5

Suspect paroxysmal AF if symptoms are episodic and last less than 48 hours (remember less than 7 days is paroxysmal) If AF is present, diagnose with an ECG the ECG will have no P-waves, a chaotic baseline, and an irregular ventricular rate.

Question 6

If paroxysmal AF is suspected and AF is not detected on standard electrocardiography, what can be carried out?

Answer 6

A 24-hour Holter ECG may be used in people with suspected asymptomatic episodes of paroxsymal AF (incidental finding of an intermittent irregular pulse)

Question 7

What are the management options of AF? Remember it is down to patient choice for this

Answer 7

Rate control - usually the option that happens - accept AF and try control ventricular rate Rhythm control - use anti-arrhythmics or DC cardioversion to maintain sinus rhythm Anti-coagulation important for both approaches if risk of thromboembolism

Question 8

If a patient with AF presents and is haemodynamically unstable (shock, myocardial ischaemia, syncope, heart failure) what is carried out as treatment?

Answer 8

Usually up to 3 attempts of DC cardioversion can be tried Amiodarone given if unsuccessful

Question 9

Haemodynamically stable patients What are the options for rate control of AF? When can digoxin be given?

Answer 9

Rate control is usually 1st line - Beta blocker (eg atenolol or bisporolol) or rate limiting calcium channel blocker (eg verapimil or dilitiazem) Digoxin can only be given in non-paroxysmal AF patient who are sedentary

Question 10

Restoration of normal sinus rhythm is the other treatment option in AF - only for paroxysmal or persistent What pharmacological agents can be given? When is DC cardioversion able to be given * ie what changes if presenting within or more than 48 hours of AF onset?

Answer 10

AF rhythm control agents- anti arrhythmic drugs eg flecainide or amiodarone If the patient is stable and presents within 48 hours and chooses DC cardiovert, this can be given If the patient is stable and AF started >48 hours ago or unclear of time of onset, and rhyhtm control is chosen, patient must be anticoagulated for >3weeks first

Question 11

What channels do the different anti-arrhythmic drugs work on?

Answer 11

Class I - block voltage activated sodium channels eg flecainide (1C) - phase 0 Class II - beta blockers - phase 4 Class III - potassium channel blockers eg amiodarone (works on other ion channels also) - phase 3 Class IV - calcium channel blockers eg verapimil, dilitiazem - phase 2

Question 12

After either pharmacological or DC cardioversion is carried out if a patient wishes to control the rhythm in AF, what is carried out to maintain the NSR?

Answer 12

Long term management Patient is given rate controlling anti-arrhythmic drugs - beta blocker or CCB or Can carry out radiofrequency catheter ablation of atrial focus/pulmonary veins

Question 13

When considering anti-coagulation for a patient, it is important to consider the CHA2DS2VASc score to indicate treatment and the HAS-BLED assessment tool to assess the risk of a major bleed Why are anti-coagulants used in atrial fibrillation?

Answer 13

In A.fib, the atrium of the heart is beating abnormally and not contracting enough causing blood to pool inside the atrium This blood can form a fibrin clot due to stasis and may break off and enter the circulation –> ending up in the cerebral circulation causing a stroke

Question 14

What are the different elements of the CHA2DS2VaSc score? What score where we are advised to start the patient on anti-coagulation?

Answer 14

* C - congestive cardiac failure * H - hypertension * A2 - age >74 (2), 65-74 (1) * D - diabetes * S2 - previous stroke/tia (2) * Va -Vascular disease * S - sex (female) If a patients score is /=1 then anticoagulation therapy

Question 15

What is atrial flutter? What causes it?

Answer 15

Atrial flutte ris a rapid and regular form of atrial tachycardia and is usually paroxysmal

Question 16

What is the mechanism of atrial flutter?

Answer 16

Atrial flutter is due to an abbnoormal foci of cells in the atrium causing a re-entrant circuit that stimulates the AV node

Question 17

AF treatment is similar to AF regarding rate and rhythm control and the need for anti-coagulation * What is the preferred method of management? * What are the options for long term therapy?

Answer 17

The first goal in atrial flutter is to terminate the flutter and prevent a recurrence. The second goal is to control the ventricular response during the arrhythmia. * If patient presents with 48 hours, DC cardiovert and maintain NSR with rate control anti-arrhythmic * If >48 hours, anti-coagulate for 3 weeks before DC * (DC cardioversion preferred to rhythm anti-arrhythmics) Radiofrequency ablation of the tricuspid valve isthmus is curative for most patients after cardioversion

Question 18

CARDIAC ARREST What is a cardiac arrest and how is it recognized?

Answer 18

A cardiac arrest is when your heart suddenly stops pumping blood around your body. When your heart stops pumping blood, your brain is starved of oxygen. Recognized by * Unresponsive patient * Not breathing normally * No pulse

Question 19

Managing cardiac arrest Basic life support and advanced life support What is carried out in basic life support? (ABC)

Answer 19

Shout for help and as someone to call the arrest team and bring the defibrillator - note the time * Airway - head tilt (if no spine injury) and chin lift (jaw thrust) * Breathing - look, listen and feel for breathing - max 10 seconds * Chest compression - heel of one hand on centre, chest, interlockk other hand and give chest compressions 5-6cm deep at a rate of 100-120bpm After 30 compressions give 2 rescue breaths, 30:2 ratio

Question 20

Advanced life support is carried out when the defibrillator/ECG monitor becomes available What are the shockable and non-shockable rhythms?

Answer 20

Shockable rhythms * Ventricular fibrillation * Pulseless ventricular tachycardia Non-shockable rhythms * Asystole * Pulseless electrical activity

Question 21

Describe the treatment of shockable rhythms When is defibrillation carried out? What happens next? When is rhythm re-assessed? When are drugs given and which ones?

Answer 21

Single person performs uninterrupted compressions (30:2) * Shock patient * Immediately resume CPR for 2 minutes * Re-assess rhythm * Repeat if shockable rhythm remains * After 3rd shock, give adrenaline and amiodorone IV * Then continue CPR and check rhythm every 2 mins * Repeat adrenaline ever 3-5 mins (essentially at alternate rhythm checks/shocks)

Question 22

Describe the treatment of non-shockable rhythms When is defibrillation carried out? What happens next? When is rhythm re-assessed? When are drugs given and which ones?

Answer 22

Single person performs uninterrupted compressions (30:2) * Rhythm assessed, non shockable * Immediately resume CPR for 2mins * Re-Assess rhythm * Give adrenaline every 3-5mins (essentially at every alternate rhythm check)

Question 23

What are the 4Hs and 4Ts of potentially reversible causes of cardiac arrest?

Answer 23

Potential reversible causes: the four Hs and the four Ts Hypoxia Hypovolaemia Hypo-/hyperkalaemia/metabolic Hypothermia Thrombosis - coronary or pulmonary Tension pneumothorax Tamponade - cardiac Toxins

Question 24

What is the difference between synchronized and non-synchronized DC cardioversion?

Answer 24

Synchronized cardioversion is a LOW ENERGY SHOCK that uses a sensor to deliver electricity that is synchronized with the peak of the QRS complex (the highest point of the R-wave) - given in Afib, Aflutter VT (with a pulse) Unsynchronized cardioversion (defibrillation) is a HIGH ENERGY shock which is delivered as soon as the shock button is pushed on a defibrillator. Unsynchronized cardioversion (defibrillation) is used when there is no coordinated intrinsic electrical activity in the heart (pulseless VT/VF) or the defibrillator fails to synchronize in an unstable patient.