Editing Post-op AF


Note that post-op atrial fibrillation and atrial flutter can be managed the same, according to UTD

== '''Epidemiology''' ==

* Incidence 0.4-3% after non-cardiac surgery
* Incidence peaks post-op day 2

== '''Secondary precipitant''' ==

* Always consider missed medication
* Infection/systemic inflammation
* Sympathetic activation in general
* Pain
* Low serum magnesium/other electrolytes
* Anaemia
* Hypothermia
* Hypoxia
* Hypervolaemia
* Acidosis
* Acute MI
* Acute alcohol consumption
* Thyrotoxicosis
* Acute pericardial disease
* Acute PE
* Other acute pulmonary pathology
* Caffeine is not proven to increase risk

== '''Classification''' ==

* Unstable
** Hypotension (for which AF is suspected to be causal or contributory, and standard therapy to treat other underlying causes has failed)
** Altered mental status
** Ischaemia
** Heart failure
** Cardiogenic shock
** Very rapid ventricular rates (accessory pathway)

== '''Investigation/initial management''' ==

* ECG
* Bloods including electrolytes, free T4, TSH
* Troponin if clinical suspicion for ACS or ECG evidence of cardiac ischaemia, or uncertainty thereof
* Septic screen including CXR
* Fix reversible causes above

== '''Drug options''' ==

* Amiodarone
** Rate control and rhythm control (can be a problem if not anticoagulated)
** Contraindications
*** Sino-atrial block
*** Severe hypotension
*** Thyroid disease
*** CCF
*** Pregnancy and breastfeeding
* Flecainide
** Contraindications
*** Atrial flutter
*** CCF
*** Structural heart disease
*** Recent MI
* Beta-blockers
** Indications
*** Preferred agents when AF is associated hyper-adrenergic states
** Contraindications
*** Asthma/COPD
*** Uncontrolled heart failure
*** Sick sinus syndrome
*** Heart block
*** Hypotension (approx <100)
*** Severe peripheral vascular disease
*** Pregnancy and breastfeeding
* Calcium channel blockers
** Contraindications
*** Heart failure
*** Hypotension
*** Sick sinus syndrome
*** Heart block
*** AF with WPW
*** VT
*** Pregnancy and breastfeeding
*** Already on beta-blocker
* Digoxin
** Popular for long-term rate control, but slow response in acute setting (peak response at least 6 hours)
** Mostly has a role in AF with heart failure
** Often used in combination with beta blockers or CCBs - works synergistically
** Doesn't tend to drop BP


== '''Initial management''' ==

* '''Approach'''
** Rate-control strategy first, unless unstable and successful ventricular rate control cannot be achieved
** Avoid RVR and the possibility of ensuing cardiac ischaemia
** HR target of <120 is reasonable post-op
** Indications for rhythm control:
*** Symptomatic AF despite good rate control
*** Rate control difficult to achieve
*** Patients unlikely to have a recurrence of AF (younger, less comorbidities, small left atrium)
*** Consider when good reason to avoid anticoagulation
** >50% with new post-op AF will convert to sinus rhythm within 24 hours
*** If this occurs, no need for further management, but should have outpatient Holter and TTE
* '''For rate control'''
** Metoprolol 25mg PO BD (75mg max; can start with 12.5mg BD in a stable patient sometimes, particularly if there might be chronicity to AF and you’d like to start slowly) or 5mg IV (in increments up to 15mg - not good on ward) OR
** Amiodarone 300mg IV (up to 5mg/kg) OR
** Digoxin 0.25mg IV every two hours, to a total dose of 1.5mg, then 0.125-0.375mg IV daily
** Calcium channel blocker or a second agent at discretion of cardiology
* '''For rhythm control (unstable patient, or other indication for rhythm control)'''
** IV amiodarone 300mg (up to 5mg/kg) or diltiazem/flecainide)
** Synchronised DCR (requires peri-procedural anticoagulation and then for 4/52 afterwards)
* '''Specific situations'''
** Able to give PO, stable - PO metoprolol, with consideration of digoxin in CCF, or PO amiodarone if second agent is required
*** Generally worth trying PO metoprolol first, even if absorption is considered to be borderline or questionable, as long as the patient is stable
** Unable to give PO, stable on ward - IV digoxin
** Able to give PO, unstable - IV amiodarone and ICU
** Unable to give PO, unstable - IV amiodarone and ICU

== '''Subsequent management''' ==

* Approach
** Re-evaluate rate control vs rhythm control
*** Rhythm - amiodarone 200mg BD for one month, then 200mg daily
*** Rate - metoprolol 25mg BD, or amiodarone same dose as above
* Anticoagulation
** If already on it, restart when safe
** Single episode AF lasting <48 hours: no anticoagulation unless other high-risk features
** Multiple episodes of AF or a single episode lasting >48 hours: anticoagulation for four weeks if CHA2DS2-VASc = 2 or more
** Reassess after four weeks and continue anticoagulation if there are recurrences after four weeks
* Telemetry
** Definitely needed
*** Significant bradycardia <40bpm or pauses
*** Use of a second agent
** Ideal but not mandatory
*** Syncope
*** Unexplained collapse
*** Non-sustained ventricular arrhythmias
** Other patients do not need telemetry, according to Austin protocol
* CCU
** Ischaemic chest pain
** Significant elevation in troponin
* TTE
* Cardiology F/U

[[Category:Cardiology]]
[[Category:Intern education]]