AF & tachycardia
Cardiology expert Adele Pope returns with an approach differentiating tachycardia and managing atrial fibrillation. We also discuss ventricular ectopics, bigeminy and peri-operative anticoagulant and anti-platelet adjustment.
Differential
- Life threatening
- VT
- SVT
- AFib
- Flutter
- Common triggers of AFib
- Post operative state
- Myocardial infarction
- Sepsis
- Anaemia
- Hypo- or hypervolaemia
- Pulmonary embolus
- Electrolyte disturbance
- Cardiac dysrhythmia
- Non-cardiac
- Anemia
- Anxiety
- Dehydration
- Electrolyte imbalance (especially hypokalemia and hypomagnesemia)
- Fever/ sepsis
- Hyperthyroidism
- Hypoglycemia
- Ischemia
- Metabolic disorders
- Pain
- Poisoning and toxic exposure
- Pulmonary embolism
- Respiratory disease (e.g. pneumonia, pneumothroax)
- Shock
- Trauma
- Withdrawal syndromes
Approach
- ECG and new set of vitals before you arrive
- Eyeball the patient/ABCs
- History
- Old or new tachyarrhythmia?
- Chest pain
- SOB
- Palpitations
- Exact time of onset of symptoms
- Cardiac history
- Prev AF
- Ischaemic heart disease
- Valvular disease
- Hypertension
- Heart failure
- ROS
- Vitals + Examination
- General inspection + peripheries for perfusion
- JVP
- Auscultation
- Confirm rhythm
- Valvular dysfunction
- Wound
- Calves/leg oedema
- ECG
- Narrow complex or wide complex?
- QRS > 3 squares could be a wide complex tachycardia (call a code)
- Concordance (V1 – V6 often point in one direction in VT)
- AV dissociation indicated VT
- If narrow complex, is it regular or irregular?
- Irregular is probably AFib
- Narrow complex or wide complex?
- Consider investigations
- FBC, U&E (including Mg), TFT
- Consider septic workup
- Consider troponin
- Management
- Consider observation
- 500 mL fluid bolus
- Metoprolol tartrate 50 mg (not if overloaded or in steroid-dependent asthma)
- Diltiazem short acting 30 mg as an alternative
- Documentation
- Review past notes
- Current medications – has a dose been missed?
- Basics (date/time/name/reason for review)
- Positives and pertinent negatives
- Impression and differential with justification.
- Have you eliminated life threatening conditions?
- Why has this arrhythmia developed?
- Is there a risk of deterioration?
- Type of AFib (first episode, paroxysmal, persistent, or permanent)
- Clear and specific plan
- Immediate investigations
- Fluids
- Electrolytes correction
- Beta blocker?
- Anti-arythmic?
- Anti-coagulation?
- Consider echo, TOE, CXR, ETT
- Consider discussion with senior and escalation, especially if called back to patient again.
Concluding remarks
- Get help early for:
- Wide complex tachycardia
- Poor perfusion/hypotension
- Pulmonary oedema
- Main triggers are post operative state, myocardial infarction, sepsis and anaemia.
- AF may be the first sign of a significant problem, so a good review of systems is needed.
- AF may precipitate cardiac and perfusion problems (ischemia, heart failure, atrial thrombus), so identify patients at risk.
- Timing:
- Assume onset of AF to be greater than 48 hours ago unless there is a clear history of onset
- AF >48 hours needs anticoagulation prior to cardioversion
- All patients should be anticoagulated for 2 weeks following cardioversion
- Bigeminy and ectopics
- Ventricular ectopics are normal. If >50% of ventricle beats are ectopic, consider structural heart disease.
- Bigeminy is also often normal (two ectopic beats in a row).
- Obtain a rhythm strip to determine the frequency of ectopics beats.
- Discuss with cardiology if >50% or recurring trigeminy.