CASE
A 59 yo male presents to the Emergency Department, 5 days post ablation for atrial fibrillation. He is complaining of dizziness and nausea. He is also seeing spots before his eyes.
​He has no other past medical history and is on a DOAC and Sotalol
His BP is 122/68 with no postural drop and his pulse rate is 49 bpm.
​His ECG is shown below. What does the ECG show? (HINT: The exam is the key)

The ECG is sinus bradycardia at a rate of 49 with a first degree block. Not much to see.

The examination showed:

• Dual Heart Sounds, with no extra sounds
• Chest clear
• Abdomen soft
• Given his dizziness, his neurological examination as per the 'Dizzy Patient' algorithm on the RESUS blog.
  • His Cranial Nerve exam showed
    • No nystagmus, no diplopia and pupils equal and reactive.
    • On visual fields he stated he saw some spots before his eyes but no 'floaters'. He also stated that in his peripheral vision he saw a 'kaleidoscope' pattern of colours.
    • Fundoscopy was normal
    • Facial nerve examination was normal and there was no speech disturbance
  • Given that he had no nystagmus, head impulse test was fruitless to do, but done anyway and was negative. Dix-Hallpike was also performed and was normal.
  • Cerebellar examination was normal
  • Upper and lower limb neurological examination was normal

What's the diagnosis?
I'll add that I did a non-contrast CT brain on him, purely because he was on a DOAC. This was normal.
Approximately one hour later the patient had improved and felt well.

What's your initial thinking and diagnosis?
​My initial thinking was as follows:

• This might be Sotalol related, as it can produce dizziness and nausea. Alternatively the dose he was on (80mg bd) may have been too high.
• Second thought was that this might be a peripheral vestibulopathy, but all the examinations were normal, head impulse test and Dix-Hallpike. Also with no nystagmus and dizziness, a central cause should be more likely.
• Could this be a bleed, because he was on a DOAC?
• It didn't sound like a stroke.
• The kaleidoscope colours and spots before his eyes sounded like a migraine, but he was not a migraine sufferer.

I initially spoke with the neurologist who agreed that it sounded migrainous and did not think he needed an MRI. I then spoke with his electrophysiologist ....
"I've got Mr X with us, who had the ablation 5 days ago. He's come in with nausea and dizziness. His ECG is normal and he is haemodynamically fine. His neurological exam looking for a peripheral or central cause is normal. The only thing I can say is that he has this kaleidoscope vision and to me, this points to a migraine, but he isn't a migraine sufferer."

The Diagnosis
The electrophysiologist said "This is a post ablation migraine".

The literature shows that a percentage of patients, up to 2%, (thought to be even higher), present with migraines, usually with no headache but aura and visual disturbances. These visual disturbances include scotomas and scintillating edges to vision. Attacks occur within one week of the ablation and usually resolve within 3 months.
The reason appears to be that during catheter ablation for atrial fibrillation, a transeptal puncture is required to provide access to the left atrium. This provides access to the pulmonary veins. The result is that it creates a transient right to left shunt.
The exact mechanism for why this might then occur is unknown, but can include factors usually cleared by the lungs, now reaching the cerebral circulation, and even microemboli. It is usually transient and no specific treatment is needed if there is no neurology and the patient is on anticoagulation. If abnormal neurology is found, then the patient should definitely be discussed with neurology. 

We see a lot of post ablation patients, given that atrial fibrillation is now becoming such a massive arrhythmia burden, that we will see post ablation migraines.

The patient was well and all symptoms (which did not involve any significant neurology) had resolved, he was discharged, to be reviewed by his cardiologist.

A 62 yo male with a previous history of paroxysmal atrial fibrillation presents to the emergency department with a rapid irregular heart beat and a complaint of palpitations, that started 2 hours previously.
His ECG is shown below.

The patient is haemodynamically stable and is not greatly distressed by the palpitations. He  is not on any anticoagulation.
Here are some important questions to answer in relation to this patient:

1. Do we shock this patient now, or give the patient 24 hours to potentially self-revert?
2. We know that if we shock early, we are doing so, to a number of patients who would self revert. Should we send the patient home and get them to come back the next day?
3. Are there any risks in waiting  for 24 to 48 hours, or is the risk of stroke equal during the first 48 hours?

​Watch the video lecture below for all the answers (From Cardiac Bootcamp).

​A 68 yo male presents with palpitations and vague chest tightness. He has noticed his heart racing for the last 2 hours. His ECG shows atrial fibrillation, with a rapid ventricular response.  He has a past medical history of hypertension and smoking.
He is afebrile, with a heart rate of 176-185 beats per minute, BP of 138/65, Sats of 96% on room air.
How would you manage this patient's atrial fibrillation?

​​A 62 yo male presents with palpitations and vague chest discomfort. He has noticed his heart racing for the last 2 hours. His ECG shows atrial fibrillation, with a rapid ventricular response. He has a past medical history of hypertension and smoking. He is febrile eat 38.3 C, a heart rate of 176-185 beats per minute, BP of 138/65, Sats of 94% on room air. On clinical examination, has midzone crepitations in his right lung.
​How would you manage this patient's atrial fibrillation and would it be different to the patient in case 1?

It’s all about primary vs secondary atrial fibrillation/flutter.
A recent review of the approach to the Emergency Department(ED) patient with atrial fibrillation/flutterwas published by the Canadian Association of Emergency Physicians(1).
Here is a synopsis of the approach.

Is it PRIMARY or SECONDARY?
Is there an underlying disease causing the atrial fibrillation/flutter(AF/Flut), or it is a primary event?
Primary AF/Flut is usually of sudden onset and is not due to an underlying medical condition causing. Secondary AF/Flut is usually due to a medical cause such as sepsis or pulmonary embolism or bleeding or acute coronary syndrome. Secondary causes are usually not sudden in onset and tend to have slower ventricular rates(<150), but not always.
Why is this important?
We can aggressively treat Primary AF/Flut, however we need to treat the cause of secondary AF/Flut, not the arrhythmia itself, as aggressive rate or rhythm control in secondary causes can be harmful.

PRIMARY AF/FLUT
We need to ensure that the patient is haemodynamically stable.
An unstable patient may show the following:

• Systolic Blood Pressure <90 mmHg or signs of shock(altered mental state)
• Signs of cardiac ischaemia: chest pain, ST depression on ECG
• Pulmonary Oedema

The unstable patient needs electrical cardio version if the arrhythmia has been present for < 48hours, or in those where it has been there for >48hours, rate control.

In the stable patient, when is it safe to cardiovert Primary AF/Flut?
Rhythm control is always preferred to rate control.
In this article it was considered safe to cardiovert if:
The patient was anticoagulated for > 3 weeks
OR
The patient is not anticoagulated for > 3 weeks but 
Has no history of TIA or stroke 
Has no valvular heart disease  and

• Onset < 12 hours ago OR
• Onset 12-48 hours ago and < 2 CHADS-65 Criteria 
  • (age >65, Diabetes, HT, heart failure Stroke or TIA- see below) OR
• No thrombus on TOE

RATE Control
Rate Control is used when cardioversion (rhythm control) is unsafe. Our target is a heart rate < 100.
If the patient is already on a beta blocker or a calcium channel blocker, more of the same medication may be given.

• Beta Blockers: 
  • Metoprolol
    • 2.5-5mg IV over 2 min. 
    • Repeat q15-20min for 3 doses. 
    • Commence 25-50 mg PO  within 30 minutes of IV control. 
    • Discharge on 25-50mg bd. 
• Calcium Channel Blockers
  • Diltiazem
    • Avoid these in acute heart failure or known LV dysfunction
    • Diltiazem 0.25 mg/kg IV over 10 min repeat q15-20 min 3 doses
• Digoxin
  • Second line, slow onset- BUT FIRST LINE if hypotension and acute heart failure
    • 0.25-0.5mg loading dose then0.25mg IV Q 4-6 hours to max 1.5mg over 24 hours
    • BEWARE RENAL FAILURE

In a recent study in the American Journal of Emergency Medicine(2), “Intravenous diltiazem has higher efficacy, shorter average onset time, lower ventricular rate, less impact on blood pressure, and with no increase in adverse events compared to intravenous metoprolol.” Unfortunately IV Diltiazem is not readily available in Australia.

RHYTHM Control
Electrical Cardioversion

• Pads – antero-lateral or antero-posterior
  • In a recent multicenter study in Circulation(3) it was found that anterolateral positioning was more effective for biphasic cardioversion of atrial fibrillation
• Start with 150-200J avoid low energy. AF is one of the most resistant arrhythmias, so start high.
• Note that pre-treatment with an anti arrhythmic is not recommended.

Pharmacological Cardioversion

• Procainamide 
  • IV 15mg/kg in 500ml NSaline over 60min. Maximum 1500mg
  • Beware:•Hypotension- do not use if SBP<100mmHg 
  • Stop the infusion if 
    • BP drops
    • Long QTc- Don’t use if QTc is >500ms
    • Stop if QTc lengthens and Check QTc after cardioversion•
• Amiodarone– NOT recommended: It has slow onset and low efficacy

STROKE PREVENTION
Who needs anticoagulation?
​CHADS-65 POSITIVE (age >65, DM, HT, CCF, Stroke/TIA)

​

• DOAC preferred
• WARFARIN MUST BE USED in
  • Mechanical Valve
  • Moderate to severe Mitral Stenosis
  • Severe renal Impairment CrCl <30ml/min
• What if the patient is on ASPIRIN?
  • If stable CAD- stop aspirin
  • If CAD with other antiplatelets OR PCI<12 months D/W Cardiology

CHADS-65 NEGATIVE

• Consider OAC for 4 weeks, but needs shared decision making with the patient.
• If stable CAD patient can continue aspirin

If planning Trans-oesophageal Echo guided cardioversion: Anticoagulate for 4 weeks
Remember that even if the patient reverts spontaneously, anticoagulation should still be given if there are risk factors.

Anticoagulation Checklist

• Dabigatran 150mg BD: 110mg bd if >80 or >75 with bleed risk
• Rivaroxaban 20mg daily: 15mg daily if CrCl 30-49ml/min
• Apixaban 5mg BD: 2.5mg bd if 2 of: Creat >133umol/L, Age > 80yo, Weight <60kg. Otherwise 5mg bd
• Edoxaban 60mg daily: 30mg if CrCl 30-50ml/min or wt<60kg
• Warfarin start 5mg daily: 1-2mg if frail, low weight or Asian descent, INR after 3-4 doses of Warfarin

Who to Admit

• Symptomatic despite treatment
• Have ACS and chest pain and ECG changes
• Acute heart failure
• NOTE: in uncomplicated Afib/Flut, admission is rarely needed
• Expect a Troponin leak

References

1. Still I.G. et al. 2021 CAEP Acute Atrial Fibrillation/Flutter Best Practices Checklist. Canadian Journal of Emergency Medicine (2021) 23:604-610.
2. Lan Q et al. Intravenous Diltiazem versus metoprolol for atrial fibrillation and rapid ventricular rate: A meta-analysis. The American Journal of Emergency Medicine. Vol51: (Jan 2022); 248-256
3. Schmidt A s et al. Anterior-Lateral versus Anterior-Posterior Electrode Position for Cardioverting Atrial Fibrillation. Circulation (2021); 144:1995-2003