.. is all of the above.
.. from triggers to reentry, from electrical to structural remodelling.
Mechanisms 2/6
- Focal source, mostly from pulmonary veins, can initiate AF.
- Mechanisms include trigger and localized reentry.
- This focal source is more involved in driving AF in paroxysmal > persistent types.
Activation of parasympathetic and/or sympathetic limbs can provokes AF.
Autonomic input arises from both central nervous system and local ganglionated plexi.
- CFAEs are EGMs with highly fractionaed potentials or with very short cycle length (<120ms).
- Correlate with areas of slowed conduction and pivot points of reentrant wavelets.
Heparin prior to or immediately following transeptal puncture for ACT ≥300s is recommended.
Post-Ablation
OACs for at least 2 months post ablation is recommended.
Decisions regarding continuation of systemic anticoagulation >2 months post ablation should be based on the patient's stroke risk profile and not on the perceived success or failure of the ablation procedure.
In an RCT, CASTLE-AF,
selected patients with HFrEF with paroxysmal or persistent AF, catheter ablation for AF had significantly reduced
overall mortality rate, reduced rate of hospitalization for worsening HF, and improved LV ejection
fraction as compared with the medical therapy
group
In this large RCT, CABANA trial, catheter ablation in patients with AF age >65 or age <65 with CV risk
did not significantly reduce the primary composite end point of death, disabling stroke, serious bleeding, or cardiac arrest.
Catheter Ablation, however, significantly improved quality of life compared to medical therapy.
Evidences 4/4
Catheter ablation for AF in Tachy-Brady Syndrome
AF can lead to atrial fibrosis and sinus node dysfunction.
Observational studies have shown the benefits of AF ablation in reverse remodelling
and potentially waive the need for pacemaker.
A 67-year-old man who has hypertension, complete heart block, and a dual-chamber pacemaker comes to the clinic for routine visit.
He feels well and reports no new problems. Current medications are metoprolol, lisinopril, and HCTZ.
Physical examination is unremarkable, including a healthy appearing pacemaker pocket.
Device interrogation shows acceptable thresholds, impedances, and electrogram features and two episodes of atrial fibrillation (lasting 25 and 33 hours respectively) that occurred three months apart.
Which of the following is most appropriate at this time?
Add ASA 325 mg OD.
Order 2D-Echocardiography.
Add Rivaroxaban 20 mg OD.
Schedule an RF ablation of AF.
Schedule a follow-up in 6 months.
The Answer is C
OAC should be initated base on the device detected AF episodes
which were >24hr, and the stroke risks.
The patient is asymptomatic from AF, so RF ablation is not indicated.
Quiz 2/4
A 50-year-old man is scheduled to undergo radiofrequency catheter ablation today.
He has frequent episodes of paroxysmal AF and a history of 2 episodes of typical-appearing atrial flutter.
His current medications are bisoprolol and dabigatran 150 mg BID.
He was told to stop taking dabigatran 24 hours before the ablation procedure. However, he forgot the instructions and took his evening dose of dabigatran yesterday.
Right now (18 hours after the last dabigatran dose), the patient is in the procedure room, but he has not been "prepped," draped, or sedated yet. His electrocardiogram shows sinus rhythm.
Which of the following is the most appropriate strategy for this patient?
Proceed with right-sided atrial flutter ablation only.
Proceed with AF and atrial flutter ablation.
Administer fresh frozen plasma and proceed with AF and atrial flutter ablation.
Reschedule the procedure.
The Answer is B
Current evidence supported the safety and superiority of
uninterupted OAC; including NOACs, for undergoing catheter ablation of AF.
Quiz 3/4
A 48 year-old man calls your office 10 days after an uncomplicated Afib ablation complaining of a recent
onset of fevers, mild chest pain, and difficulty swallowing.
What do you recommend?
Routine office visit tomorrow.
Hemoculture and empiric antibiotic.
NSAID and close f/u.
Stat CT chest.
Consult GI.
The Answer is D
The patient had classic Triads of atrioesophageal (AE) fistula (fever, chest pain, and dysphagia) that occurred 1-4wks after AF ablation. AE fistula posts
a high mortality rate (approximately 50%). Urgent diagnosis and aggresive treatment is highly recommended.
Quiz 4/4
A 47-year-old woman has had paroxysmal atrial fibrillation (AF) for 2 years.
She has received treatment in the emergency department for two separate
episodes of AF that lasted up to 12 hours, and she underwent direct-current
cardioversion two years ago, as well as one month ago. Prior evaluation
disclosed a normal thyroid function, a normal echocardiogram, and normal nuclear perfusion imaging.
Drug therapy with flecainide, 100 mg BID, and metoprolol 25 mg twice daily, was started.
Her AF episodes improved until 2 months ago, when she experienced a persistent episode of AF.
She underwent direct-current cardioversion for the second time, and her flecainide
dosage was increased to 150 mg twice daily. Despite this action, she now has
symptomatic AF episodes (rate of 90 beats per minute) up to four times each month.
In addition to discontinuing flecainide, which of the following should you do now?
Start amiodarone.
Increase dosage of metoprolol.
Add propafenone for prn use.
Recommend catheter ablation.
The Answer is D
Symptomatic paroxysmal AF, failed flecainide --> catheter ablation is indicated as
class I indication.
Her symptoms were too frequent for prn strategy.
CONCLUSIONS
Multiple arrhythmic mechanisms involve in initiation and perpetuation of AF.
Catheter ablation is helpful in improvement of symptomts and quality of life when compared to medications.
In selected populations of AF with HFrEF, catheter ablation may reduce HF hospitalization and overall mortality.
Major indication for AF ablation is symptomatic paroxysmal AF.
