Atrial fibrillation

• NICE guidance
• AF management in primary care
  • NHS flowcharts for primary care in various regions
    • South East (Kent Surrey Sussex) Clinical Networks
    • East and North Hertfordshire Place Primary Care
    • Shropshire CCG.
    • Birmingham and Solihull
• First-line ablation
• Drugs
  • Rhythm control drugs
    • Flecainide
    • Sotalol
    • Amiodarone
    • Other beta blockers
  • Rate limiting drugs
    • Diltiazem
    • Verapamil
    • Diltiazem and verapamil
    • Digoxin
• Glossary

NICE guidance

Selected links to NICE guidance on atrial fibrillation, with a few notes and quotations.

• Information for the public
• Guidance
  • Context
  • Recommendations
    • Terms used in this guideline
    • Rate and rhythm control
      Rhythm control is only recommened for patients "whose symptoms continue after heart rate has been controlled or for whom a rate‑control strategy has not been successful".
    • Left atrial ablation
      Left atrial ablation should be considered if "drug treatment is unsuccessful, unsuitable or not tolerated in people with symptomatic paroxysmal or persistent atrial fibrillation".
  • Rationale and impact
    • Rate control
      "The use of beta‑blockers or rate‑limiting calcium‑channel blockers for initial rate‑control treatment was retained by the committee because this is current practice and there was insufficient evidence to suggest an alternative option."
      There doesn't seem to be anything in the rationale about rhythm control for non-acute AF.
    • Left atrial ablation
      "Ablation may be a treatment option if antiarrhythmic drug treatment has not been successful or is not tolerated."
      "A new economic model was developed for the guideline using the clinical evidence from people with paroxysmal atrial fibrillation. It showed that radiofrequency point‑by‑point ablation was more cost effective over a lifetime than antiarrhythmic drug treatment and other ablation strategies in people for whom 1 or more antiarrhythmic drug has failed."
      They don't seem to have considered ablation as a first-line treatment.
• Evidence
  • Ablation
    Page 82: "ablation appeared to be clearly superior to medical care, both for first line patients and those who had failed at least one anti-arrhythmic drug".
  • Ablation: network meta-analysis
    Page 42: "In conclusion, medical care is relatively ineffective for preventing AF recurrence. Whilst thoracoscopy, and possibly the hybrid approach, are the most effective ways of reducing the risk of AF recurrence, the high rates of adverse events in these modalities suggest that the catheter ablation treatments, with the exception possibly of RF ME, are a safer option."
  • Ablation: health economics analysis
    Page 92: "RFPP ablation is the most cost effective rhythm control for people with paroxysmal AF who have previously failed one or more AAD. Conclusion is heavily dependent on rate of crossover to ablation in those initially treated with AADs and are sensitive to the cost of ablation techniques."

AF management in primary care

NHS flowcharts for primary care in various regions

South East (Kent Surrey Sussex) Clinical Networks

Refer to cardiologist if significant ECHO abnormalities.

"Prescribe beta blocker as first line ...Aim for heart rate < 80 bpm at rest; accept resting heart rate up to 110 bpm". I.e. prescribe rate-control drug, not rhythm control.

"Consider trial of sinus rhythm by cardioversion in 1st presentation of AF. Review stable patients every 6 months and after any change in treatment."

Refer to cardiologist if "Symptomatic (SOB, dizzy, tired, palpitations) despite strict rate control (resting HR < 80bpm & exercise HR <110bpm), vagal AF suspected, Arrhythmias - WPW Syndrome, tachy-brady syndrome, uncontrolled ventricular rate, Heart Failure, Arrhythmia post AF ablation". My bold - you have all three of these symptoms (I assume "SOB" is "shortness of breath").

Dated Jan 2018, due for review Jan 2021.

East and North Hertfordshire Place Primary Care

"NICE advises that all patient with paroxysmal AF should be referred to a cardiology specialist, but patients preferences should be taken into account", but includes pathways where initial treatment is handled in primary care.

Dated 2018.

Shropshire CCG.

Only refer to cardiologist if significant abnormalities in Echo or poor response to medication, so similar to South East.

Dated 2018.

Birmingham and Solihull

"If patient remains symptomatic despite optimal rate control, or if a rhythm control strategy more appropriate – refer to Cardiology".

Refer to cardiologist "If more specialised treatment is needed e.g. new onset AF (<48 hours) for consideration of cardioversion; when a rhythm control strategy would be more suitable; those with atrial flutter who may be suitable for ablation; heart failure caused primarily by AF; age <65 years for assessment of treatment strategy; when valve disease is suspected; management of paroxysmal AF."

Dated 2019. Review date Nov 2022.

First-line ablation

There seems to be a growing concensus that catheter ablation (CA) should be used as a "first-line" treatment for AF in preference to antiarrhythmic drugs (AADs). It seems that AADs are not very effective in preventing AF (maintaining sinus rhythm), and their adverse effects are as bad as those of AF (although different).

There are lots of papers and articles on the topic - some are listed below:

• Why Atrial Fibrillation Ablation Should Be Considered First-Line Therapy for Some Patients. This 2005 paper is quite damning of AADs, but is reluctant to recommened CA as first-line treatment for all patients since the data available at that time was mainly for more advanced cases. A very long paper, but with a good description of the rationale behind CA. Authors are based in the US.
• Is it time for first line ablation in early paroxysmal AF? A 2021 article on the British Cardiovascular Society website by a UK author. Emphasizes the progressive nature of AF and hence the importance of using CA early.
• Catheter ablation as first-line treatment for paroxysmal atrial fibrillation: a systematic review and meta-analysis. 2021 review by US authors. Conclusion: "First-line treatment with CA is superior to AAD therapy in patients with symptomatic paroxysmal AF, as it significantly reduces the recurrence of any atrial arrhythmias and symptomatic atrial arrhythmias, and healthcare resource utilisation with comparable safety profile."
• Ablation Versus Antiarrhythmic Drugs as First-Line Treatment of Paroxysmal Atrial Fibrillation: A Meta-Analysis of Randomized Trials. Another 2021 paper. RCTs are limited by small sample sizes and short periods. Conclusion: "among selected patients with symptomatic paroxysmal AF, catheter ablation as first-line rhythm control therapy was associated with lower incidence of atrial tachyarrhythmias recurrence and hospitalizations compared with AADs, with similar incidence of death, stroke/transient ischemic attack, and serious adverse effects."
• First-Line Approach for Rhythm Control in Paroxysmal Atrial Fibrillation. 2022 paper by Belgian authors. "a paradigm shift in the current guidelines is eagerly awaited. Indeed, data suggest that PVI might be considered as first-line rhythm control therapy in patients with paroxysmal AF."

The NICE guidance on AF was last updated in 2021 and still recommends first-line use of AADs, and only recommends ablation if "drug treatment is unsuccessful, unsuitable or not tolerated in people with symptomatic paroxysmal or persistent atrial fibrillation". The rationale for this decision doesn't seem to consider first-line use of ablation, probably because most of the papers on first-line ablation were published too late to be included.

The evidence review for ablation only looked at studies published up to 2020. It included some early studies of first-line ablation (latest was 2017), but they seem to have been thrown into the mix ("pooled meta-analysis") with the other studies where the patients had already had AADs and possibly prior ablations. The quality of evidence was low or very low for all but two of the studies considered. There's an interesting quote in section 1.7.1.3 page 82 (my bold):

The committee agreed that medical treatment had the highest rate of recurrence but the lowest rate of stroke, and that the catheter ablation treatments appeared to have similar efficacy and harms to each other. The committee discussed the higher risk of stroke evident from the data for radiofrequency multielectrode (RF ME) treatment, whilst noting that some of the devices responsible for the higher risk had since been discontinued. Based on this pairwise evidence, the committee concluded that the different ablation techniques appeared to have comparable balances of benefits and harms for paroxysmal AF patients. Whilst ablation appeared to be clearly superior to medical care, both for first line patients and those who had failed at least one anti-arrhythmic drug, the committee recognised that comparisons between ablation techniques were made somewhat complex and unclear by the many pairwise comparisons made.

Drugs

See NHS treatments for atrial fibrillation and  NICE prescribing information for atrial fibrillation.

Rhythm control drugs

Flecainide

This interacts with fludrocortisone: predicted to cause hypokalaemia (potentially increasing the risk of torsade de pointes) (Severity: severe).

Sotalol

This interacts with fludrocortisone: predicted to cause hypokalaemia (potentially increasing the risk of torsade de pointes) (Severity: severe).

Also, since it's a beta-blocker, hypotension and marked bradycardia are both contra-indications.

Amiodarone

This interacts with fludrocortisone: predicted to cause hypokalaemia (potentially increasing the risk of torsade de pointes) (Severity: severe).

Propafenone

Marked hypotension and severe bradychardia are both contra-indications. Needs monitoring of ECG and blood pressure.

Other beta blockers

Hypotension and marked bradycardia are both contra-indications for all beta-adrenoceptor blockers (systemic). These include all the beta-blockers licensed in the UK for atrial fibrillation: i.e. atenolol, acebutolol, metoprolol, nadolol, oxprenolol and propranolol. It also includes bisoprolol, which is listed on the NHS website.

Rate limiting drugs

According to the NHS "The aim is to reduce your heart rate to less than 90 beats per minute when you are resting", so they shouldn't be considered relevant.

Diltiazem

This is a calcium-channel blocker. Severe bradycardia is a contra-indication. Both Diltiazem and Alcohol can increase the risk of hypotension.

Verapamil

This is a calcium-channel blocker. Bradycardia and hypotension are both contra-indications. Verapamil slightly increases the exposure to Edoxaban.

Diltiazem and verapamil

This Nice page lists further information about contra-indications for these drugs:

• Severe bradycardia (below 50 beats per minute for verapamil; below 40 beats per minute for diltiazem).
• Severe hypotension (systolic blood pressure less than 90 mmHg).

Digoxin

This is a cardiac glycoside. Interaction: Fludrocortisone is predicted to increase the risk of Digoxin toxicity when given with Digoxin (Severity: severe).

Glossary

Definitions from Collins dictionary.