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Atrial Fibrillation-basics

Disorganized electrical activity in atria- most common sustained cardiac arrhythmia.

Atrial fibrillation is a supraventricular tachyarrhythmia. It is characterized by uncoordinated atrial activity on the surface ECG , with fibrillatory waves of varying shapes , amplitudes , and timing associated with an irregular ventricular response when AV conduction is intact 
( BMJ Best Practice 2019 )

pathophysiologic mechanisms can be complex and variable focal atrial ectopic activity and reentry mechanisms onset of AF & maintenance may have different mechanisms characterized by high frequency excitation of the atrium that results in both dyssynchronous atrial contraction and irregularity of ventricular excitation progressive fibrosis of the atria and structural remodelling inflammation has been observed in AF patients and inflammation is known to affect signaling pathways for AF development ( atrial electrical and structural remodelling ) a supraventricular tachycardia -chaotic electrical activation of the atrial results in mechanically ineffective atrial contraction observed changes atrial structure include atrial dilatation , atrial cardiomyocyte hypertrophy , dedifferentiations , fibrosis , apoptosis and myolysis AF is a hypercoagulable state due to turbulent blood flow -their is high chance of clot formation

age- increases with age particularly after 65 coronary artery disease family history- genetics ( more than 150 genes have been associated with AF in the last decade ) male sex hypertension diabetes obstructive sleep apnoea obesity smoking alcohol consumption physical inactivity acute illness / surgery vascular disease including atherosclerosis heart failure valve disease chronic kidney disease congenital heart disease inflammatory diseases ( e,g rheumatoid arthritis )

Why is AF important– Stroke and thromboembolism
◙ 5 times ↑ risk of stroke and thromboembolism
◙ stroke severity ↑↑ when is associated with AF
◙ peripheral thromboembolism
 Heart failure
◙ commonly associated with AF
◙ ↓ Cardiac output → pushes compromised ventricle into failure Diminished exercise capacity ↑ ed risk dementia Increased risk death ( twofold ) Tachycardia- induced cardiomyopathy and critical ischaemia Increased risk hospitalization Reduced quality of life

Any symptoms present ? enquire about Breathlessness Palpitations chest discomfort Syncope or dizziness Any signs of heart failure ↓ exercise tolerance, malaise , or polyuria Stroke , TIA or Heart failure 
( possible complications of AF )

Any identifiable cause ? Cardiac causes- as
○ hypertension
○ valvular heart disease
○ heart failure
○ IHD Respiratory causes- such as
○ chest infections
○ pulmonary embolism
○ lung cancer
○ obstructive sleep apnoea Systemic causes- as
○ excessive alcohol intake
○ thyrotoxicosis
○ electrolyte depletion
○ infections
○ diabetes H/O rheumatic fever -heart disease Obesity

Examination -Check pulse manually ~ 1 min Most patients are stable CVS and resp examination Vitals BP , Pulse , O2 , temp

What else can cause an irregular pulse -Atrial flutter Atrial extrasystoles Ventricular ectopic beats Sinus tachycardia SVTs Multifocal atrial tachycardia SR with premature atrial or ventricular palpitations

Investigations -FBC U/E LFT , GGT TFT , Bl gluocse , Hba1c Consider Calcium and magnesium CXR if suspected resp pathology CVD risk assessment

Presentation-Opportunistic finding ? in an otherwise well patient ? Symptomatic-do I need
 to admit ? for e.g for ? cardioversion or with a complication of AF is stroke , TIA or heart failure
consider admission ? AF associated with any 
of the following
 Rapid pulse > 150 bpm Low BP – systolic bp < 90 Loss of consciousness Severe dizziness Ongoing chest pain Increasing breathlessness or significantly worsened SOB Stroke , TIA or acute LVF-Admit – urgency based on
 presentation

 

in one validation study ECG recorder had a sensitivity of 99 % and a specificity of 96 % for AF detection portable , hand held single lead electrocardiographic devices were the earliest to receive FDA clearance for AF detection

Electrocardiography remains the gold standard signal used for arrhythmia detection.

 

an optical instrument that detects variations in light reflected from human tissue peripheral pulse is synchronized with the R peaks in the ECG

Current mobile technologies rely on electrocardiographic or photoplethysomgraphic signal processing to detect AF-It should be noted that some devices have both photoplethysmograph and electrovardiograph sensors – fo e.g Apple watch

REFERENCES

  1. The management of Atrial fibrillation: summary of updated NICE guidance BMJ 2014;348:g3655
  2. Atrial fibrillation: management Clinical guideline CG180 June 2014
  3. ESC Guidelines for the management of atrial fibrillation developed in collaboration with EACTS European Heart Journal (2016) 37, 2893-2962
  4. Medscape Atrial Fibrillation Lawrence Rosenthal et al Jan 2016
  5. CKS NHS Atrial Fibrillation
  6. Stroke prevention in atrial fibrillation : can we do better Br J Gen Pract 2016 ; 66 (643)
  7. Kent Surrey Sussex Academic Health Science Network Primary Care Atrial Fibrillation Pathway
  8. Herts Valleys Clinical Commissioning Group – Diagnosis and Primary Care Management of Atrial Fibrillation in Adults AF
  9. BMJ Best Practice AF Summary via https://bestpractice.bmj.com/topics/en-gb/1
  10. DePalma, Sondra M. MHS, PA-C, DFAAPA, AACC Managing atrial fibrillation in primary care, Journal of the American Academy of Physician Assistants: June 2016 – Volume 29 – Issue 6 – p 29-33 doi: 10.1097/01.JAA.0000483091.58770.f7
  11. South East Clinical Network Primary care Atrial Fibrillation Pathway https://www.swahsn.com/wp-content/uploads/2017/11/Primary-Care-Atrial-Fibrillation-Pathway-KSS-AHSN.pdf
  12. Atrial Fibrillation: Diagnosis and Treatment CECILIA GUTIERREZ, MD, and DANIEL G. BLANCHARD, MD, University of California, San Diego, La Jolla, California American Academy of Family Physician http://unmfm.pbworks.com/f/Atrial%20Fibrillation_Diagnosis%20and%20Treatment_AAFP.pdf
  13. Atrial fibrillation 2:assessment and diagnosis Christine Cottrell Practice Nursing 2012, Vol 23, No 2 https://www.educationforhealth.org/wp-content/uploads/2015/03/PN_23_2_77_AF2_NEW.pdf
  14. Managing Atrial Fibrillation in Primary Care Key issues for primary care practitioners,
    managers and commissioners of services British Heart foundation
  15.  Mina K. Chung, MD Marwan Refaat, MD Win-Kuang Shen, MD Valentina Kutyifa, PhD Yong-Mei Cha, MD Luigi Di Biase, MD Adrian Baranchuk, MD Rachel Lampert, MD Andrea Natale, MD John Fisher, MD Dhanunjaya R. Lakkireddy, MBBS on behalf of the ACC Electrophysiology Section Leadership Council
  16. Gerhard Hindricks, Tatjana Potpara, Nikolaos Dagres, Elena Arbelo, Jeroen J Bax, Carina Blomström-Lundqvist, Giuseppe Boriani, Manuel Castella, Gheorghe-Andrei Dan, Polychronis E Dilaveris, Laurent Fauchier, Gerasimos Filippatos, Jonathan M Kalman, Mark La Meir, Deirdre A Lane, Jean-Pierre Lebeau, Maddalena Lettino, Gregory Y H Lip, Fausto J Pinto, G Neil Thomas, Marco Valgimigli, Isabelle C Van Gelder, Bart P Van Putte, Caroline L Watkins, ESC Scientific Document Group, 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation developed in collaboration with the European Association for Cardio-Thoracic Surgery (EACTS): The Task Force for the diagnosis and management of atrial fibrillation of the European Society of Cardiology (ESC) Developed with the special contribution of the European Heart Rhythm Association (EHRA) of the ESC, European Heart Journal, Volume 42, Issue 5, 1 February 2021, Pages 373–498, https://doi.org/10.1093/eurheartj/ehaa612
  17. Dennis H. Lau, Ulrich Schotten, Rajiv Mahajan, Nicholas A. Antic, Stéphane N. Hatem, Rajeev K. Pathak, Jeroen M. L. Hendriks, Jonathan M. Kalman, Prashanthan Sanders, Novel mechanisms in the pathogenesis of atrial fibrillation: practical applications, European Heart Journal, Volume 37, Issue 20, 21 May 2016, Pages 1573–1581, https://doi.org/10.1093/eurheartj/ehv375
  18. Atrial fibrillation epidemiology, disparity and healthcare contacts: a population-wide study of 5.6 million individuals LANCET Published:July 06, 2021DOI:https://doi.org/10.1016/j.lanepe.2021.100157

  19. Faust, Oliver et al. “A Review of Atrial Fibrillation Detection Methods as a Service.” International journal of environmental research and public health vol. 17,9 3093. 29 Apr. 2020, doi:10.3390/ijerph17093093
  20. Staerk, Laila et al. “Atrial Fibrillation: Epidemiology, Pathophysiology, and Clinical Outcomes.” Circulation research vol. 120,9 (2017): 1501-1517. doi:10.1161/CIRCRESAHA.117.309732
  21. Eric Y. DingGregory M. MarcusDavid D. McManus

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