ATRIAL FIBRILLATION

ATRIAL FIBRILLATION:
In this type of arrhythmia, the atria beat rapidly, chaotically and ventricles respond at irregular intervals. So, pulse rhythm is irregularly irregular and average rate   is about 100-180/minute.

Cause:
1.    Mitral valve disease- commonest cause (in young and middle aged patient).
2.    Acute or chronic ischaemic heart  disease.
3.    Systemic hypertension
4.    Thyrotoxicosis
5.    Subacute bacterial endocarditis
6.    Pericarditis
7.    Atrial septal defect
8.    After thoracic  operation
9.    Alcohol drink
10.    Cardiomyopathy
11.    Pulmonary embolism
12.    Pneumonia
13.    Idiopathic


 

















 Clinical features:
1.    May be asymptomatic- commonly in the elderly.
2.    Palpitation and exertional dyspnoea.
3.    Pulse- irregularly irregular, average rate   is about 100-180/minute; pulse deficit may be present.
4.    ECG findings-
  (a)    Absence of p wave
  (b)    No change in QRS complex
  (c)    The baseline shows irregular fibrillation waves.

Investigations:
1.    X-ray chest p/a view
2.    ECG (special)


Complications:
1.    Cardiac failure
2.    Pulmonary oedema
3.    Stasis, thrombosis and then systemic thrombo-embolism.

Treatment:
1.    Digitalisation is the treatment of choice, may be combined (if necessary) with diuretice and oxygen.
2.    Digoxin dose should be continued at a rate the ventricular beast can be maintained in between 70-80/minute. Atrial fibrillation due to thyrotoxicosis is usually no responsive to digoxin therapy, in that case B-blockers may be better to be used.
3.    Elective Dc cardioversion- if fibrillation persists after correction of thyrotoxicosis.
4.    Flecanide (if digoxin is not effective)2mg/kg in i.v infusion may be given.
5.    Warfarin- as longterm anticoagulant therapy to reduce the risk of systemic embolism.
6.    Treatment of underlying causes (e.g thyrotoxicosis, post- operative chest infection, pneumonia etc).