Image Based Question-67097

Diagnostic criteria 

• P waves are absent. 
•  There are fibrillation (f) waves instead of P waves. The f waves result in an oscillating irregular baseline. 
• The R-R intervals are not equal resulting in an irregular rhythm (irregularly irregular). 

Clinical significance 

• Atrial fibrillation patients usually have a ventricular rate of 100-180 beats/minute. 
• This is why these patients frequently complain of palpitation. 
• A lower ventricular rate should suggest atrioventricular block or the use of medications decreasing the ventricular rate (digoxine, beta blocker, verapamil, diltiazem, amiodarone). 
• Wolff-Parkinson-White (WPW) Syndrome should be suspected if there is a higher ventricular rate. This high ventricular response may cause syncope or even death in these patients. 
• Since the R-R intervals continously change in atrial fibrillation patients, the heart rate on the monitor also changes continously. In such patients, the instantenous heart rates depicted on the monitor 
  usually does not give the average ventricular rate of that patient. 
  Since there is no atrial contraction, the presence of atrial fibrillation decreases cardiac output by 20-25%.  This is why these patients usually complain of exercie intolerance and easy fatigability. 
• Atrial fibrillation results in atrial statis which predisposes to the thrombus formation in the atria. This results in increased risk of systemic embolism. 
• Unless contraindicated, patients with atrial fibrillation are generally advised to be anticoagulated. 
• In some patients, atrial fibrillation is not persistent.  24-hour Holter monitoring may be very useful in such patients since it may record the paroxysmal attacks. 
•  When compared with atrial flutter, the control of ventricular rate is easier in atrial fibrillation.