A person with mitral regurgitation and atrial fibrillation presents with syncope. On examination the personhas a hea rate of 55. What is the most probable cause?
Digitalis toxicity
Incomplete hea block
Stroke
Subarachnoid Haemorrhage
Bradycardia (hea rate of 55) with atrial fibrillation suggests the probable diagnosis of a complete hea block. This patient is most likely to be on digitalis for hea failure due to mitral regurgitation. Digitalis intoxication is a common cause of complete hea block. Ref: Harrison's Internal Medicine 16th Edition, Page 1345, 1375, 1394; Essentials of Medical Pharmacology, KD Tripathi, 5th Edition, Chapter 35, Page 462 &463.