A 68 year old man presents to the emergency room complaining of multiple episodes of fainting since he woke up today. His fainting mainly occurs when he stands up. He has a history of coronary artery disease, diabetes, high cholesterol and hypertension. He takes atenolol, metformin, lovastatin and lisinopril. On physical examination, his blood pressure is 120/75, pulse is 55/min. and irregular, heart sounds are normal and lungs are clear on auscultation. ECG shows dropped beat after progressive lengthening of the PR interval. What is the most likely initial diagnosis? A- Atrial flutter B- Atrial fibrillation C- Type 1 second degree atrioventricular block ( Mobitz 1) D- Type 2 second degree atrioventricular block ( Mobitz 2) E- Third degree atrioventricular block Answer
