A 56-year-old man presents in the casualty with severe chest pain and difficulty in breathing. His ECG was taken immediately. The below ECG suggest the following diagnosis:

Atrial fibrillation. More or less normal QRS complexes Variable RR intervals and Absent P waves Absence of P waves rules out the possibility of ventricular fibrillation or second degree hea block. Although clinical features mentioned may point to a diagnosis of pulmonary embolism, ECG features are not contributory. ECG of pulmonary embolism: