History. The ECG was recorded from a 58 year old man who had presented some years previously following the insidious onset of exertional dyspnoea. There was no history of angina or previous infarction. The chest X Ray showed considerable cardiac enlargement and echocardiography demonstrated diffuse left ventricular impairment.
ECG. Rhythm: No recognizable P waves or other form of co-ordinated atrial activit)’ is seen in any lead. The baseline is irregular in VI and V2 and a waveform irregular in both amplitude and frequency representing chaotic atrial activit)’ is recorded. The QRS complexes are irregular, the R – R intervals vary unpredictably. There is no recognizable relationship between the QRS complexes and atrial activity: atrial fibrillation is present.
Morphology: The QRS complexes are abnormally wide at .16 seconds. There are no Q waves in V5 or V6 or other leads facing the left ventricle. Left bundle branch block is present.
Comment. The baseline is flat in most leads, and in these the clue that atrial fibrillation is present lies in the irregular QRS rate. Atrial activity is clearly seen in VI and V2 which show the characteristic pattern of atrial fibrillation. Dilated cardiomyopathy was responsible for this patient’s heart failure.