To the Editor:—
The electrocardiographic tracing in question appears to be strip B of Fig 1 in our recent report. Dr. Vigliano is quite right, a more advanced degree of block is present with the atria under the control of a paroxysmal atrial tachycardia at 240 beats per minute with independent activation of the ventricles. A nonparoxysmal nodal tachycardia is present at a rate of 138 beats per minute and controls the ventricles. This mechanism was also seen in strip C and properly described. Digitalis intoxication was identified in strip B, and may have contributed to the onset of ventricular fibrillation two minutes later.