False atrial dissociation (the Deitz-Marques phenomenon) and its dependence on dyspnea.

Three cases of false atrial dissociation (the Deitz-Marques phenomenon) were presented to show the dependence of this phenomenon on dyspnea. 2) The pseudo-P wave of the Deitz-Marques phenomenon coincided with the beginning of inspiration. 3) In a case of silicotuberculosis, the length of the pseudo-fibrillation was nearly equal to that of laborious inspiration. 4) In a case of aspiration pneumonia, every second cardiac contraction was synchronized with the beginning of inspiration two hours before death. 5) In a case of hyperpotassemia, the pseudo-P wave persisted even after the disappearance of the sinus P wave. 6) The pseudo-P wave was not affected by retrograde activation of the atria by the A-V junctional impulse.