Tachycardia upon swallowing. Evidence for a left atrial automatic focus.

Evaluation of a patient with tachycardia upon swallowing offers evidence of its origin from the left atrium. The tachycardia appears to arise from an automatic focus discharged after mechanical stimulation by the esophagus. Despite a left atrial origin for this arrhythmia, it does not fulfull previously described electrocardiographc criteria for "left atrial rhythms."