title: Undersensing of P waves in the presence of an adequate P wave due to automatic postventricular atrial refractory period extension.
abstract: Two cases in which a DDD pacemaker failed to track P waves due to repetitive activation of the automatic postventricular atrial refractory period (PVARP) extension are reported. In one case, the cycle was initiated by a premature ventricular contraction (PVC); in the other, by touching the unipolar pacemaker with a needle while suturing. We demonstrated that chest wall stimulation can be used to induce cycles of repetitive automatic PVARP extension and failure to track P waves. We demonstrated in vitro that touching a unipolar pacemaker with a needle can generate a signal sufficient to mimic a QRS complex, and initiate a cycle of repetitive P wave undersensing.
authors: Good Samaritan Hospital, William B. Rottenberg and Richard W. Rendall, Intermedics, Inc.
authors: J H
authors: JH
authors: Wilson
authors: S
authors: S
authors: Lattner
mesh_terms: D000368:Aged; D005117:Cardiac Complexes, Premature / Q000503:physiopathology*; D003937:Diagnosis, Differential; D004562:Electrocardiography; D004868:Equipment Failure; D006327:Heart Block / Q000628:therapy; D006801:Humans; D008297:Male; D009339:Needles; D010138:Pacemaker, Artificial; D013536:Suture Techniques