title: Inappropriate ICD discharges due to "triple counting" during normal sinus rhythm.
abstract: OBJECTIVE
  To describe the clinical course of a patient with multiple ICD shocks in the setting of advanced renal failure and hyperkalemia.
  
  
  METHODS
  The patient was brought to the Electrophysiology Laboratory where the ICD was interrogated.
  
  
  RESULTS
  The patient was found to be hyperkalemic (serum potassium 7.6 mg/dl). Analysis of stored intracardiac electrograms from the ICD revealed "triple counting" (twice during his QRS complex and once during the T wave) and multiple inappropriate shocks. Correction of his electrolyte abnormality normalized his electrogram and no further ICD activations were observed.
  
  
  CONCLUSIONS
  Electrolyte abnormalities can distort the intracardiac electrogram in patients with ICD's and these changes can lead to multiple inappropriate shocks.
authors.affiliation: Division of Cardiology, Department of Medicine, The University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: Ejaz
authors.initials: E
authors.lastname: Khan
authors.forename: Apostolos
authors.initials: A
authors.lastname: Voudouris
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Shorofsky
authors.forename: Robert W
authors.initials: RW
authors.lastname: Peters
mesh_terms: D002304:Cardiac Pacing, Artificial; D015897:Comorbidity; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D004868:Equipment Failure; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans; D006947:Hyperkalemia / Q000453:epidemiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000453:epidemiology / Q000628:therapy*