title: High-resolution mapping of scar-related atrial arrhythmias using smaller electrodes with closer interelectrode spacing.
abstract: BACKGROUND
  The resolution of mapping is influenced by electrode size and interelectrode spacing. Smaller electrodes with closer interelectrode spacing may improve mapping resolution, particularly in scar. The aims of this study were to establish normal electrogram criteria in the atria for both 3.5-mm electrode tip linear catheters (Thermocool) and 1-mm multielectrode-mapping catheters (Pentaray) and to compare their mapping resolution in scar-related atrial arrhythmias.
  
  
  RESULTS
  Normal voltage amplitude cutoffs for both catheters were validated in 10 patients with structurally normal atria. In 20 additional patients with scar-related atrial arrhythmias, similar sequential mapping with both catheters was performed. Normal bipolar voltage amplitude was similar between 3.5- and 1-mm electrode catheters with a fifth percentile of 0.48 and 0.52 mV, respectively (P=0.65). In patients with scar-related atrial arrhythmias, the total area of bipolar voltage <0.5 mV measured using 1-mm electrode catheters was smaller than that measured using 3.5-mm catheter (14.7 versus 20.4 cm2; P=0.02). The mean bipolar voltage amplitude in this area of low voltage was significantly higher with 1-mm electrode catheters (0.28 and 0.17 mV; P=0.01). Importantly, 54.4% of all low voltage data points recorded with 1-mm electrode catheter had distinct electrograms that allowed annotation of local activation time compared with only 21.4% with 3.5-mm electrode tip catheters (P=0.01). Overdrive pacing with capture of the tachycardia from within the area of low voltage was more frequent with 1-mm electrode catheters (66.7 versus 33.4; P=0.01).
  
  
  CONCLUSIONS
  Mapping with small closely spaced electrode catheters can improve mapping resolution within areas of low voltage.
authors: From the Cardiovascular Division, Department of Medicine, Harvard-Thorndike Electrophysiology Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA. eanter@bidmc.harvard.edu.
authors: Elad
authors: E
authors: Anter
authors: From the Cardiovascular Division, Department of Medicine, Harvard-Thorndike Electrophysiology Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors: Cory M
authors: CM
authors: Tschabrunn
authors: From the Cardiovascular Division, Department of Medicine, Harvard-Thorndike Electrophysiology Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA.
authors: Mark E
authors: ME
authors: Josephson
mesh_terms: D000200:Action Potentials; D000368:Aged; D062906:Cardiac Catheters; D002304:Cardiac Pacing, Artificial; D002921:Cicatrix / Q000150:complications* / Q000175:diagnosis; D022062:Electrophysiologic Techniques, Cardiac / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D006325:Heart Atria / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008839:Microelectrodes; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D013617:Tachycardia, Supraventricular / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D013997:Time Factors
keywords: arrhythmias, cardiac; catheter ablation; electrophysiology