title: Distinct left bundle branch block pattern in ischemic and non-ischemic dilated cardiomyopathy.
abstract: BACKGROUND
  A high percentage of patients with dilated cardiomyopathy have the electrocardiographic (ECG) pattern of advanced left bundle branch block (LBBB). In the present study we sought to investigate whether patients with dilated cardiomyopathy of ischemic or non-ischemic etiology can be differentiated on the basis of LBBB pattern.
  
  
  RESULTS
  The study population included 41 patients with dilated cardiomyopathy of non-ischemic (NIC) (n=26) or ischemic origin (IC) (n=15) and LBBB on surface ECG. ECG duration and voltage were digitally measured. The presence of notching of S wave in right precordial leads (V1-V3) was not statistically different between the groups. The voltages of precordial leads V2, V3 and the Sigma(V1+V2+V3 voltages) were significantly more prominent in patients with NIC (P=0.002, P<0.001 and P=0.002, respectively). The discriminative power of receiver operating characteristic analysis was best at voltages of V3 of 2100 microV (area under the curve, 0.805; standard error, 0.001). The sensitivity and specificity of V3 voltage >2100 microV on surface ECG in the presence of LBBB to identify a cardiomyopathy of non-ischemic origin were 85 and 73%, respectively.
  
  
  CONCLUSIONS
  A single ECG criteria, voltage of lead V3, appears to be a useful parameter to identify patients with dilated cardiomyopathy of ischemic or non-ischemic origin in the presence of advanced LBBB.
authors.affiliation: Servei de Cardiologia, Hospital de la Santa Creu i Sant Pau, C/ San Antonio Ma Claret 167, 08025, Barcelona, Spain. abayesgenis@hsp.santpau.es
authors.forename: Antoni
authors.initials: A
authors.lastname: Bayes-Genis
authors.forename: Laura
authors.initials: L
authors.lastname: Lopez
authors.forename: Xavier
authors.initials: X
authors.lastname: Viñolas
authors.forename: Roberto
authors.initials: R
authors.lastname: Elosua
authors.forename: Vicenç
authors.initials: V
authors.lastname: Brossa
authors.forename: Marta
authors.initials: M
authors.lastname: Campreciós
authors.forename: Miriam
authors.initials: M
authors.lastname: Mateo
authors.forename: Juan
authors.initials: J
authors.lastname: Cinca
authors.forename: Antonio
authors.initials: A
authors.lastname: Bayes de Luna
mesh_terms: D000328:Adult; D000368:Aged; D002037:Bundle-Branch Block / Q000453:epidemiology / Q000473:pathology*; D002311:Cardiomyopathy, Dilated / Q000453:epidemiology / Q000473:pathology*; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000453:epidemiology / Q000473:pathology*; D015995:Prevalence; D012372:ROC Curve; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology