title: Value of electro-vectorcardiogram in hypertrophic cardiomyopathy.
abstract: The electrocardiogram is an important tool for the initial diagnostic suspicion of hypertrophic cardiomyopathy in any of its forms, both in symptomatic and in asymptomatic patients because it is altered in more than 90 percent of the cases. Electrocardiographic anomalies are more common in patients carriers of manifest hypertrophic cardiomyopathy and the electrocardiogram alterations are earlier and more sensitive than the increase in left ventricular wall thickness detected by the echocardiogram. Nevertheless, despite being the leading cause of sudden death among young competitive athletes there is no consensus over the need to include the method in the pre-participation screening. In apical hypertrophic cardiomyopathy the electrocardiographic hallmarks are the giant negative T waves in anterior precordial leads. In the vectorcardiogram, the QRS loop is located predominantly in the left anterior quadrant and T loop in the opposite right posterior quadrant, which justifies the deeply negative T waves recorded. The method allows estimating the left ventricular mass because it relates to the maximal spatial vector voltage of the left ventricle in the QRS loop. The recording on electrocardiogram or Holter monitoring of nonsustained monomorphic ventricular tachycardia in patients with syncope, recurrent syncope in young patient, hypotension induced by strain, bradyarrhythmia, or concealed conduction are markers of poor prognosis. The presence of rare sustained ventricular tachycardia is observed in mid-septal obstructive HCM with apical aneurysm. The presence of complete right bundle branch block pattern is frequent after the percutaneous treatment and complete left bundle branch block is the rule after myectomy.
authors.affiliation: Cardiology Discipline, ABC Faculty of Medicine, ABC Foundation, Santo André, São Paulo, Brazil. riera@uol.com.br
authors.forename: Andrés Ricardo
authors.initials: AR
authors.lastname: Pérez-Riera
authors.forename: Augusto Armando
authors.initials: AA
authors.lastname: de Lucca
authors.forename: Raimundo
authors.initials: R
authors.lastname: Barbosa-Barros
authors.forename: Frank G
authors.initials: FG
authors.lastname: Yanowitz
authors.forename: Silvia Fortunato
authors.initials: SF
authors.lastname: de Cano
authors.forename: Manuel Nicolás
authors.initials: MN
authors.lastname: Cano
authors.forename: Antônio Carlos
authors.initials: AC
authors.lastname: Palandri-Chagas
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis* / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D004562:Electrocardiography / Q000379:methods; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D015995:Prevalence; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D014672:Vectorcardiography / Q000379:methods*; D055815:Young Adult
keywords: electrocardiogram; hypertrophic cardiomyopathy; vectorcardiogram