title: 'Supernormal' phase in hemiblock conduction.
abstract: A case is described where the basic sinus rhythms is associated with an advanced degree of left anterior hemiblock. The rhythm is complicated by atrial extrasystoles, associated with a lesser degree of left anterior hemiblock. This paradox of 'supernormality' is explained on a critical interplay of differential refractoriness within the divisions of the left bundle-branch.
mesh_terms: D000328:Adult; D005117:Cardiac Complexes, Premature / Q000503:physiopathology; D004562:Electrocardiography; D005260:Female; D006321:Heart / Q000503:physiopathology*; D006325:Heart Atria / Q000503:physiopathology; D006327:Heart Block / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology; D006801:Humans