title: Natural history of marked left axis deviation (left anterior hemiblock).
mesh_terms: D000328:Adult; D002037:Bundle-Branch Block / Q000209:etiology / Q000503:physiopathology*; D002170:Canada; D004562:Electrocardiography; D006327:Heart Block / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008350:Manitoba; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies