title: The quality of resonance of the first heart sound after myocardial infarction: clinical significance.
abstract: Frequency analyses of the first heart sound (S1) were performed in 80 normal subjects and 80 postinfarction patients. A readily recognizable frequency pattern characterized by a quality of resonance greater than or equal to 2, as measured by the Q factor at 3 db down, was noted in 78 of the 80 apparently normal subjects. An aberrant pattern with a Q less than 2, often accompanied by a lowering of the frequency content, was found in 78 of 80 postinfarction patients. We propose that the quality of resonance of S1 is a measure of the degree to which the structural homogeneity of the left ventricle as a compliant contractile unit has been preserved after myocardial infarction.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D004553:Electric Conductivity; D004562:Electrocardiography; D006326:Heart Auscultation; D006347:Heart Sounds; D006801:Humans; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D014732:Vibration