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Systolic time intervals and heart sounds in left bundle branch block
E Macieira-Coelho1, A Lema-Santos, H B Machado
1Department of Therapeutics, Hospital de Santa Maria, Lisbon, Portugal.
Abstract:
Systolic time intervals and heart sounds were studied in twenty patients with left bundle branch block. A definite cause for the organic heart disease was not ascertained. Abnormal duration of the electromechanical systole (Q-A2), due to a prolongation both of the preejection period (PEP) and of the Q-M1 intervals, was found to exist in all. Prolongation of Q-M1 was due to lengthening either of the electromechanical interval (EMI) or of the pre-isovolumetric contraction time (PICT). Isovolumetric contraction time (ICT) was prolonged in thirteen patients only. There was a good correlation between LVET/ICT ratio and the duration of ICT intervals. Six patients showed a first heart sound of normal intensity and duration. There was no correlation between the duration of the systolic time intervals and the characteristics of the first and second heart sounds.