The Dysrhythmic ECG

• Published in: Electrocardiogram in Clinical Medicine pp. 141 - 147
• Main Author: Darby, Andrew E
• Format: Book Chapter
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 05.08.2020
• Subjects: electrocardiogram; intraventricular conduction delay; left anterior fascicular block; left bundle branch block; left posterior fascicular block; right bundle branch block
• ISBN: 1118754557; 9781118754559
• DOI: 10.1002/9781118754511.ch12

Delayed intraventricular conduction is a common abnormality detected on the electrocardiogram (ECG). Intraventricular conduction delay (IVCD) may manifest as right bundle branch block (RBBB), left bundle branch block (LBBB), nonspecific IVCD, left anterior fascicular block (LAFB), or left posterior fascicular block (LPFB). The prevalence of RBBB increases with age and can occur in an otherwise normal heart. The prevalence of LBBB increases with age and is relatively infrequent in young, healthy subjects. A nonspecific IVCD refers to QRS complexes that are wide but without classical left or RBBB morphology. LPFB occurs when there is conduction delay or block in the left posterior fascicle of the left bundle branch. No specific therapy is recommended for patients with LAFB or LPFB in isolation. Permanent pacemaker insertion may be considered in patients with syncope, presumably cardiac in etiology, in the presence of bifascicular (e.g. RBBB and LAFB) or trifascicular block.