Rate Dependent Bundle Branch Block

Abstract

Bundle Branch Block may be transient, intermittent or permanent. Transient and intermittent left bundle branch bloci has beep the subject of many publications and reports.l’9 Transient left bundle branch block has been defined as an intraventricular (I-N) conduction defect that changes, if only temporarily, to normal intraventricular conduction,6 where as intermittent left bundle branch block is characterised by the presence in a single electrocardiographic (ECG) tracing of QRS complexes showing both left bundle branch block and norm al intraventricular conduction.’ The following review presents a critical. appraisal of the subject through a study of eight cases of intermittent bundle branch block observe d in the past 3 years at the Cardiology Department of Central Government Polv Clinic, Islamabad.